Page 1 of 84 OFFICE OF PREVENTION, PESTICIDES AND TOXIC SUBSTANCES May 11, 2006 MEMORANDUM SUBJECT: Dicloran: Revised HED Chapter of the Reregistration Eligibility Decision Document ( RED). PC Code: 031301, Case #: 0113, DP Barcode: D294460.

Regulatory Action: Reregistration Risk Assessment, Phase 3  HED Response to Public Comments Revised Risk Assessment Type: Single Chemical Aggregate FROM: Toiya Goodlow, Risk Assessor Byong Han Chin, Ph. D., Toxicologist Christine L. Olinger, Chemist Matthew G. Lloyd, M. S., Industrial Hygienist Reregistration Branch 1 Health Effects Division ( 7509P)

THROUGH: Michael S. Metzger, Branch Chief Whang Phang, Ph. D., Branch Senior Scientist Reregistration Branch 1 Health Effects Division ( 7509P)

TO: James Parker, Chemical Review Manager Special Review and Reregistration Division ( 7508P)

This document is a revision of the Human Health Risk Assessment for the Dicloran Reregistration Eligibility Decision Document ( RED) dated February 28, 2006 ( T. Goodlow). The HED chapter includes the Toxicology and Hazard Assessment from Byong Han ( Paul) Chin, Reregistration Branch I, Residue Chemistry Assessments and Dietary Exposure Analysis from Christine Olinger, Reregistration Branch 1, and the Occupational and Residential Exposure Assessments from Matthew Lloyd, Reregistration Branch 1. Information was also drawn from the Environmental Fate and UNITED STATES ENVIRONMENTAL PROTECTION AGENCY WASHINGTON, D. C. 20460 2 of 84 Effects Division ( EFED) Revised Tier 1 Drinking Water Assessment from Cheryl Sutton and the Review of Dicloran Incident Reports from Jerry Blondell, HED, Chemistry and Exposure Branch.

