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    IPCS INTERNATIONAL PROGRAMME ON CHEMICAL SAFETY
    Health and Safety Guide No. 46

    BARIUM
    HEALTH AND SAFETY GUIDE






    UNITED NATIONS ENVIRONMENT PROGRAMME

    INTERNATIONAL LABOUR ORGANISATION

    WORLD HEALTH ORGANIZATION




    WORLD HEALTH ORGANIZATION, GENEVA 1991

    This is a companion volume to Environmental Health Criteria 107:
    Barium

    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

    Barium : health and safety guide.

    (Health and safety guide ; no. 46)

    1. Barium - standards  I. Series

    ISBN 92 4 151046 3          (NLM Classification: QV 618)
    ISSN 0259-7268

    (c) World Health Organization 1991

    Publications of the World Health Organization enjoy copyright
    protection in accordance with the provisions of Protocol 2 of the
    Universal Copyright Convention.  For rights of reproduction or
    translation of WHO publications, in part or  in toto, application
    should be made to the Office of Publications, World Health
    Organization, Geneva, Switzerland.  The World Health Organization
    welcomes such applications.

    The designations employed and the presentation of the material in this
    publication do not imply the expression of any opinion whatsoever on
    the part of the Secretariat of the World Health Organization
    concerning the legal status of any country, territory, city or area or
    of its authorities, or concerning the delimitation of its frontiers or
    boundaries.

    The mention of specific companies or of certain manufacturers'
    products does not imply that they are endorsed or recommended by the
    World Health Organization in preference to others of a similar nature
    that are not mentioned.  Errors and omissions excepted, the names of
    proprietary products are distinguished by initial capital letters.

    CONTENTS

    INTRODUCTION

    1. PRODUCT IDENTITY AND USES
         1.1. Identity
         1.2. Physical and chemical properties
         1.3. Occurrence
         1.4. Analytical methods
         1.5. Production and uses

    2. SUMMARY AND EVALUATION
         2.1. Human exposure
         2.2. Uptake, metabolism, and excretion
         2.3. Effects on experimental animals
         2.4. Effects on human beings
         2.5. Effects on the environment

    3. CONCLUSIONS AND RECOMMENDATIONS

    4. HUMAN HEALTH HAZARDS, PREVENTION AND PROTECTION, EMERGENCY ACTION
         4.1. Main human health hazards, prevention and protection,
              first aid
              4.1.1. Advice to physicians
              4.1.2. Health surveillance advice
         4.2. Explosion and fire hazards, storage, transport, 
              spillage, and disposal
              4.2.1. Barium metal
                     4.2.1.1  Explosion hazards
                     4.2.1.2  Fire hazards
                     4.2.1.3  Prevention
                     4.2.1.4  Extinguishing agents
                     4.2.1.5  Storage
                     4.2.1.6  Transport
                     4.2.1.7  Spillage
                     4.2.1.8  Disposal
              4.2.2. Barium compounds
                     4.2.2.1  Explosion and fire hazards
                     4.2.2.2  Prevention
                     4.2.2.3  Extinguishing agents
                     4.2.2.4  Storage
                     4.2.2.5  Transport
                     4.2.2.6  Spillage
                     4.2.2.7  Disposal

    5. HAZARDS FOR THE ENVIRONMENT AND THEIR PREVENTION

    6. SUMMARY OF CHEMICAL SAFETY INFORMATION

    7. CURRENT REGULATIONS, GUIDELINES, AND STANDARDS
         7.1. Previous evaluations by international bodies
         7.2. Exposure limit values
         7.3. Specific restrictions
         7.4. Labelling, packaging, and transport
         7.5. Other measures
         7.6. Waste disposal

    BIBLIOGRAPHY
    

    INTRODUCTION

    The Environmental Health Criteria (EHC) documents produced by the
    International Programme on Chemical Safety include an assessment of
    the effects on the environment and on human health of exposure to a
    chemical or combination of chemicals, or physical or biological
    agents.  They also provide guidelines for setting exposure limits.

