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    INTERNATIONAL PROGRAMME ON CHEMICAL SAFETY

    CONCISE INTERNATIONAL CHEMICAL ASSESSMENT DOCUMENT NO. 26




    BENZOIC ACID AND SODIUM BENZOATE




    This report contains the collective views of an international group of
    experts and does not necessarily represent the decisions or the stated
    policy of the United Nations Environment Programme, the International
    Labour Organization, or the World Health Organization.


    First draft prepared by Dr A. Wibbertmann, Dr J. Kielhorn, Dr G.
    Koennecker, Dr I. Mangelsdorf, and Dr C. Melber, Fraunhofer Institute
    for Toxicology and Aerosol Research, Hanover, Germany



    Published under the joint sponsorship of the United Nations
    Environment Programme, the International Labour Organization, and the
    World Health Organization, and produced within the framework of the
    Inter-Organization Programme for the Sound Management of Chemicals.


    World Health Organization
    Geneva, 2000

         The International Programme on Chemical Safety (IPCS),
    established in 1980, is a joint venture of the United Nations
    Environment Programme (UNEP), the International Labour Organization
    (ILO), and the World Health Organization (WHO). The overall objectives
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    Chemicals (IOMC) was established in 1995 by UNEP, ILO, the Food and
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    sound management of chemicals in relation to human health and the
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    WHO Library Cataloguing-in-Publication Data

    Benzoic acid and sodium benzoate.

         (Concise international chemical assessment document ; 26)

         1.Benzoic acid - toxicity  2.Sodium benzoate - toxicity 
         3.Risk assessment 4.Environmental exposure 
         I.International Programme on Chemical Safety  II.Series

         ISBN 92 4 153026 X            (NLM Classification: QD 341.A2)
         ISSN 1020-6167

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         The Federal Ministry for the Environment, Nature Conservation and
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    TABLE OF CONTENTS

         FOREWORD

    1. EXECUTIVE SUMMARY

    2. IDENTITY AND PHYSICAL/CHEMICAL PROPERTIES

    3. ANALYTICAL METHODS

    4. SOURCES OF HUMAN AND ENVIRONMENTAL EXPOSURE

         4.1. Natural sources of benzoic acid

         4.2. Anthropogenic sources

              4.2.1. Benzoic acid

              4.2.2. Sodium benzoate

         4.3. Uses

              4.3.1. Benzoic acid

              4.3.2. Sodium benzoate

         4.4. Estimated global release

    5. ENVIRONMENTAL TRANSPORT, DISTRIBUTION, TRANSFORMATION, AND ACCUMULATION

         5.1. Transport and distribution between media

              5.1.1. Benzoic acid

              5.1.2. Sodium benzoate

         5.2. Transformation

              5.2.1. Benzoic acid

              5.2.2. Sodium benzoate

         5.3. Accumulation

              5.3.1. Benzoic acid

              5.3.2. Sodium benzoate

    6. ENVIRONMENTAL LEVELS AND HUMAN EXPOSURE

         6.1. Environmental levels

         6.2. Human exposure

    7. COMPARATIVE KINETICS AND METABOLISM IN LABORATORY ANIMALS AND HUMANS

         7.1. Precursors of benzoic acid

    8. EFFECTS ON LABORATORY MAMMALS AND IN VITRO TEST SYSTEMS

         8.1. Single exposure

         8.2. Irritation and sensitization

              8.2.1. Benzoic acid

              8.2.2. Sodium benzoate

         8.3. Short-term exposure

              8.3.1. Oral exposure

              8.3.2. Inhalation exposure

              8.3.3. Dermal exposure

         8.4. Long-term exposure

              8.4.1. Subchronic exposure

              8.4.2. Chronic exposure and carcinogenicity

              8.4.3. Carcinogenicity of benzyl acetate, benzyl alcohol, and benzaldehyde

         8.5. Genotoxicity and related end-points

              8.5.1. Benzoic acid

              8.5.2. Sodium benzoate

         8.6. Reproductive and developmental toxicity

              8.6.1. Fertility

              8.6.2. Developmental toxicity

              8.6.3. Reproductive toxicity of benzyl acetate, benzyl alcohol, and benzaldehyde

    9. EFFECTS ON HUMANS

    10. EFFECTS ON OTHER ORGANISMS IN THE LABORATORY AND FIELD

         10.1. Aquatic environment

         10.2. Terrestrial environment

    11. EFFECTS EVALUATION

         11.1. Evaluation of health effects

              11.1.1. Hazard identification and dose-response assessment

              11.1.2. Criteria for setting tolerable intakes or guidance values for benzoic acid and sodium benzoate

              11.1.3. Sample risk characterization

         11.2. Evaluation of environmental effects

    12. PREVIOUS EVALUATIONS BY INTERNATIONAL BODIES

         REFERENCES

         APPENDIX 1 -- SOURCE DOCUMENTS

         APPENDIX 2 -- CICAD PEER REVIEW

         APPENDIX 3 -- CICAD FINAL REVIEW BOARD

         APPENDIX 4 -- INTERNATIONAL CHEMICAL SAFETY CARD

         RÉSUMÉ D'ORIENTATION

         RESUMEN DE ORIENTACI²N
    

    FOREWORD

         Concise International Chemical Assessment Documents (CICADs) are
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    World Health Organization (WHO), the International Labour Organization
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         Risks to human health and the environment will vary considerably
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    of locally measured or predicted exposure scenarios. To assist the
    reader, examples of exposure estimation and risk characterization are
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    considered as representing all possible exposure situations, but are
    provided as guidance only. The reader is referred to EHC 1701 for
    advice on the derivation of health-based tolerable intakes and
    guidance values.

                  

    1 International Programme on Chemical Safety (1994)
       Assessing human health risks of chemicals: deriviation of
       guidance values for health-based exposure limits. Geneva, World
      Health Organization (Environmental Health Criteria 170).

         While every effort is made to ensure that CICADs represent the
    current status of knowledge, new information is being developed
    constantly. Unless otherwise stated, CICADs are based on a search of
    the scientific literature to the date shown in the executive summary.
    In the event that a reader becomes aware of new information that would
    change the conclusions drawn in a CICAD, the reader is requested to
    contact IPCS to inform it of the new information.

    Procedures

         The flow chart shows the procedures followed to produce a CICAD.
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    FIGURE 1

    1.  EXECUTIVE SUMMARY

         This CICAD on benzoic acid and sodium benzoate was prepared by
    the Fraunhofer Institute for Toxicology and Aerosol Research, Hanover,
    Germany. The two compounds are being considered together because it is
    undissociated benzoic acid that is responsible for its antimicrobial
    activity. As benzoic acid itself is only slightly soluble in water,
    sodium benzoate -- which, under acid conditions, converts to
    undissociated benzoic acid -- is often used instead.

         This CICAD was based on reviews compiled by the German Advisory
    Committee on Existing Chemicals of Environmental Relevance (BUA,
    1995), the US Food and Drug Administration (US FDA, 1972a), and the
    Joint FAO/WHO Expert Committee on Food Additives (JECFA) (WHO, 1996)
    to assess potential effects of benzoic acid and sodium benzoate on the
    environment and on humans. A comprehensive literature search of
    relevant databases was conducted in September 1999 to identify any
    relevant references published subsequent to those incorporated in
    these reports. Information on the preparation and peer review of the
    source documents is presented in Appendix 1. Information on the peer
    review of this CICAD is presented in Appendix 2. This CICAD was
    approved as an international assessment at a meeting of the Final
    Review Board, held in Sydney, Australia, on 21-24 November 1999.
    Participants at the Final Review Board meeting are listed in Appendix
    3. The International Chemical Safety Card (ICSC 0103) for benzoic
    acid, produced by the International Programme on Chemical Safety
    (IPCS, 1993), has also been reproduced in this document (Appendix 4).

         Benzyl acetate, its hydrolysis product, benzyl alcohol, and the
    oxidation product of this alcohol, benzaldehyde, are extensively
    metabolized to benzoic acid in experimental animals and humans.
    Therefore, toxicological data on these precursors were also utilized
    in the assessment of the potential health effects of benzoic acid.

         Benzoic acid (CAS No. 65-85-0) is a white solid that is slightly
    soluble in water. Sodium benzoate (CAS No. 532-32-1) is about 200
    times more soluble in water. Benzoic acid is used as an intermediate
    in the synthesis of different compounds, primarily phenol (>50% of
    the amount produced worldwide) and caprolactam. Other end products
    include sodium and other benzoates, benzoyl chloride, and diethylene
    and dipropylene glycol dibenzoate plasticizers. Sodium benzoate is
    primarily used as a preservative and corrosion inhibitor (e.g., in
    technical systems as an additive to automotive engine antifreeze
    coolants). Benzoic acid and sodium benzoate are used as food
    preservatives and are most suitable for foods, fruit juices, and soft
    drinks that are naturally in an acidic pH range. Their use as
    preservatives in food, beverages, toothpastes, mouthwashes,
    dentifrices, cosmetics, and pharmaceuticals is regulated. The
    estimated global production capacity for benzoic acid is about
    600 000 tonnes per year. Worldwide sodium benzoate production in 1997
    can be estimated at about 55 000-60 000 tonnes. Benzoic acid occurs

    naturally in many plants and in animals. It is therefore a natural
    constituent of many foods, including milk products. Anthropogenic
    releases of benzoic acid and sodium benzoate into the environment are
    primarily emissions into water and soil from their uses as
    preservatives. Concentrations of naturally occurring benzoic acid in
    several foods did not exceed average values of 40 mg/kg of food.
    Maximum concentrations reported for benzoic acid or sodium benzoate
    added to food for preservation purposes were in the range of 2000
    mg/kg of food.

         After oral uptake, benzoic acid and sodium benzoate are rapidly
    absorbed from the gastrointestinal tract and metabolized in the liver
    by conjugation with glycine, resulting in the formation of hippuric
    acid, which is rapidly excreted via the urine. To a lesser extent,
    benzoates applied dermally can penetrate through the skin. Owing to
    rapid metabolism and excretion, an accumulation of the benzoates or
    their metabolites is not to be expected.

         In rodents, the acute oral toxicity of benzoic acid and sodium
    benzoate is low (oral LD50 values of >1940 mg/kg body weight). In
    cats, which seem to be more sensitive than rodents, toxic effects and
    mortality were reported at much lower doses (about 450 mg/kg body
    weight).

         Benzoic acid is slightly irritating to the skin and irritating to
    the eye, while sodium benzoate is not irritating to the skin and is
    only a slight eye irritant. For benzoic acid, the available studies
    gave no indication of a sensitizing effect; for sodium benzoate, no
    data were identified in the literature.

         In short-term studies with rats, disorders of the central nervous
    system (benzoic acid/sodium benzoate) as well as histopathological
    changes in the brain (benzoic acid) were seen after feeding high doses
    (>1800 mg/kg body weight) over 5-10 days. Other effects included
    reduced weight gain, changes in organ weights, changes in serum
    parameters, or histopathological changes in the liver. The information
    concerning long-term oral exposure of experimental animals to benzoic
    acid is very limited, and there is no study available dealing
    specifically with possible carcinogenic effects. From a limited
    four-generation study, only a preliminary no-observed-(adverse-)effect
    level (NO(A)EL) of about 500 mg/kg body weight per day can be derived.
    With sodium benzoate, two long-term studies with rats and mice gave no
    indication of a carcinogenic effect. However, the documentation of
    effects is inadequate in most of these studies; therefore, no reliable
    NO(A)EL values can be derived. Data on its precursors support the
    notion that benzoic acid is unlikely to be carcinogenic.

         Benzoic acid tested negative in several bacterial assays and in
    tests with mammalian cells, while  in vivo studies were not
    identified. Sodium benzoate was also inactive in Ames tests, whereas
    tests with mammalian cells gave consistently positive results. In one
     in vivo study (dominant lethal assay with rats), a positive result
    was obtained. At present, a genotoxic activity of sodium benzoate
    cannot be ruled out entirely.

         For benzoic acid, two limited studies gave no indication of
    adverse reproductive or developmental effects. With sodium benzoate,
    several studies on different species have been performed, and
    embryotoxic and fetotoxic effects as well as malformations were seen
    only at doses that induced severe maternal toxicity. In a dietary
    study in rats, a NO(A)EL of about 1310 mg/kg body weight was
    established. Data on its precursors support the notion that benzoic
    acid is unlikely to have adverse reproductive effects at dose levels
    not toxic to the mother.

         In humans, the acute toxicity of benzoic acid and sodium benzoate
    is low. However, both substances are known to cause non-immunological
    contact reactions (pseudoallergy). This effect is scarce in healthy
    subjects; in patients with frequent urticaria or asthma, symptoms or
    exacerbation of symptoms was observed. A provisional tolerable intake
    of 5 mg/kg body weight per day can be derived, although benzoates at
    lower doses can cause non-immunological contact reactions
    (pseudoallergy) in sensitive persons. As there are no adequate studies
    available on inhalation exposure, a tolerable concentration for
    exposure by inhalation cannot be calculated.

         From their physical/chemical properties, benzoic acid and sodium
    benzoate emitted to water and soil are not expected to volatilize to
    the atmosphere or to adsorb to sediment or soil particles. From the
    results of numerous removal experiments, the main elimination pathway
    for both chemicals should be biotic mineralization. Data from
    laboratory tests showed ready biodegradability for both substances
    under aerobic conditions. Several isolated microorganisms (bacteria,
    fungi) have been shown to utilize benzoic acid under aerobic or
    anaerobic conditions. From the experimental data on bioconcentration,
    a low to moderate potential for bioaccumulation is to be expected.

         From valid test results available on the toxicity of benzoic acid
    and sodium benzoate to various aquatic organisms, these compounds
    appear to exhibit low to moderate toxicity in the aquatic compartment.
    The lowest EC50 value of 9 mg/litre (cell multiplication inhibition)
    reported in a chronic study was observed in the cyanobacterium
     Anabaena inaequalis. EC50/LC50 values for the other aquatic
    species tested were in the range of 60-1291 mg/litre. Immobilization
    of  Daphnia magna has been demonstrated to be pH dependent, with a
    lower 24-h EC50 (102 mg/litre) at acidic pH. For the freshwater fish
    golden ide  (Leuciscus idus), a 48-h LC50 of 460 mg/litre has been
    determined. Developmental effects have been found in frog  (Xenopus)
    embryos at a concentration of 433 mg/litre (96-h EC50 for

    malformation). For sodium benzoate, exposure of juvenile stages of
    aquatic organisms in a multispecies test (including  Daphnia magna,
     Gammarus fasciatus,  Asellus intermedius,  Dugesia tigrina,
     Helisoma trivolvis, and  Lumbriculus variegatus) resulted in 96-h
    LC50 values of greater than100 mg/litre. A 96-h LC50 of 484
    mg/litre has been determined in the freshwater fish fathead minnow
     (Pimephales promelas). Owing to the limited available data on
    exposure levels in water, a quantitative risk characterization with
    respect to aquatic organisms in surface waters could not be performed.
    Taking into account the rapid biodegradability, the low to moderate
    bioaccumulation potential, the low toxicity to most aquatic species,
    and the rapid metabolism of these substances, benzoic acid and sodium
    benzoate will -- with the exception of accidental spills -- pose only
    a minimal risk to aquatic organisms.

         The few available data indicate that benzoic acid and sodium
    benzoate have only a low toxicity potential in the terrestrial
    environment. Except for the antimicrobial action of benzoic acid,
    characterized by minimum microbiocidal concentrations ranging from 20
    to 1200 mg/litre, no data on toxic effects of benzoic acid on
    terrestrial organisms were available. For sodium benzoate, bacterial
    and fungal growth were inhibited in a pH-dependent manner by
    concentrations ranging from 100 to 60 000 mg/litre. Owing to the lack
    of measured exposure levels, a sample risk characterization with
    respect to terrestrial organisms could not be performed.
    

    2.  IDENTITY AND PHYSICAL/CHEMICAL PROPERTIES

         Benzoic acid (CAS No. 65-85-0; C7H6O2; C6H5COOH;
    benzenecarboxylic acid, phenyl carboxylic acid [E 210 
    (EU No. Regulation on Labelling of Foodstuffs)]; molecular weight 
    122.13) is a white solid that starts to sublime at 100°C, with a 
    melting point of 122°C and a boiling point of 249°C. Its solubility 
    in water is low (2.9 g/litre at 20°C), and its solution in water 
    is weakly acid (dissociation constant at 25°C = 6.335 × 10-5; 
    Maki & Suzuki, 1985; p Ka 4.19). It is soluble in ethanol
    and very slightly soluble in benzene and acetone. It has an 
    octanol/water partition coefficient (log  Kow) of 1.9. Its 
    vapour pressure at 20°C ranges from 0.11 to 0.53 Pa. Its calculated 
    Henry's law constant at 20°C was given as 0.0046-0.022 Pa.m3/mol 
    (BUA, 1995). Additional physical and chemical properties are 
    presented in the International Chemical Safety Card reproduced in 
    this document (Appendix 4).

         Sodium benzoate (CAS No. 532-32-1; C7H5O2Na; benzoic acid,
    sodium salt [E 211 (EU No. Regulation on Labelling of Foodstuffs)];
    molecular weight 144.11) has a melting point above 300°C. It is very
    soluble in water (550-630 g/litre at 20°C) and is hygroscopic at a
    relative humidity above 50%. Its pH is about 7.5 at a concentration of
    10 g/litre water. It is soluble in ethanol, methanol, and ethylene
    glycol. Dry sodium benzoate is electrically charged by friction and
    forms an explosive mixture when its dust is dispersed in air (Maki &
    Suzuki, 1985).

    CHEMICAL STRUCTURE 1

    

    3.  ANALYTICAL METHODS

         Analytical methods for the determination of benzoic acid include
    spectrophotometric methods, which need extensive extraction procedures
    and are not very specific; gas chromatographic (GC) methods, which are
    more sensitive and specific but need lengthy sample preparation and
    derivatization prior to determination; and high-performance liquid
    chromatography (HPLC), which has a high specificity and minimum sample
    preparation and does not require derivatization.

         A direct determination of benzoic acid in air by flash desorption
    at 240°C with helium into capillary-GC gave a detection limit of 
    0.1 ppm (0.5 mg/m3) in a 20-litre sample (=10 µg benzoic acid). 
    This method has been developed and used for monitoring occupational
    exposure (Halvorson, 1984).

         A method for the determination of benzoic acid in solid food at
    0.5-2 g/kg levels involves extraction with ether into aqueous sodium
    hydroxide and methylene chloride, conversion to trimethylsilyl esters,
    and detection by GC and flame ionization (Larsson, 1983; AOAC, 1990).
    For margarine, a method using HPLC and ultraviolet (UV) detection has
    been described with prior extraction with ammonium acetate/acetic
    acid/methanol (Arens & Gertz, 1990).

         When benzoic acid is used as a preservative in soft drinks and
    fruit drinks, other additives, colouring agents, and other acids
    (e.g., sorbate) may interfere with its analysis. Liquid
    chromatographic methods were developed to overcome this (e.g., Bennett
    & Petrus, 1977; Puttemans et al., 1984; Tyler, 1984). For the
    sensitive determination of benzoic acid in fruit-derived products, a
    clean-up pretreatment with solid-phase extraction followed by liquid
    chromatography with UV absorbance detection is described (Mandrou et
    al., 1998). The detection limit is 0.6 mg/kg, with a range of
    quantification of 2-5 mg/kg. For soft drinks, a simultaneous
    second-order derivative spectrophotometric determination has been
    developed (detection limit 1 mg/litre) (Castro et al., 1992). Sodium
    benzoate was measured in soya sauce, fruit juice, and soft drinks
    using HPLC with a UV spectrophotometric detector. Before injection,
    all samples were filtered (Villanueva et al., 1994).

         GC determination of low concentrations (down to 10 ng/ml) of
    benzoic acid in plasma and urine was preceded by diethyl ether
    extraction and derivatization with pentafluorobenzyl bromide (Sioufi &
    Pommier, 1980). Detection was by 63Ni electron capture. HPLC methods
    have been developed for the simultaneous determination of benzoic acid
    and hippuric acid -- the metabolite of sodium benzoate that is
    eliminated in the urine -- that require no extraction step (detection
    limit for both, 1 µg/ml; Kubota et al., 1988). Hippuric acid and
    creatinine levels have been determined simultaneously by HPLC, and
    measured hippuric acid levels corrected for urinary creatinine
    excretion (Villanueva et al., 1994).
    

