Health and Safety Guide No. 47






    Published by the World Health Organization for the International
    Programme on Chemical Safety (a collaborative programme of the United
    Nations Environment Programme, the International Labour Organisation,
    and the World Health Organization)

    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 Organisation, or the World Health Organization

    WHO Library Cataloguing in Publication Data

    Health and safety guide for Atrazine

    (Health and safety guide ; no. 47)

    1.Atrazine - standards  I.Series

    ISBN 92 4 151047 1          (NLM Classification: WA 240)
    ISSN 0259-7268

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         1.1. Identity
         1.2. Physical and chemical properties
         1.3. Analytical methods
         1.4. Production and uses

         2.1. Human exposure to atrazine
         2.2. Uptake, metabolism, and excretion
         2.3. Effects on animals
         2.4. Effects on human beings
         2.5. Effects on the environment


         4.1. Main human health hazards, prevention and protection,
               first aid
               4.1.1. Prevention and protection
               4.1.2. First aid
         4.2. Advice to physicians
         4.3. Explosion and fire hazards
         4.4. Storage and transport
         4.5. Spillage and disposal


         6.1. Exposure limit values
         6.2. Specific restrictions
         6.3. Transport and labelling



    This Health and Safety Guide is not based on an existing Environmental
    Health Criteria document, but on critical national reviews. The hazard
    evaluation in the Health and Safety Guide was made on the basis of
    carefully selected studies, after scrutiny of the original

    In order to assist the peer-review process of the present Health and
    Safety Guide, a background companion document was prepared by the IPCS
    and can be obtained from the Manager on request; the IPCS does not
    intend that the background document should be published.

    The first three sections of this Health and Safety Guide present
    essential technical information and the hazard evaluation. Section 4
    includes advice on preventive and protective measures and emergency
    action; health workers should be thoroughly familiar with the medical
    information to ensure that they can act efficiently in an emergency.
    The section on regulatory information has been extracted from the
    legal file of the International Register of Potentially Toxic
    Chemicals (IRPTC) and from other United Nations sources.

    The target readership includes occupational health services, those in
    ministries, governmental agencies, industry, and trade unions who are
    involved in the safe use of chemicals and the avoidance of
    environmental health hazards, and those wanting more information on
    this topic. An attempt has been made to use only terms that will be
    familiar to the intended user. However, sections 1 and 2 inevitably
    contain some technical terms.

    Revision of the information in this Guide will take place in due
    course, and the eventual aim is to use standardized terminology.
    Comments on any difficulties encountered in using the Guide would be
    very helpful and should be addressed to:

    The Manager
    International Programme on Chemical Safety
    Division of Environmental Health
    World Health Organization
    1211 Geneva 27



    1.1  Identity

    Common name:             atrazine

    Chemical formula:        C8H14ClN5

    Chemical structure:      CHEMICAL STRUCTURE

    Relative molecular       215.7

    Common trade             A 361; Aatrex; Aatrex 4L; Aatrex 80W; Aatrex
    names (including         Nine-O; Aktikon; Aktikon PK; Aktinit A;
    formulations):           Aktinit PK Argezin; Atazinax; Atranex;
                             Atrasine; Atratol A; Atrazin; Atred; Atrex;
                             Candex; Cekuzina-T; Crisatrina; Crisazine;
                             Cyazin; Farmco Atrazine; Fenamin; Fenamine;
                             Fenatrol; G 30027; Geigy 30,027; Gesaprim;
                             Gesoprim; Griffex; Hungazin; Hungazin PK;
                             Inakor; Oleogesaprim; Primatol; Primatol A;
                             Primaze; Radazin; Radizine; Strazine;
                             Triazine A 1294; Vectal; Vectal SC; Weedex A;
                             Wonuk; Zeazin; Zeazine