This risk assessment was revised in response to public comments. The corrections were reviewed by RRB1/ HED and revised to comply with Agency policies. See DP Barcode: D325652, dated February 28, 2006 for the complete HED Response to Public Comments. 3 of 84 Table of Contents 1.0 Executive Summary ...................................................................................................... 6 2.0 Ingredient Profile ........................................................................................................ 10 2.1 Summary of Registered/ Proposed Uses.............................................................. 10 2.2 Structure and Nomenclature............................................................................... 11 2.3 Physical and Chemical Properties ...................................................................... 14 3.0 Metabolism Assessment .............................................................................................. 15 3.1 Rat Metabolism ................................................................................................. 15 3.2 Nature of the Residue in Foods .......................................................................... 15 3.2.1. Description of Primary Crop Metabolism............................................... 15 3.2.2 Description of Livestock Metabolism..................................................... 16 3.2.3 Description of Rotational Crop Metabolism, including identification of major metabolites and specific routes of biotransformation................................ 16 3.3 Environmental Degradation ............................................................................... 18 3.4 Toxicity Profile of Major Metabolites and Degradates ...................................... 18 3.5 Summary of Residues for Tolerance Expression and Risk Assessment............... 19 3.5.1 Tabular Summary................................................................................... 19 3.5.2 Rationale for Inclusion of Metabolites and Degradates ........................... 19 4.0 Hazard Characterization/ Assessment ............................................................................. 20 4.1 Hazard Characterization..................................................................................... 20 4.1.1 Database Summary                     ... 20 <IP_ADDRESS>. Studies Available and Considered            .20 <IP_ADDRESS>. Mode of action, metabolism, toxicokinetic data      . 20 <IP_ADDRESS>. Sufficiency of studies/ data             ...  20 4.1.2. Toxicological Effects                    .... 20 4.1.3. Dose response                       ... 21 4.2 FQPA Hazard Considerations ............................................................................ 27 4.2.1 Adequacy of the Toxicity Data Base....................................................... 27 4.2.2 Evidence of Neurotoxicity...................................................................... 27 4.2.3 Developmental Toxicity Studies............................................................. 27 4.2.4 Reproductive Toxicity Study.................................................................. 29 4.2.5 Additional Information from Literature Sources ..................................... 31 4.2.6 Pre and/ or Postnatal Toxicity ................................................................... 31 <IP_ADDRESS> Determination of Susceptibility................................................... 31 <IP_ADDRESS> Degree of Concern Analysis and Residual Uncertainties for Pre and/ or Post natal Susceptibility .............................................................. 31 4.3 Recommendation for a Developmental Neurotoxicity Study .............................. 31 4 of 84 4.3.1 Evidence that supports requiring a Developmental Neurotoxicity study                      ...       . 31 4.3.2 Evidence that supports not requiring for a Developmental Neurotoxicity study  ................................................................................................. 32 4.4 Hazard Identification and Toxicity Endpoint Selection....................................... 32 4.4.1 Acute Reference Dose ( aRfD)  Females age 13 49................................. 32 4.4.2 Acute Reference Dose ( aRfD)  General Population ............................... 34 4.4.3 Chronic Reference Dose ( cRfD) ............................................................. 34 4.4.4 Incidental Oral Exposure ( Short and Intermediate Term) ........................ 37 4.4.5 Dermal Absorption................................................................................. 39 4.4.6 Dermal Exposure ( Short, Intermediate and Long Term).......................... 39 4.4.7 Inhalation Exposure ( Short, Intermediate and Long Term) ..................... 41 4.4.8 Margins of Exposure .............................................................................. 41 4.4.9 Recommendation for Aggregate Exposure Risk Assessments................. 42 4.4.10 Classification of Carcinogenic Potential ................................................. 42 <IP_ADDRESS> Carcinogenicity Study in Rats               42 <IP_ADDRESS> Carcinogenicity Study in Mice             ... 44 4.4.11 Mutagenicity                         . 45 4.5 Special FQPA Safety Factor                      50 4.6 Endocrine disruption.......................................................................................... 50 5.0 Public Health Data ...................................................................................................... 51 5.1 Incident Reports................................................................................................. 51 6.0 Exposure Characterization/ Assessment ..................................................................... 51 6.1 Dietary Exposure/ Risk Pathway......................................................................... 51 6.1.1 Residue Profile....................................................................................... 51 6.1.2 Acute and Chronic Dietary Exposure and Risk ....................................... 55 6.2 Water Exposure/ Risk Pathway........................................................................... 57 6.3 Residential ( Non Occupational) Exposure/ Risk Pathway ................................... 58 7.0 Aggregate Risk Assessments and Risk Characterization........................................... 58 7.1 Acute Aggregate Risk ........................................................................................ 59 7.2 Short Term Aggregate Risk ............................................................................... 59 7.3 Intermediate Term Aggregate Risk .................................................................... 59 7.4 Long Term Aggregate Risk ............................................................................... 59 7.5 Cancer Risk ....................................................................................................... 60 8.0 Cumulative Risk Characterization/ Assessment ......................................................... 61 9.0 Occupational Exposure/ Risk Pathway ....................................................................... 62 9.1 Short/ Intermediate/ Long Term Handler Risk ..................................................... 62 9.2 Short/ Intermediate/ Long Term Postapplication Risk.......................................... 67 10.0 Data Needs and Label Requirements ......................................................................... 72 5 of 84 10.1 Toxicology ........................................................................................................ 72 10.2 Residue Chemistry............................................................................................. 72 10.3 Occupational and Residential Exposure ............................................................. 74 References: .............................................................................................................................. 75 Appendices .............................................................................................................................. 76 1.0 TOLERANCE REASSESSMENT RECOMMENDATIONS............................. 76 2.0 TOXICOLOGY DATA REQUIREMENTS....................................................... 79 3.0 NON CRITICAL TOXICOLOGY STUDIES.................................................... 81 6 of 84 Executive Summary This risk assessment was performed to support the reregistration eligibility decision for dicloran ( 2,6 dichloro 4 nitroaniline). Dicloran, also referred to as DCNA, is a fungicide used control pathogenic species such as Botrytis, Monilinia, Rhizopus, Sclerotinia, and Sclerotium. DCNA is registered for agriculture and horticulture uses. Its registered formulations include dusts ( D), wettable powders ( WP), and flowable concentrates ( FIC). These can be applied using aerial, airblast, groundboom, chemigation, and hand application methods such as handwands and backpack sprayers.

The submitted toxicology studies provide adequate information to determine whether dicloran poses a human health hazard. The Agency is confident that the risk estimates presented in this document represent conservative approximations of human health risks associated with the use of DCNA.