    4.  SOURCES OF HUMAN AND ENVIRONMENTAL EXPOSURE

    4.1  Natural sources of benzoic acid

         Benzoic acid is produced by many plants as an intermediate in the
    formation of other compounds (Goodwin, 1976). High concentrations are
    found in certain berries (see section 6.1). Benzoic acid has also been
    detected in animals (see section 6.1). Benzoic acid therefore occurs
    naturally in many foods, including milk products (Sieber et al., 1989,
    1990).

    4.2  Anthropogenic sources

    4.2.1  Benzoic acid

         Benzoic acid is produced exclusively by the liquid-phase
    oxidation of toluene (Srour, 1998).

         According to Srour (1998), the estimated global production
    capacity of benzoic acid is 638 000 tonnes per year, although over
    half of this is converted directly to phenol. The major producers of
    benzoic acid are the Netherlands (220 000 tonnes per year) and Japan
    (140 000 tonnes per year), followed by the USA (125 000 tonnes per
    year). Another reference gives the total European capacity as less
    than 153 000 tonnes (SRI, 1998).

         Benzoic acid is detected in car exhaust gases, presumably as an
    oxidation product of toluene (Kawamura et al., 1985), and in Japanese
    cigarettes (12 and 28 µg per cigarette in mainstream and sidestream
    smoke, respectively; Sakuma et al., 1983). It can also be produced
    through the photochemical degradation of benzoic acid esters used as
    fragrance ingredients (Shibamoto & Umano, 1985; Shibamoto, 1986).
    Benzoic acid has been detected in wastewater from the wood production
    industry in Norway and Sweden (Carlberg et al., 1986; Lindström &
    Österberg, 1986) and in foundry waste leachates (Ham et al., 1989), as
    well as in extracts of fly ash from municipal incinerators 
    (Tong et al., 1984).

    4.2.2  Sodium benzoate

         Sodium benzoate is produced by the neutralization of benzoic acid
    with sodium hydroxide. Worldwide sodium benzoate production in 1997
    can be estimated at about 55 000-60 000 tonnes (Srour, 1998). The
    largest producers are the Netherlands, Estonia, the USA, and China.

    4.3  Uses

    4.3.1  Benzoic acid

         In 1988, of the benzoic acid produced in Europe, about 60% was
    further processed to phenol and 30% to caprolactam (for nylon fibres).
    Five per cent was used for the production of sodium and other
    benzoates, 3% for benzoyl chloride, and the rest for alkyd resins,
    benzoate esters, such as methyl benzoate, and various other products
    (Srour, 1989). These percentages are still approximately correct today
    (Srour, 1998). Caprolactam seems to be produced only by European
    companies (Srour, 1998).

         Benzoic acid is increasingly used in the production of diethylene
    and dipropylene glycol dibenzoate plasticizers in adhesive
    formulations (about 40 000 tonnes in 1997). It is also used to improve
    the properties of alkyd resins for paints and coatings and as a "down
    hole" drilling mud additive in secondary oil production. Its use as a
    rubber polymerization retarder is diminishing (Srour, 1998).

         Benzoic acid and sodium benzoate (see section 4.3.2) are used as
    preservatives in beverages, fruit products, chemically leavened baked
    goods, and condiments, preferably in a pH range below 4.5.
    A disadvantage is the off-flavour they may impart to foods (Chipley,
    1983). Owing to their inhibitory effect on yeast, they cannot be used
    in yeast-leavened products (Friedman & Greenwald, 1994). Examples of
    upper concentrations allowed in food are up to 0.1% benzoic acid (USA)
    and between 0.15% and 0.25% (other countries) (Chipley, 1983). The
    European Commission limits for benzoic acid and sodium benzoate are
    0.015-0.5% (EC, 1995).

         Benzoic acid and its salts and esters are found in 11 of 48 (23%)
    toothpastes (Sainio & Kanerva, 1995) to a maximum of 0.5% (Ishida,
    1996) and in mouthwashes and dentifrices. Benzoic acid is also used in
    cosmetics (in creams and lotions with pH values under 4, up to 0.5%)
    (Wallhäusser, 1984). Sixteen out of 71 deodorants tested contained
    benzoic acid (Rastogi et al., 1998).

         Benzoic acid is a breakdown product of benzoyl peroxide, which is
    used as an additive at levels of between 0.015% and 0.075% to bleach
    flour (Friedman & Greenwald, 1994) and in dermatological antifungal
    preparations (BMA, 1998). Benzoic acid is reported to leach from
    denture-base acrylic resins, where benzoyl peroxide is added as a
    polymerization initiator (Koda et al., 1989, 1990).

         Benzoic acid can be used in combination with salicylic acid
    (Whitfield's ointment) as a fungicidal treatment for ringworm (BMA,
    1998).

    4.3.2  Sodium benzoate

         Although undissociated benzoic acid is the more effective
    antimicrobial agent for preservation purposes, sodium benzoate is used
    preferably, as it is about 200 times more soluble than benzoic acid.
    About 0.1% is usually sufficient to preserve a product that has been
    properly prepared and adjusted to pH 4.5 or below (Chipley, 1983).

         A major market for sodium benzoate is as a preservative in the
    soft drink industry, as a result of the demand for high-fructose corn
    syrup in carbonated beverages. Sodium benzoate is also widely used as
    a preservative in pickles, sauces, and fruit juices (Srour, 1998).
    Benzoic acid and sodium benzoate are used as antimicrobial agents in
    edible coatings (Baldwin et al., 1995).

         Sodium benzoate is also used in pharmaceuticals for preservation
    purposes (up to 1.0% in liquid medicines) and for therapeutic regimens
    in the treatment of patients with urea cycle enzymopathies 
    (see section 9).

         Possibly the largest use of sodium benzoate, accounting for
    30-35% of the total demand (about 15 000 tonnes of benzoic acid), is
    as an anticorrosive, particularly as an additive to automotive engine
    antifreeze coolants and in other waterborne systems (Scholz &
    Kortmann, 1991; Srour, 1998). A new use is the formulation of sodium
    benzoate into plastics such as polypropylene, to improve strength and
    clarity (BFGoodrich Kalama Inc., 1999). Sodium benzoate is used as a
    stabilizer in photographic baths/processing (BUA, 1995).

    4.4  Estimated global release

         From data provided by the German producers, emissions of benzoic
    acid from industrial processes were less than 525 kg per year into the
    atmosphere, less than 3 tonnes per year into the River Rhine, and
    8 tonnes per year into sewage or water purification plants (BUA,
    1995). No data were available from other countries.

         Other anthropogenic releases of benzoic acid and sodium benzoate
    into the environment are emissions into water and soil from their uses
    as preservatives in food, toothpastes, mouthwashes, dentifrices, and
    cosmetics. There were no data available on the emission of benzoic
    acid from the disposal of antifreeze mixtures and waterborne cooling
    systems and other miscellaneous industrial uses.

         The amount of benzoic acid emitted to air from car exhaust gases
    as an oxidation product is not quantifiable from the available data.
    

    5.  ENVIRONMENTAL TRANSPORT, DISTRIBUTION, TRANSFORMATION,
        AND ACCUMULATION

    5.1  Transport and distribution between media

    5.1.1  Benzoic acid

         From its use pattern (see section 4), it can be expected that
    benzoic acid is released to surface waters and (from dumping sites) to
    leaching water (and groundwater). Minor amounts are expected to be
    emitted to the atmosphere. From its physicochemical properties (vapour
    pressure, Henry's law constant; see section 2), a significant
    volatilization of benzoic acid from water or soil is not expected.
    Owing to its solubility in water (see section 2), wet deposition from
    air may occur. Experimental data on wet and dry deposition from air
    are not available.

    5.1.2  Sodium benzoate

         No information on the environmental transport and distribution of
    sodium benzoate could be identified. Owing to its use pattern, which
    is similar to that of benzoic acid, most of the amounts released to
    the environment are also expected to be emitted to aquatic
    compartments (e.g., surface waters).

    5.2  Transformation

    5.2.1  Benzoic acid

         The experimental determination of the photodegradation of benzoic
    acid in aqueous solution (25°C; lambda = 240-300 nm) in terms of
    quantum yield (average number of photons absorbed) resulted in very
    low values -- in the order of 6 × 10-2 mol/einstein1 (Oussi et
    al., 1998). However, benzoic acid adsorbed on silica gel (SiO2) and
    irradiated with UV light (lambda > 290 nm) for 17 h showed 10.2%
    photodegradation (Freitag et al., 1985). This may be due to a
    photocatalytic effect, which was also observed with other oxides,
    notably zinc oxide (ZnO) and titanium dioxide (TiO2). When benzoic
    acid was irradiated with sunlight in aqueous suspensions of zinc or
    titanium dioxide, 67% (after 2-3 h) or 90% (after 24 h) of the applied
    amount was mineralized (Kinney & Ivanuski, 1969; Matthews, 1990).

                  

    1 An einstein is a unit of light energy used in photochemistry,
      equal to Avogadro's number times the energy of one photon of light 
      of the frequency in question.

         Indirect photolysis by reaction with hydroxyl radicals is
    expected to be low. Hydroxyl radical rate constants  (kOH) for
    benzoic acid and its anion have been estimated to be approximately 
    0.5 × 10-12 and 2 × 10-12 cm3/s, respectively (Palm et al., 1998).

         Standardized tests on ready (MITI, 1992) or inherent (Zahn &
    Wellens, 1980) biodegradation showed benzoic acid to be readily
    biodegraded. The degrees of aerobic degradation were as follows:

    MITI I        85%         (100 mg/litre;    (MITI, 1992)
    test                      2 weeks; OECD
                              No. 301C)

    Zahn-Wellens  >90%       (508 mg/litre;    (Zahn & Wellens, 
    test                      2 days)           1980)

         Easy degradation of benzoic acid to methane and carbon dioxide
    was also observed in different non-standardized experiments using
    sewage sludge as inoculum (BUA, 1995). Benzoic acid was found to be
    degraded by adapted anaerobic sewage sludge at 86-93% after 14 days
    (Nottingham & Hungate, 1969), by aerobic activated sludge (adapted) at
    >95% after 5-20 days (Pitter, 1976; Lund & Rodriguez, 1984), and by
    unadapted aerobic activated sludge at 61-69% after 2-3 days with a
    preceding lag time of 2-20 h (Urano & Kato, 1986). The use of a
    synthetic sewage inoculated with laboratory bacterial cultures led to
    complete degradation of benzoic acid after 14 days under anaerobic
    conditions (Kameya et al., 1995).

         A greater variability in degradation (0-100%) was seen in tests
    using environmental matrices (e.g., rain, lake water, seawater, soil,
    etc.). It depended mainly on substance concentration and time for
    acclimation (see Table 1). Test durations exceeding 2 days resulted in
    removal of >40% when initial concentrations were below 20 mg/litre.
    A rapid mineralization occurred in groundwater and subsurface soil
    samples. In groundwater, a half-life of 41 h has been found for
    benzoic acid (initial concentration 1-100 µg/litre; metabolized to
    14CO2) under aerobic conditions (Ventullo & Larson, 1985).
    Half-lives of 7.3 h and 18.2 h, respectively, have been observed for
    aerobic and anaerobic degradation of benzoic acid (initial
    concentration 1 mg/kg dry weight; metabolized to 14CO2) in
    subsurface soils of septic tank tile fields (Ward, 1985). Anaerobic
    degradation of benzoic acid (initial concentration 250 mg
    carbon/litre) in a methanogenic microcosm (consisting of aquifer
    solids and groundwater) required 4 weeks of adaptation, followed by
    nearly complete depletion after 8 weeks of incubation (Suflita &
    Concannon, 1995).

         Several isolated microorganisms have been shown to utilize (and
    therefore probably degrade) benzoic acid under aerobic or anaerobic
    conditions. They include, among others, fungal species such as

     Rhodotorula glutinis and other yeast-like fungi (Kocwa-Haluch &
    Lemek, 1995), the mould  Penicillium frequentans (Hofrichter &
    Fritsche, 1996), and bacteria, such as  Alcaligenes denitrificans
    (Miguez et al., 1995),  Rhodopseudomonas palustris, several strains
    of denitrifying pseudomonads (Fuchs et al., 1993; Elder & Kelly, 1994;
    Harwood & Gibson, 1997), and  Desulfomicrobium escambiense 
    (Sharak Genthner et al., 1997).

         Although benzoic acid is primarily metabolized to hippuric acid
    in rats (see section 7), some other species do excrete other
    metabolites, such as dibenzoylornithine (hen), benzoylglutamic acid
    (Indian fruit bat), benzoylarginine (tick, insects), or benzoyltaurine
    (southern flounder,  Paralichthys lethostigma) (Parke, 1968; Goodwin,
    1976; James & Pritchard, 1987).

    5.2.2  Sodium benzoate

         Experimental data on photodegradation of sodium benzoate are not
    available. As with benzoic acid, photolysis in aqueous solution is
    assumed to be unlikely with regard to its known UV spectra 
    (Palm et al., 1998). Indirect photolysis by reaction with hydroxyl 
    radicals plays only a minor role, with estimated and measured hydroxyl 
    rate constants of about 0.33 × 10-11 cm3/s
    (Palm et al., 1998).

         Sodium benzoate was readily biodegradable under aerobic
    conditions in several standard test systems:

    Modified       84%      (100 mg/litre;   (King & Painter,
    MITI test               10 days)         1983)

    Modified       80-90%   (50 mg/litre;    (Salanitro et al.,
    Sturm test              7 days)          1988)

    Closed bottle  75-111%  (5 mg/litre;     (Richterich &
    test                    30 days)         Steber, 1989)

         Degradation assays using seawater as test medium ("natural
    water") or as inoculum (marine filter material given into a synthetic
    marine medium) according to an adapted Organisation for Economic
    Co-operation and Development (OECD) guideline (301B) resulted in a
    degradation of 85% and 97%, respectively (10 mg/litre; carbon dioxide
    measurement; 28 days) (Courtes et al., 1995).

         Anaerobic mineralization of sodium benzoate (50-90 mg/litre) by
    domestic sewage sludge varied from 50% to 96.5% (measurement of carbon
    dioxide and methane; 28-61 days) (Birch et al., 1989). In another
    study using anaerobic sludge from sewage works receiving a mixture of
    domestic and industrial wastewaters, 93% mineralization was observed
    after 1 week of incubation (measurement of carbon dioxide and methane;
    initial concentration 50 mg carbon/litre) (Battersby & Wilson, 1989).


        Table 1: Removal of benzoic acid in freshwater, marine, and soil matrices.
                                                                                                                           

    Matrix              Initial          Conditions            Duration   Removal      Measured           Reference
                        concentration                          (days)     (%)          parameter
                        (mg/litre
                        or mg/kg)
                                                                                                                           

    Rainwater           0.001            22°C; shaking         2          0            benzoic acid       Kawamura & 
                                         once per day; dark    7          40                              Kaplan (1990)
                                                               45         100

    Lake water          0.059            29°C;                 7          98.7         14C (in CO2,       Rubin et al.
    (eutrophic/                          no shaking; dark                              biomass)           (1982)
    mesotrophic)

    Seawater                             20°C; dark;                                   14C (in            Shimp &
    (estuary)                            rotary shaking                                CO2, biomass)      Young (1987)
       USA              20                                     30         <10
                        0.005                                  8          70-80
       Canada           20                                     16         60
                        0.005                                  10         >70

    Seawater            2                                      5          75           BODa               Takemoto
                                                                                                          et al. (1981)

    Soil                20               2 mg benzoic acid     70         63           14CO2              Haider et al.
    (grey soil,                          in 0.1 ml acetone                                                (1974)
    alkaline)                            + 100 g soil
                                         + 10 ml H2O

    Soil                0.05             24°C; 20-25%          15         40           14CO2              Federle (1988)
    (sand;                               moisture content
    18.9 m depth)
                                                                                                                           

    a BOD = biological oxygen demand.
    
    Benzoate-acclimated sludges were reported to be capable of completely
    degrading benzoate concentrations of 3000 mg/litre within 5-7 days
    (Kobayashi et al., 1989).

    5.3  Accumulation

    5.3.1  Benzoic acid

         The  n-octanol/water partition coefficient (log  Kow) of 1.9
    (see section 2) indicates a low potential for bioaccumulation.
    Consistently, measured bioconcentration factors (BCFs) found in
    aquatic biota were low. BCFs of <10 (based on wet weight) have been
    determined for fish (golden ide,  Leuciscus idus melanotus) and green
    algae  (Chlorella fusca) after 3 and 1 days, respectively 
    (Freitag et al., 1985). A 6-day BCF of 7.6 has been reported for 
    another green alga  (Selenastrum capricornutum) (Mailhot, 1987), 
    and a 5-day BCF of 1300 (based on dry weight) in activated sludge 
    (Freitag et al., 1985). The following 24-h bioaccumulation factors 
    (focusing on uptake via medium plus feed within food chain members) 
    have been obtained in aquatic model ecosystems operated with 
    0.01-0.1 mg of radiolabelled benzoic acid per litre: 21 (mosquitofish, 
     Gambusia affinis), 102 (green alga,  Oedogonium cardiacum),
    138 (mosquito larvae,  Culex quinquifasciatus), 1772 (water flea,
     Daphnia magna), and 2786 (snail,  Physa sp.). Except for
     Daphnia and snail, the values were low (Lu & Metcalf, 1975).
    However, the very low exposure concentrations could likely have
    resulted in the calculation of the high BCF values, even with moderate
    uptake. Moreover, because this was a radiolabel study, it remains
    unclear if the label was still the parent compound.

         Geoaccumulation of benzoic acid has also been found to be low.
    Depending on soil depth, sorption coefficients  (Kd) of 0.62 (18.9
    m) to 1.92 (0.4 m) have been measured (Federle, 1988). Mobility
    determinations of 14C-labelled benzoic acid in different soils by
    means of thin-layer chromatography showed benzoic acid to be
    moderately mobile. Its mobility was positively correlated with soil pH
    and negatively correlated with aluminium and iron contents and
    effective anion exchange capacity (Stolpe et al., 1993).

    5.3.2  Sodium benzoate

         No experimental data on bioaccumulation or geoaccumulation of
    sodium benzoate have been identified. From the information on benzoic
    acid, a significant potential for accumulation is not to be expected.
    
    

    6.  ENVIRONMENTAL LEVELS AND HUMAN EXPOSURE

    6.1  Environmental levels

         Generally, benzoic acid can occur in almost all environmental
    compartments. Whether it exists in the undissociated or dissociated
    form depends on the specific physicochemical conditions. Above pH 6,
    the benzoate anion prevails (Chipley, 1983).

         There is a series of reports on positive qualitative analyses of
    benzoic acid in various environmental media, such as air (Belgium:
    Cautreels & van Cauwenberghe, 1978; Germany: Helmig et al., 1989),
    rain or snow (Norway: Lunde et al., 1977; Germany: Winkeler et al.,
    1988), surface waters (Norway, river: Schou & Krane, 1981), and soils
    (United Kingdom, heathland soil: Jalal & Read, 1983; Germany, river
    terrace soil: Cordt & Kußmaul, 1990), but these do not provide
    quantitative measurements.

         Semiquantitative measurements of concentrations of benzoic acid
    in urban air in Pasadena, California (USA) were in the range of
    0.09-0.38 µg/m3 (Schuetzle et al., 1975). This was comparable to
    quantitative measurements performed in 1984 in Los Angeles, California
    (USA), which resulted in atmospheric concentrations of 0.005-0.13
    µg/m3  (n = 8) (Kawamura et al., 1985). Most of the quantitative
    data compiled in Table 2 with respect to water samples refer to
    concentrations of benzoic acid in groundwater, with a maximum of 27.5
    mg/litre measured in the vicinity of a point source.

