INTERNATIONAL PROGRAMME ON CHEMICAL SAFETY

    WORLD HEALTH ORGANIZATION



    SUMMARY OF TOXICOLOGICAL DATA OF CERTAIN FOOD ADDITIVES
    AND CONTAMINANTS



    WHO FOOD ADDITIVES SERIES NO. 13






    The data contained in this document were examined by the
    Joint FAO/WHO Expert Committee on Food Additives*
    Rome, 3-12 April 1978




    Food and Agriculture Organization of the United Nations
    World Health Organization



    * Twenty-second Report of the Joint FAO/WHO Expert Committee on Food
    Additives, Geneva, 1978, WHO Technical Report Series No. 631

    ASBESTOS

    Explanation

         Asbestos was evaluated by the Joint FAO/WHO Expert Committee on
    Food Additives in 1974. Additional data have become available since
    the last evaluation and are summarized below.

    BIOLOGICAL DATA

    Long-term studies

    Rat

         In two studies containing 10 and 40 animals/group respectively,
    male rats were fed 0 and 1% chrysotite asbestos for their lifetime. In
    the first study, six malignant tumours were found in the treated
    animals compared to one malignant tumour in the controls. In the
    second study, 11 malignant tumours were observed in each group. Two of
    the tumours in the treated animals were associated with the
    gastrointestinal tract. A third study was performed in which two
    groups of 10 male rats were fed 0 end 1% asbestos for six weeks. At
    the time of sacrifice tissues were analysed for asbestos fibres. All
    tissues of the treated animals showed higher levels of fibres than the
    controls. The highest level was found in the omentum (Cunningham et
    al., 1978).

    Epidemiology

         Twenty-two municipalities in Quebec, grouped by evidence of
    exposure to asbestos fibres in their municipal water supplies (known
    high, probable high and probable low exposures), were evaluated in
    respect to mortality experience. The expected number of cancer deaths
    were calculated by applying the Quebec age-specific (five-year
    groups), sex-specific, site-specific and period-specific (1965-1967,
    1970-1972) mortality rates to the 1966 or 1971 census populations for
    each municipality. Excess mortality due to cancer of the stomach and
    lungs in males, and pancreas in females, was observed in the two
    asbestos mining municipalities with known high exposures. The excess
    mortality among males was probably due to occupational exposure to
    asbestos. The absence of excess mortality due to pancreatic cancer in
    the male would suggest that the excess among females was not due to
    waterborne asbestos. The author concluded that the evidence derived
    from this study would indicate that the excess mortality due to cancer
    could not be attributed to exposure to asbestos in the drinking-water
    (Wigle, 1977).

    REFERENCES

    Cunningham, H. M., Moodie, C. A., Lawrence, G. A. and Pontefract, R.
    D. (1978) Chronic effects of ingested asbestos in rats, Arch. Environ.
    Contamination and Toxicol. (In press)

    International Agency for Research on Cancer (1973) IARC Monographs
    on the evaluation of carcinogenic risk of chemicals to man. Some
    inorganic and organometallic compounds, vol. 2, p. 17, Lyon, IARC

    International Agency for Research on Cancer (1977) IARC Monographs
    on the evaluation of carcinogenic risk of chemicals to man. 
    Asbestos, Vol. 14, Lyon, IARC

    Wigle, M.D. (1977) Cancer mortality in relation to asbestos in
    municipal water supplies, Arch. environm. Hlth, 32, 185

    See Also:
       Toxicological Abbreviations
       ASBESTOS (JECFA Evaluation)
       Asbestos  (IARC Summary & Evaluation, Supplement7, 1987)
       Asbestos (IARC Summary & Evaluation, Volume 2, 1973)
       Asbestos (IARC Summary & Evaluation, Volume 14, 1977)