FOLPET EXPLANATION Folpet was evaluated for acceptable daily intake by the Joint Meeting in 1969, and reviewed in 1973, 1982, and 1984 (Annex 1, FAO/WHO, 1970a, 1974a, 1983a, and 1985b). A toxicological monograph was prepared by the Joint Meeting in 1969 (Annex 1, FAO/WHO, 1970b) and monograph addenda were prepared in 1973 and 1984 (Annex 1, FAO/WHO, 1974b and 1985c). The previously established temporary ADI was withdrawn in 1984 because of possible teratogenicity and the absence of a 90-day oral study in rats, long-term oral studies in rats and mice, a 12-month oral study in dogs, a reproduction study in rats, and a teratology study in rabbits. These and other data have now been received and are reviewed in this monograph addendum. EVALUATION FOR ACCEPTABLE INTAKE Toxicological studies Special studies on carcinogenicity Mice Groups of 52 male and 52 female B6C3F1 mice were fed folpet (89.0% pure) in the diet at 0, 0.1, 0.5, or 1.0% for 21 weeks and thereafter at 0.1, 0.35, or 0.7% for 83 weeks. Dietary analyses at weeks 0, 1, 13, and 26 showed that about 88 - 91% of the nominal dietary concentrations were fed. Food consumption was depressed among mid- and high-dose only during the first weeks of treatment. However, body-weight gain was reduced in mid- and high-dose animals throughout the study. Clear signs of toxicity, observed principally in high-dose groups, were erythema, dry flaking skin, reddish fur discoloration, and weeping skin, particularly in the first 21 weeks. There was no apparent effect of treatment on leucocyte counts of suvivors at 52, 78, or 104 weeks. The longevity of mid- and high-dose groups was reduced. At necropsy, relative weights of the brain, heart, lungs, liver, kidneys, and testes were increased in a dose-related manner, reflecting the reduced body weight of treated animals. Macro- scopically, a dose-related increase in the ulceration of the non-glandular gastric mucosa and thickening of the gastric and duodenal walls were observed. The jejunal wall was thickened in mid-dose females and in the high-dose groups. Dose-related distension of the duodenal lumen also occurred. From 79 weeks onward there was a dose-related increase in the incidence of nodules or masses on the luminal surface of the stomach or duodenum or on the duodenal serosa. Microscopically, the mid- and high-dose groups exhibited dose-related epidermal hyperkeratosis and acanthosis and oesophageal hyperkeratosis. Increased areas of marked acanthosis and hyper- keratosis of non-glandular gastric mucosa were also seen in the mid-dose groups and the high-dose males. Microscopic gastric ulceration occurred without apparent relation to dose. Dose-related areas of atypical duodenal glandular hyperplasia and mucosal gland proliferation were seen in all treated animals, but especially in the males. These atypical hyperplasia were often associated with duodenal adenomas or adenocarcinomas. Atypical glandular proliferation was seen only occasionally in the jejunum of treated female mice. Gastric papillomas and squamous cell carcinomas, which may have been secondary to mechanical obstruction of the duodenal lumen, were found in all groups of treated male mice, but not in control males. A dose-related incidence of gastric papillomas was also found in all treated female groups, but similar lesions occurred in 2/51 control females. Duodenal tumours, adenomas, and adenocarcinomas were found in all treated groups of both sexes, with an even more significant dose relationship. A single case of jejunal adenocarcinoma occurred in the highest-dose group. Primary or metastic tumours of uncertain aetiology were found in all treated male groups. However, the incidences of broncio-alveolar adenomas and malignant lymphomas were less in all treated male groups, suggesting a high incidence of these conditions in control male animals (Rubin & Nyska, 1985a; Nyska, 1985). Rats Groups of 60 male and 60 female F-344 rats were fed folpet (89% purity) in the diet at 0, 500, 1,000, or 2,000 ppm for 104 weeks. Test diets were prepared weekly and analysed for folpet content regularly. Food intake was generally less in all treated groups than in controls, but only the mean body weights of treated males were lower than those of controls throughout the study. There were no signs of toxicity attributable to treatment during the study. At necropsy, there was a tendency toward