    The purpose of a Health and Safety Guide is to facilitate the
    application of these guidelines in national chemical safety
    programmes. The first three sections of a Health and Safety Guide
    highlight the relevant technical information in the corresponding EHC. 
    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.  Within the Guide is a Summary of Chemical Safety
    Information which should be readily available, and should be clearly
    explained, to all who could come into contact with the chemical.  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.  A bibliography has been included for
    readers who require further background information.

    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
    Switzerland

    THE INFORMATION IN THIS GUIDE SHOULD BE CONSIDERED AS A STARTING POINT
    TO A COMPREHENSIVE HEALTH AND SAFETY PROGRAMME

    1.  PRODUCT IDENTITY AND USES

    1.1 Identity

    Symbol:                       Ba

    CAS registry number:          7440-39-3

    1.2  Physical and Chemical Properties

    Some physical and chemical properties of barium are given in the
    Summary of Chemical Safety Information (section 6).

    1.3  Occurrence

    Barium is an alkaline earth metal that occurs in nature in a combined
    form.  It is present in rocks, minerals, soils, air, natural waters,
    and fossil fuels.  Some barium salts (e.g., acetate, nitrate, and
    chloride) are quite soluble in water, whereas others (e.g., arsenate,
    carbonate, oxalate, chromate, fluoride, sulfate, and phosphate) are
    very poorly soluble.  The water solubility of barium salts, except for
    barium sulfate, increases with decreasing pH.

    1.4  Analytical Methods

    Sampling and handling procedures for barium are those used in general
    analytical practice.  Three atomic absorption spectrophotometry (AAS)
    methods, recommended for the determination of barium, include:the
    direct aspiration method, the furnace technique, and emission
    spectrometry, using an inductively coupled plasma (ICP) source.  Mass
    spectrometry, X-ray fluorescence, and neutron activation analysis are
    used for special applications.

    1.5  Production and Uses

    The major raw materials from which barium compounds are obtained are
    barite (barium sulfate) and witherite (barium carbonate).  The barite
    and witherite are converted to metallic barium and other barium
    compounds, including barium oxide, hydroxide, peroxide, and a variety
    of salts.

    Metallic barium is used in the manufacture of alloys.  Barium
    compounds are used: as loaders for paper, soap, rubber, and linoleum;
    in the manufacture of valves, and in the production of lights and
    green flares.  They are also used: as pigments in the manufacture of
    paints; in cement where concrete is exposed to salt-water; in the
    radio industry to capture the last traces of gases in vacuum tubes; in
    the ceramic and glass industries; as insecticides and rodenticides; as
    extinguishers for radium, uranium, and plutonium; and as contrast
    material in X-ray medical examination.

    2.  SUMMARY AND EVALUATION

    2.1  Human Exposure

    The general population is exposed to barium through air,
    drinking-water, and food.

    The concentration in air has been estimated to be <0.05 g/m3
    and, assuming an average ventilatory rate of 20 m3/day, a daily
    inhalation intake of barium of approximately 1.0 g can be derived. 
    Occupational exposure to barium has been found to range from 0.02 to
    6.1 mg/m3.

    Recent studies from the USA showed exposure levels in drinking-water
    ranging from 1 to 20 g/litre.  On the basis of this range, and
    assuming a daily consumption of 2 litres of drinking-water, the daily
    intake of barium would be 2-40 g.  However, in certain regions of the
    USA, barium concentrations of up to 10 000 g/litre have been
    reported.  In the United Kingdom (Wales), the average daily intake of
    barium from drinking-water has been estimated to be approximately
    86 g.

    The major route of barium exposure is through the diet.  On the basis
    of data from the USA, the dietary intake of barium ranges from 300 to
    1700 g/day, with an average concentration ranging from
    600-900 g/day.  In the United Kingdom (Wales), the average intake has
    been estimated to be 1240 g/day.