The available toxicity data indicate the acute oral, dermal, and primary eye and dermal irritation toxicity of dicloran to be in toxicity categories III and IV. DCNA has been shown to be a potential skin sensitizer.

Both subchronic and chronic toxicity studies in rats shows that dicloran causes reduced body weight, reduced body weight gain, increased liver weights, and histopathologic lesions in the brain and spinal cord of both sexes, optic nerve in females and Leydig cell hyperplasia in the testes in males. The developmental toxicity study in rats showed increased incidences of supernumerary rudimentary ribs and also decreased fetal weights in the presence of maternal toxicity. The data from the developmental toxicity studies in rats and of the 2 generation reproduction study indicated no increase in susceptibility of fetuses and pups to the in utero and/ or postnatal exposure to DCNA.

There are no neurotoxicity studies available. However, neuropathology ( vacuolar alterations of the brain and spinal cord) was seen at doses of 25 mg/ kg or greater in the chronic rat and dog studies. The available data did not demonstrate neurotoxicity with subchronic studies in rats, dogs, and mice. It should be noted that the chronic reference dose was established at 0.0025 mg/ kg/ day.

The mouse carcinogenicity study showed no treatment related increase in tumor incidence. The carcinogenicity study in rats found an increase in Leydig cell tumor and a marginal increase in endometrial adenocarcinoma at high dose groups. The committee members of CARC evaluated the carcinogenicity studies in rats and mice and related toxicity data on dicloran and classified this chemical as having " Suggestive Evidence of Carcinogenic Potential." The CARC recommended no quantification of cancer risk.

HED has selected acute and chronic reference doses ( RfD) for the dietary risk assessment, and calculated the Population Adjusted Dose ( PAD), which is the RfD divided by the FQPA safety factor 7 of 84 ( SF). Based on the hazard data, HED recommends the special FQPA SF equal10X due to data gaps present within the toxicity database. The developmental rat study, the one year dog study, and the 90 day oral toxicity study in dogs were the primary studies used for selecting toxicity endpoints for risk assessment. The developmental rat study was selected for acute dietary ( females 13 49 years of age) exposure scenario. The reference dose for acute effects is equal to 0.5 mg/ kg/ day, and the PAD is equal to 0.05 mg/ kg/ day. Acute dietary endpoint for the general population, including infants and children, was not selected for this population group because there were no appropriate effects observed that are attributable to a single exposure ( dose). The one year dog study was chosen for the chronic RfD. The reference dose for chronic effects ( general population) is equal to 0.025 mg/ kg/ day, and the PAD is equal to 0.0025 mg/ kg/ day. The 21 day dermal toxicity study in rabbits was selected for the short and intermediate term dermal exposure scenarios. The 90 day oral toxicity study in dogs was selected for both the short and intermediate term inhalation and incidental oral exposure scenarios. The chronic RfD was also used for the long term dermal and inhalation exposure assessments.

Dicloran is currently registered for preharvest and postharvest uses on various raw agricultural commodities under 40 CFR § 180.200 for residues of dicloran per se. Preharvest uses include apricots, beans ( snap), celery, cherries ( sweet), cucumbers, endive ( escarole), fennel, garlic, grapes, lettuce ( head and leaf), nectarines, onions, peaches, plums ( fresh prunes), potatoes, rhubarb, shallots, and tomatoes; postharvest uses are on carrots and sweet potatoes. A petition, PP# 7F04879, is pending for the establishment of permanent tolerances resulting from proposed uses on peanuts ( preharvest), carrots ( preharvest), and tomatoes ( postharvest). There are also pending pre harvest uses on fennel, shallot, and the leafy greens subgroup ( Subgroup 4a).

The HED Metabolism Assessment Review Committee ( MARC) has determined the residues of concern for both risk assessment and tolerance purposes ( D274726, 5/ 8/ 01, T. Bloem). The current tolerance expression is in harmony with the MARC's determination of the residues of concern for tolerance purposes. It is also compatible with the Codex definition of residues for dicloran. No tolerances have been established for livestock commodities.

