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    FAO/PL:1968/M/9/1

    WHO/FOOD ADD./69.35

    1968 EVALUATIONS OF SOME PESTICIDE RESIDUES IN FOOD

    THE MONOGRAPHS

    Issued jointly by FAO and WHO

    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 Geneva, 9-16 December,
    1968.

    FOOD AND AGRICULTURE ORGANIZATION OF THE UNITED NATIONS

    WORLD HEALTH ORGANIZATION

    Geneva, 1969

    BHC (TECHNICAL GRADES)

    IDENTITY

    Chemical name

         (Mixed stereoisomers of) 1,2,3,4,5,6-hexachlorocyclohexane.

    Note: Lindane, the gamma-stereoisomer of
    1,2,3,4,5,6-hexachlorocyclohexane of purity 99 per cent (minimum),
    has been evaluated earlier (FAO/WHO, 1967) when various temporary
    tolerances were proposed.

    Synonyms

         BHC: benzene hexachloride; HCH, 666: hexachlor; HCCH.

    Formula

         C6 H6 Cl6

    Technical BHC is a mixture of a number of sterioisomers, principally
    alpha-BHC, beta-BHC, gamma-BHC and delta-BHC. The proportion of the
    isomers in different technical mixtures can vary widely. Two grades
    are covered by specification WHO/SIT/2.R3 (approved 25 October 1965),
    the compositional requirements of which relate merely to the
    gamma-isomer content.

         Technical HCH: 12.0 to 16.0 per cent gamma isomer;
         Refined HCH:   16.1 to 98.9 per cent gamma isomer.

    Other isomers reported are eta-, zeta- and
    theta-hexachlorocyclohexanes and a small proportion of hepta- and
    octachlorocyclohexanes may also be present. The following analyses
    have been reported for the grade containing approximately 13 per cent
    of gamma-isomer.

                                                                                     
                           Percentage composition according to:

                                  Ramsey and    Kauer
                     Slade        Patterson,    et al.,   Riemschneider,   Lehman,
                     1945a        1946          1947         1955          1965
                                                                                 

    Alpha-BHC        Up to 70     65-70         55           55-80           64

    Beta-BHC         5            5-6           14           5-14            10

    Gamma-BHC        10-12        13            12           8-15            13

    Delta-BHC        7            6             8            2-16             9

    (continued)
                                                                                 
                           Percentage composition according to:

                                  Ramsey and    Kauer
                     Slade        Patterson,    et al.,   Riemschneider,   Lehman,
                     1945a        1946          1947         1955          1965
                                                                                 

    Eta-BHC          -            -             3-4          3-5            1-3

    Heptachloro-     -            4             -            -              -
    cyclohexane

    Octachloro-      -            0.6           -            -              -
    cyclohexane
                                                                                 
    
    Other technical grades containing approximately 36-40 per cent or
    approximately 75 per cent gamma-isomer also appear to be available.

    Other information on identity and properties

    The technical grades of BHC are amorphous off-white to brown powders
    with a persistent, musty odour and with no characteristic melting
    point. The products are stable towards light, heat, air, moisture and
    acids but are dehydrochlorinated by alkalis at ordinary temperatures.
    While the individual isomers have different chemical and physical
    properties, the differences are small in each case.  Thus, all the
    isomers are only sparingly soluble in water; the literature has been
    reviewed by Gunther et al. (1968), typical values for alpha-, gamma-
    and delta-BHC being 10 ppm and beta-BHC 5 ppm at 20░C. The solubility
    of technical BHC is also recorded as about 10 ppm; but rising with
    prolonged equilibration to 20 ppm (24 h) and 32 ppm (36 h). Like other
    organochlorine insecticides, the BHC isomers are generally soluble in
    organic solvents. Davidek and Janicek (1967) have studied the effect
    of technical BHC on the stability of beta-carotene but with somewhat
    inconclusive results; a stabilizing influence is suggested for BHC
    concentrations between 10 and 100 ppm.