    2.2  Uptake, Metabolism, and Excretion

    In human beings, the absorption of barium from the gastrointestinal
    tract largely depends on age and the solubility of the compound.  Less
    than 10% of an ingested quantity is believed to be absorbed in adults;
    however, absorption may be significantly higher in children.  Inhaled
    barium compounds are absorbed through the lungs or directly from the
    basal membrane.  Poorly soluble compounds may accumulate in the lungs
    and removal is slow.  Absorbed barium enters the bloodstream and
    various soft tissues, and is deposited in the bone.  A barium level of
    about 20 mg has been found in the average-sized person (70 kg), 93% of
    which is localized in the bone.

    The metabolism of barium is similar to that of calcium; however,
    unlike calcium, barium has no known biological function.

    Barium is eliminated in both the faeces and the urine, elimination
    varying according to the route of administration and the solubility of
    the compound.  Barium, which had been absorbed and transported by the
    plasma, was found to be almost entirely eliminated from the body
    within 24 h.

    2.3  Effects on Experimental Animals

    Barium compounds, particularly soluble compounds, are toxic in
    animals.  Oral LD50s in the rat for barium chloride, fluoride, and
    nitrate were reported to be 118, 250, and 335 mg/kg body weight,
    respectively.  Acute effects of barium ingestion include salivation,
    nausea, diarrhoea, tachycardia, hypokalaemia, twitching, flaccid
    paralysis of skeletal muscle, respiratory muscle paralysis, and
    ventricular fibrillation.  Respiratory muscle paralysis and
    ventricular fibrillation may lead to death.  Studies on dogs showed
    that acute effects were due to the rapid onset of substantial
    hypokalaemia (abnormally low potassium levels in the blood) and could
    be prevented or reversed by potassium administration.

    No clinical signs of toxicity or microscopic alterations were seen in
    rats given tap water containing <250 mg barium/litre for periods of
    up to 13 weeks.

    Lethal concentrations following acute inhalation exposure have not
    been reported.  However, at concentrations higher than 5.2 mg
    barium/m3, rats exhibited decreases in body weight, blood glucose,
    and haemoglobin, and an increase in leukocytes.

    In rabbits, topical administration of barium resulted in mild skin
    irritation and severe eye irritation.

    The results of one study on mice and rats did not reveal any evidence
    of carcinogenicity for barium.

    Both oral and inhalation exposure to barium carbonate induced adverse
    reproductive effects in male and female rats.

    There is limited evidence of the teratogenic potential of barium.

    2.4  Effects on Human Beings

    Barium doses as low as 0.2-0.5 g (3-7 mg/kg body weight), generally
    resulting from the ingestion of barium chloride or carbonate, have
    been found to lead to toxic effects in adult human beings.  In
    untreated cases, doses of 3-5 g (40-70 mg/kg body weight) were lethal. 
    Clinical features of barium poisoning include: acute gastroenteritis,
    loss of deep reflexes with onset of muscular paralysis, and
    progressive muscular paralysis.  The muscular paralysis appears to be
    related to severe hypokalaemia.  In most reported cases, rapid and
    uneventful recovery occurred after treatment with infused potassium
    salts (carbonate or lactate) and/or oral administration of sodium
    sulfate.

    Adverse health effects have been observed in sensitive individuals
    (e.g., diuresis patients) following exposure to barium as a medical
    X-ray contrast medium.

    In the workplace, inhaled barium has resulted in baritosis.  A
    significantly higher prevalence of hypertension was observed in
    workers exposed to high levels of airborne barium than in unexposed
    workers.

    The results of early, limited, epidemiological studies, relating
    exposure to low levels of barium with cardiovascular disease and
    mortality, were inconsistent and inconclusive.  In a later
    epidemiological study, no conclusive evidence of barium-induced
    effects on blood pressure was revealed.  No effects on blood pressure
    were identified in a short-term study in which volunteers consumed
    increasing levels of barium up to 10 mg/litre in drinking-water.

