METIRAM First draft prepared by M. Caris Health Canada, Ottawa, Canada EXPLANATION Metiram is a non-systemic EBDC fungicide that contains zineb and poly (ethylenethiuram disulfide). It was considered for the first time at the present Joint Meeting. EVALUATION FOR ACCEPTABLE DAILY INTAKE BIOLOGICAL DATA Biochemical aspects Absorption, distribution and excretion Rats Male and female Sprague-Dawley rats were administered a single oral dose of 14C-labelled metiram at a dose of 5 or 50 mg/kg bw or were pretreated with unlabelled test material, 5 mg/kg bw/day for 14 days followed by a single oral dose of 14C metiram of 5 mg/kg bw. Over 98% of the administered 14C metiram dose was excreted within 7 days, with the majority of the dose excreted within the first 48 hours post-dosing. Mean recovered radioactivity in the faeces accounted for 53.9-78.7% of the dose with a smaller percentage excreted in the urine, 21.3-46.6%. Slightly lower proportions of radioactivity were excreted in the urine at the high dose when compared to the low dose, suggesting that absorption of metiram was less at higher doses. Mean radioactivity excreted in the expired air represented 0.4-1.1% of the dose. The patterns of excretion of radioactivity were similar upon single or repeated exposure to metiram. Comparatively, absorption was greater and excretion more rapid in rats treated with 0.5 mg of 14C-ETU/kg bw, where 96% of the dose was excreted in the urine and only 4.2% in the faeces within 3 days post-dosing. Biliary excretion of 14C-labelled metiram accounted for 14.3% and 7.1% of a single 5 mg/kg bw dose in males and females, and 4.3% and 3.7% of a single 50 mg/kg bw dose in either sex, respectively. Peak mean plasma concentrations of radioactivity occurred after 4 hours in the 5 mg/kg bw dose and after 6 hours following administration of a single oral dose of 50 mg/kg bw, respectively. After 7 daily oral doses of 14C metiram at 5 mg/kg bw/day, the highest concentrations of radioactivity were found in the thyroid and kidneys with concentrations being slightly higher in females than in males. Whole-body autoradiography of these rats confirmed the results of the quantitative tissue distributions. The comparisons between rats sacrificed at 24 hours after a single dose or after multiple doses showed evidence of accumulation of radioactivity in the body with multiple dosing (Hawkins et al., 1985). Absorption was studied in male CD rats treated dermally on their shaved backs with 14C metiram at dose levels of 0.24 or 240 mg/kg bw equal to 0.004 or 4 mg/cm2, respectively. Groups of 4 animals were killed after 1, 2, 4 and 8 hours following application, and two groups of 4 animals had the treated skin sites washed after 8 hours with subsequent sacrifice of the animals, 24 or 96 hours post-treatment. Total radioactivity detected from urinary and faecal excretion and tissue residue levels accounted for 0.9% and 0.2% of the radioactivity at the low and high dose, respectively. The majority of the administered dose was recovered from the treated skin of the rats. Concentrations of radioactivity in plasma and tissues were generally below or at the limits of detection (Hawkins et al., 1984). Biotransformation Rats Thin layer chromatography (TLC) of the urine of rats treated with 14C-metiram as single oral doses of 5 or 50 mg/kg bw, and a single oral dose of 100 mg/kg bw of a 15N-metiram and 14C-metiram suspension (1:1 ratio), revealed eight principal radioactive components. Incubation with ß-glucuronidase/sulphatase did not significantly alter the proportion of radioactive components. Polar components accounted for the majority of the radioactivity (34-58%) and were identified as ethylenediamine, N-acetyl-ethylenediamine and possibly ethanolamine and oxalic acid. Another polar component was an acidic compound with similar chromatographic properties to glycine. Major less polar components were identified as ethyleneurea (4-11%), ethylenethiourea (10-35%) and ethylene bis(isothiocyanate) sulphide (1-3%). The proportion of radioactive components in the bile of rats treated with a single oral dose of 14C metiram at 10 mg/kg bw as separated by TLC were similar to those obtained in the urine. Metabolite patterns were determined for kidney and liver extracts from rats treated with 14C metiram at 5 mg/kg bw for 7 days. Radioactive components in the kidney were similar to those found in urine; however, of the liver extracts, only the ß-glucuronidase/sulphatase treated sample provided a satisfactory pattern which contained mainly polar material and only traces of ethyleneurea and ethylenethiourea (Hawkins et al., 1985). The proposed metabolic pathway of metiram in animals is depicted in Figure 1. Toxicological studies Acute toxicity studies Acute toxicity studies with technical metiram have been performed in the rat and mouse, the results of which are summarized in Table 1. WHO has classified metiram as unlikely to present acute hazard in normal use (WHO, 1992). Acute studies with the formulated trade product, Polyram combi (consisting of 80% metiram complex (technical active ingredient) and 20% formulating agents) were similarly conducted in several animal species, the results of which are given in Table 2. Both technical and formulated metiram, uponTable 1. Acute toxicity of technical metiram Species Sex Route (vehicle) LD50 Test material Reference (strain) (mg/kg bw) Rat M+F oral > 6810 Technical grade Jackh, 1981 (SD) (distilled water) (purity unknown) Rat M+F oral M: 9100 Technical grade Leuschner, 1979a (SD) (HPMC) F: 8900 (purity unknown) + 2% ETU M+F: 9000 Rat M+F oral 6500 Technical grade Hofmann, 1985a (SD) (tragacanth) (purity unknown) Rat M+F oral 10 000 Technical grade Hofmann, 1975 (SD) (CMC) (purity unknown) Rat (SD) M+F dermal (water) > 2000 Technical grade Grundler, 1979 (77.5% purity) + 2% ETU Mouse (NMRI) M+F intraperitoneal M: 208 Technical grade Leuschner, 1979b (HPMC) F: 215 (purity unknown) + 2% ETU M+F: 212 Mouse (NMRI) M+F intraperitoneal 80 Technical grade Hofmann, 1974a (tragacanth) (purity unknown) Rat (SD) M+F intraperitoneal M: 318 Technical grade Hofmann & Munk, 1975 (CMC) F: 317 (77.5% purity) M+F: 318 Rat (SD) M+F inhalation 4 h > 5.7 (mg/l) Technical grade Klimisch & Zeller, 1980 (77.5% purity) + 2% ETU Rat (SD) M+F inhalation 8 h (well Technical grade Hofmann, 1985b tolerated) (purity unknown) + 2.2% ETU Table 2. Acute toxicity of Polyram combi (formulated product) Species Sex Route LD50 Test Reference (strain) (vehicle) (mg/kg bw) material Rat M+F oral > 10 000 Polyram combi Hofmann, 1985c (SD) (tragacanth) (purity unknown) Dog M+F oral * Polyram combi Chesterman et al., 1973 (beagle) (water) (purity unknown) Mouse (NMRI) M+F intraperitoneal approx 80 Polyram combi Hofmann, 1974b (tragacanth) (purity unknown) Rat M+F dermal > 2000 Polyram combi Grundler, 1985 (SD) (77.5% purity) Rat M+F inhalation, (well Polyram combi Hofmann, 1985d (SD) 8 hr tolerated) (77.5% purity) Guinea-pig inhalation, >0.8 (mg/L) Polyram combi Hofmann, 1985e 8 hr (purity unknown) * Estimation of LD50 precluded due to high incidence of vomiting oral and dermal administration, were practically non-toxic in the rat with LD50 values of > 6500 mg/kg bw and > 2000 mg/kg bw, respectively. Moderate acute toxicity was demonstrated upon intraperitoneal administration of technical material in the mouse (LD50 = 80-212 mg/kg bw) and rat (LD50 = 318 mg/kg bw). Technical metiram when administered by the inhalation route resulted in an LC50 value greater than 5.7 mg/l in the rat. Eight-hour