increased incidences of gastric ulceration in treated groups, which was significant only in female rats. Folpet exposure was also associated with an increased incidence of ulceration of the non-glandular stomach of the high-dose group. Histologically, folpet treatment produced hyperkeratosis of the oesophagus of rats in the high-dose groups and of the non-glandular stomach of animals in the mid- and high-dose groups. There was also a slight increase in gastric ulceration in the non-glandular stomach of both males and females in the high-dose groups. The incidences of C-cell adenoma, benign mammary fibroepithelioma, and malignant lymphoma showed a positive significant trend with dose; only the latter neoplasms were statistically significant, but the incidences of all remained within the range of spontaneous incidences of these neoplasms in F-344 rats. Accordingly, the results of this study indicate that folpet is not carcinogenic to F-344 rats (Crown et al., 1985). Special studies on mutagenicity Folpet was mutagenic in E. coli strain PQ37, but inactive in the presence of S-9 microsomal mix. It was without genotoxic activity in Chinese hamster V79 cells and in somatic cell mutation and micronucleus tests in mice. Results are presented in Table 1. Dietary analysis confirmed the stability of folpet in the test diet for the somatic cell mutation study (Slagowski & Leary, 1985a). Special study on reproduction Rats In a 2-generation reproduction study, groups of 30 male and 30 female Crl:COBS/CD (SD)/Charles River rats were fed folpet (89.5% pure) in the diet at 0, 200, 800, or 3600 ppm during growth, mating, gestation, and lactation for 2 litters per generation. Mating was allowed after 62 days of dietary exposure. The test diets were fed to the F0 males until the end of the mating periods for the F1b litters and to the F0 females until the weaning of the F1b litters. Pups were sacrificed 21 - 23 days after parturition, with the exception of those F1b pups selected to parent the F2 generation. Mating of these F1b pups began after 12 weeks of dietary exposure and the above sequence repeated. Gross necropsy was performed on all parental rats and on the F1a, F1b, and F2b litters. The test diet was changed 3 times per week and each batch was analysed for folpet content. Analyses showed that the test diets contained 79.9 - 101% of the nominal folpet concentration. The body weights of the high-dose males (F0 and F1) and females (F1) and of the pups from high-dose litters were depressed by treatment. This effect was most marked in the adult males, especially in the second generation. Food consumption was correspondingly reduced. Treatment had no significant effect on mating, fertility indices, pregnancy rates, litter sizes, pup weights, growth, or litter survival rates. There were no treatment related effects found at necropsy or on histopathological examination. Based on the finding of reduced body weight at the high dose, the no-effect level determined in this study was 800 ppm (Hardy & Richter, 1985; Slagowski & Leary, 1985c). Special studies on teratology Rats In a pilot study, groups of 6 pregnant CD rats were treated daily with 10, 65, 420, or 2750 mg folpet/kg b.w. (88.6% pure) by intragastric gavage during days 6 to 15 of gestation. The high-dose treatment caused maternal toxicity, reduced maternal body-weight gain, and reduced fetal weight, but the lower doses were without apparent effect (Rubin, 1985a). Table 1. Results of mutagenicity studies on folpet Test Test system organism Purity Concentration Results Reference E. coli E. coli 90% 0.03, 0.10, positive Abir, 1986 PQ37 PQ371 0.3, 1.0 mutation µg/ml (-S-9) 3.0, 10.0,30.0 negative µg/ml (+S-9) Chinese V79 90.1% 0.125, 0.25, negative Bootman et al., hamster cells2 0.5, 1.0, 2.0 1986 fibroblast µg/ml (-S-9) 3.125, 6.25 negative 12.5, 50 µg/ml (+S-9) Mouse T-strain 88.7% 0, 100, 1500, negative Moore & Brusick, somatic male mice & 5000 ppm, (decreased 1985 cell C57B1/6 fed days 8.5 pup body mutation female - 12.5 of weight and mice gestation survival occurred) Mouse Charles 91.0% 10, 50, 250 negative Jacoby, 1985 micro-nucleus River CD-1 mg/kg mice3 1 Positive controls using 0.0156 - 1.0 µg/ml 4-nitroquinoline-1-oxide or 0.156 - 10.0 µg/ml 2-aminoanthracene gave positive results. 2 Positive controls using 1000 µg/ml ethylmethane sulfonate (-S-9) or 10 µg/ml 7,12-dimethylbenzanthracene (+S-9) gave positive results. 