EPA Registration Division contac t: Andrew Ertman; (703) 308-9367

IR-4

PP 1E7861

EPA has received a pesticide petitio n (1E7861) from IR-4, IR-4 Project Headquarters, Rutgers, The State University of NJ, 500 College Road East, Suite 201 W, Princeton, NJ 08540 proposing, pursuant to section 408(d) of the Federal Food, Drug, and Cosmetic Act (FFDCA), 21 U.S.C. 346a(d), to amend 40 CFR part 180 by establishing a tolerance for residues of pyrimethanil (4,6-dimethyl-N-phenyl-2- pyrimidinamine) in or on the raw ag ricultural commodities onion, bulb, subgroup 03- 07A at 0.1 parts per million (ppm), onion, gr een, subgroup 03-07B at 2.0 ppm, berry and small fruit, small fruit vine c limbing subgroup, except fuzzy kiwifruit 13-07F at 5.0 ppm, berry and small fruit, low growing berry subgroup 13-07G at 3.0 ppm and ginseng at 2.5 ppm. EPA has determined that the petition c ontains data or info rmation regarding the elements set forth in section 408 (d)(2) of the FDDCA; however, EPA has not fully evaluated the sufficiency of the submitted data at this time or whether the data supports granting of the petition. Additional data may be needed before EPA rules on the petition.

A. Residue Chemistry

1. Plant metabolism. The metabolic profile of pyrimet hanil has been investigated following application to five different crops (apple, carrots, grapes, lettuce and tomatoes) and is well understood. In plants, pyrimeth anil is the only significant residue ranging from essentially all of the Total Radioactive Residues (TRR) in carrots and tomatoes to 44% in lettuce. Limited metabolism of pyrim ethanil occurs with minor amounts (less than 10%) of the phenyl and pyrimidyl hydroxylated metabolites (AE C614276, AE C614277, AE C614278, and AE C621312) being rele ased after acid hydrolysis. Analysis of the foliage from apples and carrots conf irmed that the metabolism of pyrimethanil in plants proceeded primarily via hydroxylation of the aromatic ring structures as well as the methyl groups.

2. Analytical method. The plant metabolism studies demonstrated that analysis for the parent compound, pyrimethanil is sufficient to enable the assessment of the relevant residues in crop commodities. Pyrimeth anil was extracted from apples by homogenization with acetone. An aliquot of the extract wa s diluted with a mixture of acetonitrile and water with subsequent re sidue determination by HPLC-MS/MS. The

method allows the detection and measurem ent of residues in or on agricultural commodities at or above the proposed tolerance level.

3. Magnitude of residues. Magnitude of residue tr ials were conducted for pyrimethanil on bulb onion as a representa tive of the bulb oni on subgroup 03-07A, on green onions as a representative for the green onion subgroup 03-07B, on grapes as a representative for the small fruit vine climbing except fuzzy kiwifruit subgroup 13-07F,on strawberries as a representativ e for the low growing berry subgroup 13-07G, and on ginseng. Trials were conducted in the various required region s across the United States in accordance with EPA guidance for cr op field trials under OPPTS 860.1500.

B. Toxicological Profile

1. Acute toxicity. Pyrimethanil is of low toxicity by the oral (toxicity category III), inhalation (toxicity categ ory III), and dermal (toxicity category III) routes. It is slightly irritating to the eyes and non-irritating to the skin in rabbit studies. Pyrimethanil

is not a dermal sensitizer. In an acute neurotoxicity study, groups of 10 rats/sex/group were dosed once by oral gavage at dose levels of 0, 30, 100, 1,000 mg of pyrimethanil/kg bodyweight. On the day of dosing, high dose animals experienced transient behavioral effects attributable to receipt of a substantial bolus dose of test substance. No histopathological le sions accompanied these transient behavioral changes. The NOAEL was 100 mg/kg due to reduced body temperature for males.

2. Genotoxicty. Pyrimethanil is not mutagenic or genotoxic in any assay in either the presence or absence of metabolic activation.