    EVALUATION FOR ACCEPTABLE DAILY INTAKE

    Biochemical aspects

    Female rats were injected intraperitoneally with two per cent
    chlorine36 labeled alpha- or gamma-hexachlorocyclohexane in oil (100
    and 40 mg respectively) and the excretion pattern was determined over
    40 days. Only 75-80 per cent of the total radioactivity was excreted;
    80 per cent of this amount was eliminated in the urine and 20 per
    cent in the faeces. Of the urinary activity 60 per cent was found as

    chloride ion and 40 per cent as chlorinated organic compounds; the
    latter being greater just after administration. The gamma isomer was
    eliminated more rapidly than the alpha isomer (Koransky et al., 1964).

    The ▀ isomer is eliminated the most slowly of all the isomers. A
    possible metabolite of the mixed isomers is 1,2,4-trichlorobenzene
    (Lehman, 1965).

    The alpha, ▀ and delta-isomers appear to have an antagonistic effect
    against the biological activity of the gamma-isomer, since they lower
    the toxicity of the latter when injected into mice, rabbits and dogs
    (McNamara and Krop, 1948; van Asperen, 1954). Differences in rates of
    the metabolism of the isomers occur in mice. After subcutaneous,
    intravenous and intraperitoneal injection, the alpha, gamma and
    delta-isomers are rather rapidly broken down, none being excreted in
    the urine. The gamma and delta-isomers are metabolized at a higher
    rate than the alpha-isomer, but the ▀-isomer is metabolized very
    slowly indeed (van Asperen, 1954). The alpha, ▀ and gamma-isomers of
    BHC produce, even after a single application, a considerable
    acceleration of the detoxication processes in the liver microsomes of
    rats in vitro. The toxicity of some convulsant drugs is also lowered
    (Ghazal et al., 1964).

    The alpha, beta, gamma and delta-isomers of BHC are stored unaltered 
    in the fat of rats and dogs (Davidow and Frawley, 1951). They are also
    stored in the body fat of humans as shown in the following table:

                                                                                          
                                      BHC isomers        Total
    Country          Date        alpha   beta    gamma    BHC     References
                                                                                      

    United States    1964        0.03    0.60             0.63    Hayes et al., 1965
    of America

                                 0.28    1.39             1.67)
    India            1964                                     >   Dale et al., 1965
                                 0.06    0.80             0.86)

    New Zealand      1964-65     0.08    0.40     Tr.     0.48    Dacre, 1968

    Great Britain    1965-67             0.28             0.31    Abbott et al., 1968

    Australia        1966        0.12    0.39     0.25    0.76    Wasserman et al., 1968
                                                                                      
    
    BHC isomers have been detected in the urine of people who have not
    been exposed directly to these insecticides: alpha, 0.0003-0.0004;
    gamma, 0.0002-0.0004; delta, 0.0004-0.0009 ppm (Cueto and Biros,
    1967).

    Pharmacological activity

    The alpha and gamma isomers are both convulsant poisons, the beta and
    delta isomers are depressants, and the epsilon and eta isomers appear
    inactive (Gero, 1959).