inhalation of the formulated material, Polyram combi was well tolerated in both rats and guinea-pigs. Intentional spiking of the technical material with ETU at levels of 2 to 2.2% did not markedly alter the acute toxicity profile. Short-term toxicity studies Mice In a preliminary assessment of the toxicity of metiram (96.8% purity, containing 2.2% ETU), groups of 8 CFLP mice per sex were fed dietary concentrations of 0, 100, 300, 1000 or 3000 ppm equal to 0, 16, 40, 120 or 399 mg/kg bw/day for males and 0, 15, 44, 142 or 433 mg/kg bw/day for females, respectively, for a period of 4 weeks. Body-weight gain of males treated with metiram at 1000 and 3000 ppm were significantly lower than that of the corresponding controls during the first week of treatment with subsequent recovery of weight gain in the ensuing weeks. Although no consistent effects on body weight in treated females were observed on a weekly basis, overall weight gain of females at the high dose of 3000 ppm was marginally lower than that of the control animals. Significantly increased liver weights were recorded in both sexes treated at levels of 1000 and 3000 ppm. In the absence of routine histopathological examination, no microscopic correlation could be drawn from the increased liver weights. There were no effects of treatment on survival, clinical signs, food consumption or gross pathological changes. On the basis of the reported findings, a high dietary level of 1000 ppm was selected for the long-term study in mice (Hunter et al., 1976b). A 3-month study was performed with groups of 10 B6C3F1 mice/sex treated with metiram (94.8% purity, ETU <0.2%) at dietary levels of 0, 300, 1000, 3000 or 7500 ppm, equal to 0, 84, 302, 853 or 2367 mg/kg bw/day in males and 0, 133, 465, 1448 or 3565 mg/kg bw/day in females, respectively. Treatment-related effects were observed with respect to serum T3 and T4 concentrations. Serum T4 levels were significantly decreased in both sexes of mice treated with metiram at dietary levels of 1000 ppm and higher, whereas T3 levels were significantly increased in male mice treated at the highest dietary level of 7500 ppm. Histopathological findings attributable to treatment were denoted in the thyroid in both sexes treated at dietary levels of 3000 ppm and higher as minimal to slight hypertrophy and vacuolation of the follicular epithelium. A slight increase in the severity of fatty degeneration of the `X zone' in the adrenals was also observed in female mice treated with metiram at 3000 and 7500 ppm. A dose-related increased incidence in the presence of a refractile, granular material presumed to be the test material or a metabolite, was noted in the superficial layer of the urinary bladder urothelium in all groups of treated mice. Since no morphological changes were observed in the urothelium of the bladder to suggest disturbed epithelial function, the presence of this granular material was considered to be of doubtful toxicological consequence. Significantly increased organ weights were recorded for the adrenals in females at dietary levels of 3000 ppm and higher and for the liver in both sexes treated at 7500 ppm and in males at 3000 ppm. Statistically significant increases in kidney and testicular weights were judged to be of no biological consequence. No histopathological correlation could be determined for the increased liver, kidney or testicular weights. Group mean body weights and corresponding weight gains were decreased in males treated at the highest dietary level of 7500 ppm. Although significant decreases in body weights were recorded in females treated at dietary levels of 1000 ppm and higher, there was no dose-response relationship. There were no adverse treatment- related effects on survival, food consumption or on blood haematological parameters. The NOAEL for this study was 300 ppm, equal to 84 mg/kg bw/day, based on decreased serum T4 levels in both sexes at levels of 1000 ppm and above (Gelbke et al., 1992a). Rats Metiram (96.8% purity containing 2.2% ETU) was administered for a period of 4 weeks to groups of 20 Sprague-Dawley CD rats/sex at dietary levels of 0, 100, 300, 1000 or 3000 ppm, equal to 0, 10, 30, 100 or 296 mg/kg bw/day in males and 0, 11, 33, 114 or 292 mg/kg bw/day in females, respectively. Following termination of treatment with metiram, 10 rats per sex per group were retained for subsequent 2 and 4 week recovery periods with scheduled sacrifices of 5 rats/sex/group on each occasion. Clinical toxicity was manifest as signs of hind limb paralysis in rats treated at the highest dietary level of 3000 ppm, which due to severity, resulted in early sacrifice of 3 females for humane reasons. Histopathological examination confirmed gross morphological alterations in the muscles of the hind limbs, characterized by atrophy of the fibres, often with associated proliferation of sacrolemmal nuclei, and the presence of groups of vacuoles within muscle fibres. After 4 weeks of treatment, the microscopic changes were more marked and extensive in females, occurring in all females and in 2 of 9 males treated at 3000 ppm. After a withdrawal period of 2 weeks, a varying degree of atrophy of muscle fibres was still present in females previously treated with 3000 ppm of metiram. Although atrophy was not evident in animals after a 4-week recovery period, additional changes, not apparent earlier, were the presence of vacuoles and/or areas of fat cells within the skeletal fibres. Target organ effects of treatment with metiram were also evident on the thyroid and kidney. Changes in the thyroid were apparent as a dose-related increase in the incidence and severity of thyroid hyperplasia in both sexes treated at dietary levels of 300 ppm and higher. Microscopic examination of the kidney revealed varying degrees of hydropic vacuolation of the proximal tubular epithelial cells in 2 females from each of the 1000 and 3000 ppm groups in the absence of similar effects at any of the other dose levels or corresponding controls. Examination of bone marrow smears revealed a depressed number of myeloid cells in males treated at the high dose after 4 weeks of treatment. Group mean body-weight gains were significantly lower in males treated at 1000 ppm and higher, and in females treated at 300 ppm and higher when compared to the controls. Decreased food intake was recorded in both sexes treated at the highest dietary level of 3000 ppm. There were no adverse effects of treatment noted upon ocular examination, haematology, blood chemistry, urinalysis and estrus cycle as assessed from vaginal smears. The NOAEL was 100 ppm, equal to 10 mg/kg bw/day (Hunter et al., 1976a). Groups of 35 Sprague-Dawley CFY strain rats per sex were treated with metiram (96.8% purity containing 2.2% ETU) at dietary levels of 0, 50, 100, 300 or 900 ppm, equal to 0, 3, 6, 20 or 61 mg/kg bw/day for males and 0, 4, 8, 24 or 76 mg/kg bw/day for females, respectively, for a period of 13 weeks followed by a 6-week recovery period. The principal target organs were the thyroid and skeletal muscle. Treatment-related effects on the thyroid were manifest as increased thyroid weights of females treated at 300 and 900 ppm, decreased percentage uptake of 131I by the thyroid in males in all treated groups and in females treated at 100 ppm and higher, and decreased T4 levels in both sexes at 300 ppm and higher. Microscopically, an increased incidence of males treated at 900 ppm had slight to minimal hyperplasia of the thyroid. A minimally higher incidence at 13 weeks of slight thyroid hyperplasia