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    FAO/PL:1967/M/11/1
    WHO/Food Add./68.30

    1967 EVALUATIONS OF SOME PESTICIDE RESIDUES IN FOOD

    THE MONOGRAPHS

    The content of this document is the result of the deliberations of the
    Joint Meeting of the FAO Working Party of Experts and the WHO Expert
    Committee on Pesticide Residues, which met in Rome, 4 - 11 December,
    1967. (FAO/WHO, 1968)

    FOOD AND AGRICULTURE ORGANIZATION OF THE UNITED NATIONS
    WORLD HEALTH ORGANIZATION
    Rome, 1968

    DDT

    This pesticide was evaluated by the 1966 Joint Meeting of the FAO
    Working Party and the WHO Expert Committee on Pesticide Residues
    (FAO/WHO, 1967). Since the previous publication the results of
    additional experimental work have been reported. This new work and
    some earlier studies comparing DDT with its metabolites, DDD and DDE,
    are summarized and discussed in the following monograph addendum.

    EVALUATION FOR ACCEPTABLE DAILY INTAKE

    Biochemical aspects

    Induction of hepatic microsomal enzyme activity was found to occur in
    a dose-related manner at dietary levels of 1-50 ppm of DDT, but no
    induction was found at 0.2 ppm. Maximal induction occurred within the
    first three weeks, with fairly constant levels of increased activity
    being maintained after that time for the duration (13 weeks) of the
    study (Kinoshita et al, 1966).

    Daily oral administration of 150 mg/kg body-weight of technical DDT in
    the guinea-pig stimulated the formation of polar urinary cortisol
    metabolites. Administration of recrystallized DDT did not induce such
    an alteration of metabolism. (Balazs and Kupfer, 1966).

    Studies on rats receiving 0, 1, 5, 10 and 50 ppm of DDT in their diet
    for 4, 8 and 12 weeks, as well as 12 weeks followed by 4 weeks
    withdrawal, showed storage in the body fat at all levels with the
    possible exception of those receiving 1 ppm. Increased content of DDD
    in the diet resulted in an increase in the degree of storage. With
    continued ingestion of DDD its accumulation in the fat was progressive
    over the 12 week period. DDD appeared to have similar storage pattern
    in body fat to reported data on DDT, the major difference being that
    DDD disappears more rapidly than DDT when dietary intake of it is
    discontinued (Haag and Kampmeier, 1955).

    In a comparative study of tissue storage of DDD and DDT, 5 dogs were
    placed on 25 mg/kg/day DDD and 5 dogs ware placed on a similar amount
    of DDT. Both substances were administered orally in a 10 per cent
    solution of corn oil. Fat was found to be the major site of storage of
    a similar degree for both substances. Skin and adrenal tissue had the
    next highest content and small but measurable amounts were found in
    other tissues. Analyses of tissues of pups, born to some dogs during
    the course of the experiment showed that both DDD and DDT cross the
    placental barrier (Finnegan et al, 1949).

    Pure p,p'-DDD, technical DDD and various fractions isolated from the
    technical compound were compared in adrenocorticolytic action by
    peroral administration in normal dogs. As measured by peripheral
    eosinophil response to ACTH administration, urinary
    17-hydroxycorticoid excretion and general observation of well-being
    and morbidity, no effect of pure p,p'-DDD at 80-200 mg/kg

    body-weight/day for up to 60 days was seen, while the technical
    product and fractions identified as containing o,p'-DDD were strongly
    active. No histological change in the adrenals was found in the
    animals fed pure p,p'-DDD, while the technical product produced marked
    atrophy. Pure o,p'-DDD was found to produce massive necrosis and
    atrophy of the adrenals at 4 mg/kg body-weight/day (Cueto et al,
    1958).

    In the rat, o,p'-DDD at 300 mg/kg/day orally or 100 mg/kg/day
    sub-cutaneous for 3 days, and p,p'-DDD at 100-200 mg/kg/day orally for
    3-30 days, have been found to shorten barbiturate sleeping times
    markedly. This effect is associated with increased in vitro hepatic
    metabolizing enzyme activity and proliferation of smooth endoplasmic
    reticulum and is abolished by the administration of ethionine (Straw
    et al, 1965; Azarnoff et al, 1966).

