BENOMYL JMPR 1975 Explanation Benomyl was considered by the Joint Meeting in 1973 (FAO/WHO, 1974), but tolerances could not be established owing to lack of toxicological information. However, as a considerable amount of information on use patterns, mode of action, actual residue levels, etc. was available, a number of guideline levels reflecting good application practices were recommended. Further, some requests were made for desirable additional information. EVALUATION FOR ACCEPTABLE DAILY INTAKE BIOCHEMICAL ASPECTS Absorption, distribution and excretion A male rat was fed a basal diet supplemented with 2500 ppm benomyl for 12 days and then given a single dose of 2C14 benomyl by gastric intubation. After 24 hours, 78.9% of the radioactivity was detected in the urine and 8.7% in the faeces. A total of 91.8% of the calculated C14 dose was accounted for, of which 99.5% was found in the urine and faeces by the end of the 72-hour test period. The major metabolite was methyl-5 hydroxy 2-benzimidazolecarbamate (5 HBC) which was present in the urine as the glucuronide and/or sulfate. Very little of the parent compound or methyl 2 benzimidazolecarbamate (MBC) was present in the urine (<5%) (Gardiner et al,, 1974), A male dog was fed a diet containing 2500 ppm benomyl. After seven weeks he received a single dose of C14 benomyl by gelatin capsule. Again, the bulk of the radioactivity (>99%) was eliminated from the animal in 72 hours. The major route of excretion, in this case, was by way of the faeces where benomyl and/or MBC and 5-HBC were detected (Gardiner et al., 1974). Groups of two dairy cows were fed 0, 2, 10 and 50 ppm benomyl for 32 days. Total amounts of benomyl ingested were 0.88, 4.36 and 21.8 g. One cow at each level was killed at 32 days, the other after a one-week withdrawal period. No apparent adverse effects on the animals or on milk production were observed. No residues of benomyl and/or MBC were found in milk, urine or faeces. 5 HBC and methyl-4-hydroxy-2-benzimidazole carbamate (4 HBC) were not detected in milk at dietary levels of 2 ppm. At higher dietary levels constant levels of metabolites were present in milk within 24 hours. No residues in milk (less than 0.01 ppm) were detected 48 hours after benomyl was removed from the diet. No residues were found in the animal tissues (liver, kidney, subcutaneous fat, lean muscle). Detectable amounts of 5 HBC and 4 HBC in urine and of 5 HBC in faeces were observed (Gardiner et al., 1974). Groups of eight chickens were fed 0, 5 and 25 ppm benomyl for four weeks. Composite samples of eggs were taken the last two days of each week. At four weeks composite samples of faeces were obtained and half the birds in each group sacrificed. Liver, fat and muscle samples were taken. Remaining birds were placed on a control diet for one week prior to sacrifice. No adverse effects on body weight gain, feed consumption or egg production were noted. No residues of benomyl or its degradation products were detected in the tissue samples. Only 5 NBC (0.03-0.06 ppm) was found in the high level egg samples. Residue was not detectable (<0.02 ppm) in eggs one week after hens were placed on untreated diet (Gardiner et al., 1974). 2-C14 benomyl was administered by gastric intubation to a male rat at a dosage level of 900 mg/kg. After one hour blood was taken and analysed for benomyl and MBC by thin-layer chromatography and C14 radioscanning. The radioactivity in the blood consisted of 68% 2-C14 MBC and less than 15% intact benomyl (Sherman et al., 1975). A male ChR-CD rat was fed a diet containing 2500 ppm MBC for 14 days. The animal was then given 2-C14 MBC by intragastric intubation. Urine and faeces were collected. Animal was sacrificed after 72 hours. Bulk of the C14 activity was eliminated in the first 24-hour interval (83.5% in urine, 9.6% in faeces). One major and two minor C14 labelled compounds were detected in the urine. After enzymatic hydrolysis and thin-layer chromatography, 85% of the activity was found in a single spot corresponding to 5 HBC. No residual C14 MBC was detected (<5%) (Gardiner et al., 1974). Groups of male mice, rabbits and sheep were dosed orally with 0.1 g benomyl/kg body weight. Urine and faeces were collected