in females at 900 ppm and in males at 100 and 300 ppm when compared to the controls was considered to be of equivocal significance. There were no significant changes in the thyroid observed after the 6-week recovery period. Treatment-related morphological changes of the skeletal muscle denoted by atrophy of the muscle fibres often accompanied by fat cells and associated proliferation of sacrolemmal nuclei, were evident in both sexes treated at dietary levels of 300 ppm and higher. Varying degrees of muscular atrophy were still prevalent after a 6-week recovery period in rats previously treated at 300 and 900 ppm. Other effects of treatment were exhibited at the high-dose level of 900 ppm as clinical signs of hind limb paralysis, decreased body weights and slight reduction in food intake. There were no treatment-related effects observed with respect to survival, water consumption, ophthalmoscopy, haematology, urinalysis or examination of bone marrow smears. Although reduced iodine uptake by the thyroid was observed at all dietary levels, these changes were shown to be reversible following cessation of treatment. At the lowest dietary levels of 50 and 100 ppm, the effects on iodine uptake were not correlated with changes in thyroid hormone levels or any overt morphological alterations of the thyroid gland, thus rendering the toxicological significance of this finding at 50 and 100 ppm as doubtful. The NOAEL for this study was therefore 100 ppm, equal to 6 mg/kg bw/day, based on decreased serum T4 levels and increased thyroid weights at dietary levels of 300 and 900 ppm (Hunter et al., 1977). Metiram (94.8% purity, ETU <0.2%) was administered for a period of 3 months to groups of 13 Wistar Chbb:THOM SPF rats per sex at dietary levels of 0, 5, 80, 320 or 960 ppm, equal to 0, 0.4, 5.8, 23.5 or 73.9 mg/kg bw/day in males and 0, 0.4, 6.7, 27.3 or 88.8 mg/kg bw/day in females, respectively. Neurofunctional assessment revealed general muscle weakness expressed as ataxia and significantly reduced forelimb and hindlimb grip strength in females treated at the highest dietary level of 960 ppm. Perfusion fixation of tissues from selected rats from the control and treated groups failed to reveal any associated neuropathological or morphological alterations of the central or peripheral nervous systems. Thyroid hormone levels revealed significantly decreased T4 levels in both sexes treated at the high dose of 960 ppm. Significantly reduced RBC values were recorded in both sexes at levels of 320 and 960 ppm. In females, decreases in RBC values were accompanied by decreases in mean haemoglobin and haematocrit levels. Several statistically significant changes in blood biochemical parameters of uncertain toxicological significance were observed at the highest dietary level of 960 ppm. These changes were recorded as decreased ALAT and ALP activity (females), decreased creatinine (both sexes), decreased urea (males), and decreases in the electrolytes; potassium (both sexes), sodium (females), calcium (both sexes) and magnesium (both sexes). Decreased phosphorus levels were recorded in males at dietary levels of 320 ppm and higher. Other effects of treatment expressed in both sexes at the highest dietary level of 960 ppm were decreased body weights and corresponding weight gains, as well as significantly increased thyroid, liver, kidney and testes (males only) weights. There were no treatment-related gross or histopathological changes observed in any of the animals from the treated groups. Treatment with metiram did not result in any significant effects on survival, food consumption, ophthalmoscopy or urinalysis. The NOAEL was 80 ppm, equal to 5.8 mg/kg bw/day, based on changes in haematological and blood chemical parameters at 320 ppm (Gelbke et al., 1992b). A 13-week inhalation study was conducted with groups of 28 Sprague-Dawley CD rats/sex exposed in nose-only chambers to metiram (94% purity) 6 hours/day, 5 days/week at concentrations of 0, 2, 20 or 100 mg/m3. Concentrations of ETU in the exposure atmospheres were calculated to be 0, 0.02, 0.33 or 1.8 mg/m3, respectively. After termination of treatment, one-half of the rats were sacrificed while the remaining animals were retained for a 13-week recovery period. The NOAEL was 2 mg/m3. Pulmonary changes consisting of "subacute alveolitis", characterized by accumulations of alveolar macrophages within alveolar lumens, accompanied by some polymorpho- nuclear leukocytes were observed in rats treated at 20 and 100 mg/m3. It was conjectured that the alveolitis observed was not treatment-related, but rather, a non-specific dust reaction of the polymeric active ingredient artificially ground to particle size capable of reaching the alveoli. Intra-alveolar pigment deposition was recorded in a single male and female from the high-dose treated group. There was no evidence of damage to bronchial or bronchiolar epithelium in any of the treated groups. Mean lung/trachea weights were increased in both sexes treated at the high dose. Other changes associated with treatment were depositions of golden brown granular pigment, similar to that seen in the lungs, within the renal cortices in the high dose animals and decreased overall body- weight gain in both males and females treated at 20 (11% and 14%) and 100 mg/m3 (26% and 33% less than corresponding controls, respectively). After the 13-week recovery, effects of treatment persisted in the lungs and kidneys of previously treated animals. No treatment-related findings were noted on survival, ophthalmoscopy, haematology or blood chemistry. Tissue residue analysis performed on the urine, plasma, liver, lung and thyroid revealed measurable levels of metiram and ETU in the urine and lung in rats treated at the mid- and high-dose levels (Ulrich, 1986). Rabbits A dermal toxicity study was performed with groups of 5 New Zeeland white KFM rabbits/sex treated with Polyram DF formulation of metiram on the shaved skin of their backs under occlusive conditions for 6 hours/day at concentrations of 0 (vehicle control, distilled water), 25, 50 or 250 mg/kg bw/day for a minimum of 21 consecutive daily applications. Dermal administration of metiram resulted in minimal to moderate exfoliation and ulcerative dermatitis in the skin of rabbits treated at the high-dose level. Similar effects were not evident at lower dose levels, indicating a NOAEL for local irritation to the skin of 50 mg/kg bw/day. In the absence of treatment-related effects on survival, clinical signs, body weights, food consumption, ophthalmoscopy, haematology, blood chemistry, organ weights or histopathology of the liver and kidneys, the NOAEL for systemic toxicity was greater than 250 mg/kg bw/day (Ullmann et al., 1987). Dogs Groups of 4 beagle dogs/sex were treated with metiram (96.8% purity containing 2.2% ETU) for a period of 4 weeks at dietary levels of 0, 100, 300, 600 or 900 ppm, equal to 0, 5, 14, 28 or 41 mg/kg bw/day for males and 0, 5, 15, 27 or 43 mg/kg bw/day for females, respectively. Effects observed were an increased frequency of micro-follicles in the thyroids associated with minimal depletion of colloid and minimal hyperplasia of the follicular epithelium in 2/4 males and 2/4 females treated at the high dose of 900 ppm when compared to the controls. Other changes recorded were significantly increased liver weights in dogs receiving 600 and 900 ppm, which were not associated with any correlative histopathological findings. Significantly increased water consumption was recorded in dogs treated at 100, 