Acute and chronic dietary exposure assessments for food only were performed using DEEM FCID   . No acute endpoint was identified for the general population; therefore, females ages 13 49 were the only population subgroup included in the acute dietary assessment. Refined assessments were required for both acute and chronic exposure for all populations exceeded the level of concern assuming 100% crop treated and tolerance values. For the refined assessments, USDA Pesticide Data Program ( PDP) monitoring data were used for all commodities, except rhubarb, assuming nondetectable residues were at the limit of detection. No adjustments for percent crop treated were made. Using this refinement, the exposures for food only was 9.9% of the acute Population Adjusted Dose ( aPAD) for females 13 39. The most highly exposed subgroup for the chronic exposure was children 1 2 years old, with exposures utilizing 13% of the chronic Population Adjusted Dose ( cPAD).

EFED provided acute and chronic surface water exposure scenarios and one ground water concentration estimate for DCNA using two EFED Tier 1 screening level models: FIRST, Version 1.0 and SCI GROW, Version 2.3. Surface water ( acute and chronic) and groundwater estimated drinking water concentrations ( EDWC's) are based on DCNA use on apricots at 4.0 lb 8 of 84 a. i./ A/ application applied in a single application. All EDWC's were incorporated into the dicloran aggregate assessment.

There are no residential uses for DCNA. Therefore, residential exposures are not expected and associated risks were not calculated.

Since there are no residential uses, the aggregate exposure assessment for dicloran considered exposures from food and drinking water only. Refined acute and chronic dietary exposure assessments for food and water were performed using DEEM FCID   . The assessments incorporated PDP monitoring data for all commodities except rhubarb, assuming non detectable residues were at the limit of detection. No adjustments for percent crop treated were made. Analyses were conducted including food exposures and either EDWCs from modeled values for surface water sources or groundwater sources as the drinking water source. At the 99.9th percentile of exposure, the estimated food and water exposure for females 13 49 years old utilized 10% and 52% of the aPAD for ground water and surface water sources, respectively. The most highly exposed subgroup was children 1 2 years old for the chronic assessment, with exposures utilizing 14% and 15% of the cPAD ground water and surface water sources, respectively.

Risk calculations have been completed for short/ intermediate term exposures for all occupational scenarios. Long term risks are not expected and associated risks were not calculated.

Current dicloran labels typically require that coveralls, waterproof gloves and shoes plus socks be used for agricultural handler for both the wettable powder and flowable labels. Non agricultural applicators and other handlers are required by the wettable powder label to wear long sleeved shirt, long pants, and shoes plus socks. In addition, applicators and other handlers are required by the liquid flowable label to wear waterproof gloves. Most labels do not require respiratory protection. For the loader scenarios involving dust, the majority of aerial application exposures are of concern for both the dermal and inhalation route. For the loader scenarios involving ground application of dust, all scenarios are of concern at baseline and require some PPE to achieve MOEs of 100 or greater. For all of the mixer loader scenarios involving wettable powder formulations, the handler risks with required PPE are of concern and in some cases double layer dermal PPE are required to be achieve acceptable MOEs. This includes all aerial, chemigation, and airblast wettable powder scenarios. Groundboom wettable powder application scenarios are of concern at baseline and typically achieve acceptable MOEs with single layer PPE.

The short and intermediate term inhalation risks for mixing and loading dust formulations are of concern at baseline up through the use of a PF10 respirator for aerial application. Engineering controls are not applicable for this scenario because surrogate data for mixing and loading wettable powder is being used for the unit exposures. The short and intermediate term inhalation risks for mixing and loading wettable powders are of concern at baseline and require PF5 respirator to achieve MOEs of 100 or greater.

The risks for mixing and loading flowable formulations are acceptable at baseline and do not require mitigation. The risks of mixing/ loading/ applying flowables with handheld equipment ( e. g. low pressure handwand) are not of concern at baseline for neither the dermal or inhalation exposure route. 9 of 84 Current label requirements specify 12 hour Restricted Entry Intervals ( REIs) while Pre Harvest Intervals ( PHIs) range from one day for cherries to 14 days for a number of crops including head lettuce and onions. Postapplication risk calculations based on the current label maximum rates for workers entering treated fields or greenhouses indicated that dicloran risks are of concern at the current REI for a number of crop groups. The time for the MOEs to achieve acceptable levels varies considerably, ranging from 13 days for snap beans to 55 days for grapes for short/ intermediate term MOEs. Postapplication risk calculations for those scenarios that exceeded HED's level of concern on day 0 were conducted using average application rate data provided by the Special Review and Reregistration Division ( SRRD). Postapplication risks at the lower application rates for evergreen fruit trees, onions, garlic and shallots are no longer of concern, however postapplication risks continue to be of concern for a number of the crop groups.