for 96 hours at intervals of 24 hours. The metabolism of benomyl was also studied in vitro using various tissue homogenates as well as blood and sheep rumen fluid as enzyme sources. All three species showed similar patterns of metabolites both in vivo and in vitro. Detoxification proceeded primarily through two major routes, hydroxylation and hydrolysis. Two metabolites were formed by hydroxylation. and two by ester hydrolysis. Approximately 20% of the administered dose was excreted as the sulfate and glucuronide conjugates of hydroxylated metabolites. No unchanged benomyl was found in either urine or faeces. Urine contained 41-71% and faeces 21-46% of the excreted metabolites. The liver was found to be the major site of hydroxylation, other tissues forming only small amounts of hydroxylated metabolites (Douch, 1973). TOXICOLOGICAL STUDIES Special studies on mutagenicity Microorganisms Mutants of Neurospora crassa resistant to benomyl were isolated following ultra violet irradiation of conidia. Genetic analysis of 15 of the mutant strains revealed that the resistance was due to a single allele. Tests of heterokaryons containing both resistant and sensitive alleles indicated that the resistance was dominant. The mutants did not possess the same degree of resistance to the fungicide (Borck et al., 1974). Forward mutations were induced in Fusarium oxysporm f.sp. melonis when incubated with a culture medium containing benomyl (5 µg/ml). This effect was shown only with growing cells. In another study roots of young Allium cepa which were dipped in benomyl (0, 50 and 100 µg/ml) and incubated for up to 12 hours, did not reveal any chromosomal aberrations (Dassenay et al., 1973). Rat In a dominant lethal study four groups of 10 male ChR-CD rats received diets containing 0, 250, 1250 and 2500 ppm benomyl for seven days. Each male was then mated with three ChR-CD females. After seven days, males were removed and mated with three additional females. This procedure was followed for six weeks. In the control animals the mating index was significantly lower and the pre-implantation losses and early resorptions consistently higher than in the test groups. Due to these effects the calculation of the dominant lethal mutation rates for benomyl based on either post implantation loss or on pre- and post-implantation losses were negative (Sherman et al., 1975). Special studies on reproduction Rat In a three generation reproduction study, four groups of rats (6 male and 6 females/group - 1st generation; 12 male and 12 females - 2nd generation; 20 male and 20 females - 3rd generation) were fed 0, 100, 500 and 2500 ppm benomyl in their diet. Two litters were produced in each of the 1st and 2nd generations with three litters being produced in 3rd generation. When pups of the F3B generation were weaned, two males and two females were selected from each of five litters from each group and subjected to gross pathological evaluation. Tissues from the control and 2500 ppm, group were evaluated histopathologically. At weaning, animals of the F3C generation were kept on their respective diets for nine weeks and then placed on the control diet for an additional six weeks. Reproductive performance in all groups was satisfactory. No significant effects were observed in the number of pups born alive, fertility, gestation or lactation indices. No compound related gross or microscopic pathologic changes were observed. Slightly lower weanling weights in F2B, F3A, F3B and F3C litters at 500 and 2500 ppm were noted. However, the absence of a change in the growth curves when the F3C test animals were placed on the control diet. demonstrated that the lower weanling body weights were not compound related (Sherman et al., 1975). Special studies on teratogenicity Rat Pregnant ChR-CD rats were given 0, 100, 500, 2500 and 5000 ppm benomyl in their diet from day 6 through day 15 of gestation. Animals were killed on day 20 of gestation and foetuses removed by caesarean section. No clinical signs of toxicity were observed in any of the pregnant females. No significant effects were observed in the number of implantation sites per pregnant female, number of resorption sites, number of live foetuses, mean foetus weight, sex