600 and 900 ppm but not at 300 ppm. The significance of increased fluid intake (calculated over 5-day periods) was difficult to ascertain since there were no corresponding changes noted in urinalysis parameters. Erythrocyte, haemoglobin and packed cell volume values, although significantly decreased in dogs treated at 900 ppm when compared to the controls, were found to be within normal limits of variability and therefore of doubtful toxicological consequence. The NOAEL, based on the aforementioned findings, was 300 ppm, equal to 14 mg/kg bw/day. There were no significant effects of treatment on survival, clinical signs, body weights, food consumption, ophthalmoscopy, blood chemistry or urinalysis (Chesterman et al., 1978). Metiram (93.6% purity, ETU < 0.2%) was given to groups of 5 beagle dogs per sex at dietary concentrations of 0, 30, 80, 1000 or 3000 ppm, equal to 0, 0.9, 2.5, 29.8 or 76.9 mg/kg bw/day in males and 0, 1.1, 2.7, 29.9 or 92.7 mg/kg bw/day in females, respectively, for a period of 52 weeks. The principal effects of treatment were manifest on the thyroid. Microscopic examination revealed thyroid follicular hyperplasia in dogs of both sexes treated at 1000 and 3000 ppm. This finding was associated with an increased size and weight of this organ at 3000 ppm. Gross necropsy revealed thyroid thickening in several animals from both the control and treated groups. This observation was, however, only correlated with histopathological change at dietary levels of 1000 ppm and higher, rendering the significance of thyroid thickening at lower levels uncertain. Serum T4 levels were decreased in both sexes at 3000 ppm and in males at 1000 ppm. A dose-related increased incidence of dogs with focal hepatic lipofuscin pigment deposition was noted in both sexes at 1000 ppm and higher. Other effects of treatment with metiram were described as an increased incidence of diarrhoea in dogs treated at 80 (attributed to single male), 1000 and 3000 ppm; slight evidence of anaemia (both sexes at 1000 and 3000 ppm) involving an increased number of reticulocytes (both sexes at 3000 ppm); decreased body-weight gain at 3000 ppm in males and to a lesser extent in females; and decreased food intake in both sexes at 3000 ppm and in females at 1000 ppm. Significant changes in blood chemical parameters at dietary levels of 1000 ppm and higher were evident as increased lipid, cholesterol, triglycerides, phospholipid levels, ALP activity, and total protein, and decreased albumin and A/G ratio as well as disturbances in the protein electrophoretic pattern. There were no effects of treatment on survival, neurological parameters, ophthalmoscopy or urinalysis. The NOAEL for this study was 80 ppm, equal to 2.5 mg/kg bw/day (Corney et al., 1991). Monkeys A preliminary toxicity assessment was performed with groups of single male and female rhesus monkeys administered metiram (96.8% purity containing 2.2% ETU) orally by gavage as a suspension in 0.5% mucilage of tragacanth in water at dose levels of 50, 100 or 500 mg/kg bw/day for a period of 4 weeks. Treatment-related toxicity was evident as salivation at the time of dosing or immediately thereafter and occasional emesis in monkeys treated at 100 and 500 mg/kg bw/day, body-weight loss in the single female treated at 500 mg/kg bw/day and changes of the thyroid, representative of early follicular hyperplasia in the single high-dose female. The low dose of 50 mg/kg bw/day was well tolerated with no overt signs of toxicity (Sortwell et al., 1977). Metiram (96.8% purity containing 2.2% ETU) was administered orally by gavage to groups of 4 rhesus monkeys/sex for a period of 26 weeks at dose levels of 0 (vehicle control, 0.5% tragacanth in distilled water), 5, 15 or 75 mg/kg bw/day. After termination of treatment, 1 male and 1 female were retained untreated for a period of 15 weeks as recovery animals. In a separate, but concurrently conducted study, a further 2 male and 2 female monkeys were treated with metiram at doses of 0, 5 or 75 mg/kg bw/day for 26 weeks to monitor thyroid function. The primary effects of treatment with metiram were evident in the thyroid and were characterized at dose levels of 15 and 75 mg/kg bw/day as minimal thyroid follicular hyperplasia, significantly decreased T3 and T4 levels and increased thyroid weights. After a 15-week recovery, morphological changes of the thyroid were still apparent in monkeys previously treated at the 15 and 75 mg/kg bw/day dose levels. Assessment of thyroid function revealed an initial marked reduction in iodine uptake at dose levels of 5 and 75 mg/kg bw/day, followed by a significant increase in uptake during the latter part of the study. In the absence of any correlation to thyroid hormone levels or morphological alterations, no toxicological significance was attributed to fluctuations in iodine uptake by the thyroid at the lowest level of 5 mg/kg bw/day. Other effects resulting from treatment were an increased incidence of salivation occurring at the time of dosing at the high dose. Significantly increased liver weights at the high-dose level were not associated with any histopathological findings. Treatment with metiram did not significantly affect survival, body-weight gains, food or water consumption, ophthalmoscopy, haematology, urinalysis or examination of bone marrow smears. The NOAEL was 5 mg/kg bw/day (Sortwell et al., 1979). Long-term toxicity/carcinogenicity studies Mice Dietary administration of metiram (96.8% purity containing 2.2% ETU) to groups of 52 CFLP mice/sex at levels of 0, 100, 300 or 1000 ppm, equal to 0, 8, 24 or 79 mg/kg bw/day for males and 0, 9, 29 or 95 mg/kg bw/day for females, respectively, for a minimum period of 88 weeks resulted in a NOAEL for in-life parameters of 300 ppm, equal to 24 mg/kg bw/day. Although there were no statistically significant differences in mortality in the treated groups, a marginally higher mortality incidence from week 40 onwards was recorded in females treated at 1000 ppm, resulting in a minimum 25% survival rate being reached in this group before the corresponding controls. Group mean body weights were significantly decreased in both sexes treated at the 1000 ppm dietary level. Food consumption in males treated at 1000 ppm was only marginally (5%) lower than the corresponding controls during the first year of treatment. Clinical signs and examination of bone marrow smears were not adversely affected by treatment with metiram. Under the conditions of the present study, treatment with metiram at dietary levels up to and including 1000 ppm failed to uncover any evidence of carcinogenic potential (Hunter et al., 1979). Rats Groups of 50 Sprague-Dawley CD rats/sex were administered metiram (96.8% purity containing 2.2% ETU) in the diet at levels of 0, 5, 20, 80 or 320 ppm, equal to 0.2, 0.8, 3.1 or 12.3 mg/kg bw/day in males and 0, 0.2, 1.0, 3.8 or 15.5 mg/kg bw/day in females, respectively, for 119 weeks for males and 111 weeks for females. Satellite groups of 30 male and 30 female rats per group were used for blood sampling and thyroid function tests and were then killed after 102 weeks of treatment. Treatment with metiram resulted in a NOAEL of 80 ppm (equal to 3.1 mg/kg bw/day), based on an increased incidence of rats treated at the next higher dietary level of 320 ppm with muscular atrophy. There were no consistent treatment- related effects with respect to survival, clinical signs, body weights, food or water consumption, ophthalmoscopy, haematology, blood chemistry, thyroid function, urinalysis or