3 A positive control using chlorambucil gave the expected response. Subsequently, groups of 22 mated female Charles River CD rats were dosed daily by oral gavage with 0, 150, 550, or 2000 mg folpet/kg b.w. (91.1% pure) suspended in 0.5% acetic acid containing 0.5% carboxymethylcellulose from days 6 to 15 of gestation. The animals were sacrificed on day 20 and the uterine contents were removed for pathological examination. One dam of the high-treatment group died, while clear signs of toxicity were observed in the rest of this group, namely, soft faeces (21/21), staining of fur (4/21), and perianal staining (8/21). Food consumption was markedly decreased in the high-dose group during treatment; it was decreased in the intermediate group only during the first days of treatment. Maternal body weight was significantly reduced in the high-dose group throughout the study, and to a lesser extent in the mid-dose group. Mean gravid uterine weights were significantly depressed in the high- and mid-dose groups, but terminal maternal body weight (i.e. net of gravid uterus) was significantly depressed only in the high-dose group. Pre- and post-implantation losses were increased over controls in the mid-dose group only, while fetal weights were reduced in the high- and mid-dose groups. Fetal crown-rump length was decreased slightly in mid- and high-dose groups. The high-dose group contained a single fetus (1/277) with multiple major malformations. On sectioning, another fetus in the high-dose group was found to have unilateral microthalmia. Hepatic discolouration was significant in the high-dose group. Skeletal anomalies occurred in all treated groups. Reduced ossification of cranial and pubic bones, sternebrae, metacarpals, and metatarsals was significant in mid- and high-dose groups. There was a dose-related reduction in the ossification of the interparietal bone of all treated groups. In addition, angulated ribs occurred in a dose-related manner in all treated groups. As a consequence, this study did not demonstrate a no-observed-effect level (Rubin & Nyska, 1985b). Rabbits In a pilot study, groups of 6 mated HY/CR female New Zealand white rabbits were treated with folpet (91.1% purity) at 0, 10, 60, or 150 mg/kg b.w./day by intragastric intubation from day 6 to day 18 of gestation, inclusively. A marked loss of body weight occurred at the high dose. Although fetal size was not affected by treatment, fetal death was more marked at the high dose. Post-implantation losses were increased in the mid-dose group (Rubin & Nyska, 1985c). Subsequently, groups of 14 mated HY/CR New Zealand white rabbits were treated with technical folpet (91.1% purity) suspended in 0.5% carboxymethylcellulose in 0.5% acetic acid at 0, 10, 40, or 160 mg/kg b.w./day by oral gavage from day 7 to day 19, inclusive, of gestation. Administered doses were corrected daily for body weight. The dams were sacrificed at day 29 and their uterine contents removed and necropsied. The body-weight gain of high-dose dams was reduced after initiation of treatment, while that of the mid-dose group was reduced during the initial few days of treatment only. There was a corresponding decrease in food consumption of the high-dose animals during treatment. No animals died during treatment. At necropsy, the gravid uterine weight was significantly reduced in the mid- and high-dose groups. Fetal death (post-implantation loss) occurred more frequently in the high-dose group than in controls. The proportion of small fetuses was also greater in this group, and the mean fetal weight was reduced, but not significantly. There was evidence of delayed skeletal maturation in the high-dose group and, to a lesser degree, in the mid-dose group. The incidence of bilateral lumbar ribs increased in an apparently dose-related manner in the mid- and high-dose groups. Ossification of caudal vertebrae, sternebrae, and long-bone epiphyses were reduced at the high dose. Other minor skeletal variations were not apparently related to treatment. There was no evidence of hydrocephalus in either treated or control rabbits (Rubin, 1985b). Groups of 20 artificially inseminated female Hazleton Dutchland New Zealand white (Dla Hra; (NZW)SPF) rabbits were dosed by oral gavage with a suspension of folpet (89.5% pure) in Tween 80 (10.5% by weight) and carboxymethylcellulose (0.7% by weight) at a volume