ratio or crown-rump length. Incidence of skeletal and visceral abnormalities in the treated groups was comparable to those of the control group. The number and type of anomalies were also found to be comparable with standard values established for this strain of rat (Sherman et al., 1975). When benomyl was administered by gavage to rats from day 1 to day 20 of gestation, 100% post-implantation deaths were observed at 500 mg/kg bw. In a similar study, carbendazim was shown to be approximately half as embryotoxic as benomyl (Stenberg et al., 1975). COMMENTS In mammals, benomyl is rapidly absorbed, metabolized primarily in the liver and excreted. Metabolism apparently proceeds through two major routes, by hydroxylation and hydrolysis. The metabolites are excreted in the urine and faeces and do not appear to be stored in body tissues. In the rat a large proportion of orally administered benomyl is rapidly metabolized to methyl benzimidazol-2-yl carbamate (MBC). The elimination pattern and the identity of the major metabolite in the urine is identical after the administration of either benomyl or MBC. This indicates the rat metabolizes the two compounds in a similar manner. Thus, animals in toxicological studies exposed to benomyl are also exposed to MBC. A three generation reproduction study in the rat with dietary levels up to 2500 ppm did not indicate significant effects. Benomyl was not embryotoxic. Indications of a mutagenic action were found in a fungal system. A dominant lethal study in the rat with dietary levels up to 2500 ppm was negative. Benomyl showed no evidence of teratogenesis when fed to rats at 5000 ppm (250 mg/kg body weight) in the diet. However, a recent report from the USSR observed embryotoxic effects (100% post-implantation deaths of the embryo) when a high dose of benomyl (500 mg/kg/body weight) was administered to rats by gavage. No information is available on long-term studies in any species of animal. This precludes an estimation of an acceptable daily intake for man. TOXICOLOGICAL EVALUATION No acceptable daily intake allocated. RESIDUES IN FOOD AND THEIR EVALUATION USE PATTERN Benomyl is a systemic fungicide with many indications of a widespread and still increasing use in the control of several species of fungi. Simultaneously, however, critical studies have been published of toxic effects in earthworms (Stringer and Lyons, 1974; Krupka, 1974) residues resulting from supervised trials and of adverse phytotoxic effects (Butt et al., 1973) in the form of increased fruit russet and reduction of crop and fruit size in certain apple species after foliar treatment in the early growing season. RESIDUES RESULTING FROM SUPERVISED TRIALS A substantial amount of new information on residues from supervised trials and experimental work has been published or brought to the attention of the Meeting since 1973 from the manufacturers as well as from various governments. The majority of this, however, has confirmed the ranges of residues and general patterns which were described in the earlier monograph (FAO/WHO, 1974). The following is therefore quoted with special emphasis on its supplementary nature. In vegetables Several trials on benomyl applications to greenhouse cultures, especially lettuce, have been reported to the Meeting from some European countries. The results with lettuce (Tables 1 and 2) indicate that considerable amounts may be deposited on leaves or taken up through the roots of this leafy plant. In the winter season from four to six weeks may be required after early foliar application to achieve residues below 5 mg/kg (calculated as carbendazim) while for levels of 1-2 mg/kg more than two months will be needed, in both cases requiring a further careful trimming of outer leaves. The summer experiments indicate shorter periods of the order of two to three weeks. Comparatively, soil treatment or early watering around the plants seems to give rise to lower residues, although the continued uptake results in residues which will require practically the same preharvest intervals. TABLE 1. Benomyl trials on greenhouse lettuce, Belgium1 Residues, mg/kg,2 resulting from Time after (No. of applications) Dosage last Treatment rate application 1× 2× 3× Spraying 1.5 kg/ha 0 days - - 106 2 weeks - 36.2 33.1 3 weeks - - 21.0 4 weeks 6.2 10.5 11.6 5 weeks - 7.3 7.3 6 weeks 1.6 4.7 4.7 8 weeks 0.9 1.5 2.5 Spraying 3.0 kg/ha 0 day - - 190 2 weeks - 45.5 65 3 weeks - - 37.4 4 weeks 11.8 17.6 23.6 5 weeks - 13.9 14.8 6 weeks 5.5 11.6 12.8 8 weeks 1.6 3.8 5.1 1 From Henriet et al. (1975). 