In conclusion, DCNA showed both low acute toxicity ( toxicity categories III and IV) and low dietary risks. Cancer risk quantification was not recommended by the CARC. There are no residential uses for dicloran. However, occupational handler data shows that many of the scenarios that involve the mixing/ loading of wettable powder formulations and loader scenarios involving dust have risks of concern and require some PPE to achieve Agency risk targets. In most of the scenarios, the MOEs for dicloran do not exceed 100 at the REI; and are therefore of concern to HED.

Data gaps include:

Toxicology Guideline 870.6300 Developmental Neurotoxicity Study  rats Guideline 870.3465 Inhalation Toxicity Study, 28 day rats Residue Chemistry Guideline 860.1200 Directions for Use Guideline 860.1300 Nature of the Residue, livestock Storage stability data is required for the livestock metabolism studies. Guideline 860.1340 Residue Analytical Methods Guideline 860.1380 Storage Stability Data, plant Guideline 860.1480 Meat/ Milk/ Poultry/ Eggs ( Ruminant feeding study) Guideline 860.1500 Crop Field Trials Guideline 860.1520 Processed Food/ Feed Guideline 860.1900 Field Accumulation in Rotational Crops Occupational and Residential Exposure The Agency is requesting process descriptions and specific application rates for each data gap listed below.

° The risks of dipping sweet potato seed pieces were not assessed because dipping is no 10 of 84 longer used. According to sweet potato researchers at the Sweet Potato Research Station ( LSU), sweet potato seed pieces are treated in the plant bed using a sprayer.

° The risks of postharvest dip treatment of sweet potatoes were not assessed due to a lack of exposure data. This treatment is accomplished by using automated equipment; however, exposures can be controlled with the use of gloves.

° There are no data available to evaluate the mix/ load/ apply scenarios for backpack sprayer application of wettable powders and flowables. The PHED data for both high and low pressure handwand application of liquids ( mix/ load/ apply and apply only) is also of low quality. These data gaps make it difficult to accurately assess the risks of the handwand method of application, which is commonly used in horticulture.

° The risk of loading the dust formulation was assessed with surrogate unit exposure values form mixing and loading wettable powders.

° The risk of applying dusts was not assessed due to lack of exposure data and remains as a data gap.

° The risk for mixing/ loading/ applying dust with handheld power duster.

° Flagger exposure to aerial application of dust.

2.0 Ingredient Profile Dicloran ( 2,6 dichloro 4 nitroaniline) is a fungicide used control pathogenic species such as Botrytis, Monilinia, Rhizopus, Sclerotinia, and Sclerotium. DCNA is registered for agriculture and horticulture uses. The application rates in agriculture range from 0.0172   122 lb ai/ acre, with the allowable number of applications ranging from four times per season to once a week for the majority of product labels. The application rates in horticulture are 1 lb ai/ acre for most ornamentals with allowable applications up to once weekly with no annual limit. Current label requirements specify 12 hour REIs while preharvest intervals range from 1 14 days. DCNA registered formulations include dusts ( D), wettable powders ( WP), and flowable concentrates ( FIC). The percentage of dicloran used in each formulation type ranges from 4 75% active ingredient per pound formulated. The application methods for DCNA include aerial, airblast, groundboom, chemigation, and hand application methods such as handwands and backpack sprayers.

2.1 Summary of Registered/ Proposed Uses Table 2.1 provides a summary of registered uses for DCNA.

Table 2.1 Active Dicloran End Use Products Registered to Gowan Company, Wilbur Ellis Company, and Britz Fertilizers, Inc. 1 EPA Reg. No. Formulation Product Name 11 of 84 Table 2.1 Active Dicloran End Use Products Registered to Gowan Company, Wilbur Ellis Company, and Britz Fertilizers, Inc. 1 EPA Reg. No. Formulation Product Name Gowan Company 10163 187 8% D Botran 8% Dust 10163 188 6% D Botran 6% Dust 10163 189 75% WP Botran 75 W Fungicide 10163 190 12% D Botran 12% Dust Fungicide 10163 191 15% D Botran 15% Dust Fungicide 10163 192 10% D Botran 10% Dust 10163 193 4% D Botran 4% Dust Fungicide 10163 207 75% WP Botran 75WSB Fungicide 10163 221 4 lb/ gal FlC Botran Flowable Fungicide 10163 226 3 5 lb/ gal FlC Botran 5F Fungicide Wilbur Ellis Company 2935 529 6% D Botran 6% Dust Britz Fertilizers, Inc.