    CAS chemical name:       2-chloro-4-ethylamine-6-isopropylamino- S-

    Synonyms:                 S-triazine, 2-chloro-4-ethylamino-
                             6-isopropylamino-; 1,3,5-triazine-2,4-
                             diamine, 6-chloro- N-ethyl- N'-
                             (1-methylethyl)-; 2-aethylamino-4-
                             isopropylamino-6-chlor- 1,3,5-triazin;
                             amine- S-triazine; 1-Chloro-3-ethylamino-5-

                             1-chloro-3-ethylamino-5-isopropyl-amino- S-
                             triazine; 2-chloro-4-ethylamino-6-isopropyl-
                             amino- 1,3,5-triazine;
                             amino- S-triazine 6-chloro-  N-ethyl-
                             2,4-diamine; 2-chloro-4-(2-propylamino)-
                             6-ethylamino- S-triazine

    CAS registry
    number:                  1912-24-9

    RTECS registry
    number:                  XY5600000

    According to FAO specifications, commercial atrazine should be at
    least 92% pure, and most products are about 95% pure. Common
    impurities are sodium chloride and other symmetric triazines, such as
    simazine and propazine. It is often formulated as wettable powders,
    granules, and as flowable suspensions.

    Wettable powder formulations contain 450-800 g atrazine/kg (less if
    mixed with other pesticides), and liquid formulations (including
    suspension concentrate), 40-650 g/litre.

    1.2  Physical and Chemical Properties

    Technical atrazine is a colourless crystalline powder with low vapour
    pressure (40 nPa at 20C). A melting point range of 175-177C has been
    reported for the technical product. It is readily soluble in dimethyl
    sulfoxide (183 g/litre), moderately soluble in methanol (18 g/litre),
    diethyl ether (12 g/litre), chloroform (52 g/litre), and ethyl acetate
    (28 g/litre), and very slightly soluble in water (30 mg/litre). It is
    stable in the dry state, but is hydrolysed to the herbicidally
    inactive 2-hydroxy analogue in acid or in alkaline solutions and more
    slowly in neutral aqueous solutions, even at elevated temperatures.

    1.3  Analytical Methods

    Gas chromatography with a nitrogen-phosphorus detector (NPD) is used
    for the determination of residues and the analysis of environmental
    samples. The minimum detection limit varies according to the

    1.4  Production and Uses

    Atrazine was introduced in 1958. In 1987, total worldwide production
    was estimated to be 70 000 tonnes.

    Atrazine is a selective pre- and post-emergence herbicide used for the
    control of weeds in crops, such as asparagus, corn, sorghum, sugar
    cane, and pineapple. It is also used in forestry and, at higher
    application rates, for non-selective weed control in non-crop areas.


    2.1  Human Exposure to Atrazine

    Highest human exposure to atrazine is associated with its production
    and its use in agriculture. Widespread, low-level exposure of the
    general population may occur through contaminated drinking-water.

    2.2  Uptake, Metabolism, and Excretion

    Atrazine is readily absorbed from the gastrointestinal tract, but only
    penetrates the skin to a very limited extent. The absorbed herbicide
    is rapidly eliminated. In the rat, the whole-body half-life is about
    1.3 days, and 95% of the dose is eliminated within 7 days. The highest
    concentration of atrazine and/or its metabolites is found in the red
    blood cells, to which the triazines bind effectively. In rats given
    low, oral doses, daily, levels were found in the tissues in the
    following decreasing order: erythrocytes, liver, spleen, kidney. The
    primary route of elimination in rodents is via the urine (about 75%);
    approximately 20% is eliminated in the faeces.

    Dealkylation at the C-4 and C-6 positions of the atrazine molecule are
    the principal metabolic degradation reactions. Dechlorination at the
    C-2 position also occurs, to some extent. In the rat, the major
    urinary metabolites include the two mono- N-dealkylated metabolites
    and the fully dealkylated derivative, 2-chloro-4,6-diamino- S-triazine.