         Benzoic acid occurs naturally in free and bound form in many
    plant and animal species. It is a common metabolite in plants and
    organisms (Hegnauer, 1992). Appreciable amounts have been found in gum
    benzoin (around 20%) and most berries (around 0.05%) (Budavari et al.,
    1996). For example, ripe fruits of several  Vaccinium species (e.g.,
    cranberry,  V. vitis idaea; bilberry,  V. macrocarpon) contain as
    much as 300-1300 mg free benzoic acid per kg fruit (Hegnauer, 1966).
    Benzoic acid is also formed in apples after infection with the fungus
     Nectria galligena (Harborne, 1983) or in  Pinus thunbergii callus
    inoculated with a pathogenic pine wood nematode  (Bursaphelenchus
     xylophilus) (Zhang et al., 1997). Among animals, benzoic acid has
    been identified primarily in omnivorous or phytophageous species,
    e.g., in viscera and muscles of the ptarmigan  (Lagopus mutus)
    (Hegnauer, 1989) as well as in gland secretions of male muskoxen
     (Ovibos moschatus) (Flood et al., 1989) or Asian bull elephants
     (Elephas maximus) (Rasmussen et al., 1990).

         Owing to its occurrence in many organisms, benzoic acid is
    naturally present in foods (review in Sieber et al., 1989, 1990). Some
    typical examples specifying reported ranges of means in selected foods
    have been compiled from Sieber et al. (1989) as follows:

    Milk                          traces - 6 mg/kg
    Yoghurt                       12-40 mg/kg
    Cheese                        traces - 40 mg/kg
    Fruits (excluding             traces - 14 mg/kg
     Vaccinium species)
    Potatoes, beans, cereals      traces - 0.2 mg/kg
    Soya flour, nuts              1.2-11 mg/kg

         Honeys from different floral sources  (n = 7) were found to
    contain free benzoic acid at concentrations of <10 mg/kg  (n = 5)
    and of <100 mg/kg  (n = 2) (Steeg & Montag, 1987).

         Because benzoic acid and its compounds are used as food
    preservatives (see section 4), some processed foods contain
    artificially elevated concentrations of these substances (see section
    6.2).

    6.2  Human exposure

         The main route of exposure of the general population to benzoic
    acid or sodium benzoate is likely via foodstuffs that contain the
    substances naturally or added as antimicrobial agents. There are a few
    analyses of processed foodstuffs available. They refer to different
    types of food items (juice, soft drinks, soya sauce varieties) from
    the Philippines (a total of 44 samples) and from Japan (a total of 31
    samples) and to orange drinks sampled in England. The concentrations
    of sodium benzoate in the Philippine dietary samples ranged from 20 to
    >2000 mg/litre. The range in the Japanese products was 50-200
    mg/litre, thus reflecting the lower maximum level of sodium benzoate
    allowed to be added to food in Japan as compared with the Philippines
    (Villanueva et al., 1994). Orange drinks from England contained sodium
    benzoate at concentrations ranging from 54 to 100 mg/litre (mean 76.7
    mg/litre;  n = 6) (Freedman, 1977).

         Generally, the actual uptake depends on the individual's choice
    of food to be consumed and the different limit values in different
    countries. Several intake estimations have been published. Three
    Japanese studies reported average daily intakes of benzoic acid from
    processed foodstuffs to be 10.9 mg per person (Toyoda et al., 1983a)
    and 1.4 mg per person (Toyoda et al., 1983b; Yomota et al., 1988),
    corresponding to 0.02-0.2 mg/kg body weight (for persons with a body
    weight of 50-70 kg). Both of the latter studies used the market basket
    method for intake calculations, whereas the first-mentioned study
    calculated intakes using the results of a national nutrition survey.
    The concentrations of benzoic acid in 3319 food samples analysed for
    this study (Toyoda et al., 1983a) ranged from not detected to 2100
    mg/kg food. The maximum was found in salted fish  (n = 7; mean 754
    mg/kg). Another survey refers to the United Kingdom, where analyses of
    benzoic acid in foods and drinks in which it is permitted as well as
    intake estimates have been performed (UK MAFF, 1995). Sixty-five out
    of 122 samples tested contained detectable benzoic acid. The highest


        Table 2: Concentrations of benzoic acid in rain, snow, groundwater, and leachate samples.
                                                                                                           

    Medium              Location; sampling date                 Concentration            Reference
                                                                (µg/litre)
                                                                                                           

                        Los Angeles area, California,           Sum concentrationsa      Kawamura & Kaplan
                        USA; 1982-1983                                                   (1986)
    Rain: urban                                                 0.06-10.2 (n = 6)
    Rain: semirural                                             0.02 (n = 1)
    Snow: rural                                                 0.04-0.1 (n = 3)

    Groundwater         Wyoming, USA (near underground          16-860 (n = 3)           Stuermer et al.
                        coal gasification site; 15 months                                (1982)
                        after the end of gasification)

    Groundwater         Florida, USA (near wood treatment       10-27 500 (n = 3)        Goerlitz et al.
                        facility); 1984                                                  (1985)

    Groundwater         Ontario, Canada (near                   traces (n = 2)           Barker et al.
                        landfillb); 1983                                                 (1988)

    Groundwater         Barcelona area, Spain                   up to 0.21 (n = 3)       Guardiola et al.
                        (near landfillb)                                                 (1989)

    Leachate            Ontario, Canada; 1981                   <0.1->1000 (n = 5)       Reinhard & Goodman
    (from landfillb)                                                                     (1984)

    Leachate            Ontario, Canada; 1983                   traces (n = 2)           Barker et al. 
    (from landfillb)                                                                     (1988)

    Leachate            USA; 1986-1988                          200-400c (n = 3)         Ham et al. 
    (from foundry                                                                        (1989)
    wastes)
                                                                                                           

    a Including benzoic acid, 3-methyl benzoic acid, and 4-methyl benzoic acid.
    b Receiving rural, municipal (domestic), and industrial wastes.
    c Concentrations estimated from gas chromatography/mass spectrometry data.
    

    concentrations were found in sauces (mean 388 mg/kg;  n = 20; range
    71-948 mg/kg), reduced sugar jam (mean 216 mg/kg;  n = 4; range
    <20-333 mg/kg), non-alcoholic drinks (mean 162 mg/kg;  n = 20; range
    55-251 mg/kg), and semipreserved fish product (653 mg/kg;  n = 1).
    The survey found that the concentrations of benzoic acid detected
    would lead to a dietary intake below 5 mg/kg body weight per day, even
    for adults with an above-average consumption.

         A frequent contributor to dietary exposure is soft drinks. A
    rough estimation based on the average daily consumption in Germany of
    such drinks (372 ml non-alcoholic beverages, excluding bottled water;
    BAGS, 1995) by 19- to 24-year-old men, assuming the concentration of
    benzoic acid present corresponds to a maximum allowable level of 
    150 mg/litre (EC, 1995), would result in a mean daily intake of 
    55.8 mg benzoic acid per person (or 0.80 mg/kg body weight, assuming 
    a 70-kg body weight). For comparison, a similar calculation with 
    sugar-free marmalade, jam, and similar spreads, which are allowed to 
    contain higher levels of benzoic acid (500 mg/kg; EC, 1995), would 
    result in a possible intake of 4.1 mg per person per day, or 
    0.06 mg/kg body weight per day (assumes a daily consumption of 8.2 g, 
    according to BAGS, 1995). This was more than a possible intake via 
    fruits containing natural benzoic acid. For example, a daily 
    consumption of 40.4 g of fruits (BAGS, 1995) would lead to a possible 
    intake of 0.57 mg benzoic acid per person per day (or 0.008 mg/kg body 
    weight for a 70-kg person), if the reported maximum of 14 mg benzoic 
    acid/kg (see section 6.1) were present.

         The Joint FAO/WHO Expert Committee on Food Additives (JECFA)
    assessed the intake of benzoates from information provided by nine
    countries (Australia, China, Finland, France, Japan, New Zealand,
    Spain, United Kingdom, and USA) (WHO, 1999). Because diets differ
    among countries, the foods that contribute to benzoate intake would be
    expected to vary. The food category that contributed most to benzoate
    intake was soft drinks (carbonated, water-based, flavoured drinks) for
    Australia/New Zealand, France, the United Kingdom, and the USA. In
    Finland, 40% was in soft drinks. Soya sauce was the main source of
    benzoate in China and the second most important in Japan. The best
    estimates of national mean intakes of benzoates by consumers ranged
    from 0.18 mg/kg body weight per day in Japan to 2.3 mg/kg body weight
    per day in the USA. These estimates were based on analyses involving
    either model diets or individual dietary records and maximum limits
    specified by national governments or the European Union. The estimated
    intake by high consumers of benzoates, based on food additive levels
    in national standards, was 7.3 mg/kg body weight per day in the USA
    and 14 mg/kg body weight per day in China.

         Benzoates have been detected in groundwater, but not in
    drinking-water.

         Quantitative information on (oral or dermal/mucosal) exposure via
    cosmetic, hygienic, or medical products is rare, but the data
    available indicate a remarkable contribution to exposure. There are
    reports on leaching of benzoic acid from denture-base acrylic resins.
    After 10 days of immersion in artificial saliva, concentrations of up
    to about 3 mg/litre have been observed for benzoic acid, which is
    formed as a degradation product of the benzoyl peroxide that is  added
    as a polymerization initiator (Koda et al., 1989, 1990). In Japan,
    commercial toothpastes have been found to contain benzoic acid at
    concentrations ranging from 800 to 4450 mg/kg  (n = 18). Use of the
    toothpaste with the highest concentration (by 40 20-year-old female
    students) would result in a calculated daily intake of about 2.23 mg
    per person. This was about the same amount as their estimated intake
    from diet (Ishida, 1996). Benzoic acid is also used in dermatology as
    a fungicidal topical treatment for ringworm  (Tinea spp.). The
    emulsifying ointment preparation contains benzoic acid at 6% and is
    applied twice daily (Goodman et al., 1990; BMA, 1998). 

         Recent quantitative monitoring data on concentrations of benzoic
    acid or salts in ambient or indoor air are not available. Considering
    the few (low) levels of benzoic acid measured in urban air in the
    past, with a maximum of 0.38 µg/m3 (see section 6.1), inhalation may
    contribute only marginally to exposure of the general population.
    Using this maximum, a daily inhalative dose of 8.74 µg per person (or
    0.12 µg/kg body weight) is obtained (assuming a daily inhalation
    volume of 23 m3 for a 70-kg adult male; WHO, 1994).

         Few quantitative data on occupational exposure have been
    identified. Nevertheless, there is a potential for inhalation or
    dermal contact in the chemical and allied product industries as well
    as in workplaces where these products are used. Air samples  (n = 50)
    collected in an industrial environment (no further details given) over
    a year's time showed benzoic acid concentrations ranging from not
    detected to 1.5 mg/m3 (Halvorson, 1984). On the basis of the latter
    value, an inhalative dose of 14.4 mg per person per 8-h working time
    (or 0.2 mg/kg body weight) would result (assuming an inhalation volume
    of 9.6 m3 for an 8-h exposure with light activity; WHO, 1994).
    However, because of the lack of information on specific working
    operations and conditions involved (e.g., duration of exposure, use of
    protective clothes, etc.), it is impossible to derive a realistic
    estimate of occupational exposure.
    
    

    7.  COMPARATIVE KINETICS AND METABOLISM IN LABORATORY ANIMALS
        AND HUMANS

         After oral ingestion of benzoic acid and sodium benzoate, there
    is a rapid absorption (of undissociated benzoic acid) from the
    gastrointestinal tract in experimental animals or humans (US FDA,
    1972a, 1973). From the figures on excretion given below, 100%
    absorption can be assumed. In humans, the peak plasma concentration is
    reached within 1-2 h (Kubota et al., 1988; Kubota & Ishizaki, 1991).

         Benzoic acid is not completely absorbed by the dermal route. In a
    study with six human subjects, Feldmann & Maibach (1970) found an
    uptake of 36% of the applied dose (14C-labelled benzoic acid
    dissolved in acetone; 4 µg/cm2; circular area of 13 cm2; ventral
    surface of the forearm; non-occlusive) within 12 h. The total uptake
    within 5 days was 43%. In a second study with 6-7 subjects (comparable
    method; application of 3, 400 or 2000 µg/cm2), the percent
    absorption decreased from 35% to 14% within 24 h. However, the total
    uptake per cm2 increased from 1 to 288 µg (Wester & Maibach, 1976).
    For sodium benzoate, no data concerning dermal uptake were identified
    in the literature.

          In vivo dermal studies with benzoic acid in experimental
    animals (e.g., guinea-pigs, mice, rats, pigs, dogs, rhesus monkeys)
    confirm the results with humans (Hunziker et al., 1978; 
    Andersen et al., 1980; Wester & Noonan, 1980; Bronaugh et al., 1982a; 
    Reifenrath et al., 1984; Carver & Riviere, 1989; Maibach & Wester, 
    1989; Bucks et al., 1990). Absorption ranged from 25% in pigs 
    (Reifenrath et al., 1984; Carver & Riviere, 1989) to 89% in rhesus 
    monkeys (Wester & Noonan, 1980; Maibach & Wester, 1989; Bucks et al., 
    1990). Due to the good database on humans and animals  in vivo, 
     in vitro studies performed with animal or human skin are not 
    considered further (Franz, 1975; Bronaugh et al., 1982b;
    Hotchkiss et al., 1992; MacPherson et al., 1996).

         No information is available on absorption via inhalation.

         After oral and dermal uptake, benzoate is metabolized in the
    liver by conjugation with glycine, resulting in the formation of
    hippuric acid (Feldmann & Maibach, 1970; US FDA, 1972a; WHO, 1996;
    Feillet & Leonard, 1998). The rate of biotransformation in humans is
    high: after oral doses of 40, 80 or 160 mg sodium benzoate/kg body
    weight, the transformation to hippuric acid was independent of the
    dose -- about 17-29 mg/kg body weight per hour, corresponding to about
    500 mg/kg body weight per day (Kubota & Ishizaki, 1991). Other authors
    obtained higher values of 0.8-2 g/kg body weight per day (US FDA,
    1972a, 1973; WHO, 1996). Hippuric acid is rapidly excreted in urine.
    In humans, after oral doses of up to 160 mg/kg body weight, 75-100% of
    the applied dose is excreted as hippuric acid within 6 h after
    administration, and the rest within 2-3 days (Kubota et al., 1988;
    Fujii et al., 1991; Kubota & Ishizaki, 1991).

         The limiting factor in the biosynthesis of hippuric acid is the
    availability of glycine. The utilization of glycine in the
    detoxification of benzoate results in a reduction in the glycine level
    of the body. Therefore, the ingestion of benzoic acid or its salts
    affects any body function or metabolic process in which glycine is
    involved; for example, it leads to a reduction in creatinine,
    glutamine, urea, and uric acid levels (US FDA, 1972a, 1973; Kubota &
    Ishizaki, 1991; WHO, 1996).

         Another metabolite of benzoate is the benzoyl glucuronide. For
    example, the dog excretes considerable amounts of this metabolite in
    the urine (20% after a single dose of 50 mg/kg body weight; Bridges et
    al., 1970). In other species, this metabolite appears only after
    higher doses of about 500 mg/kg body weight (see above) of benzoic
    acid or sodium benzoate, resulting in a depletion of the glycine pool
    (Bridges et al., 1970; US FDA, 1972a; Kubota et al., 1988). In cats,
    glucuronidation is generally very low (Williams, 1967).

         In some species, including humans, minor amounts of benzoic acid
    itself are also excreted in the urine (Bridges et al., 1970; Kubota &
    Ishizaki, 1991).

         Experiments on the distribution and elimination of 14C-benzoate
    in the rat have shown no accumulation of sodium benzoate or benzoic
    acid in the body (US FDA, 1972a, 1973).

         In the acid conditions of the stomach, the equilibrium moves to
    the undissociated benzoic acid molecule, which should be absorbed
    rapidly. Benzoate from sodium benzoate would change from the ionized
    form to the undissociated benzoic acid molecule. As a result, the
    metabolism and systemic effects of benzoic acid and sodium benzoate
    can be evaluated together.

    7.1  Precursors of benzoic acid

         Benzyl acetate, its hydrolysis product, benzyl alcohol, and the
    oxidation product of this alcohol, benzaldehyde, are precursors of
    benzoic acid in experimental animals and humans. Benzyl acetate is
    metabolized to benzoic acid and further to hippuric acid and benzoyl
    glucuronide to an extent of >90% both in mice and in rats of
    different strains. Benzyl alcohol was metabolized to benzoic acid and
    its conjugates in preterm infants. Benzaldehyde is metabolized to
    benzoic acid and its conjugates in rabbits to an extent of
    approximately 90% (WHO, 1996).
    
    

    8.  EFFECTS ON LABORATORY MAMMALS AND IN VITRO TEST SYSTEMS

    8.1  Single exposure

         With oral LD50 values (administration by gavage) of 3040 mg
    benzoic acid/kg body weight in rats (Bio-Fax, 1973) and 1940-2263 mg
    benzoic acid/kg body weight in mice (McCormick, 1974; Abe et al.,
    1984), the acute toxicity of benzoic acid is low. Clinical signs of
    intoxication (reported for rats only) included diarrhoea, muscular
    weakness, tremors, hypoactivity, and emaciation (Bio-Fax, 1973). With
    oral LD50 values of 2100-4070 mg sodium benzoate/kg body weight in
    rats, the acute toxicity of sodium benzoate is similar to that of
    benzoic acid, as are the symptoms (Smyth & Carpenter, 1948; 
    Deuel et al., 1954; Bayer AG, 1977).

         In four cats given diets containing 0 or 1% benzoic acid
    (approximately 0 or 450-890 mg/kg body weight), aggression,
    hyperaesthesia, and collapse starting 14-16 h after feed uptake were
    seen at a dose level equal to 630 mg/kg body weight. The duration of
    the syndrome was about 18-176 h, and the mortality rate was 50%. The
    histopathological examination of the two cats that died revealed
    degenerative changes in liver, kidneys, and lung, but no pathological
    findings in brain or spinal cord (Bedford & Clarke, 1972). The authors
    attributed the higher toxicity of benzoic acid in cats compared with
    other species to the low capacity of cats for glucuronidation 
    (see section 7).

         In rats, exposure by inhalation to 26 mg/m3 over 1 h caused no
    mortality, but generalized inactivity and lacrimation were noted. The
    gross autopsy gave no significant findings (no further information
    available; Bio-Fax, 1973).

         In a limit test with rabbits, no mortality or signs of
    intoxication were seen after dermal application of 10 000 mg/kg body
    weight. The gross autopsy gave no significant findings (no further
    information available; Bio-Fax, 1973).

    8.2  Irritation and sensitization

    8.2.1  Benzoic acid

         Although there is a wide range of results from mostly
    non-standardized tests using various scoring systems, it can be
    concluded that benzoic acid is slightly irritating to the skin and
    irritating to the eyes.

         In different experiments with rabbits, which have not been
    performed according to current guidelines, benzoic acid applied as dry
    powder or in the form of a paste was not irritating to slightly
    irritating to the skin (score 1.66/8: Bio-Fax, 1973; no score given:
    Bayer AG, 1978; primary skin irritation index 0.5 [no further
    information available]: RCC Notox, 1988a).

         In an acute eye irritation/corrosion study with rabbits conducted
    according to OECD Guideline 405, some eye irritation was reported
    after application of benzoic acid in the form of a paste. Within 72 h,
    the scores for chemosis, reddening of the conjunctivae, iritis, and
    keratitis always remained at <2 (Bayer AG, 1986).

         In different non-standardized experiments with the solid
    substance, moderately irritating to severely irritating effects on the
    eye were noted (score 65/110: Bio-Fax, 1973; no score given: Bayer AG,
    1978; score up to 108/110 [eyes rinsed after instillation] or up to
    50/100 [eyes not rinsed]: Monsanto Co., 1983; score 35 according to
    the scheme of Kay & Calandra, 1962: RCC Notox, 1988b).

         In a maximization test, none of 15 guinea-pigs reacted positively
    after induction and challenge with a 10-20% solution of benzoic acid
    in water (Gad et al., 1986). In addition, the substance also tested
    negative in a Buehler test with guinea-pigs and in an ear swelling
    test and local lymph node assay with mice (Gad et al., 1986; Gerberick
    et al., 1992). The concentrations used for induction and challenge
    were 10-20% in acetone or water.