    In contrast to the rat, while hexobarbital sleeping time in the dog is
    decreased, pentobarbital and secobarbital sleeping times are greatly
    increased after feeding 200 mg/kg/day of p,p'-DDD (Azarnoff et al,
    1966). In dogs given 200 mg/kg/day of technical DDD or recrystallized
    p,p'-DDD or 50 mg/kg/day of technical residual liquor from the
    recrystallization for 14 days, increased pentobarbital times were
    found in all groups, most pronounced after two weeks' administration
    and most profound in the animals given technical DDD; of five animals
    in this group, one died immediately after the 40 mg/kg pentobarbital
    test injection, and two others were sacrificed after 36 hours without
    recovery. No gross or microscopic change in the hypothalamus was seen
    in any group, and hepatic change was very slight or absent. No change
    in the adrenals was seen in the group receiving p,p'-DDD, although the
    other two showed typical atrophy. The rate of barbiturate clearance
    from the blood was not affected by DDD administration (Nichols et al,
    1958).

    DDE inhibits the succinoxidase and cytochrome oxidase systems of rat
    heart to a lesser degree than DDT (Johnson, 1951).

    Acute Toxicity

                                                                                       
                                  LD50 mg/kg
    Substance   Animal   Route    body weight   Reference
                                                                                   

    DDD         Rat      Oral         3400 )    Haag and Kampmeier, 1955
    DDT         Rat      Oral          250 )

    DDE         Mouse    Oral          700      von Oettingen and Sharpless (1946)

    DDE         Mouse    Oral        1,000      Domenjoz (1946)

    DDE         Rat      Oral        1,000      Smith, et al (1946)
                                                                                   
    
    Short-term studies

    Rabbits - Five rabbits given daily doses of DDE at the rate of 50
    mg/kg/day died after 11 to 18 days, whereas six other rabbits given
    DDT at the same dosage died in 15 to 25 days. The rabbits on DDE
    showed fewer clinal effects than those on DDT. On histological
    examination of the tissues of the rabbits, as well as the tissues of
    the rats on the acute studies, it was found that DDE produced less
    injury to the liver than DDT, but slightly greater kidney damage. The
    authors estimated that DDE was about 1/6 as toxic as DDT. (Smith et
    al, 1946).

    Dog - Dogs fed diets containing 100, 500 and 1,000 ppm DDD for 6
    months to 2 years showed moderate atrophy of the adrenals at 1,000 ppm
    and slight atrophy at the lower levels. The degree of atrophy did not
    seem to become progressively greater after the first 6 months (Haag
    and Kampmeier, 1955).

    Dogs were fed different isomers of DDT, technical DDT, DDD and DDE at
    80 mg/kg/day for up to 120 days. The isomers of DDT and technical DDT
    killed the dogs in 37 to 55 days. DDD killed the dogs in 80 days,
    whereas the dogs on DDE lived the entire period (Woodard et al, 1948).

    Long-term studies

    Mouse - BALB/c inbred mice were used in a five generation long-term
    toxicity study on DDT. Fifteen bigamous families were used for
    breeding in each generation. A total of 683 animals were selected from
    the five generations in the treated group, and 406 in the control
    group.

    DDT was added at 2.8 - 3.0 ppm to the feed of the treated group. The
    food contained a background contamination of 0.2 - 0.4 ppm of DDT.
    Apart from the difference in the levels of DDT in the feed for the two
    groups, the animals were kept under identical experimental conditions.
    The pre-weaning mortality was very high in the F1 and F2 generations
    in both treated and control groups, ranging between 50 and 60 per
    cent; in the succeeding generations the mortality declined but
    remained higher than that usually observed.