3. Reproductive and developmental toxicity. Pyrimethanil is not a developmental or reproductive toxicant.

i. Developmental—Rat . Thirty Sprague Dawley rats /group received doses of 0, 7, 85, 1,000 mg/kg/day of pyrimethanil by gavage fr om gestation days 6–15. At the highest dose tested (HDT), reduced maternal body we ight gain was observ ed during gestation days 6–15, along with a slight bu t statistically significant decrease in food consumption, hair loss, hunched posture, slight emacia tion, and slightly reduced mean fetal body weight. The maternal and developmental no ob served adverse effect level (NOAEL) was 85 mg/kg/day.

ii. Developmental —Rabbit . Groups of at least 18 time-mated New Zealand white rabbits received oral gavage doses of 0, 7, 45 or 300 mg/kg/day pyrimethanil over gestation days 7–19. At the HDT, there was a decrease in body weight gain, production of feces and food consumption. Three females were euthan ized due to severe emaciation. The HDT, 300 mg/kg/day exceeded the maternal maximu m tolerated dose (MTD). The maternal NOAEL was 45 mg/kg/day due to reduced fecal production in 1/3 of the animals. The

HDT resulted in reduced mean fetal body weight, increased in cidence of runts, delayed

skeletal ossification and inci dence of fetuses with 13 thor acic vertebrae and ribs. The developmental NOAEL was 45 mg/kg/day.

iii. Two-generation reproduction—Rat . Three groups of 30 Sprague-Dawley rats per sex received dietary exposure to pyrimethanil at levels of 0, 1.7, 20.9 or 266.7 mg/kg/day. In the parental generation at the highest dose te sted there was a statistically significant decrease in mean body weight gain in bot h sexes. Mean pup weights, observed on postnatal day (PND1) through weaning, were re duced, though were within the range of historical controls. In the F1 generation at the HDT, mean body weights and mean food consumption were reduced. Though the mean score for the combined sexes was the sameas the controls, a marginally different air-r ighting reflex at PND11 associated with reduced body weight was seen in high dose male pups. The NOAEL for maternal and developmental toxicity was 20.9 mg/kg/ day. The reproductive NOAEL was 266.7 mg/kg/ day.

4. Subchronic toxicity. i. 28–day dietary - Rat . Five Sprague-Dawley rats/sex/group received dietary exposure to pyrimethanil for 28 days at 0, 844, 1,161, 1,500, and 2,710 mg/kg/ day. All doses exceeded the maximum tolerated dose. Severe

emaciation was observed at all dose levels. Body we ight gains and food consumption

were reduced. Liver and t hyroid histopathology were obs erved, along with reduced hemoglobin, Maxium Concentration Volume (M CV), and Mean Corpuscular Hematocrit (MCH). Kidney, adrenal and liver weight s were altered. No NOAEL was achieved.

ii. 90–Day dietary—Rat . Ten Sprague- Dawley rats/sex/g roup received pyrimethanil in the diet at dose levels of 0, 5.4–6.8, 54.5–66.7, 545–667 mg/kg/ day (males and females, respectively). High dose animals had reduced body weight gain and food consumption, increased urinary protein in males, colored urine (not blood or bi lirubin) and minimal hepatocellular hypertrophy. The NOAEL in males was 54.5–66.7 (males and females, respectively) due to colore d urine and a low inciden ce of minimal centrilobular hepatocellular hypertrophy.

iii. 28–Day dietary—Mouse . Five CD- 1 mice/sex/group re ceived dietary doses of 0, 167–236, 567–667, 1,960–2,357 mg/kg/day males and females respectively, for 28 days (all the mice in one additional high dose gr oup, 30,000 ppm, died within the first week of the study). At 1,960–2,357 mg/kg/day, animals e xperienced body weight loss (females), decreased body weight gain during the first 2 weeks (males), a statistically significant decrease in cholesterol, statistically signi ficant decreases in relative liver weights (females), pigmentation of thyr oid follicles, urolithiasis, m oderate urothelial hyperplasia in urinary bladder, and slight kidney t ubular degeneration (females). The NOEL was 167–236 mg/kg/day.

iv. 90–Day dietary—Mouse . Twenty CD-1 mice/sex/group received pyrimethanil diet exposure at dose levels of 0, 12–18, 139–203, 1,864–2,545 mg/kg/day males-females for 90 days. At the high dose, animals had decreased body weight and increased food consumption, cholesterol and to tal bilirubin. High dose females had increased relative liver weights. Histopathology in the high dos e animals was found in the kidneys, liver, thyroid and urinary bladder. Hi gh dose males had slight urin ary tract tubular dilation and slight to moderate hyperplasia of bladder epithelium. Based on mild hepatic glycogen depletion, the NOAEL was 139–203 mg/kg/day (m ales and females, respectively).