    There is no conclusive evidence that barium compounds induce
    reproductive, teratogenic, or carcinogenic effects in human beings.

    2.5  Effects on the Environment

    Barium has been reported to inhibit growth and cellular processes in
    microorganisms, and to affect the development of germinating spores.

    No information was obtained on the adverse effects of barium on
    terrestrial plants or wildlife.  No toxic effects have been reported
    in aquatic plants due to barium at the usual concentrations found in
    water.  Reported LC50 values for fish in fresh water range from
    46 to 78 mg/litre.  Reproduction and growth in  Daphnia spp. were
    impaired by barium concentrations of 5.8 mg/litre.

    3.  CONCLUSIONS AND RECOMMENDATIONS

    Barium, at concentrations normally found in the environment, does not
    pose any significant risk for the general population.  However, for
    specific subpopulations, and under conditions of high barium exposure,
    the potential for adverse health effects should be taken into account.

    Few data are available to evaluate the risk to the environment posed
    by barium.  On the basis of the available information on the toxic
    effects of barium in  Daphnia spp., it appears that high
    concentrations may represent a risk to populations of some aquatic
    organisms.

    In order to adopt adequate preventive measures in the workplace, more
    data on exposure levels should be obtained, including human
    monitoring data.

    4.  HUMAN HEALTH HAZARDS, PREVENTION AND PROTECTION, EMERGENCY ACTION

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

    The three stages of poisoning from soluble barium compounds are acute
    gastroenteritis, loss of reflexes with the onset of muscular
    paralysis, and progressive muscular paralysis.  When ingested, barium
    compounds exert profound effects on all muscles, especially the heart. 
    In addition, exposure to metallic barium may result in severe burns,
    through explosion and fire.  The human health hazards associated with
    certain types of exposure to metallic barium, together with preventive
    and protective measures and first-aid recommendations, are listed in
    the Summary of Chemical Safety Information (section 6).

    4.1.1  Advice to physicians

    Immediate care should consist of the administration of 30 g sodium
    sulfate in 250 ml of water (a glass of water), repeated in one hour. 
    In the case of very severe symptoms, intravenous administration of
    potassium bicarbonate or lactate, to overcome hypokalaemia, is
    necessary, and should be carried out, under controlled medical
    conditions, only by qualified medical personnel.

    4.1.2  Health surveillance advice

    Persons handling barium and its compounds should undergo periodic
    medical examination.  Special consideration should be given to the
    skin, eyes, heart, and lungs, and serum potassium levels should be
    measured at each examination.

    4.2  Explosion and Fire Hazards, Storage, Transport, Spillage, and
         Disposal

    Barium metals and barium compounds have been described separately;
    section 4.2.1 refers to barium as a metal, while section 4.2.2 refers
    to barium compounds.

    4.2.1  Barium metal

    4.2.1.1  Explosion hazards

    Metallic barium reacts exothermically on contact with water, releasing
    flammable hydrogen gas, which may be ignited by the heat of the
    reaction.  Fine powders or dusts of barium can explode when heated. 
    Barium runoff to sewer water may create an explosion or fire.

    4.2.1.2  Fire hazards

    Barium in the form of finely ground powder or fumes is flammable or
    explosive, when exposed to heat or flames.

    4.2.1.3  Prevention

    Keep barium away from water, heat, sparks, and open flames.

    4.2.1.4  Extinguishing agents

    Move barium containers from fire area, if possible.  Do not use water,
    carbon dioxide, or foam.  In case of small fires, use dry chemical
    powder, soda ash, or lime.  In case of large fires, withdraw from area
    and let fire burn.

    4.2.1.5  Storage

    Store barium under inert gas, petroleum, argon, or oxygen-free liquid. 
    Store away from the following: water, most acids, ammonia, halogens,
    and oxidizers.