    A total of 196 tumours (28.7 per cent) and, additionally, 85 cases of
    leukaemia (12.4 per cent) were observed in the treated group.  The
    corresponding figures for the controls were : 13 (3.2 per cent) and 10
    (2.4 per cent). The incidence of neoplasia was higher in the females
    than in the males. No tumours were observed in the parental generation
    of either group. Neoplasia first appeared in the F1 generation and a
    marked difference in incidence between treated and control groups was
    observed from the F2 generation onwards. This difference increased in
    the later generations. The latent period of tumours is not clearly
    stated, although there is some indication that tumours occurred late
    in life; nor is it stated whether more than one tumour occurred in the
    same animal. The most common neoplasm was leukaemia, followed by
    reticulosarcoma and pulmonary adenocarcinoma. The incidence of

    pulmonary adenoma, reported to be 5 per cent in the colony, and not
    included in the percentages above, was not altered by the DDT
    treatment.

    The DDT content of adipose tissue in mice of the F3, F4 and F5
    generations was 0.7 - 2 ppm in the controls and 5 -11 ppm in the
    treated group. Only traces of DDE were found. (Kemény and Tarján,
    1966; Tarján unpublished, 1967).

    Rats - Groups of 7 male rats each were given diets containing 150,
    300, 600, 900, 1,200, 1,800, 2,500, 5,000 and 10,000 ppm of DDD for
    one year. All animals at 5,000 and 10,000 ppm died within 10 weeks.
    Liver lesions occurred in rats at levels of 900 and above. (Haag et
    al, 1948). In another study, a dosage level of 100 ppm DDD produced
    slight liver lesions in rats. The author estimated that DDD was 1/2 as
    toxic as DDT. (Lehman, 1965).

    Observations in man

    It has been shown that the storage of DDT in man is directly
    proportional to intake over a wide range of doses (0.04 to 35.0
    mg/man/day), so that from the level in the fat the daily dose can be
    estimated. Thus, it can be calculated that the highest average intake
    of DDT of any human population yet observed is slightly less than 2
    mg/man/day. From the data which have been reported, it is also
    apparent that in the USA, where the levels of DDT and DDE in human fat
    have been repeatedly investigated in the general population over a
    number of years, no increase has been noted since 1955. (Hayes, 1966).

    In 20 industrial workers heavily exposed to DDT for 11 -19 years, it
    was estimated from the DDT content of the body fat and from urinary
    DDA excretion that the average DDT intake was 17.5 - 18 mg/man/day. No
    abnormalities attributable to DDT were found in these workers. (Laws
    et al, unpublished).

    In men having no industrial exposure to DDT, mean concentrations of
    0.0058 ppm of p,p'-DDT, 0.0010 ppm of o,p'-DDT and 0.0114 ppm of
    p,p'-DDE were found in the circulating blood, with 90 per cent, 45 per
    cent and 87 per cent of the totals respectively in the serum. (Dale et
    al, 1966).

    A female patient with Cushing's syndrome was given 13.3 mg/kg/day of
    DDD (isomer proportion not stated) orally in oil for 18 days, rested
    for 39 days, given 34.6 mg/kg/day for 30 days, rested for 73 days,
    given 63.1 mg/kg/day for 3 days, rested for 2 days, then given 15.8
    mg/kg/day for 4 days. In all, a total of 127 g was administered over
    168 days. No change wee seen in urinary 17-ketosteroids or
    11-oxy-corticosteroids nor any other signs of improvement in her
    adrenal hypertrophy. During the last two courses of treatment, marked
    signs of intoxication were seen, i.e. somnolence, depression,
    headache, vertigo and nausea and vomiting, remitting during the 2-day
    rest period. Because of the failure of this treatment with DDD,
    partial adrenalectomy was performed. The left adrenal was found to

    have normal histological architecture and a DDD content of 50 ppm
    (whole tissue). The DDD content of adipose tissue was 140 ppm.
    (Sheehan et al, 1953).

