August, 1987 820K88104 FIR APT CYANAZINE Health Advisory Office of Drinking Water U.S. Environmental Protection Agency I. INTRODUCTION The Health Advisory (HA) Program,- sponsored by the Office of Drinking Water (ODW), provides information on the health effects, analytical method- ology and treatment technology that would be useful in dealing with the contamination of drinking water. Health Advisories describe nonregulatory concentrations of drinking water contaminants at which adverse health effects would not be anticipated to occur over specific exposure durations. Health Advisories contain a margin of safety to protect sensitive members of the population. Health Advisories serve as informal technical guidance to assist Federal, State and local officials responsible for protecting public health when emergency spills or contamination situations occur. They are not to be construed as legally enforceable Federal standards. The HAs are subject to change as new information becomes available. Health Advisories are developed for one-day, ten-day, longer-term (approximately 7 years, or 10% of an individual's lifetime) and lifetime exposures based on data describing noncarcinogenic end points of toxicity. Health Advisories do not quantitatively incorporate any potential carcinogenic risk from such exposure. For those substances that are known or probable human carcinogens, according to the Agency classification scheme (Group A or B), Lifetime HAs are not recommended. The chemical concentration values for Group A or B carcinogens are correlated with carcinogenic risk estimates by employing a cancer potency (unit risk) value together with assumptions for lifetime exposure and the consumption of drinking water. The cancer unit risk is usually derived from the linear multistage model with 95% upper confidence limits. This provides a low-dose estimate of cancer risk to humans that is considered unlikely to pose a carcinogenic risk in excess of the stated values. Excess cancer risk estimates may also be calculated using the One-hit, Weibull, Logit or Probit models. There is no current understanding of the biological mechanisms involved in cancer to suggest that any one of these models is able to predict risk more accurately than another. Because each model is based on differing assumptions, the estimates that are derived can differ by several orders of magnitude. ------- Cyanazine August, 1987 -2- II. GENERAL INFORMATION AND PROPERTIES CAS No. 21725-46-2 Structural Formula HC = kJ w—PI N-C(CH,)2 N H -[ [4-Chloro-6-(ethylamino)-1 , 3, 5-triazin-2-yl]amino]-2-methylpropanenitrile Synonyms e Cyanazine (common name), Bladex, Fortrol, Payze, SD1518, VL19804, DW3418 and WL19805 (Meister, 1983). Uses 0 Cyanazine is used as a pre- and postemergence herbicide for the control of annual grasses and broad leaf weeds (U.S. EPA, 1984a). Properties (U.S. EPA, 1984a; Meister, 1983; CHEMLAB, 1985) Chemical Formula CgH Molecular Weight 240.7 Physical State ( °C) White crystalline solid Boiling Point Melting Point 167.5 to 169°C Density 0.35 (fluffed) to 0.45 (packed) g/cc Vapor Pressure (20°C) 1.6 x 10-9 to 7.5 x 10-9 mm Hg Water Solubility (259C) 171 mg/L Log Octanol/Water Partition 2.24 Coefficient Taste Threshold Odor Threshold Conversion Factor Occurrence A range of 0.0 to 900 ug/L of cyanazine in water from the analyses of 1,790 samples of water and whole water (water plus sediment) has been reported using the U.S. EPA STORET (1987) data base. A total of seven sediment-only samples were analyzed and found to have a range of 0.008 to 0.10 mg/kg cyanazine. ------- Cyanazine August, 1987 -3- 0 Cyanazine was identified in drinking water in New Orleans, Louisiana, in concentrations ranging from 0.01 to 0.35 ug/L. 0 Cyanazine was monitored in a newly-built reservoir on the Des Moines River in Iowa during September 1977 through November 1978. Agri- cultural runoff (from corn and soybeans) was a major source of pollution in the river: levels of 71 to 457 ng/L were detected during the active months of May through August; levels of 2 to 151 ng/L wre detected during September through December; and zero levels were found from January through April (U.S. EPA, 1984a; NAS, 1977). 0 Cyanazine has been found in surface water in Ohio river basins (Datta, 1984). 0 Cyanazine has also been found in ground water in Iowa and Pennsylvania; typical positives found were 0.1 to 1.0 ppb (Cohen et al. , 1986). 0 Cyanazine has been found in 4,312 of 4,285 surface water samples analyzed and in 21 of 1,564 ground water samples (STORET, 1987). Samples were collected at 337 surface water locations and 1,066 ground water locations, and cyanazine was found in 11 states. The 85th percentile of all non-zero samples was 4.11 ug/L in surface water and .20 ug/L in ground water sources. The maximum concentration found in surface water was 900 ug/L and in ground water it was 3,500 ug/L. Environmental Fate 0 14c-Cyanazine, at 5 to 10 ppm, degraded with a half-life of 2 to 4 weeks in an air-dried sandy clay loam soil, 7 to 10 weeks in a sandy loam soil, 10 to 14 weeks in a clay soil, and 9 weeks in a fresh sandy clay soil incubated in the dark at 22°C and field capacity (Osgerby et al., 1968). Three degradation products, the amide and two acids, were identified in all four soils; a fourth degradate, the amine, was found only in the air-dried sandy clay loam soil. 0 Freundlich K values were 0.72 for a sandy loan soil (2.0% organic matter), 2.0 for a sandy clay soil (5.4% organic matter), 1.25 for a sandy clay loam soil (6.8% organic matter) and 6.8 for a clay soil (16% organic matter) treated with unaged l^C-cyanazine (Osgerby et al., 1968). No linear correlation was found between organic matter content and adsorption. 0 14c-Cyanazine readily moved through columns of sandy clay loam (52% of applied compound) and loamy sand (18% of applied) soil leached with 78 cm of water over a 13-day period; unaged 14c-cyanazine was inter- mediately mobile on sandy clay loam and of low mobility on loamy sand soil thin-layer chromatography (TLC) plates (Rf 0.36 and 0.20, respectively) (McMinn and Standen, 1981). Aerobically and anaerobically aged 14c-cyanazine residues, primarily the amide degradate (SD 20258), were intermediately mobile to mobile on sandy clay loam soil TLC plates. 