    2.3  Effects on Animals

    The acute oral toxicity and the dermal toxicity of atrazine in rodents
    are both low. Acute oral studies conducted on different rodent species
    have indicated LD50 values in the range of 1700-4000 mg/kg. Young
    rats are much less sensitive to atrazine than adults. Ruminants seem
    to be much more sensitive to the acute toxic action of atrazine than
    rodents. In one study, 2 doses of 250 mg/kg caused death in both sheep
    and cattle.

    The irritant action of atrazine is only slight on rabbit skin, but is
    moderate for the rabbit eye.

    Atrazine has been subjected to extensive long-term testing on rats,
    mice, and dogs. Significant cardiac toxicity was observed in dogs
    after long-term oral administration of atrazine at doses of 5 mg/kg
    per day or more. In rats and mice, reduced food intake, decreased
    weight gain, and toxic effects on other organs were detected after
    long-term administration of atrazine at high dose levels (> 25 mg/kg
    per day). These effects included muscle degeneration, retinal
    degeneration, necrosis of the liver, and haematological effects in

    rats and in mice. An increase in mammary tumours was observed in rats,
    but not in mice. Taking into account the very high background level of
    mammary tumours in untreated animals, the compound's apparent lack of
    genotoxicity, and the fact that the maximum tolerated dose was
    exceeded, these findings do not represent convincing evidence of

    Atrazine exerts a fetotoxic action at, or close to, dose levels that
    have a deleterious action on the mothers, but does not seem to have
    any significant teratogenic action in rats, mice, or rabbits.

    2.4  Effects on Human Beings

    There are no substantiated indications that atrazine causes any health
    or safety hazards for the general population or for exposed workers.

    2.5  Effects on the Environment

    On the basis of acute and short-term dietary studies, the toxicity of
    atrazine for birds is low, with no mortality at 10 000 mg/kg diet.
    Atrazine is virtually non-toxic for bees, but is moderately toxic for
    aquatic organisms (96-h LC50 range from 0.5 to 15 mg/litre). The
    herbicide is degradable and has little tendency to bioaccumulate,
    thereby limiting possible long-term adverse effects on wildlife and
    fish. As it is an effective herbicide, its phytotoxicity may
    constitute a problem in the case of uncontrolled applications.
    However, the main concern is its relative persistence (half-life of
    125 days in sandy soils) and mobility in some types of soils (related
    to rainfall), resulting in contamination of surface and ground waters.


    The acute oral and dermal toxicities of atrazine for most mammalian
    species are low. Atrazine has no significant teratogenic action in
    rats, mice, or rabbits. There is no convincing evidence of
    carcinogenicity in rats or mice. Toxic effects, including ocular,
    cardiac, haematological, and hepatic effects, have been observed in
    both rats and mice after long-term administration.

    On the basis of acute and short-term dietary studies, the toxicity of
    atrazine is low for birds and moderate for aquatic organisms. It has a
    low capacity for bioconcentration.

    The relative persistence and mobility of atrazine in some types of
    soils can result in contamination of ground and surface waters. It is
    recommended that adequate precautions should be taken to prevent this

    A few gaps in data have been identified that indicate a need for
    further mutagenicity testing and studies of the mechanism of tumour
    induction in rats.

    Atrazine is moderately irritating to the eye. No significant health
    effects on either the general population or exposed workers are


    4.1  Main Human Health Hazards, Prevention and Protection, First Aid

    The acute toxicity of technical atrazine for human beings is thought
    to be low, and no adverse health effects from exposure to this
    herbicide have been reported. In view of the toxicity induced in
    experimental animals on repeated exposure, proper care should be taken
    during occupational use to avoid excessive inhalation of dust or spray
    particles, and to prevent accidental contamination of food products
    and water.

    4.1.1  Prevention and Protection

    In order to reduce the risk of accidental contamination, the following
    precautions should be observed during handling and use:

    (a) Avoid contact with the skin and eyes.