of 5 ml/kg b.w./day. The test material was administered at 60 mg/kg b.w. daily by stomach tube, using the pulse-dose regime tabulated in Table 2, at selected days of gestation. Table 2. Pulse-dose regime for teratology study in rabbits Dosage Treatment group (mg/kg b.w./day) Days of administration I 0 7-18 II 60 7-9 III 60 10-12 IV 60 13-15 V 60 16-18 Analysis of dosage formulations, prepared daily, for folpet content ranged from 87.8 to 104% of nominal dosage. The dams were sacrificed on gestation day 29, necropsied, and uterine contents examined. Animals which aborted or delivered (and the single animal which died) during the study were subjected to similar procedures. The abortion of 2 rabbits which received folpet on days 7 - 9 and 10 - 12 of gestation may have been related to treatment. Otherwise, no clinical signs of toxicity were observed during the study, although the incidences of dams with soft or liquid faeces increased in all treatment groups, usually after the treatment period. At necropsy, no gross lesions were attributable to treatment. Maternal body weights, however, were significantly reduced in all treated groups, although less so in groups II and III than in the others. Food consumption was correspondingly reduced. Treatment had no apparent effect on the rate of abortion or on fetal resorption. Average litter sizes were unaffected, as were average fetal weights, the number of viable fetuses, and the sex ratio. A significantly-increased incidence of fetuses with an irregularly shaped fontanelle was observed in Group IV. The control incidence was 4.5%, but this variation did not occur in Groups II and V. It was possibly related to treatment, but the significance of this effect was not clear. There were no other significant variations in fetal skull morphology, and the incidence of hydrocephalus was not increased in any group. Gastric or pulmonary anomalies were not increased in any groups. The results of this study indicate that folpet is not teratogenic in rabbits at 60 mg/kg b.w./day (Feussner et al., 1985; Slagowski & Leary, 1985b). Short-term studies Rats In a pilot study, groups of 20 male and 20 female F-344 rats were fed folpet (89% purity) in the diet at 0, 0.2, 0.4, or 0.8% for 13 weeks. During treatment, body weights and food consumption of mid- and high-dose males and of high-dose females were significantly reduced. After 10 weeks there were no significant differences between treated and control groups, but there were dose-related decreases in the following serum enzymes: alkaline phosphatase and alanine aminotransferase in treated groups, aspartate-aminotransferase in all treated males and in high-dose females, and lactate dehydrogenase in all treated male groups. Blood urea and chloride levels were increased, but total serum proteins were reduced in mid- and high-dose male groups. Blood urea was reduced in treated females, while total protein was reduced in the high-dose groups and albumin was reduced in the mid- and high-dose groups. Treatment-related irritation of the proximal gastrointestinal tract was evident at necropsy, as was hyperkeratosis of the non-glandular gastric mucosa. Slight acanthosis of the stomach occurred in 1 female rat in each group. The kidneys of mid- and high-dose male rats showed a slight but dose-related increase in the number of foci of atrophic basophilic renal tubules, which was considered to be unrelated to treatment (Sela et al., 1982). Groups of 20 male and 20 female Sprague Dawley rats received folpet (purity unspecified) in the diet at 0, 0.03, 0.1, 0.3, or 1.0% for 13 weeks. Half the rats in each group were then sacrificed, while the remainder were administered the basal diet for 2 weeks, until they too were sacrificed. There were no signs of toxicity and no deaths occurred during the study period. The growth of high-dose male and female rats was significantly reduced throughout the treatment period. This growth retardation was not recovered during the 2-week recovery period after treatment. (Dietary analyses showed that achieved doses were 85 - 106% of nominal values.) Food consumption and haematological parameters were unaffected by treatment. There were no treatment-related variations in serum hepatic enzyme levels or renal function parameters. At necropsy, high-dose groups of both sexes exhibited reduced mean body weights. Their relative brain weights were