FAO Nutrition Meetings 
    Report Series No. 48A 
    WHO/FOOD ADD/70.39




    TOXICOLOGICAL EVALUATION OF SOME
    EXTRACTION SOLVENTS AND CERTAIN 
    OTHER SUBSTANCES




    The content of this document is the 
    result of the deliberations of the Joint 
    FAO/WHO Expert Committee on Food Additives 
    which met in Geneva, 24 June  -2 July 19701




    Food and Agriculture Organization of the United Nations
    World Health Organization


                   

    1 Fourteenth report of the Joint FAO/WHO Expert Committee on Food
    Additives, FAO Nutrition Meetings Report Series in press; Wld Hlth
    Org. techn. Rep. Ser., in press.


    ACTIVATED VEGETABLE CARBON (FOOD GRADE)

    This material has been evaluated with specific reference to use as
    filtering aids or clarifying agent

    Biological data

    Biochemical aspects

    No information available.

    Acute toxicity

    No information available.

    Short-term studies

    Chicken

          Groups of 20 one-day old chicks received a diet containing 0% or
    2% charcoal for 34 days. No adverse effects other than those due to
    physical adsorption on to the charcoal of the essential nutrients
    vitamin A and K were seen. These effects could be reversed by
    additional administration of these factors (Almquist & Zander, 1940).

    Long-term studies

    Mouse

          Groups of 10-30, mostly male, occasionally female mice of either
    CFW (white) or C3H (brown) strain were fed for periods of 12-18
    months on diets containing 0% or 10% activated vegetable carbon. Diets
    had either a water or oil emulsion base. Controls received 15% flour
    using similar bases in their diet. No significant differences from
    controls were reported. Similar groups of male mice received 10% of
    benzene -extracted carbon black for 53-76 weeks. A number of tumours
    appeared irregularly and unrelated to duration of treatment or dose,
    probably due to contamination with carcinogenic extract.

          Similar groups of 10-30 mice received 200 ppm or 800 ppm of
    benzene - extracted material in their diet for 53-78 weeks. A
    significantly raised incidence of gastro-intestinal malignant lesions
    was found in test animals compared with controls. Lesions were similar
    to those produced in positive controls given 200 ppm
    methylcholanthrene in their diet (Nau et al., 1958).

    Special studies

    (a) Inhalation

          Test groups of 60 guinea-pigs, 30 rats and 131 mice, with 22
    guinea-pigs, 15 rats and 20 mice as controls were exposed to activated
    vegetable carbon dust for 7 hours per day, 5 days per week, for 1
    year. No significant effects were noted on mortality. At autopsy the
    lungs showed evidence of multifocal dust deposition. Histopathology
    showed dust deposits in alveoli with focal atelectasis and adjacent
    alveolar overexpansion as well as interstitial pneumonitis. Mice
    showed the least changes but rats had areas of lipid pneumonia. These
    findings were consistent with inert dust reaction (Gross & Nau, 1967).

    (b) injection

          0.27 g of charcoal suspended in cottonseed oil was injected
    s.c.into C3H Mice. After 16 months no gross or histopathological
    changes were observed related to the injection. Cottonseed oil, used
    to extract activated charcoal for either 30 or 90 days, was injected
    s.c. into mice. After 20 months no significant gross or
    histopathological changes were seen. 0.05-5 mg of benzene extract
    suspended in cottonseed oil was injected s.c. into mice. After 13
    months the only abnormal finding was a significant incidence of
    glomerulonephritis in treated animals as compared with controls (Nau
    et al., 1963).

    Mice

          A total of 2.9 g carbon black (suspended in mineral oil) or 3.2 g
    (suspended in cottonseed oil) were brushed three times a week on to
    the back of mice for 1 year. Animals were killed after 1 year or 16-17
    months. No significant gross or histopathological changes were seen
    compared with controls (Nau et al., 1963). 20% suspensions of
    activated vegetable carbon in water or oil were painted in another
    experiment three times per week on to the back of groups of 10-20 CFW
    or C3H mice. After 12-17 months no abnormalities were seen in test as
    compared with control groups (Nau et al., 1958a). Similar results were
    obtained when benzene-extracted carbon black was used (Nau et al.,
    1958a).

          Benzene extract of activated vegetable carbon, suspended in water
    or dissolved in benzene, was painted on to mice three times a week for
    12-17 months. Results varied with the type of activated vegetable
    carbon as regards local tumour formation but in a similar experiment
    using food grade material no significant pathological changes were
    seen (Nau et al., 1963; Nau et al., 1958a). Groups of 10 or 20 CFW or
    C3H mice were painted 3 times a week for 12-17 months using 20%
    suspensions of carbon black containing adsorbed methylcholanthrene in
    water or oil. Positive controls were treated with methylcholanthrene.
    Fewer tumours were produced in mice treated with carbon black
    containing adsorbed methylcholanthrene compared with positive controls
    observed for 12-18 months (Nau et al., 1958a).

          Rabbit

          Four rabbits were painted three times a week for 9-10 months with
    20% suspensions of carbon black in water or oil, one animal was
    treated for 23 months. No abnormal pathological findings were
    observed. Another two rabbits were treated for 8-1/2 and 21 months
    respectively with carbon black containing adsorbed 2000 ppm of
    methylcholanthrene. No abnormalities were detected (Nau et al.,
    1958a).

          Monkey

          Two monkeys were treated for 18 months with suspensions of carbon
    black. One monkey was observed for an additional 13 months without
    treatment. No abnormal pathological findings were seen (Nau et al.,
    1958a).

    Comments

    The available ingestion studies referred only to mice and produced no
    evidence that activated vegetable carbon exerted any adverse
    biological effects in this species.

    Evaluation

          When used in accordance with good manufacturing practice as a
    filtrating and clarifying agent no residues should result in food.

    REFERENCES

    Almquist, H. J. & Zander, D. (1940) Proc. Soc. exp, Biol. (N.Y.),
    45, 303

    Gross, P. & Nau, C. A. (1967) A.M.A. Arch. Eny. Hlth., 14, 450

    Nau, C. A., Neal, J. & Stembridge, V. (1958) A.M.A. Arch. ind.
    Hlth., 17, 20

    Nau, C. A., Neal, J. & Stembridge, V. (1958a) A.M.A. Arch. ind.
    Hlth., 18, 511

    Nau, C. A. et al. (1963) Unpublished Report from Atlas Chemical
    Company
    

    See Also:
       Toxicological Abbreviations