organ weights. There was no evidence of metiram-induced carcinogenic potential (Hunter et al., 1981). Reproduction studies Rats A three-generation (two-litter per generation) reproduction study was conducted with groups of 12 male and 24 female Crl:COBS CD(SD)BR rats fed metiram (96.8% purity containing 2.2% ETU) at dietary levels of 0, 5, 40 or 320 ppm, equal to 0, 0.2, 1.8 or 14.2 mg/kg bw/day in males and 0, 0.3, 2.3 or 19.8 mg/kg bw/day in females, respectively. In the F0 generation, treatment with metiram commenced at least 60 days prior to mating. In the F1 and F2 generations, the F1b and F2b derived parental animals, respectively were exposed to the test material for a minimum period of 90 days. At day 21 post-partum, 10 F3a pups/sex from each group were selected for detailed gross examination, recording of organ weights and histopathological assessment. At the second pairing of the F2b generation, all pregnant females from each of the dose levels were sacrificed on day 20 of gestation for teratological examination. Appearance of spermatozoa in the vaginal smear or the presence of a copulation plug was considered to be day 0 of gestation. Decreases in body-weight gain (4-7%) were noted in both the F0 and F1 generation males and females treated at 320 ppm when compared to the controls. Slightly depressed (7-8%) food intake was observed in males fed metiram during the F0 and F1 generations. Body weights and food consumption were not adversely affected by treatment at lower dietary levels or in any of the treated groups from the F2 generation when compared to the controls. There were no treatment-related effects on parental mortality, clinical signs, food conversion ratios, reproductive parameters or gross pathological alterations. Statistically significant decreases in the mean number of pups born were observed in all treated groups during the second mating of both the F1 and F2 generations. Although the differences were statistically significant, there was no dose-response relationship and all values in the treated groups generally fell within the reported laboratory standard values. Total litter loss was significantly decreased at 320 ppm during the second mating of the F1 generation. In the absence of similar effects in the first mating of the F1 or in either of the matings in the F0 and F2 generations, the toxicological significance of this finding was dubious. Statistically significant decreases in mean litter weights were observed in the treated groups during the F1 and F2 generations. Since the mean pup weights in the treated groups were comparable to the controls, the decreased mean litter weights may, in part, be attributed to the correspondingly smaller litter sizes observed in these groups. With regard to the teratological component, there were no effects on pregnancy rate, pre- or post-implantation loss, number of live fetuses, embryo/fetal resorptions, fetal sex ratio or fetal/litter weights. Metiram was not teratogenic as determined by gross, skeletal and visceral examination of fetuses, following in utero exposure at dietary levels as high as 320 ppm. The NOAEL was 40 ppm, equal to 1.8 mg/kg bw/day, based on decreased parental body weight and food consumption recorded in the F0 and F1 generations treated at 320 ppm (Cozens et al., 1981). Special studies on teratogenicity Rats A preliminary range-finding study was performed with groups of 6 non-pregnant Crl:Cobs CD(SD)BR female rats administered metiram (96.8% purity containing 2.2% ETU) orally by gavage at 0 (vehicle control, sodium carboxymethyl cellulose), 150, 300, 600 or 1200 mg/kg bw/day for 10 consecutive days. Dose-related clinical effects primarily affecting the nervous system were observed at all dose levels. In the absence of microscopic examination, histopathological correlation could not be ascertained. Other effects of treatment were related to decreased body-weight gains at all dose levels, depressed food intake at 300 mg/kg bw/day and higher and decreased water consumption in rats treated at 600 and 1200 mg/kg bw/day (Palmer & Simmons, 1979a). Groups of 20 time-mated female Crl:Cobs CD(SD)BR rats were treated with metiram (96.8% purity containing 2.2% ETU) daily by gavage during days 6 to 15 of gestation, inclusive, at dose levels of 0 (vehicle control, sodium carboxymethyl cellulose), 40, 80 or 160 mg/kg bw/day. The day of mating, determined by the presence of a vaginal plug or sperm in the vaginal smear, was designated as day 0 of gestation. Decreased body-weight gain (4-9%) was noted in the high-dose animals. There were no significant effects with respect to clinical signs, food or water consumption or gross organ/tissue changes. A slight increase in the pre- and post-implantation loss was recorded in the 160 mg/kg bw/day group, in conjunction with a significant decrease in the mean number of live fetuses and decreased litter weight in this group. It is unlikely that the increased pre-implantation loss at the high dose was related to treatment, since theoretically, treatment was not initiated until after implantation occurred. Nevertheless, the combined effect of pre- and post-implantation loss may have, to a certain degree, influenced the decreased litter size and weight noted at the high dose level. There were no effects of treatment on the incidence of early or late resorptions, mean fetal weight or sex ratio. The NOAEL for embryo/fetotoxicity was 80 mg/kg bw/day, based on slight decreases in litter size and weights. Treatment with metiram failed to uncover any evidence of teratogenic potential. The NOAEL for maternal toxicity was 80 mg/kg bw/day, based on decreased body- weight gain (Palmer & Simmons, 1979a). Rabbits In a range-finding study, groups of 3 pregnant Himalayan rabbits were treated orally by gavage with metiram (97.9% purity, ETU <0.2%) during days 7 through 19 of gestation at dose levels of 0 (vehicle control, distilled water with 0.5% carboxymethyl cellulose), 50, 100 or 200 mg/kg bw/day. Reduced body-weight gains and food intake were recorded at the two highest dose levels. The significance of the incidence of single abortion at each of the dose levels, upon conduct of the definitive study, was confirmed to be treatment-related. No further relevant details were provided (Gelbke et al., 1988). Metiram (97.9% purity, ETU < 0.2%) was administered orally by gavage at 0 (vehicle control, distilled water with 0.5% carboxymethyl cellulose), 10, 40 or 120 mg/kg bw/day to groups of 15 artificially inseminated Himalayan rabbits on days 7 through 19 of gestation. The day of artificial insemination was designated as day 0 of gestation. Treatment with metiram elicited signs of maternal toxicity at 40 and 120 mg/kg bw/day, denoted by abortion, decreased body weight and food consumption, the latter associated with reduction or absence of defecation. The high incidence of abortion (8/15) recorded at 120 mg/kg bw/day, in conjunction with a single death culminated in only 6/15 rabbits treated at this level with litters available for examination. Although 2 of 15 animals aborted at 40 mg/kg bw/day, there were, nevertheless, adequate numbers of litters secured in the control, 10 and 40 mg/kg bw/day dose groups. Since a dose level of 10 mg/kg bw/day was without significant effects, this dose was considered the NOAEL for maternal toxicity. The NOAEL for developmental toxicity was 40 mg/kg bw/day based on the slight decrease in mean fetal weights recorded at 120 mg/kg bw/day. A slight decrease in the number of live male fetuses in the 120 mg/kg bw/day