also reduced, while their kidney weights were increased. However, there were no significant differences in the organ weights of those animals permitted to recover for 2 weeks. No gross pathological findings attributable to treatment were observed. However, histopathological findings of acanthosis, hyperkeratosis, submucosal oedema, and pleocellular inflammatory infiltrate, together with occasional focal gastric erosions or ulcerations, were found in the non-glandular stomachs of high-dose rats after 13 weeks of treatment. These lesions were not evident in stomach sections of high-dose rats after the 2-week recovery period. Based on reduced body weight and other effects seen in the high-dose group, the 0.3% dose level was the no-observed-effect level in this study (Reno et al., 1981; Leary & Tucker, 1982). Dogs In a pilot study, groups of 4 male and 4 female beagle dogs were dosed orally with encapsulated folpet (89.8 - 91.1% purity) at 0, 790, 1800, or 4000 mg/kg b.w./day for 13 weeks. Treated dogs generally consumed less food than controls. Body-weight gain, which was reduced in all treated groups, was significantly depressed in the mid- and high-dose groups. Vomiting and diarrhoea occurred in all treated dogs, but these symptoms were especially marked in the intermediate- and high-dose groups. Treatment-related physical changes, including poor condition, abdominal distension, excessive salivation, and progressive decrease in testicular size, were especially prevalent in mid-and high-dose groups. All high-dose males and 1 high-dose female died or were killed in extremis. Neurological examination of these dogs and those males which survived 12 weeks of treatment was unremarkable, as was ophthalmoscopy of survivors. Most dogs killed in extremis had a leucocytosis and some had decreased serum phosphate levels; 1 dog had normochromic normocytic anaemia. Surviving dogs exhibited decreased serum calcium and total plasma protein concentrations but increased serum chloride levels. At necropsy, most treated dogs had decreased weights of the brain, liver, kidney, spleen, and testicles. Pathological examination showed atrophy, depletion, and fibrosis of the lymphatic and haematopoetic systems, gonadal degeneration with prostatic atrophy and fibrosis, thyroid degeneration, and muscular dystrophy (Barel et al., 1985). In a subsequent study groups of 6 male and 6 female beagle dogs received technical folpet (89.5% purity) orally in gelatine capsules at 0, 10, 60, or 140 mg/kg b.w./day. The high-dose treatment rate was reduced to 120 mg/kg b.w./day at day 50 due to poor food consumption and reduced body-weight gain. After a year of treatment, the animals were sacrificed and necropsied. All high-dose and 3 mid-dose male dogs exhibited initial loss of body weight. The mean body weights of the mid- and high-dose males and females were reduced, although not significantly, throughout the rest of the study in a dose-related manner. There were dose-related decreases in food consumption of mid- and high-dose males for the first 3 months and of the mid- and high-dose females for the first month. Although food consumption of the males was subsequently comparable to controls, there was a tendency for reduced food consumption in treated female groups, but not in a dose-related manner. Ophthalmoscopy, performed at 6 and 12 months, revealed no effects of treatment. There was a tendency for reduced male leucocyte counts at 1, 2, 3, and 6 months, but not at 9 or 12 months; however, these changes were not significantly different from control values. Clinical chemistry showed a significant decrease in mean serum cholesterol, total protein, albumin, and globulin levels in mid- and high-dose male groups. In high-dose female dogs, there were significantly reduced mean serum protein, albumin, and cholesterol levels. Urinalysis showed no significant treatment-related effects. No significant treatment-related effects were found at necropsy or subsequent histopathological examination. According to observed body-weight changes, reduced food consumption, and serum biochemical changes, the no-observed-effect level of this study was 10 mg/kg b.w./day (Daly & Knezevich, 1986). Long-term study Rats In a combined chronic toxicity and carcinogenicity bioassay, groups of 60 male and 60 female Charles River Crl: CD(SD)BR albino rats received technical folpet (89.5% purity) in the