2 All results calculated and expressed as carbendazim. TABLE 2. Benomyl trials on greenhouse lettuce, Denmark1 and Netherlands2 Residues (mg/kg)3 mean and range Dosage Time after last Treatment rate application, days May-June November-March Spraying1 1.5 kg/ha 2 50 (47-53) 32 (26-38) 9 17 (16-19) 24 (23-25) 16 6.6 (5.2-8.0) 22 (22-22) 23 0.8 (0.6-1.0) 21 (20-21) Watering1 3.75 kg/ha 2 16 (15-18) 16 (13-19) 9 6.3 (5.2-7.4) 15 (12-18) 16 2.3 (1.5-3.1) 12 (10-15) 23 0.5 (nd.-O.9) 8.9 (7.0-11) Soil treatment1 3.75 kg/ha 11 45 (39-56) 19 20 (14-28) 28 10 ( 8-11) 32/33 7.7 (3.8-18) 41 8.8 (4.6-12) 53 3.0 (1.8-4.0) 1 Green-Lauridsem et al. (1975). 2 The Netherlands (1975). 3 All results calculated and expressed as benomyl (in mg/kg). In cereals Information on benomyl residues in cereal grains (wheat, barley, oats and rice) has been collected from several countries and submitted by Kirk (1974) as shown in Table 3. This supplements that which was available earlier to the Meeting. It confirms the earlier recommended guideline level of 0.5 mg/kg in raw cereals,* covering the four mentioned species, and gives grounds for amending the guideline level of 2 mg/kg for barley straw to include also straw from rice and wheat. * The guideline level for raw cereals recommended by the 1973 Joint Meeting was correctly recorded as 0.5 mg/kg in the Evaluations (FAO/WHO, 1974b) but erroneously printed as 0.1 mg/kg in the Report (FAO/WHO, 1974a). FATE OF RESIDUES In animals Previously reviewed studies an the fate of benomyl in animals have been extended and published by Gardiner et al. (1974). These confirm that single, oral doses of benomyl (C14-labelled) are eliminated via the urine and faeces within 72 hours from both rat and dog. From 83.4 to 88.0% of the ingested amount was recovered from the urine and 11.3-16.2% from the faeces. The major metabolite was methyl 5-hydroxy-2-benzimidazolecarbamate (5-HBC) found as glucuronide and/or sulfate conjugates in the urine. The studies showed that, on the evidence of residue analyses, cows and chickens show the same route of metabolism and elimination. Other possible degradation products in animal systems include methyl 4-hydroxy-2-benzimidazolecarbamate (4-HBC) and methyl 2-bensimidazolecarbamate (MBC). The residue data from these studies, which include two-year chronic feeding tests with dogs and rats (Table 4), demonstrate that benomyl and its metabolites do not accumulate in animal tissues. Milk from dairy cows (FAO/WHO, 1974) and eggs from chickens (Table 5) contain detectable residues (0.1 mg/kg or less) only at such high dietary levels of benomyl as 25-50 mg/kg. In soil In an earlier quoted series of field trials on metabolism and disappearance rates in different soils (Baude et al., 1974) it was indicated that the leaching of benomyl and its degradation products MBC and 2-amino benzimidazole (2-AB) from soils was negligible. Additional studies by Rhodes and Long (1974) support this conclusion through direct experiments under greenhouse and laboratory conditions. Their experiments elucidate both run-off and leaching characteristics of the compounds and show that benomyl, MBC and 2-AB are all immobile in soil and do not leach or move significantly from the site of application. TABLE 3. Benomyl residues in cereals Pre-harvest Number of interval Residues Crop Treatment Dosage treatments (days) (mg/kg) Country Wheat, barley, Seed and oat treatment 200 g/100 kg 133-398 <0.4 Finland 100-600 g/100 kg 94-303 <0.1 United States of America Foliar treatment 1 kg/ha 64-77 <0.1 Netherlands 600 g/ha 3 × 12-75 0.1-0.5 France 240 g/ha 105 0.0-0.2 West Germany 400 g/ha 4 × 30-32 <0.03 Belgium Wheat straw 1 kg/ha 64-77 0.15-0.93 Netherlands Rice Foliar treatment 0.25-1 kg/ha 1-2× - 0.49 United States (<0.05-2.8) of America Rice straw 0.25-1 kg/ha 1-2× - 3.52 United States (<0.05-9.0) of America TABLE 4. Residue data from benomyl