         However, a dose-dependent positive result was obtained in an ear
    swelling test with five guinea-pigs (induction with 0.2, 1, 5, or 20%
    in absolute ethyl alcohol; no challenge) used as a model for detecting
    agents causing non-immunological contact urticaria in humans. At
    several other regions (back, abdomen, flank site), a concentration of
    20% failed to produce any reactions (Lahti & Maibach, 1984).

    8.2.2  Sodium benzoate

         An acute dermal irritation/corrosion study with rabbits conducted
    according to OECD Guideline 404 (no data about physical state; score
    0: RCC Notox, n.d., a) as well as a non-standardized experiment with
    the solid substance (score not given: Bayer AG, 1977) gave no
    indication for skin irritating effects.

         In a study performed according to OECD Guideline 405 (no data
    about physical state; RCC Notox, n.d., b), sodium benzoate was only
    slightly irritating to the eye (score 9.3, according to the scheme of
    Kay & Calandra, 1962). The application of the solid substance in a
    non-standardized experiment caused no irritation (score not given:
    Bayer AG, 1977).

         For sodium benzoate, no data on sensitizing effects were
    identified in the available literature.

    8.3  Short-term exposure

    8.3.1  Oral exposure

         In general, the database for benzoic acid and sodium benzoate is
    limited, and there are no studies available performed according to
    current guidelines. In addition, the documentation of these studies in
    most cases is insufficient. Detailed information is given in Table 3.

         From the available studies, it can be assumed that the toxicity
    of benzoic acid after short-term oral exposure is low. In high-dosed
    rats given approximately 2250 mg/kg body weight per day via diet over
    5 days, excitation, ataxia, convulsions, and histopathological changes
    in the brain were seen. The mortality was about 50%; in some cases,
    bleeding into the gut was noted (Kreis et al., 1967). In two other
    studies with rats dosed with approximately 825 mg/kg body weight per
    day over 7-35 days (Kreis et al., 1967) or with 65-647 mg/kg body
    weight per day over 28 days (Bio-Fax, 1973), no clear
    treatment-related effects occurred. The reduced weight gain at 2250
    and 825 mg/kg body weight per day may be attributed to reduced food
    intake in the study by Kreis et al. (1967). The relevance of the
    reduced relative kidney weight at 324 mg/kg body weight per day, which
    was not dose-related and not accompanied by changes in
    histopathological examinations, is unclear (Bio-Fax, 1973). As given
    in Table 3, both studies have several limitations (i.e., missing
    haematological and clinical chemical investigations, incomplete
    histopathological examinations); therefore, both of these studies were
    inadequate for derivation of a NO(A)EL.

         More information on dose-response can be gained from the study of
    Fujitani (1993), in which rats received sodium benzoate for 10 days in
    feed. At the lowest tested concentration of 1358 mg/kg body weight per
    day, changes in serum cholesterol levels occurred in females. At doses
    of 1568 mg/kg body weight per day and above, changes in further serum
    parameters and an increased relative liver weight were described.
    Histopathological changes of the liver, increased relative kidney
    weights, and disorders of the central nervous system (convulsions)
    were seen after dosing via diet with approximately 1800 mg/kg body
    weight per day. In several other studies listed in Table 3, adverse
    effects were seen only at higher doses after feeding sodium benzoate
    over periods from 10 to 42 days, so that a
    lowest-observed-(adverse-)effect level (LO(A)EL) of 1358 mg sodium
    benzoate/kg body weight per day for short-term exposure can be
    derived.

         With cats (Bedford & Clarke, 1972), also described in Table 3,
    the effect levels with benzoic acid were lower. However, due to the
    differences in the metabolism of benzoic acid in cats compared with
    other experimental animals and humans, this study was not taken into
    further consideration (see section 7).


        Table 3: Toxicity of benzoic acid and sodium benzoate after short-term oral exposure.
                                                                                                                                   

    Species; strain;     Treatment          Duration   Organs examined in           Resultsa                      Reference
    number of animals                       (days)     histopathology, clinical
    per dosea                                          chemistry, haematology

                                                                                                                                   
    Benzoic acid
                                                                                                                                   

    cat; 4 m             0 or 0.5%          3-4        liver, kidney, heart,        mild hyperaesthesia,          Bedford & Clarke
                         in diet                       stomach, lung, brain,        apprehension, and             (1972)
                         (approx. 0                    spinal cord (only            depression starting 48-92     
                         or 300-420 mg/kg              animals that died were       h after uptake; duration of   
                         body weight)                  examined); blood samples     the syndrome: about 20-48 h;  
                                                       were taken from surviving    mortality rate: 50%; 
                                                       cats                         degenerative changes in 
                                                                                    liver, kidneys, and lung,
                                                                                    but no pathological findings  
                                                                                    in brain or spinal cord;
                                                                                    surviving cats: urea and
                                                                                    serum alanine
                                                                                    aminotransferase (S-ALAT) *,  
                                                                                    indicating liver and kidney
                                                                                    damage

    cat; 4 m             a) 100 or 200      a) 15      only blood samples           no adverse effects            Bedford & Clarke
                         mg/kg body weight             were taken                   were reported                 (1972)
                         via diet
                         b) 0 or 0.25% in   b) 23
                         diet (approx. 0
                         or 130-160 mg/kg
                         body weight)

    Table 3 (cont'd)
                                                                                                                                   

    Species; strain;     Treatment          Duration   Organs examined in           Resultsa                      Reference
    number of animals                       (days)     histopathology, clinical
    per dosea                                          chemistry, haematology
                                                                                                                                   

    rat; Wistar;         0 or 3% in diet    1-5        heart, liver, spleen,        body weight gain **;          Kreis et al. 
    5-15 m               (approx. 0 or                 kidney, brain                in rats dosed over 5 days,    (1967)
                         2250 mg/kg body                                            disorders of the central
                         weight)                                                    nervous system (excitation,
                                                                                    ataxia, tonoclonic
                                                                                    convulsions); mortality
                                                                                    rate approx. 50%; in some
                                                                                    cases, bleeding into the
                                                                                    gut; brain damage (necrosis
                                                                                    of parenchymal cells of the
                                                                                    stratum granulosum of the
                                                                                    fascia dentata and the
                                                                                    cortex of the lobus
                                                                                    piriformis) in most animals
                                                                                    dosed over 3-5 days (still
                                                                                    present after 35 days)

    rat; Wistar;         0 or 1.1% in       7-35       heart, liver, spleen,        body weight gain **;           Kreis et al. 
    5-10 m               diet                          kidney, brain                no clinical signs of          (1967)
                         (approx. 0 or                                              intoxication
                         825 mg/kg body
                         weight)

    rat; albino; 10 m    0, 760, 3800, or   28         liver, kidney,               no deaths or signs of         Bio-Fax (1973)
                         7600 ppm via diet             adrenals, testes             intoxication
                         (approx. 0, 65,                                            324 mg/kg body 
                         324, or 647 mg/kg                                          weight: relative kidney
                         body weight)                                               weights **; no further
                                                                                    information available

    Table 3 (cont'd)
                                                                                                                                   

    Species; strain;     Treatment          Duration   Organs examined in           Resultsa                      Reference
    number of animals                       (days)     histopathology, clinical
    per dosea                                          chemistry, haematology

                                                                                                                                   
    Sodium benzoate
                                                                                                                                   

    rat; F344/Ducrj;     0, 1.81, 2.09, or  10         liver, kidney;               >1358 mg/kg body weight:      Fujitani (1993)
    6 m/f                2.4% in diet                  standard clinical            changes in serum levels
                         (approx. 0, 1358,             chemistry                    (cholesterol ** (f))
                         1568, or 1800                                              >1568 mg/kg body weight:
                         mg/kg body                                                 relative liver weight * (m);  
                         weight)                                                    changes in serum levels
                                                                                    (albumin * (m), total 
                                                                                    protein * (m))
                                                                                    1800 mg/kg body weight:
                                                                                    1/6 males died
                                                                                    (hypersensitivity,
                                                                                    convulsions); body
                                                                                    weight ** (m/f); relative
                                                                                    liver weight * (f); relative
                                                                                    kidney weights * (m/f);
                                                                                    absolute weights of spleen
                                                                                    and thymus ** (m);
                                                                                    absolute/relative weights
                                                                                    of thymus ** (f); changes
                                                                                    in serum levels
                                                                                    (gamma-glutamyltranspeptidase
                                                                                    (GGT) * (m), albumin * (f),
                                                                                    cholinesterase ** (f));
                                                                                    eosinophilic foci around
                                                                                    periportal vein and
                                                                                    enlargement of hepatocytes
                                                                                    with glassy cytoplasm in
                                                                                    the periportal area of the
                                                                                    liver (m); no changes in
                                                                                    the kidney (m)

    Table 3 (cont'd)
                                                                                                                                   

    Species; strain;     Treatment          Duration   Organs examined in           Resultsa                      Reference
    number of animals                       (days)     histopathology, clinical
    per dosea                                          chemistry, haematology
                                                                                                                                   

    rat; Sherman;        0, 2, or 5% in     28         no data available            2200 mg/kg body weight:       Fanelli & Halliday (1963)
    6 m/f                diet (approx. 0,                                           slight depression of
                         2200, or 6700                                              body weight gain (m)
                         mg/kg body                                                 6700 mg/kg body weight:
                         weight)                                                    mortality 100% within
                                                                                    11 days; signs of
                                                                                    intoxication included
                                                                                    hyperexcitability, urinary
                                                                                    incontinence, and
                                                                                    convulsions
                                                                                    no further information
                                                                                    available

    rat; 28 (no          0 or 5% in diet    28         no data available            mortality about 100% within   Kieckebusch & Lang
    further data)        (approx. 0 or                                              3 weeks; decreased feed       (1960)
                         3750 mg/kg body                                            intake, diarrhoea,
                         weight)                                                    intestinal haemorrhage and
                                                                                    crusted blood in the nose;
                                                                                    no further information
                                                                                    available

    rat; 5 (no           0 or 5% in diet    >28       no data available            mortality 80% within          Kieckebusch & Lang 
    further data)        (approx. 0 or                                              4-5 weeks; decreased          (1960)
                         3750 mg/kg                                                 body weight; no further
                         body weight)                                               information available

    Table 3 (cont'd)
                                                                                                                                   

    Species; strain;     Treatment          Duration   Organs examined in           Resultsa                      Reference
    number of animals                       (days)     histopathology, clinical
    per dosea                                          chemistry, haematology
                                                                                                                                   

    rat; F344;           0, 0.5, 1, 2, 4,   42         histopathology performed,    >375 mg/kg body weight:       Sodemoto & Enomoto
    10-11 m/f            or 8% in diet                 but not further specified    hypersensitivity after        (1980)
                         (approx. 0, 375,                                           dosing
                         750, 1500, 3000,                                           >3000 mg/kg body weight:
                         or 6000 mg/kg                                              mortality about 100% within
                         body weight)                                               4 weeks; apart from atrophy
                                                                                    of the spleen and lymph
                                                                                    nodes, no other
                                                                                    morphological changes were
                                                                                    noted

    rat; Sherman;        0 or 16-1090       30         adrenals, upper intestine,   no adverse effects were       Smyth & Carpenter
    5 m/f                mg/kg body                    kidney, liver, spleen        reported; no further          (1948)
                         weight via diet                                            information available

    mouse; B6C3F1;       0, 2.08, 2.5, or   10         liver, kidney; standard      „3750 mg/kg body weight:      Fujitani (1993)
    4-5 m/f              3% in diet                    clinical chemistry           changes in serum levels
                         (approx. 0, 3000,                                          (cholinesterase * (m))
                         3750, or 4500                                              4500 mg/kg body weight:
                         mg/kg body weight)                                         hypersensitivity in all
                                                                                    animals; convulsions
                                                                                    1/5 males and 2/5 females
                                                                                    (both females died);
                                                                                    absolute/relative liver
                                                                                    weight * (m/f); relative
                                                                                    kidney weight * (f);
                                                                                    changes in serum levels
                                                                                    (cholesterol * (m),
                                                                                    phospholipids * (m));

    Table 3 (cont'd)
                                                                                                                                   

    Species; strain;     Treatment          Duration   Organs examined in           Resultsa                      Reference
    number of animals                       (days)     histopathology, clinical
    per dosea                                          chemistry, haematology
                                                                                                                                   

                                                                                    enlarged hepatocytes,
                                                                                    single cell necrosis
                                                                                    and vacuolation of
                                                                                    hepatocytes in all
                                                                                    livers (m); no changes
                                                                                    in the kidney (m/f)

    mouse; albino        0, 0.5, 1, 2, 4,   35         survival, chemical           3000 mg/kg body weight:       Toth (1984)
    Swiss; 4 m/f         or 8% via                     consumption, histological    "suitable for lifelong
                         drinking-water                changes (not further         treatment" based on
                         (approx.                      specified) (prestudy         four parameters: survival,
                         0-12 000 mg/kg                for carcinogenicity study)   body weight, chemical
                         body weight)                                               consumption, and histology
                                                                                    6000 mg/kg body weight:
                                                                                    mortality 75% in m/f;
                                                                                    body weight of surviving
                                                                                    mice ** (m/f)
                                                                                    12 000 mg/kg body weight:
                                                                                    mortality 100% within
                                                                                    3 weeks
                                                                                                                                   

    a m = male; f = female.
    

    8.3.2  Inhalation exposure

         Ten CD rats per sex per group were exposed to 0, 25, 250, or
    1200 mg benzoic acid dust aerosol/m3 (analytical concentration; mass
    aerodynamic diameter [MAD]/sigma g (standard deviation): 0, 4.6/3.1,
    4.4/2.1, 5.2/2.1; mass median aerodynamic diameter [MMAD]: 4.7 µm) for
    6 h per day and 5 days per week over 4 weeks. After this time, various
    serum biochemical, haematological, organ weight, and histopathological
    examinations were conducted. At >25 mg/m3, an increased incidence
    of interstitial inflammatory cell infiltrate and interstitial fibrosis
    in the trachea and lungs in treated animals compared with controls was
    seen. Although the number of these microscopic lesions was higher in
    treated animals than in controls, there was no clear dose dependency
    for this effect. A concentration of >250 mg/m3 resulted in upper
    respiratory tract irritation, as indicated by inflammatory exudate
    around the nares, and significantly decreased absolute kidney weights
    in females. In the highest dose group, one rat per sex died, and the
    body weight gain was significantly decreased in males and females
    compared with controls. In addition, a significant decrease in
    platelets (males/females), absolute/relative liver weights (males),
    and trachea/lung weights (females) was noted (Velsicol Chemical 
    Corp., 1981).

         Studies concerning repeated exposure by inhalation to sodium
    benzoate were not identified in the available literature.

    8.3.3  Dermal exposure

         Studies concerning repeated dermal exposure to benzoic acid or
    sodium benzoate were not identified in the available literature.

    8.4  Long-term exposure

         In general, the database for benzoic acid and sodium benzoate is
    limited, and there are no studies available performed according to
    current guidelines. In addition, the documentation in most cases is
    limited. Detailed information is given in Table 4.

    8.4.1  Subchronic exposure

         In a 90-day study with rats dosed with 0, 1, 2, 4, or 8% sodium
    benzoate via diet, the mortality in the highest dose group (approx.
    6290 mg/kg body weight per day) was about 50%. Other effects in this
    group included a reduced weight gain, increased relative weights of
    liver and kidneys, and pathological changes (not further specified) in
    these organs (Deuel et al., 1954).


        Table 4: Results of studies concerning long-term oral exposure to benzoic acid and sodium benzoate.
                                                                                                                                     

    Species; strain;    Treatment            Duration        Examinations;            Resultsa                    Reference
    number of animals                                        organs in
    per dosea                                                histopathology,
                                                             clinical chemistry,
                                                             haematology
                                                                                                                                     
    Benzoic acid
                                                                                                                                     

    rat; Wistar;        0 or 1.5% in diet    18 months       no data available        reduced weight gain with    Marquardt (1960)
    dose group:         (approx. 0 or                                                 decreased feed intake;
    30 m/20 f;          750 mg/kg body                                                increased mortality rate
    controls:           weight)                                                       (15/50 vs. 3/25 in
    13 m/12 f                                                                         controls); no further
                                                                                      information available
                                                                                      (only provisional results
                                                                                      are given)

    rat; Wistar or      0 or 1.5% in diet    18 months       no data available        reduced weight gain with    Marquardt (1960)
    Osborne-Mendel;     (approx. 0 or                                                 decreased feed intake;
    dose group:         750 mg/kg body                                                no further information
    20 m; controls:     weight)                                                       available (only
    10 m                                                                              provisional results are
                                                                                      given)

    rat; not given;     0, 0.5, or 1% in     generation 1    histopathology in        no effects on growth and    Kieckebusch & Lang
    20 m/f              diet                 and 2:          animals of               organ weights; feeding of   (1960)
                        (approx. 0, 250,     lifelong        generation 3             0.5% led to prolongation
                        or 500 mg/kg body    generation 3:   (not further specified)  of survival compared with
                        weight)              16 weeks                                 controls; no further
                                             generation 4:                            information available
                                             until breeding

    Table 4 (cont'd)
                                                                                                                                     

    Species; strain;    Treatment            Duration        Examinations;            Resultsa                    Reference
    number of animals                                        organs in
    per dosea                                                histopathology,
                                                             clinical chemistry,
                                                             haematology

                                                                                                                                     
    Sodium benzoate
                                                                                                                                     

    rat; Sherman;       0, 1, 2, 4, or 8%    90 days         histopathology           6290 mg/kg body weight:     Deuel et al.
    5 m/f               in diet (approx. 0,                  performed, but           mortality about 50%;        (1954)
                        640, 1320, 2620,                     not further specified    weight gain **;
                        or 6290 mg/kg body                                            relative weights of
                        weight)                                                       liver and kidneys *;
                                                                                      pathological lesions
                                                                                      (not further specified)
                                                                                      in liver and kidneys

    rat; F344;          0, 1, or 2% in       18-24 months    histopathology           average mortality rate of   Sodemoto & Enomoto
    dose group:         diet                                 performed, but not       all animals during the      (1980)
    50 m/52 f;          (m: approx. 0, 700,                  further specified        first 16 months: 14.5%
    controls:           or 1400 mg/kg                                                 (all dead rats showed
                        body weight; f:                                               pneumonia with abscess);
                        25 m/43 f                                                     about 100 rats including
                        approx. 0, 290,                                               controls died after
                        or 580 mg/kg                                                  16 months due to
                        body weight)                                                  haemorrhagic pneumonia
                                                                                      (infection); no adverse
                                                                                      clinical signs and no
                                                                                      differences in average
                                                                                      body weight and mortality
                                                                                      in dosed animals compared
                                                                                      with controls;
                                                                                      non-carcinogenic effects
                                                                                      not reported

    Table 4 (cont'd)
                                                                                                                                     

    Species; strain;    Treatment            Duration        Examinations;            Resultsa                    Reference
    number of animals                                        organs in
    per dosea                                                histopathology,
                                                             clinical chemistry,
                                                             haematology

                                                                                                                                     

    mouse;              0 or 2% via          lifelong        liver, spleen, kidney,   no difference in survival   Toth (1984)
    albino Swiss;       drinking-water                       bladder, thyroid,        rates in treated animals
    dose group:         (approx. 0 or                        heart, pancreas,         compared with controls;
    50 m/f;             5960-6200 mg/kg                      testes, ovaries, brain,  no pathological or
    controls: 99 m/f    body weight)                         nasal turbinates, lung   statistical evidence of
                                                                                      tumour induction
                                                                                                                                     

    a m = male; f = female.
    

    8.4.2  Chronic exposure and carcinogenicity

         In two studies with rats given 1.5% benzoic acid via diet
    (approximately 750 mg/kg body weight per day), the animals showed a
    reduced weight gain with decreased feed intake after dosing over 
    18 months. In one of these studies, mortality was increased 
    (15/50 rats of both sexes versus 3/25 in controls) (Marquardt, 1960). 
    No further information on these studies is available, as only 
    provisional results were published. In a four-generation study with 
    rats, no effects on life span, growth rate, or organ weights were 
    reported after dosing with up to 1% in the diet (approximately 
    500 mg/kg body weight per day) (Kieckebusch & Lang, 1960). Only 
    animals of the third generation were autopsied after 16 weeks, but 
    it is not clear if a complete histopathological investigation was
    performed.