    Acute toxicity

                                                                   
    Animal    Route     Isomer   LD50 (mg/kg)   References
                                                                   

    Mouse     oral     Mixture        700       Furman, 1955

    Mouse     oral      alpha        1000       Burkatskaya, 1959

    Mouse     oral      beta         1500       Burkatskaya, 1959

    Mouse     oral      gamma         200       Burkatskaya, 1959

    Rat       oral      alpha         500       Burkatskaya, 1959

    Rat       oral      beta         2000       Burkatskaya, 1959

    Rat       oral      gamma         300       Burkatskaya, 1959

    Rat       oral      alpha        1500       Riemschneider, 1949

    Rat       oral      beta         2000       Riemschneider, 1949

    Rat       oral      gamma         225       Riemschneider, 1949

    Rat       oral      delta         750       Riemschneider, 1949

    Rat       oral      alpha        1700       Slade, 1945b

    Rat       oral      beta       No deaths    Slade, 1945b

    Rat       oral      gamma         190       Slade 1945b

    Rat       oral      delta        1000       Slade, 1945b

    Rat       oral     Mixture       1250       Slade, 1945b

    Rat       oral     Mixture        600       Lehman, 1951
                                                                   

    Short-term studies

    Dog. Three dogs received daily oral doses of 50 mg/kg (2000 ppm) of
    technical BHC containing 15.3 per cent gamma-isomer. They did not
    survive beyond 35, 45 and 48 days and some liver damage was noted in
    the animals (Woodard and Hagan, 1947).

    Long-term studies

    Rats. Groups of 10 male and 10 female rats were fed 0, 10, 50, 100
    or 800 ppm technical BHC in corn oil solution for two years. Mortality
    was increased, and body-weight gain was decreased at 800 ppm. Liver to
    body-weight ratio was increased at 100 and 800 ppm. Histopathological
    examination showed slight to moderate increase in the amount of focal
    nephritis, and moderate testicular atrophy at 50 ppm and above.
    Incidence of neoplasms was normal in all groups. Haematological data
    were not reported (Fitzhugh et al., 1950).

    Two year feeding studies on the various isomers to rats indicated
    no-effect levels at <10 ppm (beta), 10 ppm (alpha), <800 ppm (delta),
    and 50 ppm (gamma). Gross effects resulted from 10 ppm (beta), 100 ppm
    (alpha) and 100 ppm (gamma). (Metcalf, 1955)

    Comments

    Due to the widely differing toxicological properties of the
    constituents of BHC (technical grades), no estimate of acceptable
    daily intake for man is possible until the material is standardized
    and specific contents are laid down. The pure gamma-isomer of BHC
    (Lindane, gamma-BHC) has already been evaluated for toxicity (see FAO,
    PL:CP/15; WHO/Food Add./67.32, 1962, pp. 126-141) and an estimate of
    the acceptable daily intake for man was made at 0-0.0125 mg/kg
    body-weight. The data in that monograph should be used in conjunction
    with any assessment of the toxicity of BHC (technical grades).

    RESIDUES IN FOOD AND THEIR EVALUATION

    Use pattern

    Whereas hexachlorocyclohexane is widely used both in agricultural and
    veterinary practice and also in public health, food storage and for
    other purposes, there is no clear understanding as to what proportion
    of the use is as lindane (99 per cent plus gamma-isomer) and what
    proportion is as technical grades of BHC. The last Joint Meeting was
    informed that total BHC production in the United States of America in
    1963 was 3060 tons, including 720 tons of lindane, the annual
    world-wide use of BHC being estimated at 60 000-70 000 tons, including
    5000-6000 tons lindane (i.e. only 10 per cent of the total). The same
    meeting also noted the occurrence of different isomers of BHC,
    particularly beta-BHC, in human fat and human milk and concluded that
    this indicated a widespread use of technical grades of BHC. So far as
    is known, the general use pattern (though not necessarily the extent)
    of BHC is similar to that for lindane.

    Residues may arise from the use of technical grades of BHC; but since
    the different isomers of BHC differ in their degree of persistence,
    residues resulting from the use of "technical BHC" are of variable
    composition. Daily intakes and tolerances can only be considered in
    terms of individual isomers or (should this prove to be the case)
    specific combinations of these. Residue analyses results should

    separately record any residues of BHC isomers (particularly alpha-,
    beta-, and gamma-isomers).

    Residues resulting from supervised trials

    Little, if any, specific information is available relating to residues
    other than of gamma-BHC.