    Six males and twelve females with metastatic adrenocortical cancer
    were given average courses of treatment of 8-40 g/day of o,p'-DDD for
    4 - 8 weeks. All showed anorexia and nausea, regardless of the route
    of administration, and many showed CNS depression without alteration
    in the results of psychometric examinations. In 5 cases, EEG
    examination showed indications of non-specific deterioration. No
    clinical chemical evidence of hepatic, renal or myeloid damage was
    found. Diminished urinary excretion of 17-ketosteroids and
    17-hydroxycorticoids was reported in 14, and objective regression of
    metastases in 7. Histological evidence of destruction and functional
    impairment of the adrenal cortex was reported, but the incidence and
    the number of glands examined microscopically was not given. Of orally
    administered DDD, 30-40 per cent of the dose was absorbed and
    subsequently concentrated principally in the fat-containing tissues.
    About 25 per cent of the daily absorbed dose appeared in the urine as
    metabolites, and a lesser and variable percentage in the faeces.
    Concentrations of DDD in adipose tissue ranged from 460 to 8750 ppm
    and adrenal concentrations from 114 to 987 ppm (Bergenstal et al,
    1960; Moy, 1961).

    One male and one female were given 1-10 g/day (the "usual maintenance
    dose" was stated to be 1-1.5 g/day) of o,p'-DDD for total periods of
    one and eight months respectively. CNS depression, nausea and vomiting
    were seen in both, and the male experienced a severe cutaneous
    reaction. Urinary 17-ketosteroids and 17-hydroxy-corticosteroids were
    decreased and plasma 17-hydroxy-corticosteroids were slightly
    decreased in the male. On histological examination of an adrenal gland
    from the male, normal architecture was found. A complete autopsy was
    performed on the female (death was due to myocardial infarction and
    ventricular rupture), and no change suggestive of drug intoxication
    was found in any organ. The adrenal cortex contained some areas of
    focal necrosis believed attributable to the treatment. A third
    patient, not reported in detail, was found to have no adrenal
    histological changes following a similar regime (Wallace et al, 1961;
    Weisenfeld and Goldner, 1962).

    A female was treated with a total of 382 g of o,p'-DDD over 105 days.
    Some anorexia was noted. Urinary excretion of 17-ketosteroids was
    diminished. No alterations in the results of clinical chemical tests
    for liver function were seen although a needle biopsy of the liver
    showed marked fatty change. Adrenal tissue was not examined. (Gayer,
    1962).

    Five patients with adrenal adenoma or hyperplasia and eight without
    adrenal function, maintained on exogenous cortisol, were given 4-9
    g/day of o,p'-DDD orally for 3-42 days. Urinary
    17-hydroxy-corticosteroids were reduced in both cases; however, plasma
    17-hydroxy-corticosteroid levels and cortisol secretion rates were not
    affected, a result that was interpreted as indicating that the drug

    had no effect on adrenal function. From the further finding that the
    proportion of cortisol excreted as tetrahydrocortisol and
    tetrahydrocortisone was markedly diminished and the proportion
    excreted as 6-hydroxy-cortisol was increased; the conclusion was drawn
    that the effect of DDD on steroid excretion in the human is
    accomplished by alteration of the extra-adrenal (presumably hepatic)
    metabolism of cortisol. No change was seen in any of several clinical
    chemical parameters of hepatic function. Adrenal tissue was not
    examined in this study (Bledsoe et al, 1964).

    Comments

    Since the last evaluation further details on the long-term toxicity of
    DDT in multigeneration experiments in mice have become available
    indicating a higher incidence of neoplastic disorders in the DDT
    group. Though these studies are not yet complete, the results raise
    questions which cannot be dismissed. Taking into account the
    difficulties of extrapolating these findings to man, an alteration in
    the ADI for DDT was not considered justified pending the assessment of
    the significance of these findings.

    The animal data, with the exception of that for the DDD on dogs, show
    that both DDD and DDE are less toxic than DDT. Large doses of DDD have
    been used for therapeutic treatment of adrenal disorders in man. It
    was concluded that the relatively small residues of DDD associated
    with residues of DDT on agricultural products would cause no
    deleterious effect on the adrenal glands of humans.

    It was decided to treat mixtures of DDT and its metabolites, like DDT
    and establish the same ADI for the mixture or of each separately.

    TOXICOLOGICAL EVALUATION

    Estimate of acceptable daily intake for man

         0 - 0.01 mg/kg body weight for DDT, DDD or DDE or any combination
         of the three.