group was considered to be of no toxicological consequence, in light of the comparable number of female fetuses and the total number of fetuses in the 120 mg/kg bw/day group relative to the controls. There were no significant effects of treatment on the mean number of live fetuses, early or late resorptions, post- implantation loss, or placental weight. There was no evidence suggestive of teratogenic potential with metiram at any of the dose levels investigated (Gelbke et al., 1988). Special studies on genotoxicity Results of mutagenicity assays conducted with metiram are presented in Table 3. The tests conducted to evaluate potential for gene mutation in bacteria and induction of chromosomal aberration in rat bone marrow were negative. Unscheduled DNA synthesis in rat hepatocytes and a dominant lethal study in mice were also negative. Although metiram demonstrated potential for inducing sister chromatid exchange (SCE) in Chinese hamster ovary cells in the absence and presence of mouse microsomal activation, there was nevertheless, no significant induction of SCE observed with rat microsomal activation. Moreover, an in vivo SCE assay in bone marrow cells of the Chinese hamster was negative. Metiram exhibited a weak promotion activity in mouse embryo fibroblasts in the absence of a direct transformation response. The Meeting concluded that metiram was not genotoxic. Special studies on irritation and sensitization The eye and skin irritation potential of technical metiram (containing 2.2% ETU) were investigated in six Vienna white rabbits. There were no signs of irritation when metiram was applied to the external ear for 20 hours or to the backs for 1, 5 or 15 minutes. When applied to the back for 20 hours, slight reddening occurred 24 hours after application with subsequent scaling after 8 days. Metiram (50 mg) when introduced into the conjunctival sac of the eye of these rabbits produced slight redness and edema after 1 hour, with no signs of irritation after 8 days (Zeller, 1985a). Polyram combi, a formulation of technical metiram, was administered to eight Vienna white rabbits to determine skin and eye irritation potential. A 50% aqueous suspension of the test material when applied to the backs of the rabbits for a period of 20 hours, resulted in slight erythema of the skin, which was reversible within 8 days. The instillation of 50 mg of Polyram combi to the conjunctival sac of the rabbit eye caused redness and edema which were reversible after 8 days. When 50 µl of a 20% aqueous suspension was applied, slight reddening of the mucosa occurred, whereas 50 µl of a 2% aqueous suspension was tolerated without any irritation (Zeller, 1985b). Metiram technical demonstrated severe sensitizing effects on the skin of female Pirbright white, Dunkin Hartley guinea-pigs when tested according to the methods of the Magnusson & Kligman maximization test (Jackh, 1982). Table 3. Genotoxicity of metiram Test Test system Concentration Purity Results Reference Reverse mutation S. typhimurium 0, 1, 3, 10, 31, Technical negative Oesch, 1977 (in vitro) TA 98, 100, 1537 100, 310, 1000, 1., 2. (rat) 2000 µg/plate S. typhimurium 0, 1, 10, 50, 100, Technical + 2.2% ETU negative Gelbke & Engelhardt, TA 98, 100, 1535, 1537 500, 2500 µg/plate 1., 2. 1985 (rat & mouse) Reverse mutation/host S. typhimurium 500, 1670, Technical + 2.2% ETU negative Jagannath & Myhr, 1985 mediated (in vivo) TA 1530 5000 mg/kg bw Male CD-1 mice (single oral doses) (inoculated ip) Point mutation HGPRT locus of Chinese 0, 0.681, 1.0, 4.64, Technical + 2.2% ETU negative, 1. Gelbke & Jackh, 1985 (in vitro) hamster ovary (CHO) cell 6.81, 10, 46.4, equivocal, 2. line, K1 68.1, 100 µg/ml (rat) HGPRT locus of Chinese 0.5, 1, 5, 10, 50, Premix 95% negative Hoffman & Jackh, 1990 hamster ovary (CHO) cell 100, 500 µg/ml 1., 2. (mouse) line, K1 SCE (in vitro) Chinese hamster ovary 0, 40, 60, 80, 100, Technical + 2.2% ETU positive, 1. Ivett & Myhr, 1986a CHO, WB1 cells 125, 150, 175, 200 positive, 2. µg/ml (mouse) negative, 2. (rat) SCE (in vivo) Chinese hamster, LMP 1000, 3330, 10 000 Premix 95% negative Miltenburger et al., stock (bone marrow) mg/kg bw 1990 Table 3 (contd) Test Test system Concentration Purity Results Reference Chromosome aberration Rat, male Fischer 344 0, 0.24, 1.2, 2.4 Technical + 2.2% ETU negative Ivett & Myhr, 1986b (in vivo) (bone marrow) g/kg bw (acute) 0, 0.02, 0.1, 0.2 g/kg bw (5 repeated oral doses) Transformation Mouse embryo fibroblasts 0, 0.1, 0.25, 0.5, Technical + 2.2% ETU transformation: Tu et al., 1985 promotion (in vitro) C3H-10T 1/2 (clone 8) 0.75, 1.0 µg/ml negative cell system promotion activity: weakly positive Unscheduled DNA Rat (Fischer 344, male) 0.492, 1.23, 2.46, Technical + 2.2% ETU negative Cifone & Myhr, 1984 synthesis (in vitro) hepatocytes 4.92, 12.3, 24.6, 49.2, 160 µg/ml Dominant lethal Mouse, CD-1 male 0, 600, 1200, 2400 Technical + 2.2% ETU negative Palmer & Simons, 1979b (in vivo) mg/kg bw/day Results: 1. = in the presence of metabolic activation derived from the indicated species 2. = in the absence of metabolic activation COMMENTS Metiram was incompletely absorbed when administered orally to rats. Elimination was primarily via the faeces, with minimal biliary excretion. Comparatively higher urinary excretion at low doses suggested that metiram may be more poorly absorbed at higher doses. Highest residual tissue levels were found in the thyroid and kidney, with slightly higher concentrations present in females than in males. Comparison of tissue residues after single or multiple doses suggested slight accumulation in the body with multiple dosing. The metabolism of metiram has not been completely elucidated. In the rat, the predominant urinary components were polar and were identified as ethylenediamine, N-acetyl-ethylenediamine, ethanolamine, oxalic acid and glycine. Major, less polar components were ethyleneurea, ETU and EBIS. Metiram was practically non-toxic upon acute oral, dermal and inhalation administration to rats. WHO has classified metiram as unlikely to present acute hazard in normal use. The principal target organ upon repeated dietary exposure to metiram was the thyroid. Mice treated with metiram for three months at 0, 300, 1000, 3000 or 7500 ppm in the diet revealed minimal to slight hypertrophy and vacuolation of the thyroid follicular epithelium in both sexes at levels of 3000 ppm and higher. A NOAEL of 300 ppm (equal to 84 mg/kg bw/day) was based on decreased serum T4 levels in both sexes at levels of 1000 ppm and above. Thirteen-week dietary administration of metiram to SD CFY rats at 0, 50, 100, 300 or 900 ppm revealed a NOAEL of 100 ppm (equal to 6 mg/kg bw/day) based on decreased serum T4 levels and increased thyroid weights at dietary levels of 300 and 900 ppm. Slight to minimal hyperplasia of the thyroid was observed at 900 ppm. Although reduced iodine uptake by the thyroid was observed at all dietary levels, these changes were shown to be reversible following cessation of treatment. At the lowest dietary levels of 50 and 100 ppm, the effects on iodine uptake were not correlated with changes in thyroid hormone levels or any overt morphological alterations of the thyroid gland, thus rendering the toxicological significance of this finding doubtful. In a recently conducted three-month study with Wistar rats receiving metiram at 0, 5, 80, 320 or 960 ppm in the diet, decreased serum T4 levels and increased thyroid weights were observed at 960 ppm. Slight evidence of anaemia was observed at 320 ppm, indicating a NOAEL