    Residues in food moving in commerce or at consumption

    The Netherlands Government has consolidated residue information for
    the period 1964-66 for shipments of imported cereal produce (Anon.,
    1968). The multi-detection system of analysis used was sensitive to
    0.01 ppm gamma-BHC, small residues of which were detected in a
    relatively high proportion of the samples (received from all over the
    world); the proportion was less in 1966 than in previous years but in
    no instance is reference made to other BHC isomers, and it is not
    clear whether this is because these were not specifically sought in
    the analysis or because residues were absent.

    While there is, in general, relatively little residue information
    relating to specific BHC isomers other than gamma-BHC, much of the
    information of this kind that is available relates to total diet
    studies. Cummings (1966) however, reports United States results as
    "lindane and/or BHC". The proportion of samples found to contain
    detectable residues and the levels in individual diet categories are:

                                                                     
                             Percentage of samples
                             containing detectable    Level of residue
                                   residues               (ppm)
                                                                     

    Dairy products                    42              trace - 0.010

    Meat, fish products               47              0.001 - 0.046

    Grain, cereal products            68              trace - 0.11

    Potatoes                          20              trace - 0.001

    Leafy vegetables                  26              trace - 0.015

    Legume vegetables                 21              trace - 0.002

    Root vegetables                   16              trace - 0.015

    Garden fruit                      33              trace - 0.016

    Fruit                             32              trace - 0.009

    Oil, fats, etc.                   33              0.001 - 0.007

    (Continued)
                                                                     
                             Percentage of samples
                             containing detectable    Level of residue
                                   residues               (ppm)
                                                                     
    Sugars, etc.                      40              trace - 0.023

    Beverages                         67              less than 0.001
                                                                     

    More recently, Duggan (1968) has summarized the whole of the United
    States monitoring programme and results for the period mid-1963 to
    mid-1967. Gamma-BHC and BHC are recorded separately, the intakes for
    the high consumption (approximately twice normal) diet being shown in
    Table I, and the results for individual market-basket groups in Table
    II, Total diet study results for the period October 1966 to October
    1967 are also available for England and Wales using multidetection
    system of analysis capable of detecting alpha-, beta- and gamma-BHC
    isomers individually (limit of detection 0.001 ppm) (Abbott et al.,
    1969). Results are shown in Table III.

    TABLE I.  UNITED STATES TOTAL DIET RESULTS FOR GAMMA-BHC AND BHC
                                                                   

                             Gamma-BHC             BHC
                                                           
                             Dietary intake rate - mg/kg/day
                                                           

    1964-65                  0.00007             0.00003
    1965-66                  0.00006             0.00004
    1966-67                  0.00007             0.00003
    Three-year average       0.00007             0.00003
                                                           
                             Average incidence (per cent)
                                                           

    1964-65                  15.8                6.5
    1965-66                  12.3                6.0
    1966-67                  10.6                8.9
                                                           
                                  Daily intake (mg)
                                                           
    1964-65                  0.004               0.002
    1965-66                  0.004               0.004
    1966-67                  0.005               0.002
                                                                   

        TABLE II.  UNITED STATES INDIVIDUAL MARKET BASKET RESULTS FOR GAMMA-BHC AND BHC, PPM*
                                                                                        

                               gamma-BHC                               BHC

                   Domestic    Imported    Composite    Domestic    Imported    Composite
                                                                                        

    Large fruit        T           T          TT            T           T          TT

    Small fruit        T           T           -            T           T           -

    Grains and         T           T         0.008          T           T          TT
    cereals

    Leaf, stem
    vegetables       0.01          T          TT            T           T          TT

    Vine, ear
    vegetables         T           T         0.002          T           T          TT

    Root               T           T          TT            T         0.02         TT
    vegetables

    Beans              T           T          TT            T           T           -

    Eggs               T           T           -            T           T           -

    Nuts               T         0.01          -            T         0.08          -

    Processed        0.04        0.01          -            T           T           -
    foods

    Animal             T           T           -            T           -           -
    grains

    Milk (fat          T           -           -          0.01          -           -
    basis)

    Dairy              T         0.01          -          0.02        0.14          -
    products
                                                                                        

    *   Raw domestic and imported samples; ready-to-eat composite samples.
    T - less than 0.005 ppm;   TT - less than 0.001 ppm.