0 Aged 1^C-cyanazine residues readily leached through columns containing sand (47.8% of applied), loamy sand (69.7% of applied) and sandy ------- Cyanazine August, 1987 -4- loam (26'.9% of applied) soils eluted with 20 cm of water (Eadsforth, 1984). The amide degradation product (SD 20258) was predominant in the leachate from the sandy soil (45% of radioactivity in leachate); the acid degradate (SD 20196) was predominant in leachate from the loamy sand (84%) and sandy loam (47%) soils. Unaltered cyanazine and SD 31222 were also identified in leachate from all three soils (<6% of recovered). III. PHARMACOKINETICS Absorption 0 Studies by Shell Chemical Company (Shell Chemical Company, 1969) and Hutson et al. (1970) indicated that cyanazine is rapidly absorbed from the gastrointestinal tract when administered orally at low dosage levels to three different animal species: rat, dog and cow. Measurements of urinary, fecal and biliary excretion indicated that 80 to 88% of 2,4,6-14C-labeled cyanazine was eliminated within 4 days from the rat and dog, and within 21 days from the cow. The initial dosages were 1 to 4 mg/kg for the rat, 0.8 mg/animal for the dog and 5 ppm in the total ration of the cow. The dosages were administered by gavage in the rat studies and in gelatin capsules in the dog study. Distribution 0 In rats treated with a single oral dose of 4 mg/kg cyanazine, samples of the carcass, skin and gut reflected 2.02, 0.62 and 2.73% residual radioactivity, respectively, 4 days after exposure (Shell, 1969). 0 In cows, samples of brain, liver, kidney, muscle and fat reflected concentrations of 0.55, 0.27, 0.24, 0.14 to 0.06 and less than 0.06 ppm cyanazine, respectively, after 21 days of continuous exposure to feed that contained 5 ppm cyanazine; however, when a lower dosage (0.2 ppm) was used in the feed, the detectable residues in each of these tissues were less than 0.05 ppm (Shell, 1969). Metabolism 0 Based on the analyses of metabolites in urine, the major metabolic pathways of cyanazine in the rat and cow involved: (1) conversion of the cyano group to an amide to form 2-chloro-4-ethylamino-6-(1-amido- 1-methylethyla:nino)-s-thiazine; (2) N-deethylation to form 2-chloro-4- amino-6-(1-cyano1-methyl-ethylamino)-s-triazine; (3) conversion of the cyano group of deethylate cyanazine to form the amide of deethylated cyanazine, 2-chloro-4-amino-6( 1-amino-1-methylethylamino)-s-triazine; (4) dechlorination via glutathione, partial hydrolysis of glutathione conjugate and N-acetylation to form mercapturic acid, N-acetyl-S- [4-amino-6-(1-cyano-1-methylethylamino) L-cysteine; and (5) dechlorination via hydrolysis (occurs only in the cow) to form 2-hydroxy-4-ethylamino-6-( 1 -carboxy-1-methylethylamino)-s-triazine and 2-hydroxy-4-amino-6-( 1,carboxy-1-methylamino)-s-triazine, •respectively (Shell, 1969). ------- Cyanazine August, 1987 -5- Studies by Shell Chemical Company (1969) and Hutson et al. (1970) with ring-labeled and side-chain-labeled cyanazine (cyano-14c, isopropyl-14c and ethylamino-1 4C) indicated that only the ethylamino-1 side chain underwent extensive degradation, since 47% of the initial radioactivity was detected in the exhaled carbon dioxide. Thus, N-deethylation was found to be a major route of degradation of cyanazine. Crayford and Hutson (1972) identified 5 metabolites in urine, an additional 2 (total 7) in feces and 4 metabolites in bile. Crayford et al. (1970) studied the metabolism of two major plant metabolites, DW4385 and DW4394, in rats. These two compounds were identified in the rat metabolism studies by Crayford and Hutson (1972) as 2-hydroxy-4-ethylamino-6-(1-carboxy-1-methylamino)-s-triazine) (DW4385) and as 2-hydroxy-4-amino-6-(1-carboxy-1 -methylethylamino)- s-triazine) (DW4394). Approximately 91% of compound DW4385 and 84% of compound DW4394 were recovered unchanged from urine and feces. Excretion Orally administered low doses of cyanazine were rapidly excreted in the urine and feces of rats and dogs (Shell, 1969; Hutson et al., 1970; Crayford and Hutson, 1972). See discussion of these studies in the above sections. In rats treated with 1 to 4 mg/kg cyanazine by gavage, a total of 88% of cyanazine was eliminated in 4 days. Elimination via urine was almost equal to elimination via feces; about 5.37% of the administered cyanazine remained in the body; and approximately 21% of the 1 mg/kg dose appeared in the bile within the first 20 hours (Shell, 1969). Hutson et al. (1970) reported that 33% of an oral dose of cyanazine was excreted in the urine of rats within 24 hours. A study in rats with 14c-labeled 4-ethyl-amino cyanazine indicated that 47% of the radioactivity was eliminated in carbon dioxide (Shell Chemical Company, 1969). In dogs administered 0.8 mg of cyanazine in gelatin capsules, 51.67 and 36.29% of the dose were eliminated in the urine and feces, respectively, over a 4-day period (Shell Chemical Company, 1969). In cows exposed to treated feed (5 ppm cyanazine) for 21 consecutive days, the amount of daily excretion of radioactivity in urine and feces was constant throughout the study period. The total cyanazine equivalents in urine and feces were 53.7 and 26.8% of the dose, respectively. The concentration in milk was reported as 0.022 ppm (Shell Chemical Company, 1969). ------- Cyanazine August, 1987 -6- IV. HEALTH EFFECTS Humans No information was found in the available literature on the health effects of cyanazine in humans. Animals Short-term Exposure 0 The acute oral LD50 in rats ranged from 149 to 369 mg/kg (SRI, 1967b; NIOSH, 1977; Young and Adamik, 1979b; Meister, 1983). In these studies, the percentage of active ingredient (a.i.) in the tested product(s) was not clearly identified. However, studies by Walker et al. (1974) with technical cyanazine (97% a.i.) in three different animal species reflected LD5QS of 182, 380 and 141 mg/kg for the rat, mouse and rabbit, respectively. 