    (b) Do not smoke, drink, or eat in the work-place. Wash hands and any
    exposed skin before eating, drinking, or smoking, and after work.

    (c) Avoid raising a dust cloud when handling wettable powder

    (d) Avoid breathing dust from powder products.

    (e) When unloading and handling containers, wear protective PVC or
    neoprene gloves.

    (f) When handling leaking containers, or when dealing with leaks and
    spills, wear overalls and PVC or neoprene gloves and boots. If
    overalls become contaminated, change and wash them thoroughly before

    (g) Store products in dosed original containers, out of reach of
    children, and away from food, drink, and animal feed.

    4.1.2  First Aid

    Poisoning by atrazine is unlikely, unless large amounts have been
    ingested. In case of over-exposure, apply routine first-aid measures.
    If material has been spilled on the skin, immediately remove the
    patient from the source of contamination, remove all contaminated
    clothing, and wash affected areas with soap and running water. If the
    material is in the eyes, flush with clean water for at least 15
    minutes. In case of ingestion of significant quantities, and, if the
    patient is conscious, give a glass of water and subsequently
    administer activated charcoal. Do not induce vomiting. In serious
    cases, medical attention should be sought.

    4.2 Advice to Physicians

    The acute toxicity of atrazine for human beings is believed to be low.
    There is no specific antidote. Treat symptomatically when required.
    When large amounts have been ingested, gastric lavage may be

    4.3  Explosion and Fire Hazards

    Technical atrazine is not flammable but, on heating, it decomposes to
    form toxic fumes containing oxides of nitrogen (NOx) and hydrogen
    chloride (HCl). Extinguish small fires with carbon dioxide, dry
    powder, or alcohol-resistant foam. Water spray can be used for larger
    fires and the cooling of unaffected stock, but avoid the accumulation
    of polluted run-off from the site.

    Beware: Some liquid formulations may be highly flammable and require
    alcohol-resistant foam as an extinguishing agent.

    4.4  Storage and Transport

    All products should be stored in secure buildings, out of reach of
    children and animals, and local regulations should be complied with.
    Containers should be sound and adequately labelled.

    4.5  Spillage and Disposal

    Keep spectators away from any leakage. Prevent contamination of other
    goods or cargo, or nearby vegetation and waterways.

    Absorb spilled liquid products with sawdust or sand, sweep up and
    place in separate container.

    Empty any product remaining in damaged or leaking containers into a
    clean empty container, which should be suitably labelled.

    Sweep up any spilled powder with damp earth or sand or other suitable
    absorbent, such as sawdust, taking care not to raise a dust cloud (use
    a vacuum cleaner). Place in separate container for subsequent
    disposal. Contaminated absorbents, used containers, surplus product,
    etc., should be burnt in an incinerator, preferably designed for
    pesticide disposal. Hydrolysis under alkaline conditions (10% w/v
    sodium hydroxide) is a suitable method to dispose of small quantities
    of atrazine. Heating speeds the process. After hydrolysis, dilute and
    dispose of via the sewage system. Atrazine is relatively stable and
    characterized by high mobility in some soils and should not be buried
    in dump sites, etc. Comply with any local legislation applying to
    waste disposal.


    Triazines may be ingested by domestic animals. In view of the
    relatively high toxicity of atrazine for ruminants, exposure to
    atrazine of sheep and cows should be avoided. Because of its relative
    persistence and mobility in some types of soils, atrazine has a
    significant potential for contamination of ground and surface waters.
    The contamination of ponds, waterways, and ditches should be avoided.


    The information given in this section has been extracted from the
    International Register of Potentially Toxic Chemicals (IRPTC) legal
    file. A full reference to the original national document from which
    the information was extracted can be obtained from IRPTC. When no
    effective date appears in the IRPTC legal file, the year of the
    reference from which the data are taken is indicated by (r).