diet at 0, 200, 800, or 3200 ppm for 104 weeks. An interim sacrifice of 10 rats randomly selected from each group was conducted at 52 weeks. Ophthal- moscopy was conducted on all rats prior to initiation and at weeks 52 and 105. Blood and urine samples were collected from 10 rats/sex/group at weeks 27, 78, and 104 for clinical and biochemical analysis and urinalysis. Rats dying during the course of the study were necropsied and subjected to the usual investigations. Growth rates and survival were not significantly affected by treatment, although there was a slight tendency for reduced body weights in the high-dose females during the first year. Food consumption was correspondingly reduced at this dose level. There were no treatment-related ophthalmoscopic findings. Conventional haemato- logical, biochemical, and urinalysis parameters were unaffected by treatment. At necropsy, there were no organ-weight changes attributable to treatment. Histopathology revealed an increase in lesions of the non-glandular stomach, principally hyperkeratosis and/or acanthosis, but also erosion and/or ulceration in both high-dose treatment groups. These lesions occasionally were accompanied by submucosal oedema and submucosal inflammatory cellular infiltrate. As there were no other significant histopathological findings, the no-observed-effect level in this study was determined to be 800 ppm (Cox et al., 1985). Observations in humans In a retrospective mortality study, a cohort of 134 workers occupationally exposed during manufacture of captan for up to 9 months annually, and to folpet for up to 3 months annually, was studied. There was an apparent increase in the total number of mortalities from all causes (18) for the cohort, compared to the number expected from US mortality rates (S.M.R. 164). The excess mortality was principally attributable to cardiovascular disease and "external causes" unrelated to occupation. Statistically-significant increases were not observed for any specific cause of death, including neoplasia, but the number of deaths was too few to evaluate cause-specific mortality. Lack of adequate industrial-hygiene monitoring data precluded satisfactory estimation of the historical exposures (Palshaw, 1980). COMMENTS The 1984 Joint Meeting withdrew the ADI for folpet because of substantial deficiencies in its toxicological data base and because of possible teratogenicity in rabbits. Two independent studies now indicate that folpet is not teratogenic in rabbits, even at a dose that is clearly maternally toxic. Folpet was also without apparent effect on the reproduction of rats in a 2-generation reproduction study, but it apparently reduced the body weight and survival of murine pups. Further mutagenicity studies have confirmed that folpet is mutagenic in procaryotes in vitro. It is not genotoxic in the Chinese hamster fibroblast or mouse micronucleus assays, and it did not induce mouse somatic cell mutations in vivo. A short-term feeding study in rats produced acanthosis, hyperkeratosis, submucosal oedema and cellular infiltration, and occasional focal erosions in the non-glandular stomach. These lesions resolved 2 weeks after cessation of exposure and are suggestive of an irritant effect of folpet treatment. Similar irritative effects were found in a chronic feeding bioassay in rats but, significantly, there was no indication of a carcinogenic response. No remarkable pathology was seen in a 1-year feeding study in dogs. The carcinogenicity of folpet to mice has been demonstrated further. Dietary exposure produced dose-related increases in gastric papillomas and squamous cell carcinomas, duodenal adenomas, and adenocarcinomas. Accompanying irritant changes, oesophageal hyperkeratosis, acanthosis and hyperkeratosis of the non-glandular gastric mucosa, microscropic gastric ulceration, duodenal glandular hyperpalsia, and mucosal glandular proliferation were also present. Although the 1984 Joint Meeting noted that folpet produced a dose-related increase in the incidence of duodenal adenomas and adenocarcinoams in CD-1 mice at dietary concentrations of 5000 and 12,000 ppm, but not at 1000 ppm, the present study clearly demonstrated carcinogenicity in B6C3F1 mice at 1000 ppm. Duodenal adenomas and carcinomas, observed in the previous study with CD-1 mice, occurred in all treatment groups. In addition, gastric papillomas and squamous cell