0 The acute dermal LD50 in rabbits treated with technical cyanazine (purity unspecified) was >2,000 mg/kg (SRI, 1967a; Young and Adamik, 1979c); in rats, the LD50 was >1,200 mg/kg (97% a.i.) (Walker et al., 1974). 0 The acute inhalation LCso for cyanazine dust (% a.i. not specified) in rats was >2.28 mg/L/hr (Bishop, 1976) (toxicity category III). 0 In a study by Walker et al. (1968), groups of 10 female CFE rats, 5 months old, were treated by gavage with single oral doses of 1, 5 or 25 mg/kg of a wettable powder formulation (75% a.i.); the control group received water. No diuretic effects were produced in the rats receiving the formulation; however, serum protein and potassium concentrations increased at the high dose, and serum osmolality increased at 5 mg/kg, the Lowest-Observed-Adverse-Effect-Level (LOAEL). The No-Observed-Adverse-Effect-Level (NOAEL) in this study appeared to be 1 mg/kg; however, this study did not provide enough information to determine the presence or absence of more significant effects at this dosage level. 0 A 4-week oral toxicity study by Walker et al. (1968) was performed using groups of 10 male and 10 female CFE rats, 5 weeks of age, receiving diets containing 1, 10 or 100 ppm cyanazine (75% or 97% a.i.) for 4 weeks; These doses are equivalent to 0.05, 0.5 or 5 mg/kg/day (Lehman, 1959). A control group of 20 animals/sex was used. After 4 weeks, urine samples were collected for 16 hours (overnight), and blood samples were used to determine the kidney function. Reductions in body weight and food intake were noted at the high-dose level. Osmolal clearance decreased in males, and this change was associated with a decrease in free water clearance -in both the low- and mid-dose groups. In females, decreased urine and increased serum osmolality were observed in the mid-dose group, and both creatinine clearance and urine potassium concentrations increased in the low-dose group. The LOAEL in this study appeared to be 0.05 mg/kg/day (lowest dose ------- Cyanazine August, 1987 -7- tested) based on kidney function tests, although additional information was not available to determine if any other significant adverse effects were noted at this level. Dermal/Ocular Effects 0 Cyanazine caused mild eye irritation (100 mg) and slight skin irrita- tion (2,000 mg) in rabbits. A skin sensitization test in guinea pigs was negative (Walker et al., 1974; Young and Adamik, 1979d). Long-term Exposure 0 In a 13-week oral study in dogs (Walker and Stevenson, 1968a, 1974), groups of 5- to 7-month old beagle dogs, four animals/sex/treatment group, were given daily doses of 1.5, 5 or 15 mg/kg/day cyanazine in gelatin capsules. A control group of five animals/sex was given empty capsules. The test material caused emesis within the first hour of dosing in all of the high-dose males. Reduced body weight gain was also noted in the high-dose group during the second half of the study period as well as increased kidney and liver weights in the females of this group. Thus, the LOAEL was 15 mg/kg/day and the NOAEL was 5 mg/kg/day. 0 In a 13-week mouse feeding study (Fish et al., 1979), groups of 12 animals/sex/dose were fed diets containing 10, 50, 500, 1,000 or 1,500 ppm, equivalent to 1.5, 7.5, 75, 150 or 225 mg/kg/day (Lehman, 1959). The control group consisted of 24 animals/sex. Body weight gain reduction was observed in both sexes at 75 mg/kg/day and above. Statistically significant increases in liver weights were observed in both sexes at 75 mg/kg/day and above. Thus, the LOAEL was 75 mg/kg/day and the NOAEL was 7.5 mg/kg/day. 0 An initial 13-week rat feeding study by Walker and Stevenson (1968a) was performed using 0.1, 1.0 or 100 ppm (equivalent to 0.005, 0.05 or 0.5 mg/kg/day; Lehman, 1959) of technical cyanazine (purity not specified: 97% or 75% a.i. WP) in feed. Each dosage group had 20 animals/sex; the control group had 40 animals/sex. Body weight gain decreased in all dosage groups in males and in the high-dose female group. A NOAEL was not reflected in this study for males, although it appeared to be 0.05 mg/kg/day for females. 0 Walker and Stevenson (1968b) repeated the above study in rats at dose levels of 1.5, 3, 6, 12, 25, 50 or 100 ppm; these levels are equivalent to 0.075, 0.15, 0.30, 1.25, 2.5 or 5 mg/kg/day (Lehman, 1959). Similar effects were noted; however, a NOAEL of 25 ppm (1.25 mg/kg/day) was identified. 0 In a 2-year study in dogs (Walker et al., 1970a), groups of 4- to 6-month-old beagle dogs were treated with technical cyanazine (97% a.i., in gelatin capsules) at dose levels of 0.625, 1.25 or 5 mg/kg/ day. Each group consisted of four animals/sex. The control group consisted of six animals/sex and received empty gelatin capsules. Frequent emesis within 1 hour of dosing was observed throughout the ------- Cyanazine August, 1987 -8- study period in the high-dose group; this effect was associated with reduction of growth rate and serum protein. The NOAEL appeared to be 1.25 mg/kg/day; however, this NOAEL should be considered with reser- vations because the study did not provide adequate explanation relative to missing histological data on one of four female dogs in the 1.25- mg/kg/day dosage group. In addition, the reported data were limited to a summary report. 0 In a 2-year study in mice (Shell, 1981), cyanazine technical (purity not specified) was given in feed to CD mice at 10, 25, 50, 250 or 1,000 ppm, equivalent to 1.5, 3.75, 7.5, 37.5 or 150 mg/kg/day (Lehman, 1959); 50 animals/sex were used in the treatment groups, and 100 animals/sex were used as controls. Toxic effects reported at the two high-dose levels, 37.5 and 150 mg/kg/day, included poor appearance and skin sores, increased mortality in the female animals in both groups, increased relative brain weight in both sexes, increased relative liver weight in the two female groups, and decreased absolute and differential leukocyte values in both sexes. Anemia was noted at 150 mg/kg/day in the females, as well as increased blood protein and increased relative kidney weight. Cyanazine did not demonstrate an oncogenic potential in this study. The NOAEL for systemic toxicity in mice appeared to be 50 ppm (7.5 mg/kg/day). 