v. 90–Day dietary—Dog . Four beagle dogs/sex/group received pyrimethanil by gavage for 90 days at doses of 0, 6, 80, 1,000 mg/ kg/day. The high dose was lowered to 800 mg/kg/day on day 7 due to frequent and consistent vomiting. Decreased body weight, food and water consumption were observe d. Males had a signif icant reduction in phosphate, while females experienced a slight reduction in sodium, anion gap and total protein. At 80 mg/kg/day, infrequent vomiting after dosing and decreased waterconsumption were observed. After 4 weeks of dosing at 80 mg/kg/day, males had significantly reduced phosphate. The NOAEL was 80 mg/kg/day.

vi. Subchronic Neurotoxicity – rat. Groups of 12 Sprague-Dawley rats per sex were treated for 13 weeks with pyrimethanil via the diet at 0, 4, 38.7-44.3, 391.9-429.9 mg/kg/d (males and females, respectively). There were no treatment-related findings in behavioral assessments, neuropathology or brain morphometrics. The NOAEL was 44.3 mg/kg/day in females based upon decreased body weight and food consumption in the high dose group

. There were no treatment re lated effects in males.

vii. Dermal toxicity evaluation . No dermal studies have been conducted for pyrimethanil.

vii. Pyrimethanil was evaluated for immunotoxi c potential in female rats following 28 consecutive days of treatment by dietary administration. This st udy revealed no evidence of immunotoxic potential at do se levels up to and includ ing 652 mg/kg/day, the highest

dose tested.

5. Chronic toxicity. i. Chronic toxicity—Dog. Four beagle dogs/sex/ group received pyrimethanil by gavage at levels of 0, 2, 30, or 250 mg/kg/day for 12 months. The high dose was reduced from 400 to 250 mg/kg/day on day 8 of treatment due to

excessive vomiting during the first week of treatment. At the high dose, there was a decrease in mean body weight gain and mean consumption of food and water. The NOAEL for the study was 30 mg/kg/day.

ii. Combined chronic toxicity/ oncogenicity—Rat . Seventy Sprague- Dawley rats/sex/group received pyrimethanil by diet at levels of 0, 1.3–1.8, 17–22, 221–291 mg/kg/day (males and females, respectively) for 2 years. At the HDT, body weight gain

and food consumption were decreased. Absolute liver weights were increased. Histopathology revealed centrilobular hepatocyte hypertrophy, increased incidence of eosinophilic foci (males), thyroid follicular hyperplasia, hypertrophy and colloid depletion, and the presence of a brown pigment, identified as lipofuscin in thyroid follicular cell epithelium. There was a statistically significant, dose-dependent increase in the incidence of benign thyroid follicular cell adenomas. There was no increased incidence in any malignant tumor or increase in tumor multiplicity as a result of daily dietary ingestion of pyrimethanil at any dose level. The results of special studies, discussed below, demonstrate that the benign thyroid tumors are likely a secondary result of a disruption of thyroid-pitu itary homeostasis, a well known, threshold-mediated mechanism. The NOAEL was 17 mg/kg/day (males) and 22 mg/kg/day (females).

iii. Oncogenicity —Mouse. Two oncogenicity studies were conducted us ing CD-1 mice continually exposed to pyrimethanil by admini stration in the diet. These lifetime feeding

studies demonstrated no evidence of onc ogenic potential at dos e levels up to and including 1000 mg/kg/day, th e highest dose tested.

iv. Special studies . Since rodent thyroid tumors are fairly common, and since the EPA has