carcinomas occurred. The development of squamous cell neoplasia may correspond to the hyperkeratotic changes and acanthosis seen in rats. The other neoplastic changes may be related to the localized effects of the compound. If tumour induction is related to "swamping" of the gut and passage of large amounts of irritant compound into the small bowel, the significance of the lesions for man is limited. An epidemiological study showed no evidence of neoplasia among workers occupationally exposed to captan and to a lesser degree to folpet during manufacture, but the data are inadequate to evaluate long-term exposure to folpet in man. Since the concern over the potential teratogenicity of folpet has been resolved and the previous toxicological data deficiencies now have been met, the meeting agreed to re-establish a temporary ADI. TOXICOLOGICAL EVALUATION LEVEL CAUSING NO TOXICOLOGICAL EFFECT Rat: 800 ppm in the diet, equal to 40 mg/kg b.w./day. Dog: 10 mg/kg b.w./day. ESTIMATE OF TEMPORARY ACCEPTABLE DAILY INTAKE FOR MAN 0 - 0.01 mg/kg b.w. STUDIES WITHOUT WHICH THE DETERMINATION OF A FULL ADI IS IMPRACTICABLE, TO BE SUBMITTED TO WHO BY 1988: 1. Investigations directed towards determining the mechanism of gastrointestinal neoplasia. The dynamics of passage of the compound through the stomach, rate of release, and time spent in the duodenum should be studied at varying doses in mice and rats to investigate the possibility that induction of adenocarcinoma is a local exposure effect. An evaluation of whether 2 mechanisms are operating, 1 for squamous and another for adenocarcinomatous lesions, should be made. Noting that a jejunal tumour occurred only at the highest dose, local administration of the compound (via a gut loop) would also be of interest. This may be impractical. 2. Comparative studies of the metabolic fate of the trichloromethylthio moiety in mice and rats. STUDIES WHICH WILL PROVIDE INFORMATION VALUABLE IN THE CONTINUED EVALUATION OF THE COMPOUND Further observations in man. REFERENCES Abir, H. An assessment of the mutagenic potential of folpet technical 1986 using in vitro bacterial cell test system. Unpublished report from Makhteshim Chemical Works Ltd. Submitted to WHO by Makhteshim Chemical Works Ltd., Beer-Sheva, Israel. Barel, Z., Nyska, A., & Waner, T. Folpan: 90-day preliminary toxicity 1985 study in beagle dogs. Unpublished report No. MAK/061/FOL from Life Science Research Israel Ltd., Ness Ziona, Israel. Submitted to WHO by Makhteshim Chemical Works Ltd., Beer-Sheva, Israel. Bootman, J., Hodson-Walker, G., & Lloyd, J.M. Folpan Tech.: 1986 Investigation of mutagenic activity at the HGPRT locus in a Chinese hamster V79 cell mutation system. Unpublished report No. 86/MAK/054/188 from Life Science Research Israel Ltd., Ness Ziona, Israel. Submitted to WHO by Makhteshim Chemical Works Ltd., Beer-Sheva, Israel. Cox, R.H., Marshall, P.M., Voelker, R.W., Vargas, K.J., Alasker, R.D., 1985 & Dudeck, L.D. Combined chronic oral toxicity/oncogenicity study in rats: Chevron folpet technical (SC-1388). Unpublished report No. 2107-109 from Hazleton Laboratories America, Inc., Vienna, VA, USA. Submitted to WHO by Chevron Chemical Company, Richmond, CA, USA. Crown, S., Nyska, A., & Waner, T. Folpan. Carcinogenicity study in the 1985 rat. Unpublished report No. MAK/022/FOL from Life Science Research Israel Ltd., Ness Ziona, Israel. Submitted to WHO by Makhteshim Chemical Works Ltd., Beer-Sheva, Israel. Daly, I.W. & Knezevich, A.L. A one-year subchronic oral toxicity study 1986 in dogs with folpet technical. Unpublished report No. 82-2677 from Bio-Dynamics, Inc., East Millstone, NJ, USA. Submitted to WHO by Chevron Chemical Company, Richmond, CA, USA. Feussner, E.L., Hoberman, A.M., Johnson, E.M., & Christian, M.S. 1985 Teratology study in rabbits with folpet technical using a "pulse-dosing" regimen. Unpublished final report on Project No. 303-004 from Argus Research Laboratories, Inc., Horsham, PA, USA. Submitted to WHO by Chevron Chemical Company, Richmond, CA, USA. Hardy, L.M. & Richter, W.R. SOCAL 2140 (S-2323): Two generation (two 1985 litter) reproduction study in rats with Chevron folpet technical. Unpublished report from Chevron Environmental Health Center, Inc. Submitted to WHO by Chevron Chemical Company, Richmond, CA, USA. Jacoby, O. Folpan. Mouse micronucleus test. Unpublished report 1985 No. MAK/071/FOL from Life Science