    Further work required

    This will depend on the outcome of further re-evaluation of
    carcinogenicity of this chemical in the light of the new data. If
    further experiments were necessary the meeting urged that those should
    be given a high priority.

    EVALUATION FOR TOLERANCES

    USE PATTERN

    Pre-harvest treatments

    DDT is used to a minor extent as a soil treatment, primarily for the
    control of cutworms which attack vegetable crops. It is suggested for

    use in many countries on a wide variety of food crops. It is suggested
    for the control of about 20 different insects which attack cane
    fruits, about 50 different insects which attack vegetables, 50
    different insects which attack tree fruits, as well as for control of
    insects of nut trees and other food crops. The usual rate of
    application is about 2 to 4 lb. of the active chemical per acre;
    however, some treatments may go as high as 12 lb. per acre.

    RESIDUES RESULTING FROM SUPERVISED TRIALS

    Although there have been many analyses made for DDT in agricultural
    products, many of then were not made on controlled experiments
    designed explicitly to ascertain the fate of the residue following
    application. A summary of numerous data, which is too long to
    reproduce here and which contains the related bibliography, is held at
    the FAO headquarters in Rome. Table 1 has been prepared from this
    summary. It contains estimates of the average high residues likely to
    result from the practical use of DDT to control insects which attack
    the different food commodities or that in animal products from animals
    exposed to "unavoidable" or very limited feed residues.

        TABLE 1
                                                                                    

                       Residues of DDT resulting from good agricultural practice

    Crop Type                 Preharvest                 Usage          Resulting
                              period days                lbs/A          residue ppm
                                                                                    

    Tree fruits

    Apples and quinces            30                     12                7
                           (42 if more than
                            3 applications)

    Peers                          "                     12                7

    Apricots and                  30
    nectarines             (42 if more than              12                7
                            1 application)

    Cherries                      30                     8                 3.5

    Peaches                       30                     8                 7

    Plums                         30                     8                 3.5

    Citrus

    All citrus fruits             30                     4                 3.5

    TABLE 1 (cont'd)
                                                                                    

                       Residues of DDT resulting from good agricultural practice

    Crop Type                 Preharvest                 Usage          Resulting
                              period days                lbs/A          residue ppm
                                                                                    
    Tropical Fruits

    Avocados                      30                     12                3.5

    Guavas               Soil application only                             1

    Mangoes                       30                     12                7

    Papayas                       30                     8                 3.5

    Pineapples                    90                     3                 1

    Cranberries
    and small fruits

    Blackberries  )
    Boysenberries )       Do not apply after             2                 1
    Loganberries  )           fruit forms
    Raspberries   )

    Blueberries                   21                     2                 7

    Cranberries                   35                     6                 7

    Grapes                        40                     1.5               7
                                                         lbs/100 gal.

    Strawberries          Do not apply after             4                 1
                              fruit forms

    Melons                         5                     12                7

    Leafy vegetables

    Celery                    3 - 4 weeks                1.2               1

    Collards                      21                     2.5               3.5

    Endive                Do not apply after             2                 1
                            seedling stage

    Kale                          21                     2.5               3.5

    Leaf lettuce          Do not apply after             2.5               1
                            seedling stage

    TABLE 1 (cont'd)
                                                                                    

                       Residues of DDT resulting from good agricultural practice

    Crop Type                 Preharvest                 Usage          Resulting
                              period days                lbs/A          residue ppm
                                                                                    

    Mustard greens                21                     2.5               3.5

    Spinach                       21                     2.5               3.5

    Swiss chard                   21                     2.5               3.5

    Turnip, parsnip, etc.         21                     2.5               3.5
    tops

    Brassica crops

    Broccoli              Do not apply after             4                 1
                           edible parts form

    Brussels sprouts      Do not apply after             4                 1
                           edible parts form

    Cabbage                       14                     1.2               7
                          (if wrapper leaves
                             are stripped)

    Cauliflower           Do not apply after             1.2               1
                           edible parts form

    Kohlrabi              Do not apply after             4                 1
                           edible parts form