    The reader should be aware that regulatory decisions about chemicals,
    taken in a certain country, can only be fully understood in the
    framework of the legislation of that country. Furthermore, the
    regulations and guidelines of all countries are subject to change and
    should always be verified with the appropriate regulatory authorities
    before application.

    6.1  Exposure Limit Values

    Exposure limit values for atrazine are given in the following table.

    6.2  Specific Restrictions

    The National Swedish Chemicals Inspectorate has recently announced its
    intention to prohibit the use of atrazine and other triazine
    herbicides for weed elimination on gravel roads and similar surfaces.

    Atrazine constitutes a contaminant required to be regulated by the US
    Safe Water Drinking Act of 1986, including the promulgation of a MCLG
    (Maximum Concentration Limit Goal).

    6.3  Transport and Labelling

    The United Nations Committee of Experts on Transportation of Dangerous
    Goods classifies atrazine in:

    - Hazard Class 6.1: poisonous substances;

    - Packing group III: substance presenting a relatively low risk of
    poisoning in transport.


    Medium     Specification           Country/                 Exposure limit description                  Value               Effective
                                       organization                                                                             date

    AIR        Occupational            Australia                Time-weighted average (TWA)                 5 mg/m3             1983

                                       Belgium                  Time-weighted average (TWA)                 5 mg/m3             1988

                                       Germany, Federal         Time-weighted average (TWA)                 2 mg/m3             1988
                                       Republic of,             - Maximum worksite concentration            2 mg/m3

                                       Switzerland              Time-weighted average (TWA)                 10 mg/m3            1987

                                       United Kingdom           Maximum allowable concentration             2 mg/m3             1977

                                       USSR                     (Ceiling value)

    WATER      Drinking-               Canada                   Interim maximum acceptable                  0.06 mg/litre       1987

                                       EEC                      Maximum allowable concentration             0.1 g/litre

                                       Switzerland              Maximum residue limit                       0.1 g/litre        1980

                                       WHO/EURO                 Guideline value                             2.0 g/litre        1987

    WATER      Oral intake             WHO/EURO                 Acceptable daily intake (ADI)               0.7 mg/g            1987
                                                                                                            body weight

    FOOD       Plant (general)         EEC                      Maximum residue limit                       0.1 mg/kg

    FOOD       Plant (specified)       Brazil                   Acceptable limit                            0.1-0.2 mg/kg       1984


    Medium     Specification           Country/                 Exposure limit description                  Value               Effective
                                       organization                                                                             date

    FOOD       Plant (general)         Germany, Federal         Maximum residue limit                       0.1 mg/kg           1984
                                       Republic of,

               Plant (specified)       Germany, Federal         Maximum residue limit                       0.5-10 mg/kg        1984
                                       Republic of,

    FOOD       Specified food          Kenya                    Maximum limit                               0.02-0.25 mg/kg

    FOOD       Raw agricultural        USA                      Tolerance (Acceptable residue limit)        0.02-15 mg/kg       1982
               (specified plant
               and animal

               Oral intake             USA                      Reference dose                              0.005 mg/kg
                                                                                                            body weight

    FOOD       Specified food          USSR                     Acceptable daily intake (ADI)               0.004 mg/kg         1983

    FOOD       Oral intake             USA                      Tolerance                                   0.005 mg/kg

    GOODS                              Brazil                   Use in domestic sanitation not

    a  For other regulatory data see complete legal file of IRC data profile.
        The label should be as follows:

    FIGURE 1

    The European Economic Community legislation requires labelling as a
    dangerous substance, using the symbol:

    FIGURE 2

    The label must read:

     Harmful by inhalation, in contact with the skin, and if swallowed;
     keep out of reach of children; keep away from food drink; and animal

    See Also:
       Toxicological Abbreviations
       Atrazine (ICSC)
       Atrazine  (IARC Summary & Evaluation, Volume 53, 1991)
       Atrazine  (IARC Summary & Evaluation, Volume 73, 1999)