    TABLE III.  BHC ISOMERS IN TOTAL DIETS (ENGLAND AND WALES) PPM
                                                                                        

                     Alpha-BHC               Beta-BHC                 Gamma-BHC

                  Mean       Range         Mean      Range         Mean       Range
                                                                                        

    Meats         0.0045     nil-0.060     0.0055    nil-0.050     0.0065     nil-0.060

    Fats          0.0305     nil-0.160     0.0165    nil-0.080     0.0125     nil-0.080

    Fruit,        0.001      nil-0.006     0.002     nil-0.012     0.002      nil-0.007
    preserves

    Root            *        nil-0.004     0.002     nil-0.008     0.0015     nil-0.012
    vegetables

    Green         0.001      nil-0.020     0.0015    nil-0.010     0.003      nil-0.035
    vegetables

    Milk          0.0015     nil-0.007     0.0005    nil-0.002     0.001      nil-0.004

    Cereals       0.002      nil-0.011     0.003     nil-0.018     0.0085     0.001-0.050

    Total         0.003      nil-0.012     0.003     nil-0.010     0.004      0.002-0.013
                                                                                        

    *  Less than 0.0005.
    
    Bro-Rasmussen et al. (1968) have examined 260 samples of Danish milk
    and dairy produce during the period 1964-65 and found a mean alpha-BHC
    residue level of 0.05 ppm on a fat basis (approximately 0.002 ppm on
    the whole milk) with a maximum value of 0.28 ppm. Corresponding values
    for gamma-BHC were: average 0.02 ppm; maximum 0.11 ppm. The average
    alpha-BHC residue in butter was also 0.05 ppm on a butter fat basis
    (gamma-BHC 0.01 ppm). From 0.005 to 0.04 ppm alpha-BHC was found in
    animal feeds.

    Fate of residues

    General comments

    All hexachlorocyclohexane isomers are fat soluble and are persistent
    to different extents.

    In plants

    There is little or no information on the terminal residues arising
    from the use of technical mixtures of BHC isomers on plants.

    In animals

    Egan (1965a) has reported the residue levels of alpha- and
    gamma-isomers in sheep fat following dipping with BHC.

    In storage and processing

    Duggan (1968) has summarized recent United States market basket
    residue survey work. A summary of the results for raw produce in the
    United States of America, imported and otherwise, are given above.

    In man

    Egan et al. (1965b) and Abbott et al. (1968) have reported residues of
    BHC isomers in human fat and human milk. Alpha-, beta- and
    gamma-isomer residues were normally found in all fat samples with
    beta-BHC predominating to the extent of 90 per cent of the total BHC
    residue. The mean total BHC residues 1964-1965 was 0.42 ppm; standard
    error, 0.03 ppm; median value, 0.39 ppm; geometric mean, 0.34 ppm; 95
    per cent confidence limits of 0.29-0.41 ppm. Similar results were
    found 1965-1967, with 90-95 per cent, beta-BHC, the remainder of the
    residue containing roughly equal amounts of alpha- and gamma-BHC; mean
    total level, 0.31 ppm; standard error, 0.01 ppm; median value, 0.29
    ppm; geometric mean, 0.25 ppm; 95 per cent confidence limits,
    0.22-0.27 ppm. The arithmetic mean beta-BHC level for the whole period
    was 0.28 ppm. For 23 prematurely born infants the mean beta-BHC level
    was 0.12 ppm (range 0.0-0.55 ppm). The average total BHC residue found
    in 19 samples of human milk was 0.013 ppm, nearly all of it beta-BHC.