of 80 ppm (equal to 5.8 mg/kg bw/day). Other effects of treatment in the diet with metiram in the rat were manifest as hind limb paralysis with corresponding atrophy of muscle fibres. In the 13-week study with SD CFY rats, microscopic changes in muscle fibres at levels of 300 ppm (equal to 20 mg/kg bw/day) and higher were still prevalent in previously treated rats after the 6-week recovery period. Muscular atrophy was observed in a long-term study in SD CD rats treated at the highest level of 320 ppm (see below). General muscle weakness/ataxia and reduced grip strength of the limbs with no histopathological consequences were observed in the 3-month study with Wistar rats fed metiram at the highest level of 960 ppm. A 52-week study in dogs at dietary levels of 0, 30, 80, 1000 or 3000 ppm yielded a NOAEL of 80 ppm (equal to 2.5 mg/kg bw/day) based on thyroid follicular hyperplasia with increased size, thickening and weight of this organ, in conjunction with decreased serum T4 levels at dietary levels of 1000 ppm and above. Other effects recorded at 1000 ppm and above were a dose-related increased incidence of focal hepatic lipofuscin pigment deposition, slight evidence of anaemia, diarrhoea and changes in blood biochemical parameters. A preliminary 4-week study in dogs uncovered an increased frequency of microfollicles in the thyroid, in association with colloid depletion and minimal hyperplasia in both sexes treated at the highest level of 900 ppm (equal to 41 mg/kg bw/day). Metiram given by gavage to rhesus monkeys at dose levels of 0, 5, 15 or 75 mg/kg bw/day for a period of 26 weeks indicated a NOAEL of 5 mg/kg bw/day based on significantly decreased serum T3 and T4 levels, increased thyroid weights and minimal thyroid follicular hyperplasia at 15 and 75 mg/kg bw/day. Morphological changes of the thyroid were still apparent after a 15-week recovery period. In the absence of any correlation between thyroid hormone levels and morphological alterations, no significance was attributed to fluctuations in iodine uptake by the thyroid recorded at 5 mg/kg bw/day. Long-term dietary treatment of mice with metiram at 0, 100, 300 or 1000 ppm resulted in a NOAEL of 300 ppm (equal to 24 mg/kg bw/day) based on decreased body weights recorded at 1000 ppm. Chronic dietary administration of metiram to SD CD rats at 0, 5, 20, 80 or 320 ppm revealed muscular atrophy at 320 ppm (equal to 12 mg/kg bw/day), with a NOAEL of 80 ppm (equal to 3.1 mg/kg bw/day). Metiram was not carcinogenic when fed to mice or rats at dietary levels of up to 1000 and 320 ppm, respectively. A three-generation, two litter per generation reproduction study in rats treated at 0, 5, 40 or 320 ppm in the diet failed to reveal any adverse effects on reproductive parameters. The NOAEL was 40 ppm (equal to 1.8 mg/kg bw/day), based on decreased parental body weight and food consumption recorded in the F0 and F1 generations treated at 320 ppm. Metiram when administered to pregnant rats at 0, 40, 80 or 160 mg/kg bw/day or rabbits at 0, 10, 40 or 120 mg/kg bw/day during critical periods of organogenesis was not teratogenic at any dose. The NOAEL for maternal toxicity in the rat was 80 mg/kg bw/day based on decreased body-weight gain and in the rabbit the NOAEL was 10 mg/kg bw/day based on increased abortions, decreased body weights and food consumption. The NOAELs for embryo/fetotoxicity were 80 mg/kg bw/day in the rat based on slight decreases in litter size and weight and 40 mg/kg bw/day in the rabbit based on decreases in mean fetal weights. Metiram has been tested in a series of in vitro and in vivo genotoxicity assays. The Meeting concluded that metiram is not genotoxic. The Meeting allocated an ADI of 0-0.03 mg/kg bw based on a NOAEL of 2.5 mg/kg bw/day in the 52-week study in dogs, using a 100- fold safety factor. This ADI is supported by the NOAEL of 3.1 mg/kg bw/day observed in the long-term study in rats. This ADI served as the basis for a group ADI that was established for metiram alone or in combination with mancozeb, maneb, and zineb. TOXICOLOGICAL EVALUATION Level causing no toxicological effect Mouse: 300 ppm, equal to 24 mg/kg bw/day (88-week study) Rat: 80 ppm, equal to 3.1 mg/kg bw/day (111-week study) 40 ppm, equal to 1.8 mg/kg bw/day (reproduction study) Rabbit: 10 mg/kg bw/day (teratogenicity study) Dog: 80 ppm, equal to 2.5 mg/kg bw/day (52-week study) Monkey: 5 mg/kg bw/day (26-week study) Estimate of acceptable daily intake for humans 0-0.03 mg/kg bw (group ADI with mancozeb, maneb, and zineb). Studies which will provide information valuable in the continued evaluation of the compound Observations in humans. REFERENCES Chesterman, H., Heywood, R. & Barker M. (1973) Polyram Combi acute oral toxicity study in beagle dogs. Report BASF 73/0047, BASF 40/73703. Unpublished report dated October 5, 1973 from Huntingdon Research Centre, Huntingdon, England. Submitted to WHO by BASF Aktiengesellschaft, FRG. Chesterman, H., Heywood, R., Ball, S., Street, A. & Prentice, D. (1978) Metiram (active ingredient) oral toxicity study in beagle dogs (dietary intake for 4 weeks). Report BASF 78/0154, BSF 201/76422. Unpublished report dated April 26, 1978 from Huntingdon Research Centre, Huntingdon, England. Submitted to WHO by BASF Aktiengesellschaft, FRG. Cifone, M. & Myhr, B. (1984) Report on the evaluation of metiram tech. in the rat primary hepatocyte unscheduled DNA synthesis assay. Report RZ 84/209. Unpublished report dated July 5, 1984 from Litton Bionetics Inc., Maryland, USA. Submitted to WHO by BASF Aktiengesellschaft, FRG. Corney, S.J., Allen, T.R., Janiak, T. & Springall, C. (1991) 52-week oral toxicity (feeding) study with metiram premix 95% in the dog. Report No. 91/10786. Unpublished report dated August 22, 1991 from RCC, Research & Consulting Company Ltd., Itingen, Switzerland. Submitted to WHO by BASF Aktiengesellschaft, FRG. 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(1988) Report on the study of the prenatal toxicity of metiram-premix 95% in rabbits after oral administration (gavage). Report BASF 88/0154 and Supplement BASF 88/0262. Unpublished report dated May 26, 1988 from BASF, Department of Toxicology, Ludwigshafen/Rhein, FRG. Submitted to WHO by BASF Aktiengesellschaft, FRG. Gelbke, H., Mellert, W. and Hildebrand, B. (1992a) Study of the oral toxicity of metiram premix 95% in B6C3F1 mice. Administration in the diet for 3 months. Report No. 92/11223. Unpublished report dated October 16, 1992 from BASF, Department of Toxicology, Ludwigshafen/Rhein, FRG. Submitted to WHO by BASF Aktiengesellschaft, FRG. Gelbke, H., Mellert, W. & Hildebrand, B. (1992b) Study of the oral toxicity of metiram premix 95% in Wistar rats. Administration in the diet for 3 months including the examination of neurotoxicology (neurofunctional observational battery). Report No. 92/11224. 