    4.2.1.6  Transport

    Package barium in sealed containers.  Pack glass bottles together with
    cushioning material in a wooden box; pack cans together in a wooden
    box.  Label metal drums with the warning "Dangerous When Wet".  Limit
    transportation of barium to cargo ships or passenger ships carrying
    not more than 25 passengers; on ships, limit stowage to above the deck
    or under the deck, preferably the latter.  During transportation by
    air (single or combination packagings), steel drums, aluminum drums,
    plastic drums, or plastic jerricans are required as the inner shell,
    and wooden, plywood, or fibreboard boxes are required as the outer
    shell.

    4.2.1.7  Spillage

    In case of spillage, shut off ignition sources.  Do not touch spilled
    material.  Stop leak, if possible to do so without risk.  Water should
    not come into contact with spilled material or the inside of the
    container.  For small dry spills, use a clean shovel to place material
    into a clean, dry container and cover; move containers from area of
    spillage.  Cover dry powder spills with plastic sheet or tarp to
    minimize spreading.  Keep unnecessary persons away.  Isolate area and
    prevent anyone from entering.

    4.2.1.8  Disposal

    Material in the elemental state should be recovered for re-use or
    recycling. Recovered metal should be stored under a layer of kerosene
    and kept dry.

    4.2.2  Barium compounds

    4.2.2.1  Explosion and fire hazards

    Specific soluble barium compounds, such as barium oxide, peroxide, and
    nitrate, can cause an explosion or fire, when in contact with water,
    carbon dioxide, or hydrogen sulfide.

    4.2.2.2  Prevention

    Handle with care, avoid inhalation and contact with skin.  Do not eat,
    drink, or smoke in the workplace.

    4.2.2.3  Extinguishing agents

    Move containers from the fire area, if possible.  In case of small
    fires, use dry chemical powder, soda, or lime.  In case of large
    fires, withdraw from the area and let the fire burn.

    4.2.2.4  Storage

    Store in closed labelled containers.

    4.2.2.5  Transport

    Package barium compounds in sealed containers.  Pack glass bottles,
    together with cushioning material, in a wooden box; pack cans together
    in a wooden box.  Label metal drums with the warning "Dangerous When
    Wet".  Limit transportation of barium compounds to cargo ships or
    passenger ships carrying not more than 25 passengers; on ships, limit
    stowage to above the deck or under the deck, preferably the latter. 
    During transportation by air (single or combination packagings), steel
    drums, aluminum drums, plastic drums, or plastic jerricans are
    required as the inner shell, and wooden, plywood, or fibreboard boxes,
    as the outer shell.

    4.2.2.6  Spillage

    In case of spillage, shut off ignition sources.  Do not touch spilled
    material.  Stop leak, if possible to do so without risk.  Water should
    not come into contact with the spilled material or the inside of the
    container.  For small dry spills, use a clean shovel to place in
    clean, dry container and cover; move containers from area of spillage. 
    Take up liquid spills with sand or absorbent material and place in
    containers for later disposal.  Larger spills should be contained with
    a barrier for later disposal.  Cover dry powder spills with plastic
    sheet or tarpaulin, to minimize spreading.  Keep unnecessary persons
    away.  Isolate area, and prevent anyone from entering.

    4.2.2.7  Disposal

    Soluble barium compounds can be removed from water by the addition of
    controlled amounts of sulfuric acid or acidified sulfate salts, to
    form insoluble barium sulfate.

    5.  HAZARDS FOR THE ENVIRONMENT AND THEIR PREVENTION

    As barium at a concentration of 5.8 mg/litre has been observed to
    impair reproduction and growth in  Daphnia spp., similar
    concentrations may present a risk for other aquatic organisms.

    Avoid contamination of soil, water, and the atmosphere by using proper
    methods of processing, transport, and waste disposal.