    Methods of residue analysis

    The general remarks on methods of residue analysis, on multidetection
    systems and on methods for residues of organochlorine pesticides
    (FAO/WHO, 1967) apply to the determination of BHC isomer residues. The
    quantitative gas chromatography determination of alpha-, beta-,
    gamma-, delta-, epsilon- and eta-BHC isomers, together with gamma- and
    epsilon-heptachlorocyclohexanes, in admixture has been described by
    Davis and Joseph, 1967. A number of published gas chromatographic
    multidetection systems of organochlorine pesticide residue analysis
    can be used for the separate detection and estimation of alpha-, beta-
    and gamma-BHC isomers although for optimum separations, special column
    fillings are desirable. Thus the separation of beta- and gamma-BHC
    isomers can be controlled by the amount of Epikote resin included in
    the column stationary phase; a cyanosilicone column is particularly
    useful for BHC isomer analysis.

    National tolerances

    There are no established tolerances for technical mixtures of BHC
    isomers as such; nor for individual isomers other than the
    gamma-isomer. There are some tolerances for total BHC; in some there
    is need for clarification of the position as between tolerances for
    total BHC and for gamma-BHC.

    RECOMMENDATIONS FOR TOLERANCES AND PRACTICAL RESIDUE LIMITS

    Appraisal

    While technical grades of BHC are widely used in agriculture, there is
    a range of different commercial products but little information on the
    composition and relative use of these. There is also little residue
    data for isomers of hexachlorocyclohexane other than the gamma-isomer;
    but some indication that the beta-isomer is the most persistent.

    There are published residue methods capable of separating, and
    measuring separately, the principal steroisomers. Analyses should
    report separately any residues of these (and in particular of the
    alpha, beta, and gamma-isomers) found.

    Recommendations

    For the above reasons no recommendations for residue tolerances can be
    made at the present time.

    Further work or information

    Required (before acceptable daily intakes or tolerances can be
    established):

    1. Information on all of the principal technical grades of BHC,
       expressed in terms of specific isomers, as follows:

         (a) the chemical nature of terminal residues in plants, animals
         and their products;

         (b) the required rates and frequencies of application,
         pre-harvest intervals and the resultant residues;

         (c) residue levels in raw agricultural products moving in
         commerce;

         (d) the disappearance of residues during storage and processing;

         (e) residue levels in total diet studies.

    2. Short- and long-term feeding studies and a reproduction study in
       animals on individual isomers and commonly marketed technical
       products.

    3. Metabolic studies of isomers in animals.

    4. Determination of the effects on enzyme processes, especially those
       involving liver microsomes (cf. lindane).

    5. Study of the interaction of the isomers of BHC and residue levels
       in tissues.

    Desirable:

    1. Information on the relative amounts of lindane and technical grades
       of benzene hexachloride used in various countries.

    2. Clarification by governments of whether established tolerances are
       for technical grades of benzene hexachloride or for lindane (99 per
       cent gamma-isomer only).

    3. Further information on the composition of all commercially
       available technical BHC products and on the amounts of these used 
       for agriculture and veterinary purposes in the different countries 
       of the world.

    REFERENCES

    Abbott, D. C., Goulding, R. and Tatton, J. O'G. (1968) Organochlorine
    pesticide residues in human fat in Great Britain. Brit. Med. J., 3:
    149

    Abbott, D. C., Holmes, D. C. and Tatton, J. O'G. (1969) Organochlorine
    pesticide residues in the total diet in England and Wales, in press

    Anon. (1968) Residues of insecticides in cereals and related products
    imported in the Netherlands. Codex Alimentarius Commission document
    CCPR.68/2

    Bro-Rasmussen, F., Dalgard-Mikkelsen, S., Jakobsen, T.,  Koch, D. C.,
    Rodin, F., Uhl, E. and Voldum-Clausen, K. (1968) Examination of Danish
    milk and butter for contaminating organochlorine insecticides. Residue
    Reviews, 23: 55-69