chronic feeding studies in rat and dog (Gardiner et al., 1974) Residue1, mg/kg (male and female) Dietary level Benomyl+ Tissue (mg/kg) carbendazim 5-HBC 4-HBC Rat Muscle 0 <0.05 <0.05 <0.1 2500 <0.05-0.06 0.51-0.52 <0.1 Fat 0 <0.05 <0.05 <0.1 2500 <0.05 <0.05-0.08 <0.1 Liver 0 <0.05 <0.05 <0.1 2500 0.20-0.61 1.7-2.5 <0.1 Kidney 0 <0.05 <0.05 <0.1 2500 0.20-1.4 2.8-22 <0.1-0.45 Dog Muscle 0 <0.05 <0.05 <0.1 2500 <0.05 <0.05 <0.1 Fat 0 <0.05 <0.052 <0.1 2500 <0.05-0.15 <0.05-0.14 <0.1 Liver 0 <0.05 <0.05 <0.1 2500 <0.05 <0.05 <0.1 Kidney 0 <0.05 <0.05 <0.1 2500 <0.05 <0.05-0.12 <0.1 1 All results corrected for average recoveries (benomyl+MBC: 79%; 5-HBC: 65%; 4-HBC: 55%). 2 An apparent contamination corresponding to 1.2 mg/kg noted in one male dog. EVIDENCE OF RESIDUES IN COMMERCE Market sample surveys carried out in the Netherlands in 1973 on (mainly domestically grown) fruit and vegetables showed that residues from benzimidazole fungicides, among which benomyl would be included, were regularly present in some crops (Table 6), In strawberries about 20% of the samples were positive, while in leafy vegetables, apples and tomatoes taken together about 4-5% were positive. At the time of the survey, the tolerances were 2 mg/kg for fruits and vegetables and 0.05 mg/kg for potatoes, expressed and calculated as carbendazim. Similarly, Belgian surveys on strawberries carried out in 1972 and 1974 showed 26% of the samples to be positive (Dejonckheere et al., 1975). A total of 188 market samples were analysed and none contained residues exceeding 5 mg/kg (expressed as carbendazim). METHODS OF RESIDUES ANALYSIS Since the Joint Meeting in 1973, the greatest interest in the analytical methodology of benomyl and other benzimidazoles has been directed to two problems, namely the extraction efficiency from crops and soils and the selective determination of benzimidazole compounds, especially by means of high speed liquid chromatography (HSLC). Austin and co-workers (1975) in a recent review deal with these questions and offer a convenient extraction solvent for aged carbendazim residues from soils consisting of 1 M NH4Cl-solution (aqueous) mixed with an equal volume of acetone or methanol. Further, they conclude that HSLC using UV-absorption detectors still shows promise (FAO/WHO, 1974), but is not yet at a suitable stage of development for routine purposes owing to some lack of selectivity and sensitivity. The need for further work on the separate determination of carbendazim and its precursors, which include benomyl, is still emphasized. APPRAISAL Extensive new data on use patterns, mode of action, residue levels etc. of benomyl have been published or otherwise come forward since 1973. Much of this provides support for previously considered information and confirms recommendations for already established guideline levels. There are however additional data on residues in greenhouse grown lettuce which permit a recommendation to be made for a guideline level for this crop. Further information on cereals confirms the earlier recommendation for a guideline level of 0.5 mg/kg in raw cereals. TABLE 5. Residues in chickens' eggs after benomyl feeding at 5 and 25 mg/kg level (Gardiner et al., 1974) 5-hydroxy-MBC found, mg/kg Sample description Control 5mg/kg level 25 mg/kg level Eggs 7 days <0.02 <0.02 0.03 14 days <0.02 <0.02 0.06 28 days <0.02 <0.02 0.03 Breast, 28 days <0.02 <0.02 <0.02 Fat, 28 days <0.02 <0.02 <0.02 Liver, 28 days <0.1 <0.1 <0.1 Faeces, 28 days 0.161 1.6 7.5 TABLE 6. Residues of methylbenzimidazole (including benomyl) in marketed samples, Netherlands Number of samples containing ... mg/kg1 Crop <0.1 0.1-1.0 1.0-2.0 >2.0 Potatoes 10 2 - Endive 29 - 12 Lettuce 57 2 - Spinach 28 - - Tomatoes 10 2 - Apples (imported) 5 13 Strawberries 129 20 8 4 1 Expressed as carbendazim. 