BROMOPHOS         JMPR 1977


    Bromophos was evaluated by the Joint Meeting in 1972 (FAO/WHO, 1973),
    when a temporary acceptable daily intake was allocated and temporary
    tolerances were established. Further work was required to elucidate
    renal function and testicular pathology in dogs, and to assess the
    carcinogenic potential of bromophos. The additional studies described
    below have been received and are discussed in this monograph addendum.

    Residue aspects of bromophos were again evaluated in 1975 (FAO/WHO,
    1976). The requirements for further information from that Meeting, and
    questions arising from the Codex Committee on Pesticide Residues, are
    listed in the section "Residues in Food and Their Evaluation".




    Bromophos is subject to the reactions which are common to the
    organophosphorothionates: conversion of the thiono sulphur to oxygen;
    removal of one or both methyl groups, removal of the
    bromodichlorophenyl group (with subsequent conversion of the resulting
    phenol to conjugates), and almost any combination of the above.

    The administration of bromophos to rats results in the formation of
    type I substrate - cytochrome P450 binding (Szutkowski, 1975).

    When doses of 20 mg of bromophos were given orally to pregnant rats,
    the compound could be detected within 30 min. in maternal liver,
    placenta, foetal brain, liver and muscle. The oxygen analogue was also
    detected in foetal muscle. (Ackermann, 1975). The degradation of
    bromophos in the presence of reduced glutathione occurred at about the
    same rate in human and rat hepatic post-mitochondrial fractions, but
    at a slower rate in porcine fractions. The primary detoxification
    reaction was that of O-demethylation. (Palut, 1974).

    The metabolism of 32P-labelled bromophos and its oxygen analogue
    in vitro has been studied in post-mitochondrial supernatant
    fractions of rat liver; the O-analogue was more rapidly hydrolyzed
    than bromophos, and the principal metabolites were the monodesmethyl
    derivates (Palut et al., 1970).

    After spraying 20 mg of 32P-labelled bromophos on the skin of
    lactating cows, labelled phosphate was detectable in blood and milk.
    The blood concentration, calculated as bromophos, was about 0.01 mg/kg
    and was not in the form of the O-analogue. The principal metabolite,
    desmethylbromophos, was identified in blood and milk at concentrations

    of 0.4-0.7 mg/kg, but these residues were not toxicologically
    significant (Dedek and Schwarz, 1969)*. Bromophos does not act
    systemically in tomato plants; rather, it penetrates from the surface
    into the interior of the leaf, and from a nutrient solution into the
    root. In addition to unchanged bromophos, bromodichlorophenol was
    found as a main metabolite, with small amounts of thio-analogue,
    monodesmethyl bromophos, dimethyl phosphorothionate and inorganic
    phosphate (Stiasni at al., 1969).

    50 strains of bacteria were isolated from garden soil degraded
    bromophos. Some strains produced dimethyl phosphorothionate and
    monomethyl-phosphorothionate. Others produced mainly the bisdesmethyl
    compound. Other metabolites, possibly the oxygen analogues of dimethyl
    and monomethyl phosphorothionate, were sometimes detected. (Stenersen,


    Special studies on mutagenicity

    Bromophos has been tested for mutagenicity using
    Drosophila melanogaster as a test organism and no mutagenic activity
    was seen (Benes and Stram, 1969)


    Groups of albino mice of the strain Chbb = NMRI (SPF) were fed
    bromophos in the diet for 18 months at dose levels of 0, 85, 350 and
    1400 ppm to assess a carcinogenic potential in mice. The number of
    mice was 100 males and 100 females in the control group and 50 males
    and 50 females in each test group.

    Body weights of males and females from the high-dose group were
    slightly depressed. Food consumption showed no relevant differences
    between the groups.

    Plasma cholinesterase was markedly inhibited at all dosage levels.
    Erythrocyte and brain cholinesterase inhibition was clear at 350 ppm
    and 1400 ppm levels.