    Burkatskaya, E. N. (1968) On the toxicology of isomers of
    hexachlorocyclohexane (Eng. trans). Farmikol. i. Toksikol., 22:
    273-274. (Chem. Abstr. 53: 22515d, 1959)

    Cueto, C. and Biros, F. J. (1967) Chlorinated insecticides and related
    materials in human urine. Toxicol. appl. Pharmacol., 10: 261-269

    Cummings, J. G. (1966) Pesticides in the total diet. Residue Reviews,
    16: 30-45

    Dacre, J. C. (1968) A summary of the levels of BBC isomers in human
    fat of the New Zealand population. Unpublished report

    Dale, W. E., Copeland, M. F. and Hayes, W. J. jr. (1965) Chlorinated
    insecticides in the body fat of people in India. Bull. Wld Hlth Org.,
    33: 471-477

    Davidek, J. and Janicek, G. (1967) Effect of technical
    hexachlorocyclohexane on the stability of beta-carotene in pure
    solutions. Sci. Papers Inst. Chem. Technol: Food (Prague), 16: 71-81

    Davidow, B. and Frawley, J. P. (1951) Tissue distribution,
    accumulation and elimination of the isomers of benzene hexachloride.
    Proc. Soc. exp. Biol. Med., 76: 780-783

    Davis, A. and Joseph, H. M. (1967) Quantitative determination of
    benzene hexachlorides by gas chromatography. Anal. Chem., 39:
    1016-1018

    Duggan, R. E. (1968) Residues in food and feed. Pesticides Monitoring
    J., 2: 2-12

    Egan, H. (1965a) Chlorinated pesticide residues in lamb and mutton fat
    following dipping and other treatment. J. Sci. Food Agric., 15:
    489-498

    Egan, H., Goulding, R., Roborn, J. and Tatton, J. O'G. (1965b)
    Organochlorine pesticide residues in human fat and human milk. Brit.
    Med. J., 2: 66-69

    FAO/WHO. (1967) Evaluations of some pesticide residues in food:
    Monographs (FAO/PL:1967/M/11/1; WHO/Food Add/68.30)

    Fitzhugh, O. G., Nelson, A. A. and Frawley, J. P. (1950) The chronic
    toxicities of technical benzene hexachloride and its alpha, beta and
    gamma isomers. J. Pharmacol. exp. Therap., 100: 59-66

    Furman, D. P. (1955) Toxicity of benzene hexachloride to mammals. J.
    Econ. Entomol., 40: 518-521

    Gero, A. (1959) A structure-activity relationship in BHC
    stereoisomers. J. Med. Pharm. Chem., 1: 391-394

    Ghazel, A., Koransky, W., Portig, J., Vohland, H. W. and Klempau, I.
    (1964) Beschleunigung von Entgiftungs-reaktionen durch verschiedene
    Insecticide. Arch. exp. Path. Pharmakol., 249: 1-10

    Gunther, F. A., Westlake, W. E. and Jaglan, P. S. (1968) Reported
    solubilities of pesticide chemicals in water. Residue Reviews, 20:
    1-148

    Hayes, W. J. jr, Dale, W. E. and Burse, F. W. (1965) Chlorinated hydro 
    carbon pesticides in the fat of people in New Orleans. Life Sciences,
    4: 1611-1615

    Kauer, K., Duvall, R. and Alquist, F. (1947) Ind. Eng. Chem. (Ind),
    39: 1335

    Koransky, W., Portig. J,, Vohland, H. W. and Klempau, I. (1964)
    Elimination of alpha- and gamma-hexachlorocyclohexane and the effects
    of liver microsomal enzymes (Eng. trans.). Arch. exp. Path.
    Pharmakol., 247: 49-60 (Chem. Abstr., 61: 13818a, 1964)

    Lehman, A. J. (1951) Chemicals in foods: A report to the Association
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    See Also:
       Toxicological Abbreviations