established that five lines of evidence are required to prove the thyroid-pituitary disruption mode of action for rodent thyroid tumors, spec ial studies were undertaken.a)Thyroid mechanistic study (14–day). Sprague Dawley rats received 378.5 mg/ kg/day of pyrimethanil for 14 days to study the eff ects of pyrimethanil on the thyroid and liver microsomal enzymes. An increase in the levels of UDPGT and a corresponding statistically significant increase in liver we ight were observed. T hyroid hormones T4 and T3 were decreased, while TSH levels were significantly increased. All effects were shown to be reversible. b) Dietary thyroid function test using perc hlorate discharge (7– day). Sprague Dawley rats received 5 09 mg/kg/day pyrimethanil or 177 mg/kg/day propylthiouracil, or 109 mg/kg/day phenobarbit al in order to study the function of the thyroid gland. The animals fed pyrimethan il had 43% decreased body weight gain, 21% decreased food consumption and a 150% incr ease in uptake of iodi ne-125. There was no significant discharge of radioactive iodine from the t hyroid after administration of perchlorate. The required five lines of evid ence to support the thre shold mode of action for thyroid pituitary disrupti on and rat thyroid tumors are satisfied in the pyrimethanil studies. EPA’s final rule establishing a tole rance for pyrimethanil in wine stated that ‘‘The Agency’s Carcinogenicity Peer Re view Committee (CPRC) chose a non-linear approach MOE based on a NOAEL of 17 mg/kg/ day for increased incidences of thyroid tumors in rats. The MOE methodology was select ed because of thyroid tumors associated with administration of pyrimethanil in the ra t, which may be due to a disruption in the thyroid pituitary status. This chemical has been classi fied as a Group C chemical (possible human carcinogen) and a nonlinear methodology MOE was applied for the

estimation of human cancer risk. The estimat ed MOE does not exceed the Agency’s level of concern and therefore, EPA has a reasonable certainty that no harm will result from exposures to residues of pyrimethanil.”

6. Animal metabolism. When pyrimethanil was orally administered to rats, it was absorbed rapidly and eliminated within 24 hour s. The major routes of elimination were the urine (approximately 72% of the administ ered dose), and the feces (1 7-1 8% of the administered dose). The main pathways of metabolism involved oxidation to phenols in either or both aromatic rings. The minor pathway of metabolism involved oxidation of the methyl group to the corresponding alcohol.

7. Metabolite toxicology . Not applicable. The primary residue of concern in both crop and animal commodities is pyrimethanil.

8. Endocrine disruption . Chronic, life span, and multi-generational bioassays in

mammals and acute and subchronic studies on aquatic organisms and wildlife did not

reveal endocrine effects.

C. Aggregate Exposure

1. Dietary exposure

. For dietary analysis, an acute reference dose (aRfD) of 0.45 mg/kg/day was derived for females 13 - 50 from an NOAEL of 45 mg/kg/day in the rabbit developmental study, based on an increas ed incidence of fetuses with 13 thoracic vertebrae and ribs, and an uncertainty fact or of 100. For the gene ral population including infants and children, the acute reference dos e is 1 mg/kg/day fr om on an NOAEL of 100 mg/kg/day in the acute rat neurotoxicity study, based on transient behavioral effects, and an uncertainty factor of 100. A chronic re ference dose (cRfD) of 0.17 mg/kg/day for allpopulations was derived from the chronic toxici ty study in the rat, based on decreased body weight gain and food consumption, increa sed liver weights and histopathological changes, and an uncertainty factor of 100. EPA has evaluated the pot ential for increased susceptibility of infants and children from exposure to pyrimethanil and has determined there was no quantitative or qualitative evidence of increased susceptibility following prenatal exposure (in rats and rabbits), or postnatal exposure (in rats). There were no effects on fertility or reproduc tion in the two-generation re production study in rats. The special FQPA SF has been reduced to 1X based on toxicological considerations, the nature of the assumptions used in the dietary exposure risk assessments, th e completeness of the residue chemistry and environmental fate databases, and the lack of the potential for residential exposures. Acute and chronic Population Adjusted Doses (aPAD and cPAD) are, therefore, the same as the reference doses for the populati ons and subpopulations of interest.

i. Food. Dietary exposure to pyrimethanil wa s estimated from potential residues on food using CARES Version 3.0 software fo r dietary analyses. The acute Tier One assessments used 100% crop treated and toleranc e level residue values . The chronic Tier 2 assessment is based on tolerances, averag e residue values for key crops and percent crop treated values for key crops from th e 2004 EPA assessment. All registered uses, pending uses on caneberry and bushberry s ubgroups, and new proposed uses on ginseng and the bulb onion, green onion, small fruit vine climbing except fuzzy kiwifruit, and low growing berry subgroups were included in the assessment. Acute exposure utilizes

16.3% of the aPAD for Females 13-49 and 10.3% and 31.5% of the aPAD for the US Population and Children 1-2 respectively. Ch ronic exposure utili zes 1.0% for the US Population and 4.7% for Children 1-2, the most highly exposed subpopulation. These are conservative estimates and actual exposur es are likely to be much less.