    6.  SUMMARY OF CHEMICAL SAFETY INFORMATION

     This summary should be easily available to all health workers
     concerned with, and users of, barium. It should be displayed at, or
     near, entrances to areas where there is potential exposure to barium,
     and on processing equipment and containers.  The summary should be
     translated into the appropriate language(s).  All persons potentially
     exposed to the chemical should also have the instructions in the
     summary clearly explained.

     Space is available for insertion of the National Occupational
     Exposure Limit, the address and telephone number of the National
     Poison Control Centre, and local trade names.


        Barium (Ba)

                                                                                                                                         

    PHYSICAL PROPERTIES                                                   OTHER CHARACTERISTICS
                                                                                                                                         

    Relative molecular mass            56                                 Extremely reactive with water, ammonia, halogens, 
    Appearance                         yellowish-white                    oxygen and most acids
                                       solid
    Melting point (C)                 725
    Boiling point (C)                 1640
    Solubility in water (20C)         reacts with
                                       release of H2
    Density (20C)                     3.51
    Vapour pressure (20C)             2
    Electronegativity                  1.02
    Flame coloration test              green

                                                                                                                                         

    HAZARDS/SYMPTOMS                        PREVENTION AND PROTECTION                    FIRST AID
                                                                                                                                         

    SKIN: Irritation                        Avoid exposure; wear protective              Remove contaminated clothing; wash skin 
                                            clothing and gloves                          with plenty of water and soap

    EYE: Irritation; redness: pain          Wear safety goggles if there is a            Flush eyes with plenty of water for 15
                                            possibility of eye contact                   minutes

    INHALATION (metallic powder):           Avoid exposure by using ventilation,         Fresh air, administer oxygen, if 
    Sore throat, coughing, shortness        local exhaust, or breathing protection       required
    of breath, trembling, vomiting          by a suitable respirator

    INGESTION: Salivation, vomiting,        Do not eat, drink, or smoke when             Rinse mouth; induce vomiting in 
    abdominal pain; gastroenteritis;        handling the material                        conscious patients; administer sodium
    giddiness; stimulation of all muscle                                                 sulfate (30 g in 250 ml water); if 
    types; hypokalaemia; delayed kidney                                                  swallowed, begin gastric lavage (stomach
    damage; vasoconstriction, irregular                                                  wash) followed by saline catharsis,
    heartbeat; death may occur from                                                      seek medical attention immediately
    cardiac or respiratory failure

                                                                                                                                         

    SPILLAGE                                STORAGE                                      FIRE AND EXPLOSION
                                                                                                                                         

    Do not touch spilled material;          Store under inert gas, petroleum,            Finely ground particle or 
    do not get water on the spillage;       argon, or oxygen-free liquid                 fumes are flammable or 
    for dry spills, use a clean shovel                                                   explosive
    to place material in clean, dry
    container

                                                                                                                                         

    WASTE DISPOSAL
                                                                                                                                         

    Recover elemental barium for re-use     National Occupational Exposure Limit:
    or recycling; store under a layer of
    kerosene and keep it dry                National Poison Control Centre:

                                                                                                                                         
        7.  CURRENT REGULATIONS, GUIDELINES, AND STANDARDS

    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 appropriate regulatory authorities
    before application.

    7.1  Previous Evaluations by International Bodies

    The International Agency for Research on Cancer (IARC) evaluated the
    carcinogenicity of barium chromate (VI) and concluded that there was
    sufficient evidence for carcinogenicity in human beings (positive
    carcinogen) and insufficient evidence in animals.  However, the
    carcinogenic properties of barium chromate are related to the presence
    of chromium (VI) and not barium.

    7.2  Exposure Limit Values

    See table on pages 24-25. 

    7.3  Specific Restrictions

    No specific restrictions were found.

    7.4  Labelling, Packaging, and Transport

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

    FIGURE 1

    The label must read: 

          Harmful by inhalation - avoid contact with skin.