2 Contained 4 mg/kg. 3 Contained 15 mg/kg. Imported. Further studies have been presented on residues in animal products. They demonstrate that neither benomyl nor its metabolites accumulate in animal tissues and that residues of the hydroxylated MBC metabolites are present in barely detectable amounts in milk and eggs only after feeding high dietary levels of benomyl. In response to the request from an earlier Meeting, information on market sample surveys made in the Netherlands and in Belgium has been presented to the Meeting. The data show that residues of benzimidazole fungicides, presumably including benomyl, may be present in up to 20-26% of a number of fruits, vegetables and berries. Residues in positive samples are generally low and only in occasional individual samples approach or exceed earlier established guideline levels. RECOMMENDATIONS The recommendations for guideline levels made in 1973 (FAO/WHO, 1974) are amended as follows. They refer to total residues of benomyl carbendazim and 2-aminobenzimidazole, expressed as carbendazim. GUIDELINE LEVELS Commodity Limits mg/kg Lettuce 5 Rice straw, wheat straw 2 Raw cereals (wheat, barley, rye, rice) 0.5* Meat or poultry, eggs 0.1** * Attention is drawn to the footnote on p. [text missing] of this monograph addendum. ** At or about limit of determination. FURTHER WORK OR INFORMATION REQUIRED (before an acceptable daily intake can be allocated) 1. Long-term studies in at least one mammalian species. 2. Short-term studies in several animal species including a non-rodent mammalian species. 3. Acute oral studies in several animal species. DESIRED 1. A supplementary carcinogenic study. 2. Observations in man. 3. Further development of analytical methods for the separate determination of benomyl and carbendazim. 4. Further information on residues in food in commerce. REFERENCES Austin, D. J., Briggs, G. G. and Lord, K. A. (1975) Problems in the assay of residues of carbendazim and its precursors. Proc. 8th Brit. Insec. Fund. Conf. Brighton. November Baude, F. J., Pease, H. L. and Holt, R. F. (1974) Fate of benomyl on field soil and turf. J. Agric. Food Chem., 22 (3), 413-418 Borck, K. and Braymer, H. D. (1974) The genetic analysis of resistance to benomyl in Neurospora crassa. Journal of General Microbiology, 85, 51 Butt, D. J., Kirby, A. H. M. and Williamson, C. J. (1973) Fungitoxic and phytotoxic effects of fungicides controlling powdery mildew on apple. Ann. appl. Biol., 75, 217-228 Dassenay, B. and Meyer, J. A. (1973) Mutagenic effect of benomyl on Fusarium oxysporum. Mutation Research, 21, 119 Dejonckheere, W., Steurbaut, W. and Kips, R. H. (1975) Report received from Rijksnoviversiteit Gent, Laboratorium voor Fytofarmacie, Gent. 11 September Douch, P. G. C. (1973) The metabolism of benomyl fungicide in mammals. Xenobiotica, 3, 367-380 Gardiner, J. A., Kirkland, J. J., Klopping, H. L. and Sherman, H. (1974) Fate of benomyl in animals. Journal Agriculture Food Chemistry, 22, 419-427 Green-Lauridsen, M. (1975) Prepublication data submitted from National Food Institute, Soborg, Denmark, November Henriet, J., Meens, P., Baelus, F. and Valange, B. (1975) Beschouwingen over het gebruik van benomyl in glassla en aanbevelingen voor slakwekers. Technische Nota 9/18 from Rijksstation voor Phytopharmacie, Gembloux, Belgium Kirk, W. F. (1974) Information on Benlate treatments on cereals covering seed treatments and foliar applications submitted by DuPont de Nemours International, Geneva, 3 April (Unpublished report) Krupka, R. M. (1974) On the anti-cholinesterase activity of benomyl. Pesticide Science, 5, 211-216 Netherlands. (1975) Information of the Netherlands on pesticides to be considered by the JMPR 1975 November Rhodes, R. C. and Long, J. D. (1974) Run-off and leaching studies on benomyl in soils and turf. Bull. Environ. Contamin. Toxicol., 12, 385-393 Sherman, H., Culik, R. and Jackson, R. A. (1975) Reproduction, teratogenic and mutagenic studies with benomyl. Toxicology and Applied Pharmacology, 32, 305-315 Stenberg, A. I., Orlova, N. V. and Torchinskii, A. M. (1975) Action of pesticides of different chemical structure on the gonads and embryogenesis of experimental animals. Gig. Sanit. (8), 16-20 (Russ.) Stringer, A, and Lyons, C. H. (1974) The effect of benomyl and thiophanatemethyl on earth-worm populations in apple orchards. Pesticide Science, 5, 189-196
See Also: Toxicological Abbreviations Benomyl (EHC 148, 1993) Benomyl (HSG 81, 1993) Benomyl (ICSC) Benomyl (WHO Pesticide Residues Series 3) Benomyl (Pesticide residues in food: 1983 evaluations) Benomyl (JMPR Evaluation 1995 Part II Toxicological and environmental)