0 Two chronic feeding studies in rats were available for review. In one study (Walker et al., 1970b; also cited in Walker et al., 1974), groups of 24 CFE rats/sex/dose received diets containing 6, 12, 25 or 50 ppm, equivalent to 0.3, 0.6, 1.25 or 2.5 mg/kg/day (Lehman, 1959) cyanazine (97% a.i.); 45 rats/sex were used as controls. The authors indicated that no effects due to cyanazine were noted in this study, although reduction in growth rate was noted in both sexes at 2.5 mg/kg/day and in females at 1,25 mg/kg/day. A review of this study (U.S. EPA, 1984b) indicated that cyanazine appeared to be tumorigenic in both male and female rats based on the increased incidences of thyroid tumors in all treatment groups as compared to the study's control group; increased incidences of adrenal tumors also were noted in all male treatment groups. However, this study was considered unacceptable because of several deficiencies: a limited number of tissues per animal were examined microscopically; the tumor incidences were calculated based on the number of animals tested rather than on the number of specific tissues histologically examined; gross examination and histologic findings for nonneoplastic lesions were not adequately reported; and only limited hematology, clinical blood chemistry and urinalyses data were presented. 0 Simpson and Dix (1973) repeated the above 2-year study using 1, 3 or 25 ppm, equivalent to 0.05, 0.15 or 1.25 mg/kg/day (Lehman, 1959); however, convulsions were noted in the rats 3 months after the study initiation and throughout the remainder of the study period. Approximately 42% of the animals were affected, and the incidence was not considered to be dose-related. The incidence of animals with convulsions was similar in both the control and high-dose male groups (21/48 and 11/24, respectively). ------- Cyanazine August, 1987 -9- Reproductive Effects 0 A three-generation reproduction study in Long-Evans rats (Eisenglord et al., 1969) using technical cyanazine (unknown percentage a.i.) at dietary levels of 3, 9, 27 or 81 ppm (0.15, 0.45, 1.35 or 4.05 mg/kg/day) did not reflect a significant effect on reproduction parameters. The NOAEL in this study appeared to be 1.35 mg/kg/day; the LOAEL was 4.05 mg/kg/day (highest dose tested) based on findings related to reduced body weight gain in parental animals, and increased relative brain weight and decreased relative kidney weight in F3J-, female weanlings. Developmental Effects 0 Cyanazine appeared to cause teratogenic effects and developmental toxicity in two animal species, the rabbit and the rat (Bui, 1985b). 0 In the rabbit study (Shell Toxicology Laboratory, 1982), 7- to 11- month-old New Zealand White rabbits were orally dosed with cyanazine (98% a.i.) in gelatin capsules at levels of 0, 1, 2 or 4 mg/kg/day on gestation days 6 through 18 (22 dams/dose/group). At 2 and 4 mg/kg/day, maternal toxic effects included anorexia, weight loss, death and abortion. Alterations in skeletal ossification sites, decreased litter size, and increased postimplantation loss were observed at 2 and 4 mg/kg/day. Malformations were also noted at 4 mg/kg/day as demonstrated by anophthalmia/microphthalmia, dilated brain ventricles, domed cranium and thoracoschisis; however, these responses were observed at levels in excess of maternal toxicity. The maternal and developmental toxicity NOAELs were 1 mg/kg/day. 0 In a rat study by Lu et al. (1981, 1982), 122-day-old Fischer 344 rats (30 dams/group) were administered cyanazine (97% a.i.) by gavage at dose levels of 0, 1.0, 2.5, 10.0 or 25.0 mg/kg/day on gestation days 6 through 15; the dosages were suspended in a 0.2% Methocal emulsion as vehicle. Maternal body weight reductions during dosing were noted at the 10- and 25-mg/kg/day levels. Diaphragmatic hernia. associated with liver microphthalmia was observed at the 25 mg/kg/day dose level. A teratogenic NOAEL could not be determined from this study. 0 The above study was repeated in the same strain of rats, Fischer 344, by Lochry et al. (1985) in order to further examine the malformations reported in the study by Lu et al. (1981). In this study, the dams (70/dosage group) were 86 days old. Cyanazine (98% a.i.) was admini- stered by gavage in an aqueous suspension of 0.25% (w/v) methyl cellulose at dose levels of 0, 5, 25 or 75 mg/kg/day on days 6 through 15 of gestation. One-half of the dams in each group were selected for Cesarean delivery on day 20 of gestation. The remaining half of the dams in each group were allowed to deliver, and both they and their pups were observed for 21 days before sacrifice. Maternal body weight reductions during dosing were noted in all dosage groups and appeared to be partly associated with lower food intake during the dosing period. Alteration in skeletal ossification sites were also observed in the fetuses at all dose levels. Teratogenic effects were ------- Cyanazine August, 1987 -10- demonstrated at 25 and 75 mg/kg/day as anophthalmia/microphthalmia, dilated brain ventricles and cleft palate in the fetuses, and abnor- malities of the diaphragm (associated with liver protrusion) in pups sacrificed at time of weaning. The maternal and developmental toxicity NOAELs were lower than 5 mg/kg/day (lowest dose tested), and the teratogenic NOAEL was 5 mg/kg/day (Bui, 1985a). 0 An additional study in Sprague-Dawley rats (Shell Development Company, 1983) did not reflect any maternal or developmental toxicity at the highest dose tested, 30 mg/kg/day. Mutagenicity 8 The mutagenic potential of cyanazine has not been investigated adequately, and only limited information was available for evaluation. 