    The European Economic Community legislation on labelling classifies
    barium as a poisonous substance for the purpose of determining the
    label on preparations containing this substance.

    The United Kingdom legislation on regulations requires that all
    general requirements concerning labelling, containers, storage, and
    transport are laid down; this applies to all barium salts except
    barium sulfate.

    The label that both recommend is:

    FIGURE 2


        EXPOSURE LIMIT VALUES

                                                                                                                                         

    Medium      Specification    Country/         Exposure limit description                            Value             Effective
                                 organization                                                                             date
                                                                                                                                         

    AIR         Occupational     Argentina        Maximum allowable concentration (MAC)                 0.5 mg/m3         1979
                                                  - Time-weighted average (TWA)
                                                  Short-term exposure limit (STEL)                      0.5 mg/m3         1979

                                 Australia        Threshold limit value (TLV)                           0.5 mg/m3         1985(r)
                                                  - Time-weighted average (TWA)

                                 Belgium          Threshold limit value (TLV)                           0.5 mg/m3         1980(r)
                                                  - Time-weighted average (TWA)

                                 Canada           Maximum allowable concentration (MAC)                 0.5 mg/m3         1985(r)
                                                  - Time-weighted average (TWA)

                                 Finland          Maximum allowable concentration (MAC)                 0.5 mg/m3         1985(r)
                                                  - Time-weighted average (TWA)

                                 Germany,         Maximum at work-site concentration (MAK)              0.5 mg/m3         1987(r)
                                   Federal        - 8 h time-weighted average 
                                   Republic of    Short-term exposure limit (STEL) - 30 minutes         1.0 mg/m3         1987(r)

                                 United Kingdom   Recommended limits (RECL)                             0.5 mg/m3         1987(r)
                                                  - Time-weighted average

                                 USA (ACGIH)      Threshold limit value (TLV)                           0.5 mg/m3         1986(r)
                                                  - Time weighted average

                                 USA (OSHA)       Threshold limit value (TLV)                           0.5 mg/m3         1985(r)
                                                  - Time weighted average

                                                                                                                                         

    Medium      Specification       Country/            Exposure limit description                   Value                Effective
                                    organization                                                                          date
                                                                                                                                         

    WATER       Drinking-           Canada              Maximum allowable concentration (MAC)        1.0 mg/litre         1987
                                                        - Guideline level for water quality

                                    European            Maximum allowable concentration (MAC)        0.1 mg/litre         1982
                                    Economic            - Guideline level requirements
                                    Community

                                    USA                 Reported quantity requirement (RQR)          1.0 mg/litre         1981(r)
                                                        - Bottled water

                                                        Maximum allowable concentration (MAC)        1.0 mg/litre         1986(r)
                                                        - Public water systems

                Surface             European            Reported quantity requirement (RQR)          0.1 mg/litre         1977
                                    Economic            - intended for the abstraction of            
                                    Community           drinking water; simple water treatment
                                                        methods
                                                        - for normal and intensive methods           1.0 mg/litre         1977

    FOOD                            USA                 Maximum permissible concentration (MPC)      0.5 g/kg             1986 (r) 
                                                        - for colours that may be used in food,
                                                          drugs, and/or cosmetics

    TWA = Time-weighted average over one working day (usually 8 h).

                                                                                                                                         
        7.5  Other Measures

    United Kingdom legislation classifies barium as a poisonous substance
    that is not to be sold except by a person lawfully conducting a retail
    pharmacy business, and requires that proper records be kept of the
    sales.

    Under the Hazardous Products Act, Canadian legislation prohibits the
    advertising, sale, or import of toys, equipment, or other products,
    for use by children in learning or play, which have a decorative or
    protective coating that contains 0.1% barium.