    Tumours (including leukaemias) were detected in the control and the
    three dose groups. The percentage of tumours per group was: 23% in the
    control group, 13% in the 85 ppm group, 22% in the 350 ppm group, and
    18% in the 1400 ppm group. Primary lung tumours were the most
    frequent, followed by lymphocytic leukaemia, lymphosarcoma,
    hepatocellular adenoma and reticulum cell neoplasms. Tumours observed
    only in a few animals were: granulosa cell tumours of the ovaries,
    adenoma and pheochromocytoma of the adrenals, cutis fibrosarcoma,

    * In this connection, see also Stiasni, Rehbinder and Deckers,
    J. Agr. Fd. Chem. 15: 474, 1967, who concluded that the distribution
    pattern of bromophos shows no accumulation in the tissues.
    urinary bladder carcinoma, intestinal adenocarcinoma and pleomorphic
    sarcoma in the abdominal cavity. The tumours were found in the control
    group and/or the three dose groups presenting no dose-related
    distribution. Tumours occurred no earlier in the dose groups than in
    the control group and there was no difference in the intercurrent
    mortality rate. (Kreuzer et al., 1976).

    Short-term studies


    Groups of beagle dogs (4 males and 4 females/group) were fed bromophos
    in the diet at dosage levels of 0, 20, 80, 320 and 1280 ppm for one
    year. Bodyweight was comparable to control at levels of 0, 20, 80 and
    320 ppm; a marked depression was observed at the 1280 ppm level. Food
    consumption was reduced at the 1280 ppm level. No specific clinical
    symptoms were observed and no mortality occurred over the course of
    the study. Oestrus occurred less frequently than normal in the female
    animals at the 1280 ppm level. There were no differences from control
    values in the haematology and urine parameters examined. The clinical
    chemistry studies revealed a slight reduction of calcium at the
    highest dose and a slightly dose-dependent rise in the serum chloride
    level at the 80, 320 and 1280 ppm groups. Total serum proteins were
    reduced at the highest dose due to the fall in albumin. Plasma
    cholinesterase inhibition occurred at 80, 320 and 1280 ppm levels.
    Erythrocyte cholinesterase was inhibited at the 320 and 1280 ppm
    levels. Brain cholinesterase inhibition was observed at the 1280 ppm
    level. No significant dose-related changes were noted on gross and
    histological examination of tissues. Pyelitis was observed in isolated
    animals of all study groups. Unilateral atrophy of the germinal
    epithelium of a group of tubules in the testis occurred in one dog of
    the control group, two at the 80 ppm, one at the 320 ppm and one at
    the 1280 ppm level. Focal lymphocytic infiltrates in the epididymis
    occurred in one male dog at the 80 ppm and 320 ppm levels and in two
    male dogs at the high level dose. Ophthalmological examination
    revealed no pathological findings, (Herbst et al., 1975).

    Acute Toxicity
        TABLE 1. Acute Toxicity of bromophos
                             Route of            LD50,
    Species        Sex       Administration      mg/kg              Reference

    Rat                      Oral                3750-5180          Jones, et al., 1968
    Rat                      Oral                6000               Novozhilov, 1975
    Rat            M         Oral                1600(1322-1936)    Gaines, 1969
    Rat            F         Oral                1730(1373-2180)    Gaines, 1969

    TABLE 1. (continued)

                             Route of            LD50,
    Species        Sex       Administration      mg/kg              Reference

    Rat            M         Oral                4000               Kinkel et al., 1966
    Rat            F         Oral.               6100               Kinkel et al., 1966
    Rat                      Dermal              1625-3125          Kinkel et al., 1966
    Rat            M,F       Dermal              >5000              Gaines, 1969
    Rat                      Subcut.             1460               Pallade et al., 1970

    Mouse          M         Oral                3700-5850          Kinkel et al., 1966
    Mouse          F         Oral                2829               Kinkel et al., 1966
    Mouse                    Dermal              1040               Kinkel et al., 1966

    Guinea Pig               Oral                1500               Kinkel at al., 1966

    Rabbit         M         Oral                720                Kinkel et al., 1966
    Rabbit                   Dermal              >1000              Jones et al., 1968
    Rabbit                   Dermal              2181               Kinkel et al., 1966


    Bromophos was administered to four groups of four male and four female
    volunteers at levels of 0, 0.2, 0.4 and 0.8 mg/kg body weight/day for
    28 days. The material was given orally in capsules.

    The lowest dosage did not influence the cholinesterase activity in
    either erythrocytes or plasma when administered for 28 days. Higher
    dosages inhibited the cholinesterase activity in plasma. This
    inhibition showed a time dependence; at 14 and 28 days it was more
    than 20% at 0.8 mg/kg bw/day.