    Root Vegetables

    Beets                                                1.5               1

    Carrots                                              1.5               1

    Dry onions                                           1.5               1

    Parsnips                                             1.5               1

    Radishes                                             1.5               1

    Rutabagas                                            1.5               1

    Turnips                                              1.5               1

    TABLE 1 (cont'd)
                                                                                    

                       Residues of DDT resulting from good agricultural practice

    Crop Type                 Preharvest                 Usage          Resulting
                              period days                lbs/A          residue ppm
                                                                                    

    Legumes and
    other vegetables

    Artichokes            Do not apply after             2.5               1
                           edible parts form

    Asparagus             Do not apply during            3                 1
                            cutting season

    Beans                          7                     2                 3.5

    Cucumbers                                           10 (soil only)
    Pumpkins and Squash                                  2 (soil only)

        OR

    Cucumber                       5                     4                 2
    Pumpkins and Squash            5                     2                 2

    Eggplant                       5 (wash or brush)     2                 7

    Lettuce (Head)                 7 (if outer leaves    2.5               7
                                      are removed)

    Mushrooms             Spray houses before                              1
                         mushrooms are present

    Okra                           7                     1.2               1

    Pepper                         5                     3                 7

    Peas                  Do not apply after             1.2               3.5
                               pods form
                                                                                    
    

    RESIDUES IN FOOD AT TIME OF CONSUMPTION

    A number of samples from total diet studies have been analyzed in the
    United States. Although a high proportion have had detectable amounts
    of DDT, DDE and DDD, the average values are very low (Mills, 1963;
    Williams, 1964; Cummings, 1965). The highest values were found in the
    meat and meat products portion of the diet. In a two-year summary

    (Duggan, Barry and Johnson, 1967) the average values for all samples
    of meat and meat products was 0.30 ppm DDT, 0.25 ppm DDE, and 0.14 ppm
    TDE. However, when the total diet values were calculated to daily
    intake values (Duggan and Dawson, 1967), the value 0.0005 mg/kg/day
    was found, which is much below the WHO ADI value of 0.01 mg/kg/day.

    FATE OF RESIDUES

    In storage and processing

    DDT is stable under most of the conditions which prevail when it is a
    residue on stored food products. Therefore, residues in food products
    will not normally diminish greatly from most food products during
    shipping and storage. It is especially stable in a fatty medium.

    Recent studies reported by Lamb et al (1967) show that during short
    storage periods for tomatoes (6 days at 55°F), green beans (16 days at
    45°F), spinach (15 days at refrigerator temperature), and potatoes (40
    days at 45°F), the residues of DDT did not diminish nor did isomeric
    composition of the residue change.

    On the other hand, washing and processing produced a marked reduction
    in residues. Surface residues of DDT applied as a wettable powder were
    easily removed, especially from tomatoes. A high proportion was
    removed from green beans and spinach. For instance, a cold water wash
    of green beans removed about half of the o,p'-DDT, about 75 percent of
    the p,p'-DDT, and better than 40 percent of the p,p'-DDE. DDT and
    related compounds present on potatoes can be almost completely removed
    by removal of the skins, but cannot be removed to any significant
    extent by washing without peeling or by cooking when skins are not
    removed.

    Data are also presented which show a very significant conversion of
    DDT to DDD during certain heat processing. The extent to which DDT is
    converted to DDD depends on the time and temperature of processing.
    After processing green beans for 12 minutes at 250°F, DDT and DDD were
    found in the canned product, but after processing spinach for 50
    minutes at 252°F only DDD and DDE could be found. The DDD and DDE
    found in these products account for less than half of the DDT. (Lamb,
    et al, 1967 and Farrow, et al, 1966).

    NATIONAL TOLERANCES

    Additional information on national tolerances will be found in the
    Report of the Second Session of the Codex Committee on Pesticide
    Residues (FAO/WHO, 1967b).