0 A study by Dean et al. (1975) using technical cyanazine (80% a.i.) in mice of both sexes did not reflect any increase in chromosomal aberrations in the bone marrow cells. The animals were examined at 8- and 24-hour intervals after oral dosing with 50 or 100 mg/kg cyanazine. However, the sensitivity of this test was potentially compromised because the positive control data did not reflect a significant number of aberrations: the percent of cells showing chromatid gaps in the positive control (cyclophosphamide) was not statistically significant at the p <0.05 level (U.S. EPA, 1985b). 0 Dean et al. (1974) used technical cyanazine (purity not specified) to induce dominant lethal effects in male CF1 mice. The test was negative at the dose levels tested (80, 160 and 320 mg/kg). However, this study appeared to be invalid because there was no positive control for comparison of data, and a range-finding test was not performed to select the appropriate dosages used in this study (U.S. EPA, 1984b). 0 Cyanazine is a member of the triazine family of herbicides. It is known that the triazines follow similar metabolic pathways (i.e., N-dealkyla- tion, S-dealkylation or 0-dealkylation and conjugation with glutathion) that result in common or closely related metabolites. Waters, et al. (1980) noted that a triazine herbicide (atrazine) gave a positive mutagenic response in the Drosophila sex-linked recessive lethal test (DRL), although this chemical gave a negative response in an in vitro test battery with microorganisms. Hence, the potential for cyanazine to give a positive response in a similar test exists (U.S. EPA, 1984b). Carcinogenicity 0 Cyanazine was not determined to have a carcinogenic potential in a 2-year mouse study (Shell, 1981). 0 Cyanazine was not oncogenic in 2-year rat studies by Walker et al. (1970b) or by Simpson and Dix (1973); however, these studies were deficient (see description of these studies under the section entitled Long-term Exposure) and are considered to be inadequate by design to determine the oncogenic potential of cyanazine. ------- Cyanazine August, 1987 -11- V. QUANTIFICATION OF TOXICOLOGICAL EFFECTS Health Advisories (HAs) are generally determined for one-day, ten-day, longer-term (approximately 7 years) and lifetime exposures if adequate data are available that identify a sensitive noncarcinogenic end point of toxicity. The HAs for noncarcinogenic toxicants are derived using the following formula: HA = (NOAEL or LOAEL) X (BW) = mg/L ( ug/L) (UF) x ( L/day) where: NOAEL or LOAEL = No- or Lowest-Observed-Adverse-Effect-Level in mg/kg bw/day. BW = assumed body weight of a child (10 kg) or an adult (70 kg). UF = uncertainty factor (10, 100 or 1,000), in accordance with NAS/ODW guidelines. L/day = assumed daily water consumption of a child (1 L/day) or an adult (2 L/day). One-day Health Advisory No information was found in the available literature for determination of the One-day HA for cyanazine. It is, therefore, recommended that the Ten-day HA value for a 10-kg child, calculated below as 0.10 mg/L (100 ug/L), be used at this time as a conservative estimate of the One-day HA value. Ten-day Health Advisory The teratology study in rabbits by Shell Toxicology Laboaratory (1982) has been selected as the basis for determination for the Ten-day HA for cyanazine because it provides a short-term NOAEL (1 mg/kg/day for 13 days) for both maternal and fetal toxicity. This study also reflects the lowest NOAEL when compared with the teratology studies in rats described earlier, two in Fischer 344 rats (Lu et al., 1981; Lochry et al., 1985) and one in Sprague- Dawley rats (Shell Development Company, 1983). Using a NOAEL of 1 mg/kg/day, the Ten-day HA for a 10 kg child is calculated as follows: Ten-day HA = (1 mg/kg/day) (10 kg) = 0.10 mg/L (100 ug/L) (100) (1 L/day) where: 1 mg/kg/day = NOAEL based on maternal and fetal effects in rabbits exposed to technical cyanazine orally for 13 days. 10 kg = assumed body weight of a child. ------- Cyanazine August, 1987 -12- uncertainty factor, chosen in accordance with NAS/ODW guidelines for use with a NOAEL from an animal study. 1 L/day * assumed daily water consumption by a child. Longer-term Health Advisory No information was suitable for the determination of the Longer-term HA for cyanazine. It is, therefore, recommended that the adjusted Drinking Water Equivalent Level (DWEL) of 0.013 mg/L (13 ug/L) be used for a 10-kg child as a conservative estimate for the Longer-term HA value and the DWEL of 0.046 mg/L (46 ug/L), calculated below, be used for a 70-kg adult. Lifetime Health Advisory The Lifetime HA represents that portion of an individual's total exposure that is attributed to drinking water and is considered protective of noncar- cinogenic adverse health effects over a lifetime exposure. The Lifetime HA is derived in a three-step process. Step 1 determines the Reference Dose (RfD), formerly called the Acceptable Daily Intake (ADI). The RfD is an esti- mate of a daily exposure to the human population that is likely to be without appreciable risk of deleterious effects over a lifetime, and is derived from the NOAEL (or LOAEL), identified from a chronic (or subchronic) study, divided by an uncertainty factor(s). From the RfD, a Drinking Water Equivalent Level (DWEL) can be determined (Step 2). A DWEL is a medium-specific (i.e., drinking water) lifetime exposure level, assuming 100% exposure from that medium, at which adverse, noncarcinogenic health effects would not be expected to occur. The DWEL is derived from the multiplication of the RfD by the assumed body weight of an adult and divided by the assumed daily water consumption of an adult. The Lifetime HA is determined in Step 3 by factoring in other sources of exposure, the relative source contribution (RSC). The RSC from drinking water is based on actual exposure data or, if data are not available, a value of 20% is assumed for synthetic organic chemicals and a value of 10% is assumed for inorganic chemicals. If the contaminant is classified as a Group A or B carcinogen, according to the Agency's