         With sodium benzoate, two long-term studies with rats
    (administration of up to 1400 mg/kg body weight per day via diet over
    18-24 months; Sodemoto & Enomoto, 1980) or mice (lifelong application
    of up to 6200 mg/kg body weight per day via drinking-water; Toth,
    1984) are available. The results gave no indication of a carcinogenic
    effect in the tested animals. Although the study with mice was not
    performed according to current guidelines, the results seem to be
    reliable, due to a sufficient number of animals and detailed
    histopathological examinations. However, the results from the study
    with rats are uncertain, due to a very high mortality in animals of
    all dose groups, including controls (from an "infection" after 
    16 months), no detailed information about dosing regimen (only mean
    values given), and the considerable differences in the body weight of
    male and female rats (the body weight of females was about twice that
    of males).

    8.4.3  Carcinogenicity of benzyl acetate, benzyl alcohol, and
           benzaldehyde

         As benzyl acetate, benzyl alcohol, and benzaldehyde are
    practically quantitatively metabolized via benzoic acid (see section
    7.1), data on their carcinogenicity from 2-year studies may be used as
    supportive evidence in the assessment of the hazards associated with
    benzoic acid.

         Benzyl acetate was administered in corn oil via gavage to F344/N
    rats (0, 250, or 500 mg/kg body weight per day) or B6C3F1 mice 
    (0, 500, or 1000 mg/kg body weight per day). In high-dose male rats, 
    the incidence of acinar cell adenomas of the exocrine pancreas was
    increased, whereas there was no evidence of carcinogenicity in female
    rats. In high-dose male and female mice, benzyl acetate caused
    increased incidences of hepatocellular adenomas and squamous cell
    neoplasms of the forestomach (US NTP, 1986). In contrast to these
    findings, no such tumours were observed in another study with the same
    strain of rats and mice when benzyl acetate was administered via diet
    (rats: <575 mg/kg body weight per day; mice: <375 mg/kg body
    weight per day) (US NTP, 1993).

         With benzyl alcohol, no treatment-related increase in tumours was
    observed in F344/N rats or B6C3F1 mice after administration of
    <400 mg/kg body weight per day in rats or <200 mg/kg body weight
    per day in mice by gavage in corn oil (US NTP, 1989).

         In B6C3F1 mice dosed with benzaldehyde in corn oil by gavage
    (males: 0, 200, or 400 mg/kg body weight per day; females: 0, 300, or
    600 mg/kg body weight per day), the incidences of squamous cell
    papillomas of the forestomach were significantly greater in both
    exposure groups than in controls. A dose-related increase in the
    incidence of forestomach hyperplasia was also observed. In F344/N rats
    dosed with <400 mg/kg body weight per day, there was no evidence of
    carcinogenic activity (US NTP, 1990).

    8.5  Genotoxicity and related end-points

    8.5.1  Benzoic acid

         Benzoic acid tested negative in several Ames tests and in one DNA
    damage assay with different  Salmonella typhimurium strains in the
    presence or absence of metabolic activation (McCann et al., 1975;
    Ishidate et al., 1984; Nakamura et al., 1987; Zeiger et al., 1988).
    Only in one recombination assay with  Bacillus subtilis H17 and M45
    was a positive result obtained (Nonaka, 1989). However, due to missing
    experimental details (only results given), the validity of this study
    cannot be judged. There was no indication of genotoxic activity
    (chromosome aberrations, sister chromatid exchange) in tests with
    mammalian cells (Chinese hamster CHL and CHO cells, human
    lymphoblastoid cells, human lymphocytes) without metabolic activation
    (Oikawa et al., 1980; Tohda et al., 1980; Ishidate et al., 1984;
    Jansson et al., 1988).

          In vivo studies with benzoic acid were not identified in the
    literature.

    8.5.2  Sodium benzoate

         Sodium benzoate also gave negative results in some Ames tests and
    in  Escherichia coli in the presence or absence of metabolic
    activation (Ishidate et al., 1984; Prival et al., 1991). As with
    benzoic acid in recombination assays with  Bacillus subtilis H17 and
    M45, positive results were obtained (Ishizaki & Ueno, 1989; Nonaka,
    1989). Although sodium benzoate tested negative in a cytogenetic assay
    with WI-38 cells in the absence of metabolic activation (US FDA,
    1974), consistently positive results (in contrast to the negative
    results of benzoic acid) were obtained in tests on sister chromatid
    exchange and chromosome aberrations with CHL/CHO and DON cells or
    human lymphocytes without metabolic activation (Abe & Sasaki, 1977;
    Ishidate & Odashima, 1977; Ishidate et al., 1984, 1988; Xing & Zhang,
    1990). However, from the limited information given in the publications
    (i.e., only results given), it cannot be judged if these positive
    results may have been attributable to cytotoxic effects.

         In a valid  in vivo study performed by the US FDA (1974), sodium
    benzoate tested negative in a cytogenetic assay (bone marrow) in rats
    after single or multiple oral application of doses up to 5000 mg/kg
    body weight. In a study with mice (comparable dosing scheme), there
    was also no indication of mutagenic activity in a host-mediated assay
    (US FDA, 1974).

         However, in a dominant lethal assay with rats (comparable dosing
    scheme; males were mated with untreated females following 7 or 8 weeks
    of dosing), some statistically significant and dose-related findings
    were reported in week 7: decreased fertility index for both treatment
    regimens and an increased number of preimplantation losses after
    single dosing (US FDA, 1974).

         In summary, the  in vitro studies with benzoic acid gave no
    indications for genotoxic effects, whereas  in vivo studies were not
    identified. Sodium benzoate was also inactive in bacterial test
    systems, whereas tests with mammalian cells gave consistently positive
    results. In addition, in an  in vivo study with sodium benzoate
    (dominant lethal assay in rats), a positive result was obtained. As a
    result, a genotoxic activity of sodium benzoate cannot be ruled out
    entirely at present.

         Detailed information concerning the genotoxicity of benzoic acid
    and sodium benzoate  in vitro is given in Table 5.

    8.6  Reproductive and developmental toxicity

    8.6.1  Fertility

         There are no studies available dealing specifically with the
    effects of benzoic acid or sodium benzoate on fertility that have been
    conducted according to current protocols.

         In a four-generation study with male and female rats, no adverse
    effects on fertility or lactation (only investigated parameters) were
    seen after dosing with benzoic acid at up to 1% in the diet
    (approximately 500 mg/kg body weight per day) (see also section 8.4.2;
    Kieckebusch & Lang, 1960).

         In studies with repeated oral application, no effects on the
    testes were observed in rats after dosing with benzoic acid at up to
    647 mg/kg body weight per day in the diet for 4 weeks (see also Table
    3; Bio-Fax, 1973) or in mice after lifelong application of 6200 mg
    sodium benzoate/kg body weight per day via drinking-water (see also
    Table 4; Toth, 1984).

         In summary, no clear statement can be given as to the possible
    effects of benzoic acid or sodium benzoate on fertility.

    8.6.2  Developmental toxicity

         In a study with pregnant rats given only one oral dose of benzoic
    acid (510 mg/kg body weight on gestation day 9), there was no
    indication of an increase in resorption rates or malformations 
    (Kimmel et al., 1971).

         For sodium benzoate, several teratogenicity studies are available
    that have been performed with different species. As given in Table 6,
    no effects were seen in dams or offspring of rats, mice, rabbits, or
    hamsters given oral doses of up to 300 mg/kg body weight per day
    (highest dose tested) during gestation (US FDA, 1972b). In a study
    with rats by Onodera et al. (1978), doses of 4% or 8% via diet (uptake
    of 1875 or 965 mg/kg body weight per day) induced severe maternal
    toxicity (no weight gain/loss in body weight, increased mortality) and
    were associated with embryotoxic and fetotoxic effects as well as
    malformations. However, the authors suggested that the effects on the
    dams and fetuses at >4% dietary levels were caused by reduced
    maternal feed intake, leading to malnutrition. The intake of sodium
    benzoate in the highest dose group (8%) was lower than that at 2%,
    where no adverse effects were seen. From this study, a NO(A)EL of
    about 1310 mg/kg body weight per day can be derived. In a study with
    rats by Minor & Becker (1971), however, fetotoxic and teratogenic
    effects occurred at 1000 mg/kg body weight per day. In this study,
    sodium benzoate was applied by intraperitoneal injection. Therefore,
    differences in pharmacokinetics between oral and intraperitoneal
    administration may be the reason for the higher sensitivity.

         Studies performed with eggs of leghorn hens (single injection of
    <5 mg per egg), chick embryo neural retina cells
    (lowest-observed-effect concentration [LOEC] of 34.7 mmol/litre), and
    a chick embryotoxicity screening test (single injection of <0.1 mg
    per embryo) gave no indication of embryotoxic or teratogenic effects
    (Verrett et al., 1980; Jelinek et al., 1985; Daston et al., 1995).

    8.6.3  Reproductive toxicity of benzyl acetate, benzyl alcohol,
           and benzaldehyde

         As benzyl acetate and benzyl alcohol are practically
    quantitatively metabolized via benzoic acid (see section 7.1), data on
    their reproductive toxicity may be used as supportive evidence in the
    assessment of the hazards associated with benzoic acid.

         Dietary benzyl acetate (up to 5% in the diet for 13 weeks) had no
    effect on the weights of the epididymis, cauda epididymis, or testis,
    on sperm motility or density, or on the percentage of abnormal sperm
    in mice or rats (US NTP, 1993).

         Benzyl acetate (0, 10, 100, 500, or 1000 mg/kg body weight per
    day by gavage on days 6-15) had no significant effects on maternal
    health in rats and did not induce changes in the numbers of corpora
    lutea, implantations, live or dead fetuses, or resorptions,
    implantation ratio, sex ratio, external or internal malformations, or
    placental weight. Fetal weights were significantly reduced at the
    highest dose (Ishiguro et al., 1993).

         Benzyl alcohol at 550 mg/kg body weight per day by gavage on days
    6-15 of pregnancy had no effect on gestation index, average number of
    live pups per litter, postnatal survival, or pup body weight on days 
    0 and 3 in CD-1 mice (York et al., 1986), while 750 mg/kg body weight
    per day (days 7-14) induced a reduction in the pup weight and maternal
    weight gain, but no pup mortality or changes in mating or gestation
    indices, the total number of resorptions, or the number of live pups
    per litter (Hardin et al., 1987).


        Table 5: Genotoxicity of benzoic acid and sodium benzoate in vitro.
                                                                                                                              

                                                            Resultsa
                                                                             
    Species             End-point       Concentration    Without      With             Remarks                Reference
    (test system)                       range            metabolic    metabolic
                                                         activation   activation
                                                                                                                              
    Benzoic acid
                                                                                                                              

    Salmonella          Reverse         10-1000          -            -                                       McCann et al.
    typhimurium         mutations       µg/plate                                                              (1975)
    TA 98, TA 100,
    TA 1535, TA 1537

    Salmonella          Reverse         33-10 000        -            -                cytotoxic effects      Zeiger et al.
    typhimurium         mutations       µg/plate                                       at >5000               (1988)
    TA 97, TA 98,                                                                      µg/plate
    TA 100, TA 1535,
    TA 1537

    Salmonella          Reverse         up to 10 000     -            -                10 000 µg/plate was    Ishidate et al.
    typhimurium         mutations       µg/plate                                       the highest            (1984)
    TA 92, TA 94,                                                                      non-cytotoxic
    TA 98, TA 100,                                                                     concentration tested
    TA 1535, TA 1537

    Salmonella          DNA damage      up to            -            -                no further             Nakamura et al.
    typhimurium         (umu test)      1670 µg/ml                                     information available  (1987)
    TA 1535/pSK 1002                                                                   (only results given)

    Bacillus            Recombination   not given                                      tested positive (no    Nonaka
    subtilis            assay                                                          further information    (1989)
    H17, M45                                                                           available, only
                                                                                       summary given)

    Table 5 (cont'd)
                                                                                                                              

                                                            Resultsa
                                                                             
    Species             End-point       Concentration    Without      With             Remarks                Reference
    (test system)                       range            metabolic    metabolic
                                                         activation   activation
                                                                                                                              

    Chinese hamster     Chromosome      up to            ?            0                1500 µg/ml was given   Ishidate et al.
    cells (CHL)         aberration      1500 µg/ml                                     as maximum effective   (1984)
                                                                                       concentration; result  
                                                                                       given as negative in
                                                                                       Ishidate et al.
                                                                                       (1988)

    Human               Sister          1-30             -            0                cytotoxic effects      Tohda et al.
    lymphoblastoid      chromatid       mmol/litre                                     at 30 mmol/litre       (1980)
    cells               exchange
    (transformed
    by Epstein-Barr
    virus)

    Human               Sister          up to 2          -            0                                       Jansson et al.
    lymphocytes         chromatid       mmol/litre                                                            (1988)
                        exchange


    Chinese             Sister          up to            -            0                                       Oikawa et al.
    hamster             chromatid       10 mmol/litre                                                         (1980)
    cells (CHO)         exchange

    Table 5 (cont'd)
                                                                                                                              

                                                            Resultsa
                                                                             
    Species             End-point       Concentration    Without      With             Remarks                Reference
    (test system)                       range            metabolic    metabolic
                                                         activation   activation
                                                                                                                              
    Sodium benzoate
                                                                                                                              

    Salmonella          Reverse         up to            -            -                3000 µg/plate was      Ishidate et al.
    typhimurium         mutations       3000 µg/plate                                  the highest            (1984)
    TA 92, TA 94,                                                                      non-cytotoxic
    TA 98, TA 100,                                                                     concentration tested
    TA 1535, TA 1537

    Salmonella          Reverse         33-10 000        -            -                                       Prival et al. 
    typhimurium         mutations       µg/plate                                                              (1991)
    TA 98, TA 100,
    TA 1535, TA 1537,
    TA 1538

    Escherichia coli    Reverse         33-10 000        -            -                                       Prival et al.
    WP2                 mutation        µg/plate                                                              (1991)
                        assay

    Bacillus            Recombination   not given                                      tested positive        Nonaka (1989)
    subtilis            assay                                                          information
    H17, M45                                                                           available, only
                                                                                       summary given)

    Bacillus            Recombination   -S9:             (+)          (+)                                     Ishizaki & Ueno
    subtilis            assay           20 mg/disc                                                            (1989)
    H17, M45                            +S9:
                                        16 mg/disc

    Table 5 (cont'd)
                                                                                                                              

                                                            Resultsa
                                                                             
    Species             End-point       Concentration    Without      With             Remarks                Reference
    (test system)                       range            metabolic    metabolic
                                                         activation   activation
                                                                                                                              
    WI-38 cells         Cytogenetic     10-1000 µg/ml    -            0                examination of         US FDA (1974)
                        assay                                                          anaphase preparations
                                                                                       cytotoxic effects
                                                                                       at >500 µg/ml

    Chinese hamster     Chromosome      up to            +            0                2000 µg/ml was         Ishidate et al.
    cells (CHL)         aberration      2000 µg/ml                                     given as maximum       (1984, 1988)
                                                                                       effective
                                                                                       concentration

    Chinese hamster     Chromosome      139 mg/ml        +            0                only maximum           Ishidate &
    cells (CHL)         aberration                                                     effective dose given   Odashima (1977)

    Chinese hamster     Chromosome      290 µg/ml        0            0                only minimum           Ishidate et al.
    cells (DON)         aberration                                                     effective dose given   (1988)

    Chinese hamster     Chromosome      1-10             +            0                                       Abe & Sasaki
    cells (DON)         aberration      mmol/litre                                                            (1977)

    Chinese hamster     Sister          1-10             (+)          0                slight increase        Abe & Sasaki 
    cells (DON)         chromatid       mmol/litre                                     without dosage         (1977)
                        exchange                                                       effect

    Human               Sister          10               +            0                                       Xing & Zhang 
    lymphocytes         chromatid       mmol/litre                                                            (1990)
                        exchange
                                                                                                                              
    a -, negative; +, positive; (+) weakly positive; ?, equivocal; 0, not tested.

    Table 6: Results of studies concerning reproductive and developmental toxicity of benzoic acid and sodium benzoate.
                                                                                                                                     

    Species; strain;   Application       Durationb    Parameters              Results                    NO(A)EL       Reference
    number of animals                                 investigated                                       (mg/kg
    per dosea                                                                                            body 
                                                                                                         weight)
                                                                                                                                     
    Benzoic acid
                                                                                                                                     

    rat; Wistar;       0 or 510          gd 9         F0: implantation        F0: resorption rates       510           Kimmel et al.
    dose group:        mg/kg body                     and resorption sites    were given as                            (1971)
    7 f; controls:     weight                         F1: malformations       "comparable with
    not given          via gavage                                             controls"
                                                                              F1: malformations
                                                                              (not further specified)
                                                                              were given as
                                                                              "comparable with controls"
                                                                              no further information
                                                                              available

    rat; not given;    0, 0.5, or 1%     F0 and F1:   fertility and           F0-F3: no adverse         500           Kieckebusch &
    20 f               in diet           lifelong     lactation               effects compared with                    Lang (1960)
                       (approx. 0,       F2: 16                               controls were reported
                       250, or 500       weeks                                no further information
                       mg/kg body        F3: until                            available
                       weight)           breeding

                                                                                                                                     
    Sodium benzoate
                                                                                                                                     

    rat; Wistar;       0, 1.75, 8,       gd 6-15      F0: numbers of corpora  F0 and F1: no adverse      175           US FDA 
    20 f               38, or 175                     lutea, implantation     effects compared with                    (1972b)
                       mg/kg body                     and resorption sites,   controls were reported
                       weight via                     examination of the      
                       gavage                         urogenital tract        

    Table 6 (cont'd)
                                                                                                                                     

    Species; strain;   Application       Durationb    Parameters              Results                    NO(A)EL       Reference
    number of animals                                 investigated                                       (mg/kg
    per dosea                                                                                            body 
                                                                                                         weight)
                                                                                                                                     

                                                      F1: numbers of live     
                                                      and dead fetuses, body  
                                                      weights, gross          
                                                      examination for         
                                                      external 
                                                      malformations,
                                                      microscopic visceral
                                                      and skeletal
                                                      examination

    mouse;             0, 1.75, 8,       gd 6-15      F0: numbers of corpora  F0 and F1: no adverse      175           US FDA
    CD-1;              38, or 175                     lutea, implantation     effects compared with                    (1972b)
    25-31 f            mg/kg body                     and resorption sites,   controls were reported
                       weight via                     examination of the
                       gavage                         urogenital tract

                                                      F1: numbers of live
                                                      and dead fetuses, body
                                                      weights, gross
                                                      examination for
                                                      external
                                                      malformations,
                                                      microscopic visceral
                                                      and skeletal
                                                      examination

    rabbit; Dutch      0, 2.5, 12,       gd 6-18      F0: numbers of corpora  F0 and F1: no              250           US FDA 
    belted; 14-32 f    54, or 250                     lutea, implantation     adverse effects                          (1972b)
                       mg/kg body                     and resorption sites,   compared with
                       weight via                     examination of the      controls were
                       gavage                         urogenital tract        reported

    Table 6 (cont'd)
                                                                                                                                     

    Species; strain;   Application       Durationb    Parameters              Results                    NO(A)EL       Reference
    number of animals                                 investigated                                       (mg/kg
    per dosea                                                                                            body 
                                                                                                         weight)
                                                                                                                                     

                                                      F1: numbers of live
                                                      and dead fetuses, body
                                                      weights, gross
                                                      examination for
                                                      external
                                                      malformations,
                                                      microscopic visceral
                                                      and skeletal
                                                      examination

    hamster;           0, 3, 14, 65,     gd 6-10      F0: numbers of corpora  F0 and F1: no adverse      300           US FDA 
    golden;            or 300 mg/kg                   lutea, implantation     effects compared with                    (1972b)
    22 f               body weight                    and resorption sites,   controls were reported
                       via gavage                     examination of the
                                                      urogenital tract