    RECOMMENDATIONS FOR TOLERANCES AND PRACTICAL RESIDUE LIMITS

    Considering the additional data summarized above, the Joint Meeting
    withdraws the previously published Recommendations for Tolerances on
    pages 63 and 64 of the 1966 monographs (FAO/WHO, 1967a) and
    substitutes the following therefor :

    Temporary tolerances

    When DDT is utilized in accordance with good agricultural practice to
    protect food products, when necessary, against insect infestation, the
    treated product may have residues as high as those shown below :

    Fruits

    Apples, pears, peaches, apricots                  7

    Cherries, plums, citrus, tropical fruits          3.5

    Small fruits (except strawberries)                7

    Strawberries                                      1

    Vegetables

    Leafy and brassica                                7

    Root vegetables                                   1

    Other                                             7

    Meat, fish, poultry                               7 (in fat)

    By no means will all samples of these products contain this amount of
    residue; in fact, only a relatively small, yet unknown, portion of
    each product in these categories is likely to be treated. Also, an
    extensive study on the effect of washing and other preparation of food
    processing (Lamb, et al, 1967) shows a significant amount of reduction
    in incurred residues. (Data reviewed above).

    Other data which gives support to the above factors is that in the
    United States "total diet" samples DDT and metabolites DDD and DDE are
    found at very low levels (data reviewed above).

    The Joint Meeting is convinced that under the conditions of practical
    use, the above residues on products which need to be protected will
    not produce a total diet which will contain an amount of DDT and
    metabolic analogues in excess of the ADI for DDT.

    Because further work is required for the Evaluation for Acceptable
    Daily Intake, the meeting recommends that temporary tolerances be
    adopted for a period ending December 31, 1970, for the residue values
    for the products shown above. The temporary tolerances apply to DDT
    and its related compounds DDD and DDE.

    Practical residue limits :

              Milk                0.005 ppm

              Milk products       0.2 ppm (fat basis)

    Recommendations for practical residue limits are made because the
    widespread use and stability of DDT have resulted in small residues
    being ubiquitous. Small residues have been found to be present in most
    dairy products. This is considered to be undesirable but is also
    unavoidable at the present time. Since this residue is generally not
    present from direct application to the animals or their feed, no
    tolerance recommendation is made. However, to assist regulatory
    officials in identifying those samples which have residues much in
    excess of the unavoidable level, a practical residue limit of 0.20
    ppm DDT is suggested.

    Residues of DDT in animal products are invariably associated with
    varying amounts of the DDT metabolites DDE and DDD. In many instances
    the residues of either of these or the sum of the two exceeds the
    residue of DDT. As shown in the paragraph on fate of residues during
    processing, DDD and DDE may be found in processed food by conversion
    by the processing.

    FURTHER WORK

    Further work desirable

    Further data on the possible disappearance of residues during washing,
    cooking and other preparation of food products for consumption.

    REFERENCES PERTINENT TO EVALUATION FOR ACCEPTABLE DAILY INTAKES

    Azarnoff, D.L., Grady, H.J. and Svoboda, D.J. (1966) Biochem.
    Pharmacol., 15, 1985

    Balazs, T. and Kupfer, D. (1966) Toxicol. appl. Pharmacol., 9, 40

    Bergenstal, D.M., Herts, R., Lipsett, M.B. and Moy, R.H. (1960) Ann.
    intern. Med. 53, 672.

    Bledsoe, T., Island, D.P., Ney, R.L. and Liddle, G.W. (1964) 
    J. Clin. Endocrinol., 24, 1303.

    Cueto, C., Brown, J.H. and Richardson, A.P. jr. (1958)
    Endocrinology, 62, 334

    Dale, W.E., Curley, A. and Cueto, C. jr. (1966) Life Sci., 5, 47

    Domenjoz, R., Arch. int. Pharmacodyn. 73, 128

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    See Also:
       Toxicological Abbreviations
       Ddt (ICSC)
       DDT (JECFA Evaluation)
       DDT (PIM 127)
       DDT (FAO Meeting Report PL/1965/10/1)
       DDT (FAO/PL:CP/15)
       DDT (FAO/PL:1968/M/9/1)
       DDT (FAO/PL:1969/M/17/1)
       DDT (Pesticide residues in food: 1979 evaluations)
       DDT (Pesticide residues in food: 1980 evaluations)
       DDT (Pesticide residues in food: 1984 evaluations)
       DDT (JMPR Evaluations 2000 Part II Toxicological)