classification scheme of carcinogenic potential (U.S. EPA, 1986), then caution should be exercised in assessing the risks associated with lifetime exposure to this chemical. Four chronic studies were available for evaluation: (1) a 2-year oncogenic study in mice (Shell, 1981) with a potential NOAEL of 50 ppm (approximately 7.5 mg/kg/day when using a conversion factor for food consumption of 15% of the body weight); (2) a 2-year feeding study in dogs (Walker et al., 1970a) with a NOAEL of 1.25 mg/kg/day; (3) a 2-year feeding/oncogenic study in rats (Walker et al., 1970b, also cited in Walker et al., 1974) with a NOAEL of 12 ppm (approximately 0.6 mg/kg/day when using a conversion factor for food consumption of 5% of the body weight); however, this study was considered unacceptable (U.S. EPA, 1984b) due to several deficiencies in the study report (see Longer-term Exposure); and (4) a second 2-year feeding study in rats (Simpson and Dix, 1973), which was also considered inadequate because the control group reflected an effect, i.e., convulsions, that was suggestive of cross-dosing. ------- Cyanazine August, 1987 -13- The NOAEL in the mouse study (7.5 mg/kg/day) can be considered for this calculation; however, this NOAEL is higher than the NOAEL in the Walker et al. (1970a) dog study (1.25 mg/kg/day) or in the Walker et al. (1970b) rat study (0.6 mg/kg/day). Since this rat study is considered unacceptable and since the second rat study (Simpson and Dix, 1973) appeared to be flawed by the invalidity of the control group, it is concluded that the 2-year dog study (Walker et al., 1970a) will be used for the Lifetime HA. The NOAEL of 1.25 mg/kg/day is used; however, because the data in this study were of marginal acceptability, an uncertainty factor of 1,000 fold will be applied to the HA calculations. This study NOAEL is also similar to the NOAEL reflected in the suchronic study in rats by Walker and Stevenson (1968b); thus the RfD value calculated below can be equally based on either one of these studies (or both) using the same uncertainty factor. Using a NOAEL of 1.25 mg/kg/day, the Lifetime HA is calculated as follows: Step 1: Determination of the Reference Dose (RfD) RfD = (1.25 mg/kg/day) = Q.0013 mg/kg/day (1,000) where: 1.25 mg/kg/day = NOAEL based on absence of toxicity in both the 2-year dog study and the 13-week rat study. 1,000 = uncertainty factor, chosen in accordance with NAS/ODW guidelines for use with a NOAEL from an animal study of less-than-lifetime duration (as in the 13-week rat study) or for a study with limited acceptability (as in the 2-year dog study). Step 2: Determination of the Drinking Water Equivalent Level (DWEL) DWEL = (0.0013 mg/kg/day) (70 kg) = Q.0455 mg/L (46 ug/L) (2 L/day) where: 0.0013 mg/kg/day = RfD. 70 kg = assumed body weight of an adult. 2 L/day = assumed daily water consumption by an adult. Step 3: Determination of the Lifetime Health Advisory Lifetime HA = (0.046 mg/L) (20%) = 0.009 mg/L (9 ug/L) ------- Cyanazine August, 1987 -14- where: 0.046 mg/L = DWEL. 20% = assumed relative source contribution from water. Evaluation of Carcinogenic Potential 0 Available toxicity data indicate that cyanazine was not carcinogenic in mice (Shell, 1981) or rats (Walker et al., 1970b, 1974; Simpson and Dix, 1973); however, in the rat, some increases were noted in the incidences of both thyroid tumors (male and female rats) and adrenal tumors (male rats); however, these increases were not statistically significant. 0 Cyanazine is a chloro-s-triazine derivative that has a chemical structure analagous to atrazine, propazine and simazine, the first two of which were found to significantly (p <0.05) increase the incidence of mammary tumors in rats. A new oncogenic study in rats using simazine is not yet completed. Based on structure-activity relationship, cyanazine may reflect a similar patteinof toxicity in the rat. A new 2-year oncogenic study is required from the manufacturer of this chemical to fill this data gap in the toxicity profile of this chemical. 0 Applying the criteria described in EPA's guidelines for assessment of carcinogenic risk (U.S. EPA, 1986), cyanazine may be classified in Group D: not classified. This category is used for substances with inadequate animal evidence of carcinogenicity. VI. OTHER CRITERIA, GUIDANCE AND STANDARDS 0 U.S. EPA Office of Pesticide Programs (OPP) has established residue tolerances for cyanazine ranging from 0.05 to 0.10 ppm in or on raw agricultural commodities (U.S. EPA, 1985a) based on a Provisional ADI (PADI) of 0.0013 mg/kg/day. VII. ANALYTICAL METHODS 0 Analysis of cyanazine is by a high-performance liquid chromatographic (HPLC) method applicable to the determination of cyanazine in water samples (U.S. EPA, 1985b). In this method, 1 L of sample is solvent extracted with methylene chloride using a separatory funnel. The methylene chloride extract is dried and exchanged to methanol during concentration to a volume of 10 mL or less. Separation and measure- ment of cyanazine is by HPLC with an ultraviolet (UV) detector. The estimated method detection limit for cyanazine is 6 ug/L. ------- Cyanazine August, 1987 -15- VIII. TREATMENT TECHNOLOGIES 0 Available data indicate that granular-activated carbon (GAC) adsorption will remove cyanazine from water. 0 Whittaker (1980) experimentally determined adsorption isotherms for cyanazine on GAC. 0 GAC adsorption appears to be an effective method of cyanazine removal from water. However, selection of individual or combinations of technologies to attempt cyanazine removal from water must be based on a case-by-case technical evaluation, and an assessment of the economics involved. ------- Cyanazine August, 1987 -16- IX. REFERENCES Bishop, A.L.* 1976. Report to Shell Chemical Company: Acute dust inhalation toxicity study in rats. (Unpublished study received July 18, 1979 under 201-279; prepared by Industrial Bio-Test Laboratories, Inc., submitted by Shell Chemical Co., Washington, D.C.; CDLs098395-A). MRID #00022789. (Cited in U.S. EPA, 1984b) Bui, Q.Q.