ii. Drinking Water. EPA drinking water values (2004) were used in the

assessment. EDWCs were calculated for use on strawberries (the scenario resulting in the highest drinking water exposure), and incl uded pyrimethanil and its major metabolite (2-amino-4,6-dimethylpyrimidine). The su rface water estimated drinking water concentrations (EDWCs) were determined using PRZM/EXAMS (Pesticide Root Zone Model/Exposure Analysis Modeling System). Ground water EDWCs, calculated using SCI-GROW (Screening Concentration in Gr ound Water), model were lower than the surface water EDWCs. For surface water, the maximum estimated peak acute

concentration of the combined residues is 37.8 μ g/L. The maximum estimated annual mean non-cancer chronic exposure concentration for the combined residues (adjusted for regional percent cr opped area) is 5.1 μ g/L. These estimates are well below the Drinking Water Levels of Comparison (DWLOC) for all subpopulations. The aDWLOC is 22608,

31413 and 6851 μ g/L for Females 13-49, the US Population and Children 1-2 ( the most highly exposed subpopulation ), respectively. The cDWLOC is 5899 and 1624 μ g/L for the US Population and Children 1-2 ( the most highly exposed subpopulation ), respectively.These conservative estimates indicate there is no concern for dietary exposures from potential residues of pyrimetha nil in food and drinking water.

2. Non-dietary exposure . Pyrimethanil is not register ed for use on any sites that would result in residential exposure. Therefore, the aggregate risk is the sum of the risk

from food and water.

D. Cumulative Effects

Section 408(b)(2)(D)(v) re quires that, when considering whether to establish, modify, or revoke a tolerance, the Agency consider “available information” concerning the cumulative effects of a part icular pesticide’s residues and “other substances that have a common mechanism of toxicity.” EPA ha s not made a common mechanism of toxicity finding as to pyrimethanil and any other subs tances and pyrimethanil does not appear to produce a toxic metabolite pr oduced by other substances.

E. Safety Determination

1. U.S. population. Risk assessments for pyrimethanil are based on a complete and reliable toxicity data package and highly conservative assumptions. Chronic dietary (food) exposure will utilize 1% of the cP AD for the US Population. The chronic EDWC

is more than 1000 fold lower than the cDWLOC. EPA generally has no concern for exposures below 100% of the cPAD because th e cPAD represents the level at or below which daily aggregate exposure over a lifetim e will not pose appreciable risk to human health. Acute dietary (food) exposure for females 13-49, representing the most sensitive subpopulation of the overall U.S. adult popula tion, utilizes only 10.3% of the aPAD using highly conservative assumptions and the aEDW C is more than 500 fold lower than the aDWLOC. Therefore, there is a reasonable ce rtainty that no harm will occur to the US Population from aggregate exposure (food, dri nking water and non-dietar y) to residues of pyrimethanil.

2. Infants and children . EPA has determined that the toxicology database for pyrimethanil regarding potentia l pre- and post-natal effects in children is complete and does not indicate any particular developmen tal or reproductive concerns. The special FQPA SF has been reduced to 1X. Using the conservative assumpti ons described in the exposure section above, chronic dietary expos ure to residues of pyrimethanil in food for Children 1-2 (the most highly exposed sub gr oup) is less than 5% of the cPAD. The

chronic EDWC is more than 300 fold lowe r than the cDWLOC. Acute dietary exposure to residues of pyrimethanil in food for Childre n 1-2 (the most highl y exposed sub group)

is 31.5% of the aPAD. The chronic EDWC is more than 180 fold lower than the

cDWLOC. There are no non-dietar y concerns for infants and ch ildren. Therefor e, there is a reasonable certainty that no harm will occur to infants and children from aggregate exposure to residues of pyrimethanil.

F. International Tolerances

Codex MRLs have been established for pyrimethanil on bulb onions at 0.2 ppm.Codex MRLs have not been established fo r pyrimethanil on ginseng and the bulb onion, green onion, small fruit vine climbing excep t fuzzy kiwifruit, and low growing berry subgroups. Codex MRLs are esta blished on grapes at 4.0 ppm and strawberries at 3.0 ppm. In addition, MRLs have been establishe d for onions and strawberries in the EU at 0.1 ppm and 5.0 ppm, respectively.