                                                      F1: numbers of live
                                                      and dead fetuses,
                                                      body weights, gross
                                                      examination for
                                                      external
                                                      malformations,
                                                      microscopic visceral
                                                      and skeletal
                                                      examination

    Table 6 (cont'd)
                                                                                                                                     

    Species; strain;   Application       Durationb    Parameters              Results                    NO(A)EL       Reference
    number of animals                                 investigated                                       (mg/kg
    per dosea                                                                                            body 
                                                                                                         weight)
                                                                                                                                     

    rat;               0, 100, 315,      a) gd 9-11   F0: not specified       a) F0: no data given       315           Minor & Becker (1971)
    Sprague-Dawley     or 1000 mg/kg     b) gd 12-14  F1: body weights, in    F1: 1000 mg/kg body
    (no further data)  body weight                    utero deaths,           weight: body weights **;
                       intraperitoneally              gross anomalies         in utero deaths * (16%); 
                                                                              gross anomalies * (not
                                                                              further specified)
                                                                              b) F0: no data given
                                                                              F1: 1000 mg/kg body
                                                                              weight: body weights **;
                                                                              in utero deaths * (12%);
                                                                              gross anomalies <--> (not
                                                                              further specified)
                                                                              no further information
                                                                              available


    rat; Wistar;       0, 1, 2, 4,       gd 1-20      a) all but five         a) >4% (1875 or 965 mg/kg  1310          Onodera et al. (1978)
    27-30 f            or 8% via diet                 animals in each group   body weight):
                       (approx. 0, 700,               were sacrificed on      F0: weight gain <-->
                       1310, 1875, or                 gd 20 (numbers of       feed intake **; 
                       965 mg/kg body                 viable/dead fetuses,    mortality * (convulsions,
                       weight)                        early/late              depressed motor activity)
                                                      resorptions, fetal,     F1: number of
                                                      placental, and ovarian  dead/resorbed fetuses *;
                                                      weights, and            body weight of viable
                                                      abnormalities of        fetuses **; mild
                                                      maternal organs and     systemic oedema,
                                                      fetal appearance were   anophthalmia,
                                                      recorded)               microphthalmia,

    Table 6 (cont'd)
                                                                                                                                     

    Species; strain;   Application       Durationb    Parameters              Results                    NO(A)EL       Reference
    number of animals                                 investigated                                       (mg/kg
    per dosea                                                                                            body 
                                                                                                         weight)
                                                                                                                                     
                                                      b) the remaining five   hydrocephalus,
                                                      dams delivered          pyelectasis, hydroplasia,
                                                      naturally (number of    cerebral hypoplasia;
                                                      offspring, survival,    delayed ossification,
                                                      body weight, and        lumbar or cervical ribs,
                                                      abnormalities were      and varied sternebrae
                                                      recorded); 3 weeks      8%: F0: body weight **
                                                      after birth, all        b) F1:
                                                      surviving pups were     <2% (1310 mg/kg body
                                                      weaned and examined     weight): no adverse
                                                      for gross               effects compared with
                                                      abnormalities           controls
                                                      (one-half of the pups   >4% (1875 or 965 mg/kg
                                                      and all dams were       body weight): delivery
                                                      necropsied); the        rates ** (50 and 8.2%,
                                                      remaining pups were     respectively); complete
                                                      necropsied at 8 weeks   loss of litters after
                                                      of age (body weight     parturition
                                                      and food intake were
                                                      measured weekly until
                                                      necropsy)
                                                                                                                                     

    a m = male; f = female.
    b gd = gestation day.
    
    


    9.  EFFECTS ON HUMANS

         Cases of urticaria, asthma, rhinitis, or anaphylactic shock have
    been reported following oral, dermal, or inhalation exposure to
    benzoic acid and sodium benzoate. The symptoms appear shortly after
    exposure and disappear within a few hours, even at low doses (Maibach
    & Johnson, 1975; Clemmensen & Hjorth, 1982; Larmi et al., 1988; Ring,
    1989; Gailhofer et al., 1990; Aberer et al., 1992; Lahti et al., 1995;
    Anderson, 1996; Bindslev-Jensen, 1998; Coverly et al., 1998).

         In the literature, several studies (e.g., oral provocation tests
    or patch tests) are available, which have been performed with small
    groups of patients suffering from urticaria, dermatitis, asthma, and
    Melkersson-Rosenthal syndrome (Juhlin et al., 1972; Freedman, 1977;
    Osterballe et al., 1979; Lahti & Hannuksela, 1981; Clemmensen &
    Hjorth, 1982; Ibero et al., 1982; Moneret-Vautrin et al., 1982; Veien
    et al., 1987; Aguirre et al., 1993; McKenna et al., 1994; BUA, 1995;
    Munoz et al., 1996; Petrus et al., 1996; Vogt et al., 1999). In most
    of these studies, atopic individuals have demonstrated reactions to
    oral and dermal challenge with benzoic acid or sodium benzoate.

         The information concerning skin reactions caused by benzoic acid
    or sodium benzoate in the general population is limited. In a study
    with 2045 patients of dermatological clinics, only 5 persons
    (approximately 0.2%) showed a positive reaction in patch tests
    (Brasch et al., 1993), while 34 of 5202 patients (approximately 0.7%)
    with contact urticaria reacted positively (Broeckx et al., 1987). From
    these data, it can be concluded that skin reactions caused by benzoic
    acid or sodium benzoate in the healthy general population are rare.

         In US FDA (1972a) and WHO (1996), several older studies
    concerning oral exposure to benzoic acid or sodium benzoate are
    described. However, owing to the limited number of individuals (mostly
    single case studies), the validity of these studies is limited. No
    adverse effects were reported after a single oral dose of 10 000 mg
    benzoic acid or up to 1000 mg per day over a period of up to 92 days
    (Gerlach, 1909). In another study with volunteers given 1000, 1500,
    2000, or 2500 mg/day for 5 days each, marked symptoms, signs of
    discomfort, and malaise (nausea, headache, weakness, burning and
    irritation of oesophagus) were reported (Wiley & Bigelow, 1908).
    Chittenden et al. (1909) found no abnormalities in blood picture,
    urine composition, nitrogen balance, or well-being in six men given
    300-400 mg per day via diet for up to 62 days. In nine patients on
    penicillin treatment given 12 000 mg benzoic acid divided into eight
    doses over 5 days in eight subjects and over 14 days in one subject,
    no adverse effects on blood urea nitrogen or creatinine clearance were
    reported (Waldo et al., 1949). A single dose of 2000-3000 mg sodium
    benzoate caused signs of intoxication similar to those described for
    benzoic acid by Wiley & Bigelow (1908).

         Sodium benzoate is used in the treatment of patients with urea
    cycle enzymopathies (i.e., hyperammonaemia due to inborn errors of
    urea synthesis) in order to facilitate an alternative pathway of
    nitrogen excretion. The therapeutic dose given over several years is
    in the range of 250-500 mg/kg body weight per day (Batshaw & Brusilow,
    1981; Green et al., 1983; Batshaw & Monahan, 1987; O'Connor et al.,
    1987; Kubota & Ishizaki, 1991; Tremblay & Qureshi, 1993; Feillet &
    Leonard, 1998). At this dose level, clinical signs of toxicity are
    rare and in most cases limited to anorexia and vomiting, especially
    after intravenous bolus infusions.
    

    10. EFFECTS ON OTHER ORGANISMS IN THE LABORATORY
        AND FIELD

    10.1 Aquatic environment

         For the toxicity data mentioned in this section, it is not always
    stated whether the cited effect values are based on nominal or
    measured concentrations of benzoic acid or sodium benzoate. However,
    because of their water solubility, their insignificant volatility, and
    their low adsorption potential (see sections 2 and 5), all nominal
    concentrations of the test substances are expected to correspond to
    effective concentrations, even in tests with open systems and longer
    exposure durations.

         In Table 7, several valid toxicity test results for the most
    sensitive aquatic species of various taxonomic groups -- bacteria,
    cyanobacteria, green algae, protozoa, invertebrates, and vertebrates
    -- with benzoic acid have been compiled. From the aquatic organisms
    tested so far, cyanobacteria  (Anabaena inaequalis) proved to be most
    sensitive, showing a 14-day EC50 of 9 mg/litre in the cell
    multiplication inhibition test (Stratton & Corke, 1982). EC50/LC50
    values (24-96 h) for most of the other aquatic species tested
    (protozoa, molluscs, crustaceans, fish, amphibians) were in the range
    of 100-1291 mg/litre. As seen with daphnids, the pH value of the test
    medium influences the toxicity of benzoic acid, which proved to be
    more toxic at lower pH levels (Bringmann & Kuehn, 1980). Developmental
    toxicity effects seen in frog  (Xenopus) embryos were craniofacial
    defects, especially microcephaly, and abnormal gut coiling 
    (Dawson et al., 1996). A recently developed cytotoxicity assay with 
    cultured fathead minnow  (Pimephales promelas) cells resulted in a 
    PI50 (the concentration required to induce a 50% reduction in total 
    protein content) of 1450 mg/litre (Dierickx, 1998).

         Ninety-six-hour LC50 values of >100 mg sodium benzoate/litre
    have been found for  Daphnia magna (first and second larval instar)
    and  Gammarus fasciatus (juvenile: 7 mg in size) under static test
    conditions (multispecies test; pH 6.5-8; 20°C) (Ewell et al., 1986).
    The same was true for juveniles of other invertebrates tested
    simultaneously:  Asellus intermedius (Arthropoda; 12 mg body weight),
     Dugesia tigrina (Platyhelminthes; 6 mg body weight),  Helisoma
    trivolvis (Mollusca; 180 mg body weight), and  Lumbriculus variegatus
    (Annelida; 6 mg body weight) (Ewell et al., 1986).

         Two different tests with the freshwater fathead minnow
     (P. promelas; juvenile stages) resulted in 96-h LC50 values of 484
    mg sodium benzoate/litre (measured concentration; flow-through system;
    pH 7.4; 24°C) (Geiger et al., 1985) and >100 mg/litre (nominal
    concentration; static system; pH 6.5-8.5; 20°C) (Ewell et al., 1986).

        Table 7: Aquatic toxicity of benzoic acid.
                                                                                     

    Most sensitive species     Special      Effective                 Reference
    (test method/end-point)    features     concentration
                                            (mg/litre)
                                                                                     
    Mixed microbial inoculum
                                                                                     

    Activated sludge           pH 7.5       3-h EC50         >1000    Klecka et al.
    (respiration inhibition                                           (1985)
    test; OECD Guideline
    209)

                                                                                     
    Bacteria
                                                                                     

    Pseudomonas putida         pH neutral   16-h MICa        480      Bringmann & 
    (cell multiplication                                              Kuehn (1977)
    inhibition test)
    (static)

    Photobacterium             -            30-min EC50      16.85    Kaiser et al.
    phosphoreum                                                       (1987)
    (Microtox test:
    bioluminescence
    reduction)

                                                                                     
    Cyanobacteria
                                                                                     

    Anabaena inaequalis                                               Stratton &
    (cell multiplication       -            14-day EC50      9        Corke (1982)
    inhibition test)
    (static)
    (photosynthesis            -            3-h EC50         5
    reduction)

                                                                                     
    Algae
                                                                                     

    Scenedesmus quadricauda
    (cell multiplication       pH neutral   8-day MIC        1630     Bringmann &
    inhibition test)                                                  Kuehn (1977)
    (static)
    (photosynthesis
    reduction)                 -            3-h EC50         75       Stratton &
                                                                      Corke (1982)

    Table 7 (cont'd)
                                                                                     

    Most sensitive species     Special      Effective                 Reference
    (test method/end-point)    features     concentration
                                            (mg/litre)
                                                                                     

    Chlorella pyrenoides
    (photosynthesis
    reduction)                 -            3-h EC50         60       Stratton &
                                                                      Corke (1982)

                                                                                     
    Protozoa
                                                                                     

    Uronema parduczi
    (cell multiplication       pH 6.9       20-h MIC         31       Bringmann &
    inhibition test)                                                  Kuehn (1980)

    Tetrahymena pyriformis
    (cell multiplication       -            2-day EC50       252      Schultz et al.
    inhibition test)                                                  (1996)

                                                                                     
    Invertebrata: Mollusca
                                                                                     

    Teredo digensis            larvae       72-h LC50        100      Vind & 
    (marine) (static)                                                 Hochman 
                                                                      (1960)

                                                                                     
    Invertebrata: Crustacea
                                                                                     
    Daphnia magna              pH neutral   24-h EC50        500      Bringmann & 
    (immobilization)                                                  Kuehn (1982)
                               pH acid      24-h EC50        102

                                                                                     
    Vertebrata: Fish
                                                                                     

    Leuciscus idus 
    (lethality, DEV L15)       pH 7-8       48-h LC50        460      Juhnke & 
                                                                      Luedemann 
                                                                      (1978)

    Table 7 (cont'd)
                                                                                     

    Most sensitive species     Special      Effective                 Reference
    (test method/end-point)    features     concentration
                                            (mg/litre)

                                                                                     
    Vertebrata: Amphibia
                                                                                     

    Xenopus laevis
    (lethality)                embryos                                Dawson et al.
    (malformation)             pH 7.2-7.4   96-h LC50        1291     (1996)
                                            96-h EC50        433
                                                                                     

    a MIC = minimum inhibitory concentration.
    
    10.2 Terrestrial environment

         It is undissociated benzoic acid that is responsible for its
    antimicrobial activity. As benzoic acid itself is only slightly
    soluble in water, sodium benzoate -- which, under acidic conditions,
    converts to undissociated benzoic acid -- is often used instead. Their
    antimicrobial properties are used for different applications, such as
    food preservation (Chipley, 1983; see section 4), optimally under
    acidic conditions.

         Minimum microbiocidal concentrations ranged from 20 to 1200 mg
    benzoic acid/litre in suspension tests (pH 6) with different bacterial
    or fungal species (Wallhäusser, 1984; Russell & Furr, 1996). Minimum
    inhibitory concentrations (serial dilution technique) were in the
    range of 50-1000 mg/litre (Wallhäusser, 1984; Russell & Furr, 1996).

         The pH dependence of benzoic acid's antimicrobial activity is
    shown in several studies. Growth inhibition of the fungus  Fusarium
     oxysporum (related to dry weight) measured 5 days after incubation
    with 610 mg benzoic acid/litre was 23.7% at pH 7.2 and 83.5% at pH 4
    (Soni & Bhatia, 1980). There was no visible growth of yeast
     (Saccharomyces cerevisiae, Willia anomala) or mould  (Penicillium
     glaucum) fungi at sodium benzoate concentrations of 120-600 mg/litre
    at pH 2.6, 1000-4000 mg/litre at pH 5, or 20 000-60 000 mg/litre at pH
    7 (Schelhorn, 1951). Minimum inhibitory concentrations preventing
    growth of  Talaromyces flavus on agar plates after 35 days of
    incubation were 100 mg/litre at pH 3.5 and >600 mg/litre at pH 5.4
    (King & Halbrook, 1987).

         The minimum inhibitory concentrations of benzoic acid on the
    growth of several species of yeasts ranged from 170 to 1250 mg/litre
    in cultures preadapted to benzoic acid and from 100 to 600 mg/litre in
    unadapted cultures (pH 3.5; 25°C; 6 weeks of incubation) (Warth,
    1988).

         No information on the toxic effects of benzoic acid or sodium
    benzoate on plants, earthworms, or other terrestrial organisms or on
    ecosystems was identified.
    

    11. EFFECTS EVALUATION

    11.1 Evaluation of health effects

    11.1.1 Hazard identification and dose-response assessment

         After oral ingestion of benzoic acid and sodium benzoate in
    experimental animals or humans, there is rapid absorption of the
    undissociated benzoic acid from the gastrointestinal tract. The
    substances are metabolized in the liver mainly by conjugation with
    glycine, resulting in the formation of hippuric acid, which is rapidly
    excreted via the urine. Benzoates applied dermally can penetrate
    through the skin. Owing to their rapid metabolism and excretion, an
    accumulation of the benzoates or their metabolites is not to be
    expected.

         With oral LD50 values of >1940 mg/kg body weight, the acute
    toxicity of benzoic acid and sodium benzoate in rodents is low.

         Benzoic acid is slightly irritating to the skin and irritating to
    the eye, whereas sodium benzoate is not irritating to the skin and is
    only a slight eye irritant. Benzoic acid was not skin sensitizing in
    several animal models. For sodium benzoate, no data were identified
    covering this specific end-point.

         Studies concerning short-term, subchronic, or chronic oral
    exposure conducted according to current guidelines are not available
    for benzoic acid or sodium benzoate. Effects on the central nervous
    system, weight gain (in several cases without reduced food intake),
    and liver and kidney were recorded at high concentrations of both
    compounds. As expected, and as far as it is possible to conclude with
    the limited database, toxic effects and effect levels seem to be
    similar for both compounds. A preliminary NO(A)EL of about 500 mg/kg
    body weight per day (the highest dose tested) may be derived based on
    a limited four-generation study (Kieckebusch & Lang, 1960; see section
    8.4.2 and Table 4). This is supported by two short-term studies in
    which no adverse effects were observed at the highest tested dose
    levels of 647-825 mg/kg body weight per day (Kreis et al., 1967;
    Bio-Fax, 1973) and by the fact that no serious side-effects have been
    reported after therapeutic use of sodium benzoate at a dose level of
    250-500 mg/kg body weight per day in humans, although occasionally
    anorexia and vomiting were observed.

         In a short-term inhalation study with rats exposed to benzoic
    acid (0, 25, 250, or 1200 mg dust aerosol/m3; 6 h per day, 5 days
    per week, over 4 weeks), indications of fibrosis in the lung were seen
    even at the lowest concentration. The number of these microscopic
    lesions was higher in treated animals than in controls, but there was
    no clear dose dependency for this effect. Therefore, a
    no-observed-(adverse-)effect concentration (NO(A)EC) value cannot be
    derived. Long-term inhalation studies with benzoic acid or sodium
    benzoate were not identified.

         Two long-term studies with rats (application of up to 1400 mg/kg
    body weight per day via diet over 18-24 months; quality of the study
    questionable) or mice (lifelong application of up to 6200 mg/kg body
    weight per day via drinking-water) gave no indication of a
    carcinogenic effect in either species. Studies on the precursors of
    benzoic acid -- benzyl acetate, benzyl alcohol, and benzaldehyde --
    support the notion that it is unlikely that benzoic acid is
    carcinogenic.

         In several  in vitro tests on genotoxicity, benzoic acid and
    sodium benzoate tested negative. For sodium benzoate, in contrast to
    benzoic acid, consistently positive results were obtained in tests on
    sister chromatid exchange and chromosome aberrations without metabolic
    activation.  In vivo studies for benzoic acid were not identified.
    For sodium benzoate, negative results were obtained  in vivo in a
    cytogenetic assay with rats and a host-mediated assay with single or
    multiple oral application. However, a dominant lethal assay with rats
    gave a positive result. Therefore, a possible genotoxic activity of
    sodium benzoate cannot be ruled out entirely at present.

         For benzoic acid, two limited studies gave no indication of
    adverse reproductive or developmental effects. With sodium benzoate,
    several studies on different species have been performed. Embryotoxic
    and fetotoxic effects as well as malformations were seen only at doses
    that induced severe maternal toxicity. In a dietary study in rats, a
    NO(A)EL of about 1310 mg/kg body weight per day was established.
    Studies on the precursors of benzoic acid support the notion that
    benzoic acid is unlikely to have adverse reproductive effects at dose
    levels not toxic to the mother.

         The acute toxicity of benzoic acid and sodium benzoate in humans
    is low. However, both substances are known to cause contact dermatitis
    (pseudoallergy). In patients with urticaria or asthma, an exacerbation
    of the symptoms was observed after testing (oral provocation test or
    patch tests), whereas this effect is unusual in healthy subjects.

    11.1.2 Criteria for setting tolerable intakes or guidance values for
           benzoic acid and sodium benzoate

         As given in section 11.1.1, the database is insufficient for
    deriving NO(A)EL values for oral uptake. If the provisional NO(A)EL of
    about 500 mg/kg body weight per day is applied, and by incorporating
    an uncertainty factor of 100 (10 for uncertainty of the database, 10
    for interspecies variation), a provisional tolerable intake would be
    5 mg/kg body weight per day.