    The cholinesterase activity in erythrocytes did not show any
    inhibition even at 0.8 mg/kg/day.

    Checks of behaviour, general condition, appetite, stools, blood count,
    clinico-biochemical parameters and ECG did not indicate any
    intolerance reactions (Anon., 1977).


    Bromophos was previously evaluated and a temporary ADI for humans of
    0-0.006 mg/kg was allocated.

    An adequate study in dogs previously requested has been provided.
    Renal function tests and testicular histology did not confirm previous
    concern. Plasma cholinesterase was more susceptible to depression than
    erythrocyte cholinesterase; however, the previous study revealed the
    opposite. A no-effect level was demonstrated in the 20 ppm group.

    A carcinogenic study was also previously requested and has become
    available. In this long-term carcinogenicity study in mice, no
    compound-related effect was observed.

    A 28-day study in human volunteers showed no significant effect of
    bromophos at a level of 0.4 mg/kg bw/day based on plasma
    cholinesterase activity.

    Attention was paid to the 2,5-dichloro-4-bromophenol part of the
    bromphos molecule. The available information indicated that the
    synthesis of this phenolic compound does not incur any risk of forming

    As the required studies were provided and observations in humans were
    available, a higher ADI for humans was allocated.


   Level causing no toxicological effects

    Dog: 20 mg/kg in diet, equivalent to 0.5 mg/kg bw

    Humans: 0.4 (mg/kg bw)/day


    0-0.04 mg/kg bw


    Residue aspects of bromophos were last evaluated by the 1975 Joint
    Meeting (FAO/WHO, 1976). The Meeting then required residue data on fat
    of meat of domestic animals other than sheep (including residues in
    milk products, poultry and eggs) and on peanuts before additional
    maximum residue limits could be recommended. Further data on residues
    in stored wheat and on rice following storage and processing under
    full-scale commercial conditions were recorded as desirable.

    At the 9th Session of the Codex Committee on Pesticide Residues in
    1977 (ALINORM 78/24, paras. 54-55):

    1. The Netherlands delegation drew attention to the varying maximum
    residue limits for the different kinds of currants. The Joint Meeting
    was requested to review the proposed maximum residue limits for red
    currants in the light of the proposed figures for blackberries and

    2. The Netherlands delegation stated that the use of bromophos on
    sugar beet could not only leave residues in the roots, but also on the
    tops of the beet which were used extensively as cattle feed and,
    therefore, could give rise to residues in meat and milk. The Joint
    Meeting was requested to propose a maximum residue limit for meat in
    the light of the use of bromophos on sugar beet.

    No information was supplied concerning the requests of the 1975 Joint
    Meeting or the 2nd request of the CCPR.

    In response to the first request of the CCPR, the maximum residue
    limits recommended by the 1972 Meeting were reviewed. The reported
    residue data indicate residues of 0.18-0.36 mg/kg for blackcurrants,
    0.14-0.19 mg/kg for blackberries and 0.11-0.76 mg/kg for red currants
    7 days after the application of comparable dosages of bromophos. In
    view of the range of variation in red currants, and since no further
    residue data are available, a uniform MRL of 1 mg/kg for these fruits
    is recommended.

    The question was raised whether bromophos in grain causes taint. Wheat
    treated with 8-12 mg bromophos/kg was milled 0-12 months after storage
    and processed to bread. No taint was detectable and no differences in
    odour or flavour from bread prepared from untreated wheat were
    observed (Bisle and Deckers, 1974).

    Information on residues in food moving in commerce was supplied by the
    Netherlands (Food Inspection Services, 1977; Table 2).


    The maximum residue limits for bromophos in blackberries and black
    currants are raised to the limit previously recommended for red
    Commodity                     Limit, mg/kg

    Blackberries, currants
    (red & black)                     1

        Table 2A. Residue of bromphos in food moving in commerce; Netherlands, 1976


                   lettuce   celery    spinach   Brussels  white     butter-bean         leek      potato    radish    summer
                                                 sprouts   cabbage                                                     carrot
    SOURCE         N         N         N         N         N         N                   N         N         N         N


    0 - 0.05       4         4         1         24        1         0                   3         0         0         0
    0.051 -0.10                                                      3                             0         0         0
    0.101 -0.50                                                                                    0         1         2
    0.501 -1.00                                                                                    0
    1.001 -1.50                                                                                    2
        >1.50                                                                                     2