* 1985a. Review of a developmental toxicity study (teratology and post-natal study). U.S. EPA, internal memo from author to Robert Taylor (reviewing study cited in Shell Development Company (1985), report no. 619-002, accession no. 257867). Bui, Q.Q.* 1985b. Overview of the teratogenic potential of Bladex (cyanazine) U.S. EPA, internal memo from author to Herb Harrison, dated June 5, 1985. CHEMLAB. 1985. The Chemical Information System. CIS Inc., Bethesda, MD. Cohen, S.Z., C. Eiden and M.N. Lorber. 1986. Monitoring ground water for pesticides in the U.S.A. In; Evaluation of pesticides in ground water. American Chemical Society Symposium Series, (in press) Crayford, J.V., E.G. Hoadley, B.A. Pikering et al.* 1970. The metabolism of the major plant metabolites of Bladex (DW 4385 and DW 4394) in the rat: Group research report TLGR.OQ81 .70. (Unpublished study prepared by Shell Research, Ltd). MRID #000223871. (Cited in U.S. EPA, 1984b) Crayford, J.V., and D.H. Hutson.* 1972. Metabolism of the herbicide 2-chloro- 4-(ethylamino)-6-(1-cyano-1-methylethylamino)-S-triazine in the rat. Pesticide Biochem. Physiol. 2:295-307. MRID #00022856. (Cited in U.S. EPA, 1985a; U.S. EPA, 1984b) Datta, P.R. 1984. Internal memorandum: Review of six documents regarding monitoring of pesticides in northwestern Ohio rivers. U.S. Environmental Protection Agency, Washington, DC. Dean, B.J., E. Thorpe and D.E. Stevenson.* 1974. Toxicity studies on Bladex: Dominant-lethal assay in male mice after single dose of Bladex. (Unpub- lished study received August 13, 1976 prepared by Shell Research, Ltd. for Shell Chemical Co., Washington, D.C.; CDL:095245-C). MRID #00023837. (Cited in U.S. EPA, 1984b) Dean, B.J., K.R. Senner, B.D. Perquin and S.M.A. Doak.* 1975. Toxicity studies with Bladex chromosome studies on bone marrow cells of mice after two daily oral doses of Bladex. (Unpublished study report no. TLGR.0032074 received August 13, 1976 under 6F1729 prepared by Shell Research, Ltd., submitted by Shell Chemical Co., Washington, D.C<>; CDL:095245-B). MRID #00023836. (Cited in U.S. EPA, 1984b) Eadsforth, C.V. 1984. The leaching behavior of Bladex and its degradation products in German soils under laboratory conditions. Expt. No. 2994. Unpublished study submitted by Shell Chemical Company, Washington, DC. ------- Cyanazine August, 1987 -17- Eisenglord, G., G.S. Loqunam and S. Leung.* 1969. Results of reproduction study of rats fed diets containing SD 15418 over three generations: Report No. 47. (Unpublished study received on unknown date under 9G0844; prepared by Hine Laboratories, Inc., submitted by Shell Chemical Co., Washington, DC.; CDL:095023-D). MRID #00032346. (Cited in U.S. EPA, 1985b) Fish, A., R.W. Hend and C.E. Clay.* 1979. Toxicity on the herbicide Bladex: A three-month feeding study in mice: TLGR.0021.79. (Unpublished study received July 19, 1979 under 201-279; submitted by Shell Chemical Co., Washington, DC.; CDL:09835-C). (Cited in U.S. EPA, 1984b> Hutson, D.H., E.G. Hoadley, M.H. Griffiths and C. Donninger. 1970. Mercap- turic acid formation in the metabolism of 2-chloro-4-ethylamino-6- (1-methyl-1-cyanoethylamino)-s-triazine in the rat. J. Agric. Food. Chem, 18:507-512. (Data also available in U.S. EPA, 1984b, MRID # 00032348, Shell Chemical Co., 1969.) Lehman, A.J. 1959. Appraisal of the safety of chemicals in foods, drugs and cosmetics. Assoc. Food Drug Off. U.S. Lochry, E.A., A.M. Hoberman and M.S. Christian.* 1985. Study of the develop- mental toxicity of technical Bladex herbicide (SO-15418) in Fischer-344 rats. (Unpublished report, submitted by Shell Oil Company; prepared by Argus Research Laboratory, Inc., Horsham, PA, Report No. 619-002, dated 4/18/85) Lu, C.C., B.S. Tang, E.Y. Chai et al.* 1981. Technical Bladex (R) (SD 15418) teratology study in rats: Project no. 61230. (Unpublished study received January 4, 1982 under 201-179; submitted by Shell Chemical Co., Washington, DC.; CDL:098395-C). MRID #00091020. (Cited in Lu et al., 1982, and in U.S. EPA, 1984b) Lu, C.C., B.S. Tang and E.Y. Chai. 1982. Teratogenicity evaluations of technical Bladex in Fischer-344 rats. Teratology. 25(2):59A-60A. McMinn, A.L., and M.E. Standen. 1981. The mobility of Bladex and its degradation products in soil under laboratory conditions. Unpublished study submitted by Shell Chemical Company, Washington, DC. Meister,R., ed. 1983. Farm chemicals handbook. Willoughby, OH: Meister Publishing Company. Mirvish, S.S. 1975. Formation of N-nitroso compounds: Chemistry, kinetics, and in vivo occurrence. Submitted by Shell Oil Co., Washington, DC.; CDL:070584-A). Fiche/Master ID 00000000. NAS. 1977. National Academy of Sciences. Drinking water and health. Washington, DC.: National Academy Press. NIOSH. 1977. National Institute for Occupational Safety and Health. Registry of Toxic Effects of Chemical Substances. U.S. DHEW, PHS, CDC, Rockville, MD. (Cited in U.S. EPA, 1984a) ------- Cyanazine August, 1987 -18- Osgerby, J.M., D.F. Clarke and A.T. Woodburn. 1968. The decomposition and adsorption of DW 3418 (WL 19,805) in soils. Unpublished study submitted by Shell Chemical Company, Washington, DC. Plewa, M.J., and J.M. Gentile. 1976. Mutagenicity of atrizine: A maize- microbe bioassay. Mutat. Res. 38:287-292. Shell.* 1981. Two-year oncogenicity study in the mouse. (Unpublished report submitted under pesticide petition number 9F2232, EPA accession number 247,295-298). Shell Development Company.* 1983. Teratogenic evaluation of Bladex in SD CD rats. (Unpublished report submitted by Shell Development Company, prepared by Research Triangle Institute, Project No. 31T-2564, Report dated 5/16/83, submitted to the EPA on 7/6/83; EPA Accession No. 071738). (Cited in U.S. EPA, 1984b) Shell Chemical Company.* 1969. Metabolism. Unpublished study. MRID #00032348, (Cited in U.S. EPA, 1984b) Shell Toxicology Laboratory (Tunstall).