         Applying this tolerable intake, one has to keep in mind that
    benzoates at lower doses can cause non-immunological contact reactions
    (pseudoallergy) in sensitive persons.

         There are also no studies available concerning longer-term
    exposure by inhalation, and the only short-term inhalation toxicity
    study is not adequate for confidently establishing a NO(A)EC.
    Therefore, a tolerable concentration for exposure by inhalation cannot
    be calculated.

    11.1.3 Sample risk characterization

         As given in section 6.2, workers may be exposed to benzoic acid
    or sodium benzoate via inhalation or skin contact during production
    and processing. However, owing to the lack of information on specific
    working operations and conditions (e.g., duration of exposure)
    involved, it is impossible to derive a realistic estimate of
    occupational exposure.

         For the general population, the main route of exposure to benzoic
    acid and sodium benzoate is likely via foodstuffs, which contain the
    substances naturally or added as antimicrobial agents. As given in
    section 6.2, the uptake depends on the individual's choice of food to
    be consumed and the limit values for benzoates in different countries.
    Therefore, considerable deviations may occur. Recent intake
    estimations from surveys from several countries gave mean values in
    the range of 0.18-2.3 mg/kg body weight. Only in high consumers was an
    intake of up to 14 mg/kg body weight calculated. Benzoates have not
    been detected in drinking-water. As given in section 6.1, the
    inhalative uptake via ambient or indoor air may contribute only
    marginally to exposure of the general population.

         For normal consumers, the uptake of benzoates is about 2-28 times
    lower than the provisional tolerable intake of 5 mg/kg body weight
    day, and only in high consumers would this value be exceeded 3 times.

         Additional information is required in order to evaluate whether
    sodium benzoate has a possible genotoxic activity.

    11.2 Evaluation of environmental effects

         Significant releases of benzoic acid and sodium benzoate into the
    environment are primarily into water and soil from their uses as
    preservatives in food, mouthwashes, dentifrices, and cosmetics.
    Benzoic acid occurs naturally in many plants.

         From their physical/chemical properties, benzoic acid and sodium
    benzoate are not expected to volatilize from water and soil to the
    atmosphere or to adsorb to sediment or soil particles. The main
    elimination pathway for both chemicals should be biotic
    mineralization. Because of their ready biodegradability and their low
    volatility, both substances are not considered to contribute directly
    to the depletion of the stratospheric ozone layer or to global
    warming. From experimental data on bioconcentration, a low to moderate
    potential for bioaccumulation is to be expected.

         Benzoic acid and sodium benzoate exhibited low to moderate
    toxicity to aquatic organisms. The lowest reported EC50 value of
    9 mg/litre was determined in a chronic study (14 days) for cell
    multiplication inhibition by benzoic acid in the cyanobacterium
     Anabaena inaequalis. EC50/LC50 values for the other aquatic
    species tested were in the range of 17-1291 mg/litre. Exposure levels
    of benzoic acid and benzoate in water have been determined only in
    rain and snow, groundwater, and leachate in the vicinity of point
    sources. Thus, a quantitative risk characterization with respect to
    aquatic organisms in surface waters could not be performed. Taking
    into account the rapid biodegradability, the low to moderate
    bioaccumulation potential, the low toxicity to most aquatic species,
    and the rapid metabolism of these substances, benzoic acid and sodium
    benzoate will -- with the exception of accidental spills -- pose only
    a minimal risk to aquatic organisms.

         The few available data from the antimicrobial action of benzoic
    acid and sodium benzoate indicate only a low toxicity potential of
    both substances in the terrestrial compartment. Due to the lack of
    measured exposure levels, a sample risk characterization with respect
    to terrestrial organisms could not be performed.
    

    12. PREVIOUS EVALUATIONS BY INTERNATIONAL BODIES

         JECFA (WHO, 1996) has allocated an acceptable daily intake (ADI)
    for benzoic acid and sodium benzoate of 0-5 mg/kg body weight.
    

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    APPENDIX 1 -- SOURCE DOCUMENTS

    US FDA (1972a)  GRAS (Generally Recognized As Safe) food ingredients:
     benzoic acid and sodium benzoate. Washington, DC, US Food and Drug
    Administration

         This report was prepared by Informatics Inc., Rockville, MD, for
    the US Food and Drug Administration.

    BUA (1995)  BUA-Stoffbericht Benzoesaeure, Natriumbenzoat.
    Beratergremium fuer Umweltrelevante Altstoffe. Stuttgart, S. Hirzel
    Verlag (Stoffbericht Nr. 145)

         For the BUA review process, the company that is in charge of
    writing the report (usually the largest producer in Germany) prepares
    a draft report using literature from an extensive literature search as
    well as internal company studies. This draft is subject to a peer
    review in several readings of a working group consisting of
    representatives from government agencies, the scientific community,
    and industry.

    WHO (1996)  Toxicological evaluation of certain food additives.
    Prepared by the 46th meeting of the Joint FAO/WHO Expert Committee on
    Food Additives (JECFA). Geneva, World Health Organization (WHO Food
    Additives Series 37)

         The first draft on benzyl acetate, benzyl alcohol, benzaldehyde,
    and benzoic acid and its salts was prepared by E. Vavasour, Chemical
    Health Hazard Assessment Division, Bureau of Chemical Safety, Food
    Directorate, Health Protection Branch, Health Canada, Ottawa, Ontario.
    The meeting of the Joint FAO/WHO Expert Committee on Food Additives
    was held from 6 to 15 February 1996 in Geneva.
    

    APPENDIX 2 -- CICAD PEER REVIEW

         The draft CICAD on benzoic acid and sodium benzoate was sent for
    review to institutions and organizations identified by IPCS after
    contact with IPCS National Contact Points and Participating
    Institutions, as well as to identified experts. Comments were received
    from:

         A. Aitio, International Programme on Chemical Safety, World
         Health Organization, Switzerland

         M. Baril, Institut de Recherche en Santé et en Sécurité du
         Travail du Québec (IRSST), Canada

         R. Benson, Drinking Water Program, US Environmental Protection
         Agency, USA

         W.F. ten Berge, WXS, Netherlands

         R. Cary, Health and Safety Executive, United Kingdom

         R.S. Chhabra, National Institute for Environmental and Health
         Sciences/National Institutes of Health (NIEHS/NIH), USA

         S. Dobson, Institute of Terrestrial Ecology, United Kingdom

         P. Edwards, Department of Health, United Kingdom

         R. Hertel, Federal Institute for Health Protection of Consumers
         and Veterinary Medicine (BgVV), Germany

         C. Hiremath, US Environmental Protection Agency, USA

         P. Schulte, National Institute for Occupational Safety and
         Health, USA

         D. Willcocks, National Industrial Chemicals Notification and
         Assessment Scheme (NICNAS), Australia

         P. Yao, Chinese Academy of Preventive Medicine, People's Republic
         of China

         K. Ziegler-Skylakakis, Beratergremium für Umweltrelevante
         Altstoffe (BUA), Germany
    

    APPENDIX 3 -- CICAD FINAL REVIEW BOARD

    Sydney, Australia, 21-24 November 1999

    Members

    Dr R. Benson, Drinking Water Program, US Environmental Protection
    Agency, Region VIII, Denver, CO, USA

    Dr T. Berzins, National Chemicals Inspectorate (KEMI), Solna, Sweden

    Dr R.M. Bruce, National Center for Environmental Assessment, 
    US Environmental Protection Agency, Cincinnati, OH, USA

    Mr R. Cary, Health and Safety Executive, Merseyside, United Kingdom

    Dr R.S. Chhabra, National Institute of Environmental Health Sciences,
    National Institutes of Health, Research Triangle Park, NC, USA

    Dr S. Chou, Agency for Toxic Substances and Disease Registry, 
    Atlanta, GA, USA

    Dr S. Dobson, Institute of Terrestrial Ecology, Monks Wood,
    Cambridgeshire, United Kingdom

    Dr H. Gibb, National Center for Environmental Assessment, 
    US Environmental Protection Agency, Washington, DC, USA

    Dr R.F. Hertel, Federal Institute for Health Protection of Consumers
    and Veterinary Medicine, Berlin, Germany

    Dr J. Kielhorn, Fraunhofer Institute for Toxicology and Aerosol
    Research, Hanover, Germany

    Dr S. Kristensen, National Occupational Health and Safety Commission
    (Worksafe), Sydney, NSW, Australia

    Mr C. Lee-Steere, Environment Australia, Canberra, ACT, Australia

    Ms M. Meek, Environmental Health Directorate, Health Canada, Ottawa,
    Ontario, Canada

    Ms F. Rice, National Institute for Occupational Safety and Health,
    Cincinnati, OH, USA

    Dr J. Sekizawa, National Institute of Health Sciences, Tokyo, Japan

    Dr D. Willcocks, National Industrial Chemicals Notification and
    Assessment Scheme (NICNAS), Sydney, NSW, Australia  (Chairperson)

    Professor P. Yao, Institute of Occupational Medicine, Chinese Academy
    of Preventive Medicine, Beijing, People's Republic of China

    Observers

    Mr P. Howe, Institute of Terrestrial Ecology, Huntingdon,
    Cambridgeshire, United Kingdom

    Dr K. Ziegler-Skylakakis, GSF-Forschungszentrum für Umwelt und
    Gesundheit, GmbH, Oberschleissheim, Germany


    Secretariat

    Dr A. Aitio, International Programme on Chemical Safety, World Health
    Organization, Geneva, Switzerland

    Ms M. Godden, Health and Safety Executive, Bootle, Merseyside, United
    Kingdom

    Dr M. Younes, International Programme on Chemical Safety, World Health
    Organization, Geneva, Switzerland
    

        APPENDIX 4 -- INTERNATIONAL CHEMICAL SAFETY CARD

                                                                                                                

    BENZOIC ACID                                                                      ICSC: 0103

                                                                                    October 1999

                                                                                                                
    CAS#             65-85-0                 Benzenecarboxylic acid
    RTECS#           DG0875000               Phenyl carboxylic acid
                                              C7H6O2/C6H5COOH

                                              Molecular mass: 122.1

                                                                                                                
    TYPES OF HAZARD        ACUTE HAZARDS/             PREVENTION               FIRST AID / FIRE
    / EXPOSURE             SYMPTOMS                                            FIGHTING
                                                                                                                
    FIRE                   Combustible.               NO open flames.          Powder, water spray,
                                                                               foam, carbon dioxide.
                                                                                                                
    EXPLOSION                                                                  In case of fire: keep drums, 
                                                                               etc., cool by spraying with
                                                                               water.
                                                                                                                
    EXPOSURE
                                                                                                                
    Inhalation             Cough. Sore throat.        Local exhaust            Fresh air, rest.
                                                      or breathing
                                                      protection.
                                                                                                                
    Skin                   Redness. Burning           Protective gloves.       Remove contaminated clothes.
                           sensation. Itching.                                 Rinse and then wash skin with
                                                                               water and soap.

                                                                                                                
    Eyes                   Redness. Pain.             Safety goggles.          First rinse with plenty
                                                                               of water for several minutes
                                                                               (remove contact lenses if
                                                                               easily possible), then take
                                                                               to a doctor.
                                                                                                                
    Ingestion              Abdominal pain.            Do not eat, drink, or    Rinse mouth. Induce vomiting
                           Nausea. Vomiting           smoke during work.       (ONLY IN CONSCIOUS PERSONS!)
                                                      Wash hands before        Refer for medical
                                                      eating.                  attention.
                                                                                                                
    SPILLAGE DISPOSAL                                 PACKAGING & LABELLING
                                                                                                                

    Sweep spilled substance into plastic              EU Classification
    containers; if appropriate, moisten               UN Classification
    first to prevent dusting.
    Use face shield and (extra personal
    protection: protective clothing).
    Wash away remainder with plenty of water.

                                                                                                                

    EMERGENCY RESPONSE                                STORAGE
                                                                                                                
    NFPA Code: H 2; F 1; R -;










                                       IMPORTANT DATA
                                                                                                                

    PHYSICAL STATE; APPEARANCE:                       ROUTES OF EXPOSURE:
    WHITE CRYSTALS OR POWDER.                         The substance can be absorbed
                                                      into the body by inhalation and
                                                      by ingestion.

    PHYSICAL DANGERS:
    Dust explosion possible if in powder
    or granular form, mixed with air.                 INHALATION RISK:
                                                      No indication can be given about the
                                                      rate in which a harmful concentration
    CHEMICAL DANGERS:                                 in the air is reached on evaporation
    The solution in water is a weak acid.             of this substance at 20°C.
    Reacts with oxidants.

    OCCUPATIONAL EXPOSURE LIMITS:                     EFFECTS OF LONG-TERM OR REPEATED EXPOSURE:
    TLV not established.                              The substance irritates the eyes, the skin
                                                      and the respiratory tract. The substance
                                                      may cause a non-allergic rash on contact.

                                                                                                                

                                       PHYSICAL PROPERTIES
                                                                                                                
    Boiling Point:         249°C                      Flash point:                121°C c.c
    Melting Point:         122°C (see Notes)          Auto-ignition temperature:  570°C
    Density:               1.3 g/cm3                  Octanol/water partition
                                                      coefficient as log Pow:     1.87
    Solubility in water, g/100 ml at 20°C: 0.29
    Vapour pressure, Pa at 25°C: 0.1
    Relative vapour density (air = 1):  4.2
    Relative density of the vapour/air-mixture at 20°C (air = 1): 1

                                                                                                                
                                     ENVIRONMENTAL DATA
                                                                                                                


                                                                                                                
                                     NOTES
                                                                                                                
    The substance begins to sublime at 100°C.
                                                                                                                
                            ADDITIONAL INFORMATION
                                                                                                                















                                                                                                                
    LEGAL NOTICE        Neither the CEC nor the IPCS nor any person acting on
                        behalf of the CEC or the IPCS is responsible for the use
                        which might be made of this information.
        

    RÉSUMÉ D'ORIENTATION

         Ce CICAD consacré à l'acide benzoïque et au benzoate de sodium
    a été préparé par l'Institut Fraunhofer de Toxicologie et d'étude
    des Aérosols de Hanovre (Allemagne). Ces deux composés sont
    examinés ensemble car c'est l'acide benzoïque non dissocié qui est
    responsable de l'activité anti-infectieuse de ces produits. Comme
    l'acide benzoïque lui-même n'est que peu soluble dans l'eau, c'est
    le benzoate de sodium - qui en milieu acide redonne l'acide non
    dissocié - que l'on utilise à sa place.

         Ce CICAD est basé sur des études bibliographiques effectuées
    par le Comité consultatif allemand sur les produits chimiques qui
    posent des problèmes écologiques (BUA, 1995), la Food and Drug
    Administration des États-Unis (US FDA, 1972a) et le Comité mixte
    FAO/OMS d'experts des Additifs alimentaires (JECFA) (WHO/OMS, 1996)
    dans le but d'évaluer les effets possibles de l'acide benzoïque et
    du benzoate de sodium sur l'environnement et sur l'organisme
    humain. Une étude bibliographique exhaustive sur les bases de
    données appropriées a été effectuée en septembre 1999 afin de
    rechercher toute référence intéressante qui aurait été publiée
    postérieurement à celles qui figurent dans ces différents rapports.
    On trouvera à l'appendice 1 des indications sur la préparation de
    l'examen par des pairs et sur les sources documentaires utilisées
    pour cet examen. Les renseignements concernant l'examen du présent
    CICAD font l'objet de l'appendice 2. Ce CICAD a été approuvé en
    tant qu'évaluation internationale lors de la réunion du Comité
    d'évaluation finale qui s'est tenue à Sydney (Australie) du 21 au
    24 novembre 1999. La liste des participants à cette réunion figure
    à l'appendice 3. La fiche d'information internationale sur la
    sécurité chimique (ICSC 0103) relative à l'acide benzoïque, établie
    par le Programme international sur la sécurité chimique (IPCS,
    1993) est également reproduite dans ce document (appendice 4).

         Chez les animaux de laboratoire et chez l'Homme, l'acétate de
    benzyle, l'alcool benzylique, son produit d'hydrolyse, et le
    produit qui en résulte par oxydation, c'est-à-dire le benzaldéhyde,
    sont largement métabolisés en acide benzoïque. On a donc utilisé
    les données toxicologiques relatives à ces précurseurs dans
    l'évaluation des effets sanitaires potentiels de l'acide benzoïque.

         L'acide benzoïque (No CAS 65-85-0) se présente sous la forme
    d'un solide blanc légèrement soluble dans l'eau. La solubilité dans
    l'eau du benzoate de sodium (No CAS 532-32-1) est environ 200 fois
    plus élevée. On utilise l'acide benzoïque comme intermédiaire dans
    la synthèse de divers composés, principalement le phénol (plus de
    50 % de la production mondiale) et la caprolactame. Il sert
    également à la préparation de divers sels, dont le sel de sodium,
    du chlorure de benzoyle ainsi que de plastifiants comme les
    dibenzoates de diéthylène- et de dipropylène-glycol. Le benzoate de
    sodium est principalement utilisé comme conservateur et inhibiteur

    de corrosion (par ex. comme additif à l'antigel des moteurs à
    explosion). L'acide benzoïque et le benzoate de sodium sont
    employés comme conservateurs dans l'alimentation et ils conviennent
    particulièrement bien pour les produits comme les jus de fruits et
    les boissons non alcoolisées, qui ont un pH acide. Leur utilisation
    comme conservateurs dans les denrées alimentaires, les boissons,
    les pâtes dentifrices, les bains de bouche, les cosmétiques et les
    produits pharmaceutiques est réglementée. On estime que la capacité
    mondiale de production d'acide benzoïque est d'environ 600 000
    tonnes par an. On estime en outre qu'en 1997 la production mondiale
    de benzoate de sodium a été comprise entre 55 000 et 60 000 tonnes.
    L'acide benzoïque est naturellement présent dans beaucoup de
    végétaux et chez un grand nombre d'animaux. C'est donc un
    constituant normal de nombreux aliments, notamment du lait et des
    produits laitiers. Les rejets d'acide benzoïque et de benzoate de
    sodium dans l'environnement qui sont imputables aux activités
    humaines aboutissent essentiellement dans les eaux et dans le sol
    et proviennent de leur utilisation comme conservateurs. On constate
    que dans un certain nombre de denrées alimentaires, la
    concentration de l'acide benzoïque d'origine naturelle ne dépasse
    pas 40 mg/kg en moyenne. Les concentrations maximales d'acide
    benzoïque ou de benzoate de sodium relevées dans des produits
    alimentaires auxquels ils avaient été ajoutés comme conservateurs
    sont de l'ordre de 2000 mg/kg.

         Après ingestion, l'acide benzoïque et le benzoate de sodium
    sont rapidement résorbés dans les voies digestives et métabolisés
    dans le foie par conjugaison avec la glycine pour donner de l'acide
    hippurique, rapidement excrété dans les urines. Les benzoates
    appliqués sur la peau sont résorbés dans une moindre proportion par
    voie transcutanée. En raison de la rapidité du métabolisme et de
    l'excrétion, il n'y a vraisemblablement pas d'accumulation des
    benzoates ou de leurs métabolites.

         Chez les rongeurs, la toxicité aiguë par voie orale de l'acide
    benzoïque et du benzoate de sodium est faible (la DL50 par voie
    orale est supérieure à 1940 mg/kg de poids corporel). Chez le chat,
    qui semble plus sensible que les rongeurs, on a signalé des effets
    toxiques et une mortalité à des doses beaucoup plus faibles
    (environ 450 mg/kg p.c.).

         L'acide benzoïque est légèrement irritant pour la peau et
    irritant pour la muqueuse oculaire, tandis que le benzoate de
    sodium n'irrite pas la peau est n'est que légèrement irritant pour
    l'oeil. En ce qui concerne l'acide benzoïque, les données
    disponibles n'indiquent aucun effet sensibilisateur; dans le cas du
    benzoate de sodium, aucune donnée n'a été relevée dans la
    littérature à ce sujet.