    Total          4         4         1         24        1         3                   3         4         1         2

    Exceeding      -         -         -         -         -         -         -         -         4         -         -

    ___ -  National maximum residue limit

    N - Produced in Netherlands

    I - Imported

    Table 2B. Residue of bromphos in food moving in commerce; Netherlands, 1976


                   winter    pear      currant   strawberry      mandarin
    SOURCE         N         N         N         N               I


    0 -0.05        4         0         0         4               0
    0.051 -0.10    0         0         0         1               3
    0.101 -0.50    1         1         1         2               3
    0.501 -1.00    
    1.001 -1.50
    Total          5         1         1         7               6
    Exceeding      -         -         -         -               -

    ___ -  National maximum residue limit

    N - Produced in Netherlands

    I - Imported



    1. Further information on residues in rice following storage and
    processing under full-scale commercial conditions.

    2. Information on the level and fate of bromophos residues in products
    of animal origin.


    Anonymous Influence of Bromophos pure on the Cholinoesterase-Activity
    in Plasma and Erythrocytes of healthy volunteers when administered
    orally. Unpublished report by Boehringer Sohn submitted to WHO by
    Celamerck Co. (unpublished report). (1977)

    Benes, V. and Stram, R. (1969) Ind. Med. Surg. 38:442.

    Bisle and Deckers Organoleptische, Boehringer, Beurteilung von mit
    Bromophos behandelten Weizen. Boehringer, Wissenschaftl. Abteilung,
    Ingelheim, Federal Republic of Germany 17 May 1974. (1974)

    Dedek, W. and Schwarz, H. (1969) Zeits. Naturforsch., B. 24:744.

    FAO/WHO (1973) 1972 evaluations of some pesticide residues in food.
    AGP:1972/M/9/1; WHO Pesticide Residues Series, No. 2.

    FAO/WHO (1976) 1975 evaluations of some pesticide residues in food.
    AGP:1975/M/13; WHO Pesticide Residues Series No. 5.

    Food Inspection Services of the Netherlands 1976 (1977);
    Bromophos-Residues in Food in Commerce, 25 October 1977.

    Gaines T.B. (1969) Acute toxicity of pesticides. Toxicol. Appl.
    Pharmacol. 14:515.

    Jones, K.H., Sanderson, D.M. and Noakes, D.M. (1968)
    World Rev. Pest. Control (London), 7:138.

    Kinkel J., Mauacevic, G., Sehring, R. and Bodenstein, G. (1966)
    Arch. Toxikol 22:36.

    Kreuzer, H., Weibe, J., Guénard, J., Knappen, F. and Stötzer, H.
    (1976) Carcinogenicity study with the substance bromophos in mice
    using oral administration -- 80 weeks. Unpublished report by H.
    Boehringer Sohn submitted to the WHO by Celamerck Co. (unpublished


    * In cases in which the original paper has appeared in very obscure
    journals, references to Chemical Abstracts are given.

    Pallade, S., Gabrielescu, E., London, M. and Siminovici, R. (1970)
    Toxicity of some organophosphoric pesticides. Chem. Abstr. 73:97847.

    Palut, D. (1974) Detoxication mechanisms of organic phosphorus and
    carbamate insecticides. Chem. Abstr. 80:116892.

    Palut, D., Grzymala, W. and Syrowatka, T. (1970) Metabolism of some
    organophosphorus insecticides in animal model systems. II. Hydrolytic
    mechanisms. Chem. Abstr. 72:120478.

    Stenersen, J. (1969) Demethylation of the insecticide bromophos by a
    glutathione-dependent liver enzyme and by alkaline buffers. J. Econ.
    Entomol. 62:1043-45.

    Stiasni, M., Deckers, W., Schmidt, K. and Simon, H. (1969) J. Agr.
    Fd. Chem. 17:1017.

    Szutkowski, M.M. (1975) Effect of a carbon tetrachloride on activation
    and detoxification of organophosphorus insecticides in the rat.
    Toxicol. Appl Pharmacol. 33:350-55.

    See Also:
       Toxicological Abbreviations
       Bromophos (WHO Pesticide Residues Series 2)
       Bromophos (WHO Pesticide Residues Series 5)
       Bromophos (Pesticide residues in food: 1982 evaluations)
       Bromophos (Pesticide residues in food: 1984 evaluations)