Research Israel Ltd., Ness Ziona, Israel. Submitted to WHO by Makhteshim Chemical Works Ltd., Beer-Sheva, Israel. Leary, J.B. & Tucker, B.V. Phaltan 90-day dietary study in rats. 1982 Unpublished report (Hazleton Project No. 2107-100 and Chevron Test No. S-1440/Diet Analysis) from Chevron Chemical Company Agricultural Chemicals Division. Submitted to WHO by Chevron Chemical Company, Richmond, CA, USA. Moore, M.R. & Brusick, D.J. Evaluation of Chevron folpet technical in 1985 the mouse somatic mutation assay. Unpublished Project No. 20994 from Litton Bionetics, Inc., Kensington, MD, USA. Submitted to WHO by Chevron Chemical Company, Richmond, CA, USA. Nyska, A. Neoplasia in the stomach. Unpublished report No. MAK/015/FOL 1985 from Life Science Research Israel Ltd., Ness Ziona, Israel. Submitted to WHO by Makhteshim Chemical Works Ltd., Beer-Sheva, Israel. Palshaw, M.W. An epidemiologic study of mortality within a cohort of 1980 captan workers. Unpublished report from Stauffer Chemical Company. Submitted to WHO by Chevron Chemical Company, Richmond, CA, USA. Reno, F.E., Burdock, G.A., Serota, D.G., Voelker, R.W., Alasker, R.D., 1981 & Milad, G.M. Subchronic toxicity study in rats. Unpublished report No. 2107-100 from Hazleton Laboratories America, Inc., Vienna, VA, USA. Submitted to WHO by Chevron Chemical Company, Richmond, CA, USA. Rubin, Y. Folpan. Preliminary teratology study in rats. Unpublished 1985a report No. MAK/048/FOL from Life Science Research Israel Ltd., Ness Ziona, Israel. Submitted to WHO by Makhteshim Chemical Works Ltd., Beer-Sheva, Israel. Rubin, Y. Folpan. Preliminary teratology study in the rabbit. 1985b Unpublished report No. MAK/051/FOL from Life Science Research Israel Ltd., Ness Ziona, Israel. Submitted to WHO by Makhteshim Chemical Works Ltd., Beer-Sheva, Israel. Rubin, Y. & Nyska, A. Folpan. Oncogenicity study in the mouse. 1985a Unpublished report No. MAK/015/FOL from Life Science Research Israel Ltd., Ness Ziona, Israel. Submitted to WHO by Makhteshim Chemical Works Ltd., Beer-Sheva, Israel. Rubin, Y. & Nyska, A. Folpan. Teratology study in the rat. Unpublished 1985b report No. MAK/049/FOL from Life Science Research Israel Ltd., Ness Ziona, Israel. Submitted to WHO by Makhteshim Chemical Works Ltd., Beer-Sheva, Israel. Rubin, Y. & Nyska, A. Folpan. Preliminary teratology study in rabbits. 1985c Unpublished report No. MAK/050/FOL from Life Science Research Israel Ltd., Ness Ziona, Israel. Submitted to WHO by Makhteshim Chemical Works Ltd., Beer-Sheva, Israel. Sela, J., Nyska, A., Pitel, Z., & Rambach, H. Folpan. Toxicity in 1982 dietary administration to rats for 13 weeks. Unpublished final report No. MAK/021/FOL from Life Science Research Israel Ltd., Ness Ziona, Israel. Submitted to WHO by Makhteshim Chemical Works Ltd., Beer-Sheva, Israel. Slagowski, J.L. & Leary, J.B. Addendum to an evaluation in the mouse 1985a somatic cell mutation assay with Chevron folpet technical (SX-1388). Unpublished report (Litton Bionetics Project No. 21994-491 and Ortho Test No. S-1971 diet analysis) from Chevron Chemical Company, Ortho Agricultural Chemicals Division, Development Research Department. Submitted to WHO by Chevron Chemical Company, Richmond, CA, USA. Slagowski, J.L. & Leary, J.B. Addendum to teratology study in rabbits 1985b with folpet technical (SX-1388) using a "pulse-dosing" regimen. Unpublished report (Argus Research Laboratories Project No. 303-004 and Ortho Test No. S-2512 dosage formula analysis) from Chevron Chemical Company, Ortho Agricultural Chemicals Division, Development Research Department. Submitted to WHO by Chevron Chemical Company, Richmond, CA, USA. Slagowski, J.L. & Leary, J.B. Addendum to reproduction study in rats 1985c with folpet technical (SX-1388). Unpublished report (SOCAL Project No. 2140 and Ortho Test No. S-2323 diet analysis) from Chevron Chemical Company, Ortho Agricultural Chemicals Division, Development Research Department. Submitted to WHO by Chevron Chemical Company, Richmond, CA, USA.
See Also: Toxicological Abbreviations Folpet (HSG 72, 1992) Folpet (ICSC) Folpet (FAO/PL:1969/M/17/1) Folpet (WHO Pesticide Residues Series 3) Folpet (WHO Pesticide Residues Series 4) Folpet (Pesticide residues in food: 1984 evaluations) Folpet (Pesticide residues in food: 1990 evaluations Toxicology) Folpet (Pesticide residues in food: 1995 evaluations Part II Toxicological & Environmental)