* 1982. A teratology study in New Zealand White rabbits given Bladex orally. A report prepared by Sitting- bourne Research Center, England; project no. 221/81, experiment no. AHB-2321, November, 1982. Submitted on February 1, 1983 as document SBGR.82.357 by Shell Oil Co., Washington, DC. under accession no. 071382. (Cited in U.S. EPA, 1984b) Simpson, B.J., and K.M. Dix.* 1973. Toxicity studies on the s-triazine herbicide Bladex: Second 2-year oral experiment in Research Limited, London. Dated July 1973. EPA Accession No. 251954-955-956. SRI.* 1967a. Stanford Research Institute Project 868-1, Report No. 39, January 4, 1967. Acute dermal toxicity of SD-15418 (technical cyanazine). Submitted by Shell Chemical Co., Washington, DC., Pesticide Petition #9G0844, Accession #91460. (Cited in U.S. EPA, 1984b) SRI.* 1967b. Stanford Research Institute Project 55 868, Report No. 43, May 26, 1967. Acute oral toxicity of SS-15418 (technical cyanazine). Submitted by Shell Chemical Co., Washington, DC., Pesticide Petition #9G0844, Accession #91460. (Cited in U.S. EPA, 1984b) U.S. EPA. 1984a. U.S. Environmental Protection Agency. Draft health and environmental effects profile for cyanazine. Cincinnati, OH: Environmental Criteria and Assessment Office. U.S. EPA.* 1984b. U.S. Environmental Protection Agency. Cyanazine toxicology data review for registration standard. Washington, DC: Office of Pesticide Programs. U.S. EPA. 1985a. U.S. Environmental Protection Agency. 40 CFR. 180.307. U.S. EPA. 1985b. U.S. Environmental Protection Agency. U.S. EPA Method 629 - cyanazine. Fed. Reg. 50:40701. October 4. ------- Cyanazine August, 1987 -19- ' U.S. EPA. 1986. U.S. Environmental Protection Agency. Guidelines for carcinogen risk assessment. Fed. Reg. 51(185):33992-34003. September 24. Walker, A.I.T., R. Kampjes and G.G. Hunter.* 1968. Toxicity studies in rats on the s-triazine herbicide (DW 3418): (a) 13-Week oral experiments; (b) The effect on kidney function: Group research report TLGR.0007.69. (Unpublished study received Oct. 17, 1969 under 9G0844; prepared by Shell Research, Ltd., England, submitted by Shell Chemical Co., Washington, DC.; CDL:091460-H. ) MRID #00093200. (Cited in U.S. EPA, 1984b; Walker, et al., 1974) Walker, A.I.T., and D.E. Stevenson.* 1968a. The toxicity of the s-triazine herbicide (DW 3418): 13-Week oral toxicity experiment in dogs: Group research report TLGR.0016.68. (Unpublished study received Oct. 17, 1969 under 9G0844; prepared by Shell Research, Ltd., England, submitted by Shell Chemical Co., Washington, DC.; CDL:091460-G.) MRID #00093199. (Cited in U.S. EPA, 1984b; Walker et al., 1974) Walker, A.I.T., and D.E. Stevenson.* 1968b. The toxicity of the s-triazine herbicide (DW 3418): 13-Week oral experiment in rats: Group research report TLGR.0017.68. (Unpublished study received Oct. 17, 1969 under 9G0844; prepared by Shell Research, Ltd., England, submitted by Shell Chemical Co., Washington, DC.) MRID #00093198. (Cited in U.S. EPA, 1984b; Walker et al., 1974) Walker, A.I.T., E. Thorpe and C.G. Hunter.* 1970a. Toxicity studies on the s-triazine herbicide Bladex (DW 3418): Two-year oral experiment with dogs: Group research report TLGR.0065.70. (Unpublished study received December 4, 1970 under OF0998; prepared by Shell Research, Ltd., England, submitted by Shell Chemical Co., Washington, DC.; CDL:091724-R.) MRID #00065483. Walker, A.I.T., E. Thorpe and C.G. Hunter.* 1970b. Toxicity studies on the s-triazine herbicide Bladex (DW 3418): Two-year oral experiment with rats: An unpublished report prepared by Tunstall Laboratory, submitted by Shell Research, Ltd., London. (TLGR.0063.70). EPA Accession Nos. 251, 949-251, 953; PP# OF0998 (CDL: 091724-Q). MRID #00064482. Walker, A.I.T., V.K. Brown, J.R. Kodama, E. Thorpe and A.B. Wilson. 1974. Toxicological studies with the 1,3,5-triazine herbicide cyanazine. Pestic. Sci. 5(2):153-159. (Cited in U.S. EPA, 1984a) Waters, M.D., V.F. Simmon, A.D. Mitchell, T.A. Jorgenson and R. Valencia. 1980. An overview of short-term tests for the mutagenic and carcinogenic potential of pesticides. J. Environ. Sci. Health. 6:867-906. Whittaker, K.F., 1980. Adsorption of selected pesticides by activated carbon using isotherm and continuous flow column systems. Ph.D. Thesis. Lafayette, IN: Purdue University. Wolfe, N.L., R.G. Zapp, J.A. Gordon and R.C. Fincher. 1975. N-Nitrosoatra- zine: Formation and degradation. 170th Amer. Chem. Soc. Meeting. Abstracts. American Chemical Society, p. 23. ------- Cyanazine August, 1987 -20- . « Young, S.M., and E.R. Adamik.* 1979a. Acute eye irritation study in rabbits with SD 15418 (technical Bladex (R) herbicide): Code 16-8-0-0: Project no. WIL-1223-78. (Unpublished study received Jan. 10, 1980 under 201- 281: submitted by Shell Chemical Co., Washington, DC.; CDL:099198-E. ) MRID #00026427. (Cited in U.S. EPA, 1984b) Young, S.M., and E.R. Adamik.* 1979b. Acute oral toxicity study in rats with SD 15418 (technical Bladex (R) herbicide): Code 16-8-0-0: Project no. WIL-1223-78. (Unpublished study received Jan. 10, 1980 under 201- 281: submitted by Shell Chemical Co., Washington, DC.; CDL:099198-C.) MRID #00026424. (Cited in U.S. EPA, 1984b) Young, S.M., and E.R. Adamik.* 1979c. Acute oral toxicity study in rabbits with SD 15418 (technical Bladex (R) herbicide): Code 16-8-0-0: Project no. WIL-1223-78. (Unpublished study received Jan. 10, 1980 under 201- 281: submitted by Shell Chemical Co., Washington, DC.; CDL:099198-C.) MRID #00026425. (Cited in U.S. EPA, 1984b) Young, S.M., and E.R. Adamik.* 1979d. Delayed contact in hypersensitivity study in guinea pigs with SD 15418 (technical Bladex (R) herbicide): Code 16-8-0-0: Project no. WIL-1223-78. (Unpublished study received Jan. 10, 1980 under 201-281: submitted by Shell Chemical Co., Washington, DC.; CDL:099198-P.) MRID #00026428. (Cited in U.S. EPA, 1984b) Zendzian, R.P. 1985. Review of a study on Bladex dermal absorption. U.S. EPA, internal memo to G. Werdig dated 2/20/85, reviewing study by Jeffcoat, A.R. (Research Triangle Institute, RTI/3134/01F, Dec. 1984), Accession no. 256324. •Confidential Business Information submitted to the w^fice of Pesticide Programs ------- |