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(1985b) Report on the study of the acute inhalation toxicity (inhalation hazard) of Polyram Combi, technical active ingredient, in the rat (Translation of original report dated March 25, 1974). Report RZ 85/028. Unpublished report dated February 4, 1985 from BASF, Department of Toxicology, Ludwigshafen/Rhein, FRG. Submitted to WHO by BASF Aktiengesellschaft, FRG. Hofmann, H. (1985c) Report on the study of the acute oral toxicity of Polyram Combi (BAS 222 01 F) to rats (Translation of original report dated March 25, 1974). Report RZ 85/121. Unpublished report dated April 12, 1985 from BASF, Department of Toxicology, Ludwigshafen/Rhein, FRG. Submitted to WHO by BASF Aktiengesellschaft, FRG. Hofmann, H. (1985d) Report on the study of the acute inhalation toxicity (inhalation hazard) of Polyram Combi (BAS 222 01 F) in rats (Translation of original report dated March 25, 1974). Report RZ 85/124. Unpublished report dated April 12, 1985 from BASF, Department of Toxicology, Ludwigshafen/Rhein, FRG. Submitted to WHO by BASF Aktiengesellschaft, FRG. Hofmann, H. (1985e) Report on the study of the acute inhalation toxicity of the spray of a 5% aqueous suspension of Polyram Combi (BAS 222 01 F) to guinea-pigs (Translation of original report dated March 25, 1974). Report RZ 85/125. Unpublished report dated April 12, 1985 from BASF, Department of Toxicology, Ludwigshafen/Rhein, FRG. Submitted to WHO by BASF Aktiengesellschaft, FRG. Hofmann, H. & Jackh, R., 1990. Report on the point mutation test carried out on CHO cells (HGPRT locus) with the test substance metiram premix 95% with B6C3F1 mice microsomal fraction. Report No. 90/0285. Unpublished report dated August 2, 1990 from BASF, Department of Toxicology, Ludwigshafen/Rhein, FRG. Submitted to WHO by BASF Aktiengesellschaft, FRG. Hunter, B., Barnard, A., Heywood, R., Street, A. & Prentice, D. (1976a) Preliminary assessment of metiram toxicity to rats in dietary administration for four weeks followed by a two and a four week withdrawal period. Report RZ 76/024, BSF 172/76245. Unpublished report dated October 20, 1976 from Huntingdon Research Centre, Huntingdon, England. Submitted to WHO by BASF Aktiengesellschaft, FRG. Hunter, B., Bridges, J. & Prentice, D. (1976b) Preliminary assessment of metiram toxicity to mice in dietary administration for 4 weeks. Report RZ 76/014, BSF 170/76108. Unpublished report dated June 7, 1976 from Huntingdon Research Centre, Huntingdon, England. Submitted to WHO by BASF Aktiengesellschaft, FRG. Hunter, B., Barnard, A., Heywood, R., Street, A., Prentice, D. & Offer, J. (1977) Metiram toxicity to rats in dietary administration for 13 weeks followed by a 6 week withdrawal period (final report). Report RZ 77/043, BSF/197/77612 and Addendum BASF 87/0205, BSF 197/8713. 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(1986a) Report on the mutagenicity evaluation of metiram in an in vitro sister chromatid exchange assay in Chinese hamster ovary (CHO) cells/amended final report. Report RZ 86/082. Unpublished report dated March 11, 1986 from Litton Bionetics Inc., Maryland, USA. Submitted to WHO by BASF Aktiengesellschaft, FRG. Ivett, J. & Myhr, B. (1986b) Report on the mutagenicity evaluation of metiram technical K38/33A in the rat bone marrow cytogenetic assay. Report RZ 86/265. Unpublished amended report dated August 4, 1986 from Litton Bionetics, Maryland, USA. Submitted to WHO by BASF Aktiengesellschaft, FRG. Jackh, R. (1981) Report on the study of the acute oral toxicity of metiram technical grade in the rat (Translation). Report BASF 92/10669. Unpublished report dated July 9, 1981 from BASF, Department of Toxicology, Ludwigshafen/Rhein, FRG. Submitted to WHO by BASF Aktiengesellschaft, FRG. Jackh, R. 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(1979a) The acute oral toxicity of the preparation metiram, techn. agent with 2% ETU in rats. Report BASF 79/0161, WNT- Nr. 77/951. Unpublished report dated August 20, 1979 from Laboratorium fur Pharmakologie und Toxikologie, Hamburg, FRG. Submitted to WHO by BASF Aktiengesellschaft, FRG. Leuschner, F. (1979b) The acute intraperitoneal toxicity of the preparation metiram, techn. agent with 2% ETU in mice. Report BASF 79/0162, WNT-Nr. 77/951. Unpublished report dated August 20, 1979 from Laboratorium fur Pharmakologie und Toxikologie, Hamburg, FRG. Submitted to WHO by BASF Aktiengesellschaft, FRG. Miltenburger, H., Volkner, W. & Heidemann, A. (1990) Sister chromatid exchange assay in bone marrow cells of the Chinese hamster with metiram premix 95%. Report No. 90/0569. Unpublished report dated September 18, 1990 from CCR, Cytotest Cell Research Gmbh & Co., Rossdorf, FRG. Submitted to WHO by BASF Aktiengesellschaft, FRG. Oesch, F. (1977) Ames test for metiram. Report RZ 77/027. Unpublished report dated August 22, 1977 from the Institute of Pharmacology, University of Mainz, Germany. Submitted to WHO by BASF Aktiengesellschaft, FRG. Palmer, A. & Simons, R. (1979a) Effect of metiram technical on pregnancy of the rat. Report RZ 79/065, BSF 302/79616. Unpublished report dated August 3, 1979 from Huntingdon Research Centre, Huntingdon, England. Submitted to WHO by BASF Aktiengesellschaft, FRG. Palmer, A. & Simons, R. (1979b) Dominant lethal assay of metiram technical in the male mouse. Report RZ 79/069, BSF 304/79860. Unpublished report dated November, 1979 from Huntingdon Research Centre, Huntingdon, England. Submitted to WHO by BASF Aktiengesellschaft, FRG. Sortwell, R., Heywood, R., Allen, D., Prentice, D. & Cherry, C. (1977) Metiram preliminary oral toxicity study in rhesus monkeys. Repeated dosage for 4 weeks. Report BASF 77/0149, BSF 265/77264. Unpublished report dated April 15, 1977 from Huntingdon Research Centre, Huntingdon, England. Submitted to WHO by BASF Aktiengesellschaft, FRG. Sortwell, R., Allen, D., Heywood, R. & Street, A. (1979) Metiram (containing 2.2% ethylenethiourea) oral toxicity study in rhesus monkeys (repeated dosage for 26 weeks with recovery period). Final report. Report BASF 79/0082, BSF 267/78263. Unpublished report dated January 15, 1979 from Huntingdon Research Centre, Huntingdon, England. Submitted to WHO by BASF Aktiengesellschaft, FRG. Tu, A., Sivak, A., Breen, P. & Hatch, K. (1985) Report on the evaluation of metiram in the C3H-10T 1/2 cell system for transformation and promotion activities. Report RZ 85/209. Unpublished report dated June 18, 1985 from Arthur D. Little, Inc., Maryland, USA. Submitted to WHO by BASF Aktiengesellschaft, FRG. Ullmann, L., Sacher, R., Porricello, T., Luetkemeier, H., Vogel, W., Vogel, O., Wilson, J. & Terrier, H. (1987) Report on the subacute 21-day repeated-dose dermal toxicity study with polyram DF in rabbits. Report BASF 87/0260, ZNT No. 86/314. Unpublished report dated June 24, 1987 from RCC, Research and Consulting Company AG, Switzerland. Submitted to WHO by BASF Aktiengesellschaft, FRG. Ulrich, C. (1986) Report on the thirteen week subchronic inhalation toxicity study on metiram in rats. Report RZ 86/407 and addendum BASF 87/0414. Unpublished report dated December 31, 1986 and addendum dated October 7, 1987 from International Research and Development Corporation, Mattawan, Michigan, USA. Submitted to WHO by BASF Aktiengesellschaft, FRG. WHO (1992). The WHO recommended classification of pesticides by hazard and guidelines to classification 1992-1993 (WHO/PCS/92.14). Available from the International Programme on Chemical Safety, World Health Organization, Geneva, Switzerland. Zeller, H. (1985a) Report on the study of the irritation of Polyram Combi, technical active ingredient, to the skin and eye of rabbits (Translation of original report dated March 25, 1974). Report RZ 85/027. Unpublished report dated February 4, 1985 from BASF, Department of Toxicology, Ludwigshafen, FRG. Submitted to WHO by BASF Aktiengesellschaft, FRG. Zeller, H. (1985b) Report on the study of the irritation of Polyram Combi (BAS 222 01 F) to the skin and eyes of rabbits (Translation of original report dated March 25, 1974). Report RZ 85/122. Unpublished report dated April 12, 1985 from BASF, Department of Toxicology, Ludwigshafen, FRG. Submitted to WHO by BASF Aktiengesellschaft, FRG.
See Also: Toxicological Abbreviations