    7.6  Waste Disposal

    European Economic Community legislation on waste disposal requires
    that Member States should take the necessary steps to limit the
    introduction of barium and its compounds into ground water, by
    subjecting to prior investigation and authorization all direct
    discharges, and disposal or tipping that might lead to indirect
    discharges, and all indirect discharges.

    United Kingdom legislation classifies barium as a "special waste" that
    requires completion of a consignment note for the disposal
    authorities.  This applies to controlled waste containing, or
    consisting of, barium compounds.

    United States legislation requires an owner or operator of a certain
    type of hazardous waste storage, treatment, or disposal facility to
    install a ground water monitoring system and to periodically report on
    the  concentrations of this substance.  In addition, permits are
    required for the discharge of any pollutant from any point source into
    US waters.  Quantitative data must be reported in the application. 
    The level applies to total barium.  Waste regulations also require
    that the analytical method(s) used in determining the presence of
    barium in solid waste be specified.

    BIBLIOGRAPHY

    ACGIH  (1986)  Documentation of the threshold limit values and
     biological exposure indices. 5th ed, Cincinnati, Ohio, American
    Conference of Governmental Industrial Hygienists, p.47.

    BRANSFORD, J., ed.  (1989)  Material Safety Data Sheet (MSDS). 
    CD-ROM. New York, Occupational Health Services, Inc.

    BRETHERICK, L., ed.  (1986)  Hazards in the chemical laboratory.
    London, London Royal Society of Chemistry.

    IARC  (1980)  Some metals and metallic compounds. Lyon, International
    Agency for Research on Cancer, p. 205 (IARC Monographs on the
    Evaluation of the Carcinogenic Risk of Chemicals to Humans, Vol. 23).

    IATA  (1986)  IATA Dangerous goods regulations. 27th ed., Montreal,
    International Air Transport Association.

    IMCO  (1983)  International maritime dangerous goods Code. Vol. III.
    Amendment 21-83.  London, Intergovernmental Maritime Consultative
    Organization, p. 4147.

    IRPTC  (1989)  Data profile: Barium. Geneva, (International Register
    of Potentially Toxic Chemicals), United Nations Environment Programme.

    ITI  (1978)  Toxic and hazardous industrial chemicals safety manual.
    Tokyo, International Technical Information Institute, pp. 57-58.

    LENGA, R. (1985)  The Sigma-Aldrich library of chemical safety data.
    Steinheim, Federal Republic of Germany, Sigma-Aldrich Chemical
    Corporation, p. 143.

    NATIONAL LIBRARY OF MEDICINE  (1989)  Hazardous Substance Data Bank
     (HSDB).  Online, Washington, DC, National Institutes of Health,
    MEDLARS Management Section.

    PROCTOR, N. & HUGHES, J. (1978)  Chemical hazards of the workplace.
    Philadelphia, Pennsylvania, J.B. Lippincott Company, pp. 116-117.

    SITTIG, M. (1979)  Hazardous and toxic effects of industrial
     chemicals. Park Ridge, New Jersey, Noyes Data Corporation,
    pp. 51-52.

    US EPA  (1988)  Risk screening guide. Barium. Washington, DC, US
    Environmental Protection Agency, Office of Toxic Substances
    (Attachment SARA Section 313 ROADMAPS Information).

    US EPA  (1989)  Integrated Risk Information System (IRIS). Reference
     dose (RfD) for oral exposure for barium. Online, Cincinnati, Ohio,
    Office of Health and Environmental Assessment, Environmental Criteria
    and Assessment Office.

    US NIOSH  (1989)  Registry of toxic effects of chemical substances
     (RTECS). Online, Cincinnati, Ohio, National Institute of
    Occupational Safety and Health, US Department of Health and Human
    Services, Public Health Service, Centers for Disease Control.

    WHO  (1989)  Environmental Health Criteria 107: Barium. Geneva, World
    Health Organization.

    


    See Also:
       Toxicological Abbreviations
       Barium (EHC 107, 1990)
       Barium (ICSC)
       Barium  (SIDS)