         Les études à court terme effectuées sur des rats ont révélé la
    présence de troubles du système nerveux central (acide benzoïque /
    benzoate de sodium) ainsi que des anomalies histopathologiques dans
    l'encéphale (acide benzoïque) après administration de doses élevées
    dans l'alimentation (>1800 mg/kg p.c.) pendant 5 à 10 jours. Les
    autres effets constatés étaient les suivants : réduction du gain de
    poids, modification du poids des organes, modification des
    paramètres sériques ou encore anomalies histopathologiques au
    niveau du foie. On ne dispose que de données très limitées sur
    l'exposition de longue durée des animaux de laboratoire à l'acide
    benzoïque par voie orale et il n'existe pas d'étude qui soit
    spécialement consacrée à la recherche d'effets cancérogènes
    éventuels. Une étude limitée, portant sur quatre générations, n'a
    permis d'obtenir qu'une estimation préliminaire de la dose sans
    effet (nocif) observable (NO(A)EL), estimation qui est d'environ
    500 mg/kg p.c. par jour. En ce qui concerne le benzoate de sodium,
    les deux études à long terme effectuées sur des rats et des souris
    n'ont pas mis en évidence d'effet cancérogène. Il faut dire
    cependant que dans la plupart de ces études, les effets ne sont pas
    parfaitement attestés, d'où l'impossibilité d'en tirer des valeurs
    fiables pour la dose sans effet observable et la dose sans effet
    nocif observable. Les données concernant leurs divers précurseurs
    corroborent l'hypothèse selon laquelle l'acide benzoïque ne serait
    pas vraisemblablement pas cancérogène.

         L'acide benzoïque a donné des résultats négatifs dans un
    certain nombre de tests sur bactéries ou cellules mammaliennes,
    mais on n'a pas trouvé de comptes rendus de tests  in vivo. Le
    benzoate de sodium s'est également révélé inactif dans le test
    d'Ames mais il a donné des résultats systématiquement positifs sur
    cellules mammaliennes. Dans une étude  in vivo (test de létalité
    dominante chez le rat) on a également obtenu un résultat positif.
    Dans ces conditions, on ne peut pour l'instant exclure que le
    benzoate de sodium ait une activité génotoxique.

         Dans le cas de l'acide benzoïque, on dispose de deux études
    limitées qui n'indiquent aucun effet indésirable sur la
    reproduction ou le développement. En ce qui concerne le benzoate de
    sodium, plusieurs études ont été menées sur un certain nombre
    d'espèces et si des effets embryotoxiques et foetotoxiques ou même
    des malformations ont été observés, c'est uniquement à des doses
    déjà toxiques pour les mères. Une étude d'alimentation sur des rats
    a permis de fixer à environ 1310 mg/kg p.c. la dose sans effet
    (nocif) observable. Les données concernant ses divers précurseurs
    corroborent l'hypothèse selon laquelle l'acide benzoïque n'a
    vraisemblablement pas d'effets indésirables sur la reproduction aux
    doses qui ne sont pas toxiques pour la mère.

         Chez l'Homme, l'acide benzoïque et le benzoate de sodium sont
    peu toxiques. On sait cependant que ces deux composés peuvent
    produire des réactions de contact non immunologiques
    (pseudoallergie). Cet effet est rare chez les sujets en bonne

    santé. En revanche, chez les personnes qui souffrent fréquemment
    d'asthme ou d'urticaire, on a observé une exacerbation des
    symptômes. On peut établir une dose journalière tolérable
    provisoire par ingestion de 5 mg/kg de poids corporel, encore que
    les benzoates soient susceptibles de provoquer chez les sujets
    sensibles des pseudoallergies de contact à des doses plus faibles.
    Comme on ne dispose pas d'étude appropriée sur l'exposition par
    inhalation, on ne peut déterminer la concentration tolérable en cas
    d'exposition par cette voie.

         Compte tenu de leurs propriétés physiques et chimiques, il est
    exclu que l'acide benzoïque et le benzoate de sodium rejetés dans
    le sol ou dans l'eau soient à même de s'évaporer dans l'atmosphère
    ou de s'adsorber aux sédiments ou aux particules du sol. De
    nombreuses expériences on permis de constater que la principale
    voie d'élimination de ces deux composés était la minéralisation
    biologique. Des essais en laboratoire ont montré qu'en aérobiose,
    les deux composés sont facilement biodégradables. Un certain nombre
    de microorganismes isolés (bactéries, champignons) se sont révélés
    capable d'utiliser l'acide benzoïque en aérobiose comme en
    anaérobiose. Les données fournies par les expériences de
    bioconcentration montrent que ces produits ont un potentiel de
    bioaccumulation faible à modéré.

         Ú en juger d'après les tests effectués sur des organismes
    aquatiques dans de bonnes conditions de validité, l'acide benzoïque
    et le benzoate de sodium se révèlent peu à modérément toxiques dans
    ce milieu. La valeur la plus faible de la CE50 qui ait été
    mesurée, soit 9 mg/litre (critère : inhibition de la multiplication
    cellulaire), a été obtenue dans une étude de toxicité chronique sur
    une corynébactérie,  Anabaena inaequalis. Les valeurs de la CE50
    et de la CL50 obtenues sur d'autres espèces aquatiques, se
    situaient aux alentours de 60-1291 mg/litre. On a montré que
    l'immobilisation de la daphnie dépendait du pH, la CE50 à 24 h
    étant plus basse (102 mg/litre) pour les pH acides. Dans le cas de
    l'ide rouge  (Leuciscus idus), on a trouvé une CL50 à 48 h de
    460 mg/litre. Des effets ont été constatés sur le développement des
    embryons de grenouille  (Xenopus) à la concentration de 433
    mg/litre (CE50 à 96 h; critère : malformation). Dans le cas du
    benzoate de sodium, l'exposition des stades juvéniles d'organismes
    aquatiques appartenant à plusieurs espèces  (Daphnia magna,
     Gammarus fasciatus,  Asellus intermedius,  Dugesia tigrina,
     Helisoma trivolvis et  Lumbriculus variegatus) a permis de
    constater que la CL50  à 96 h était supérieure à 100 mg/litre.
    On a mesuré une CL50 à 96 h de 484 mg/litre pour le vairon à
    grosse tête  (Pimephales promelas). Compte tenu du caractère
    limité des données concernant le niveau d'exposition dans l'eau, il
    n'a pas été possible de quantifier le risque couru par les
    organismes qui peuplent les eaux de surface. En s'appuyant sur la
    biodégradation rapide des composés, la valeur faible à modérée de
    leur potentiel de bioaccumulation, la faible toxicité qu'ils
    présentent pour la plupart des espèces aquatiques et leur

    métabolisation rapide, il apparaît que l'acide benzoïque et le
    benzoate de sodium ne représentent qu'un risque minimum pour les
    organismes aquatiques, mis à part le cas de déversements
    accidentels.

         Les quelques données disponibles indiquent que l'acide
    benzoïque et le benzoate de sodium n'ont qu'un faible potentiel
    toxique dans l'environnement terrestre. Ú l'exception de l'action
    antimicrobienne de l'acide benzoïque, qui se caractérise par une
    concentration microbicide comprise entre 20 et 1200 mg/litre, on ne
    possède aucune donnée sur les effets toxiques de ce composé sur les
    organismes terrestres. Dans le cas du benzoate de sodium, il y a
    inhibition de la croissance bactérienne et fongique pour des
    concentrations comprises entre 100 et 60 000 mg/litre et cette
    inhibition dépend du pH. Faute de connaître la valeur des niveaux
    d'exposition, il n'a pas été possible de caractériser le risque
    pour les organismes terrestres.
    

    RESUMEN DE ORIENTACI²N

         El presente CICAD sobre el ácido benzoico y el benzoato de
    sodio se preparó en el Instituto Fraunhofer de Toxicología y de
    Investigación sobre los Aerosoles de Hannover, Alemania. Se
    examinan los dos compuestos juntos porque es el ácido benzoico no
    disociado el responsable de su actividad antimicrobiana. Debido a
    que el propio ácido benzoico es sólo ligeramente soluble en agua,
    con frecuencia se utiliza en su lugar el benzoato de sodio, que en
    condiciones ácidas se convierte en ácido benzoico no disociado.

         El presente CICAD se basa en exámenes compilados por el Comité
    Consultivo Alemán sobre las Sustancias Químicas Importantes para el
    Medio Ambiente (BUA, 1995), la Administración de Alimentos y
    Medicamentos de los Estados Unidos (US FDA, 1972a) y el Comité
    Mixto FAO/OMS de Expertos en Aditivos Alimentarios (JECFA)
    (WHO/OMS, 1996) para evaluar los efectos potenciales del ácido
    benzoico y el benzoato de sodio en el medio ambiente y en el ser
    humano. En septiembre de 1999 se realizó una búsqueda bibliográfica
    amplia de las bases de datos pertinentes para localizar cualquier
    referencia de interés publicada después de las incorporadas a estos
    informes. La información relativa a la preparación de los
    documentos originales y su examen colegiado figura en el apéndice
    1. La información sobre el examen colegiado de este CICAD aparece
    en el apéndice 2. Este CICAD se aprobó como evaluación
    internacional en una reunión de la Junta de Evaluación Final
    celebrada en Sidney, Australia, los días 21-24 de noviembre de
    1999. En el apéndice 3 figura la lista de los participantes en esta
    reunión. La Ficha internacional de seguridad química (ICSC 0103)
    para el ácido benzoico, preparada por el Programa Internacional de
    Seguridad de las Sustancias Químicas (IPCS, 1993), también se
    reproduce en el presente documento (apéndice 4).

         El acetato de bencilo, su producto de hidrólisis, el alcohol
    de bencilo, y el producto de la oxidación de este alcohol, el
    benzaldehído, se metabolizan ampliamente a ácido benzoico en
    animales experimentales y en el ser humano. Por consiguiente,
    también se utilizaron datos toxicológicos sobre estos precursores
    en la evaluación de los efectos potenciales del ácido benzoico para
    la salud.

         El ácido benzoico (CAS No 65-85-0) es una sustancia sólida
    blanca ligeramente soluble en agua. El benzoato de sodio
    (CAS No 532-32-1) es alrededor de 200 veces más soluble en
    agua. El ácido benzoico se utiliza como producto intermedio en la
    síntesis de distintos compuestos, fundamentalmente el fenol (>50
    por ciento de la cantidad producida en todo el mundo) y la
    caprolactama. Otros productos finales son el sodio y otros
    benzoatos, el cloruro de benzoílo y los agentes plastificantes de
    dibenzoato de dietilenglicol y dipropilenglicol. El benzoato de
    sodio se utiliza sobre todo como conservante e inhibidor de la
    corrosión (por ejemplo, en sistemas técnicos como aditivo de los
    refrigerantes anticongelantes de los motores de automóviles).

    El ácido benzoico y el benzoato de sodio se utilizan como
    conservantes de los alimentos y son los más idóneos para los
    productos alimenticios, los jugos de frutas y las bebidas no
    alcohólicas, que por su naturaleza tienen un pH ácido. Su
    utilización como conservantes en alimentos, bebidas, pastas de
    dientes, colutorios, dentífricos, cosméticos y productos
    farmacéuticos está reglamentada. La capacidad de producción mundial
    estimada de ácido benzoico es de alrededor de 600 000 toneladas al
    año. La producción mundial de benzoato de sodio en 1997 puede
    estimarse en unas 55 000-60 000 toneladas. El ácido benzoico está
    presente de manera natural en muchas plantas y en los animales. Por
    consiguiente, es un elemento constitutivo natural de numerosos
    alimentos, entre ellos los productos lácteos. Las liberaciones
    antropogénicas de ácido benzoico y benzoato de sodio en el medio
    ambiente son primordialmente emisiones al agua y al suelo a partir
    de su uso como conservantes. Las concentraciones del ácido benzoico
    presente de manera natural en varios productos alimenticios no
    superaron el valor medio de 40 mg/kg de alimentos. Las
    concentraciones máximas notificadas de ácido benzoico o benzoato de
    sodio añadido a los productos alimenticios con fines de
    conservación fueron del orden de 2000 mg/kg de alimentos.

         Tras la ingesta oral, el ácido benzoico y el benzoato de sodio
    se absorben con rapidez del tracto gastrointestinal y se
    metabolizan en el hígado por conjugación con la glicina, dando
    lugar a la formación de ácido hipúrico, que se excreta rápidamente
    a través de la orina. Los benzoatos aplicados por vía cutánea
    pueden penetrar en menor medida a través de la piel. Debido a la
    rapidez del metabolismo y de la excreción, no cabe prever una
    acumulación de benzoatos o sus metabolitos.

         En roedores, la toxicidad oral aguda del ácido benzoico y el
    benzoato de sodio es baja (valores de la DL50 por vía oral >1940
    mg/kg de peso corporal). En gatos, que parecen ser más sensibles
    que los roedores, se notificaron efectos tóxicos y mortalidad con
    dosis mucho menores (unos 450 mg/kg de peso corporal).

         El ácido benzoico es ligeramente irritante de la piel e
    irritante de los ojos, mientras que el benzoato de sodio no irrita
    la piel y es sólo ligeramente irritante de los ojos. En cuanto al
    ácido benzoico, en los estudios disponibles no apareció ningún
    indicio de efecto sensibilizante; para el benzoato de sodio no se
    encontraron datos en la bibliografía. 

         En estudios de corta duración con ratas, se observaron
    trastornos del sistema nervioso central (ácido benzoico/benzoato de
    sodio), así como cambios histopatológicos en el cerebro (ácido
    benzoico) después de administrar dosis elevadas (>1800 mg/kg de
    peso corporal) durante 5-10 días. Otros efectos fueron una
    reducción del aumento del peso corporal, cambios en el peso de los
    órganos, cambios en los parámetros del suero o cambios

    histopatológicos en el hígado. La información relativa a la
    exposición oral prolongada de animales experimentales al ácido
    benzoico es muy limitada y no hay ningún estudio disponible que
    trate expresamente de los posibles efectos carcinogénicos. De un
    estudio limitado de cuatro generaciones sólo puede derivarse una
    concentración sin efectos (adversos) observados (NO(A)EL) de
    carácter preliminar de alrededor de 500 mg/kg de peso corporal al
    día. Con el benzoato de sodio, en dos estudios de larga duración
    con ratas y ratones no se obtuvo ningún indicio de efecto
    carcinogénico. Sin embargo, la documentación de los efectos es
    insuficiente en la mayoría de estos estudios; por consiguiente, no
    pueden derivarse valores de la NO(A)EL fidedignos. Los datos sobre
    sus precursores respaldan la idea de que probablemente el ácido
    benzoico no es carcinogénico.

         El ácido benzoico dio resultados negativos en varias
    valoraciones bacterianas y en pruebas con células de mamífero, pero
    no se localizaron estudios  in vivo. El benzoato de sodio también
    fue inactivo en pruebas Ames, mientras que las pruebas con células
    de mamífero dieron sistemáticamente resultados positivos. En un
    estudio  in vivo (valoración letal dominante con ratas) se obtuvo
    un resultado positivo. En la actualidad no se puede excluir
    totalmente la actividad genotóxica del benzoato de sodio.

         En cuanto al ácido benzoico, en dos estudios limitados no se
    obtuvieron indicios de efectos adversos reproductivos o en el
    desarrollo. Con el benzoato de sodio se han realizado varios
    estudios en distintas especies y solamente se observaron efectos
    embriotóxicos y fetotóxicos, así como malformaciones, con dosis que
    inducían una toxicidad materna grave. En un estudio de alimentación
    en ratas se estableció una NO(A)EL de alrededor de 1310 mg/kg de
    peso corporal. Los datos sobre sus precursores respaldan la idea de
    que no es probable que el ácido benzoico tenga efectos
    reproductivos adversos con los niveles de dosis que no son tóxicos
    para la madre.

         En el ser humano, la toxicidad aguda del ácido benzoico y el
    benzoato de sodio es baja. Sin embargo, se sabe que ambas
    sustancias provocan reacciones de contacto no inmunológicas
    (pseudoalergia). Este efecto no es frecuente en personas sanas; en
    pacientes con ataques frecuentes de urticaria o asma se observaron
    síntomas o su exacerbación. Puede derivarse una ingesta tolerable
    provisional de 5 mg/kg de peso corporal al día, aunque dosis
    menores de benzoatos pueden producir reacciones de contacto no
    inmunológicas (pseudoalergia) en personas sensibles. Debido a que
    no hay estudios adecuados disponibles sobre la exposición por
    inhalación, no se puede calcular una concentración tolerable para
    este tipo de exposición.

         Dadas sus propiedades físicas/químicas, no cabe prever que el
    ácido benzoico y el benzoato de sodio que pasan al agua y al suelo
    se volatilicen a la atmósfera o se adsorban sobre los sedimentos o
    las partículas del suelo. Según los resultados de numerosos
    experimentos de eliminación, la principal vía que siguen ambos
    productos químicos debe ser la mineralización biótica. Los datos
    obtenidos en pruebas de laboratorio pusieron de manifiesto una
    biodegradabilidad rápida de ambas sustancias en condiciones
    aerobias. Se ha comprobado que varios microorganismos aislados
    (bacterias, hongos) utilizaron el ácido benzoico en condiciones
    aerobias o anaerobias. De acuerdo con los datos experimentales
    sobre la bioconcentración, cabe prever un potencial de bajo a
    moderado para la bioacumulación.

         Según los resultados de las pruebas válidas disponibles sobre
    la toxicidad del ácido benzoico y el benzoato de sodio para
    diversos organismos acuáticos, estos compuestos parecen mostrar una
    toxicidad de baja a moderada en el compartimento acuático. El valor
    más bajo de la CE50, de 9 mg/litro (inhibición de la
    multiplicación celular), notificado en un estudio crónico se
    observó en la cianobacteria  Anabaena inaequalis. Los valores de
    la CE50/CL50 para otras especies acuáticas estudiadas fueron
    del orden de 60-1291 mg/litro. Se ha demostrado que la
    inmovilización de  Daphnia magna es dependiente del pH, con una
    CE50 más baja en 24 horas (102 mg/litro) cuando el pH es ácido.
    Para un pez de agua dulce, el cacho  (Leuciscus idus), se ha
    determinado una CL50 en 48 horas de 460 mg/litro. Se han
    encontrado efectos en el desarrollo en embriones de rana  (Xenopus)
    con una concentración de 433 mg/litro (CE50 en 96 horas para la
    malformación). Para el benzoato de sodio, en una exposición de
    estadios juveniles de organismos acuáticos en una prueba
    multiespecífica (con inclusión de  Daphnia magna,  Gammarus
     fasciatus,  Asellus intermedius,  Dugesia tigrina,  Helisoma
     trivolvis, y  Lumbriculus variegatus) se obtuvieron valores de la
    CL50 en 96 horas superiores a 100 mg/litro. En el pez de agua
    dulce  Pimephales promelas se ha determinado una CL50 en 96
    horas de 484 mg/litro. Debido a los limitados datos disponibles
    sobre los niveles de exposición en agua, no se pudo realizar una
    caracterización cuantitativa del riesgo con respecto a los
    organismos acuáticos de aguas superficiales. Teniendo en cuenta la
    rápida biodegradabilidad, el potencial de bioacumulación entre
    moderado y bajo, la escasa toxicidad para la mayoría de las
    especies acuáticas y el rápido metabolismo de estas sustancias, el
    ácido benzoico y el benzoato de sodio - con la excepción de
    vertidos accidentales - representan un riesgo sólo mínimo para los
    organismos acuáticos.

         Los escasos datos disponibles indican que el ácido benzoico y
    el benzoato de sodio tienen solamente un potencial de toxicidad
    bajo en el medio terrestre. Salvo la acción antimicrobiana del
    ácido benzoico, que se caracteriza por concentraciones microbicidas
    mínimas que oscilan entre 20 y 1200 mg/litro, no se encontraron

    datos sobre los efectos tóxicos del ácido benzoico en los
    organismos terrestres. En cuanto al benzoato de sodio, inhibió el
    crecimiento bacteriano y fúngico de manera dependiente del pH en
    concentraciones que oscilaban entre 100 y 60 000 mg/litro. Debido a
    la falta de mediciones de los niveles de exposición, no se pudo
    realizar un muestreo de la caracterización del riesgo con respecto
    a los organismos terrestres.
    


    See Also:
       Toxicological Abbreviations