10951 13 6% D Britz Botran 6% Dust 10951 14 6% D Britz Botran Sulfur 6 25 Dust 1 Four additional SLNs ( CA950011, MT940003, OR940017, and WA940017) were listed in the OPPIN Product Listing as registered products, however, the study reviewer could not ascertain the parent registration and if the SLN products contained food or nonfood uses. 2 Includes SLNs CA930023, CA940007, ID940006, OR990056, and WA940009; SLNs were listed in the BEAD Table and the OPPIN Product Listing. 3 Includes SLNs ID970002, OR990055, and WA960037; SLNs were listed in the BEAD Table and the OPPIN Product Listing.

2.2 Structure and Nomenclature Tables 2.2a and 2.2b provide structures and nomenclature for dicloran and its metabolites.

Table 2.2a Dicloran ( DCNA) Nomenclature Chemical structure NH2 Cl Cl NO2 Common name Dicloran; DCNA 12 of 84 Table 2.2a Dicloran ( DCNA) Nomenclature Molecular Formula C6H4Cl2 N2O2 Molecular Weight 207.0 IUPAC name 2,6 dichloro 4 nitroaniline CAS name 2,6 dichloro 4 nitrobenzenamine CAS # 99 30 9 Table 2.2a DCNA Metabolite Nomenclature Chemical Name Chemical Structure Identified in the Following DCAP 4 amino 2,6 dichlorophenol OH Cl Cl NH2 Rotational crops, livestock commodities DCPD 4 amino 2,6 dichloroaniline NH2 Cl Cl NH2 Rotational crops 3,5 DCHA 3,5 dichhloro 4 hydroxyacetanilide OH Cl Cl NH C CH 3 O Rotational crops DCAA 4 amino 3,5 dichloroacetanilide NH2 Cl Cl NH C CH3 O Rotational crops, livestock commodities 13 of 84 DCHA 2,6 dichloro 4 hydroxyaniline NH2 Cl Cl OH Primary crops, rotational crops, livestock commodities DCNP 2,6 dichloro 4 nitrophenol OH Cl Cl NO2 Rotational crops, livestock commodities 2,6 DCP 2,6 dichlorophenol OH Cl Cl Rotational crops 2,6 DCA 2,6 dichloroaniline NH2 Cl Cl Rotational crops Component of Unknown 1 Molecular weight = 182 NH2 OH HO NHCOCH3 Potatoes, rotational crops Component of Unknown 1 Molecular weight = 218 NH2 SCH3 Cl NO2 Potatoes, rotational crops 14 of 84 Component of Unknown 1 Molecular weight = 222 NH2 ONa Cl NHCOCH3 Potatoes, rotational crops Component of Unknown 1 Molecular weight = 288 NH2 SCH2CH2 Cl NHCOCH3 COOH Potatoes, rotational crops Component of Unknown 1 Molecular weight = 346 OH SCH2CH Cl NHCOCH3 COOH NHCOCH3 Potatoes, rotational crops Component of Unknown 1 Molecular weight = 360 NH2 SCH2CH Cl NHCOCH3 CNHCH2COH NH2 O O Potatoes, rotational crops Component of Unknown 1 Molecular weight = 575 OH SCH2CHCOOH HCCH2S NHCOCH3 NH2 HOOCCHCH2CH2OCHN HOOCCH2NHOC H2N Potatoes, rotational crops 2.3 Physical and Chemical Properties Technical dicloran is a yellow powder with a melting point range of 193.3 194.8 ° C. DCNA is practically insoluble in water and other compounds with a water solubility of 6 x 10 3 g/ L at 20 ° C. It has a vapor pressure of 2.61 x 10 4 Pa at 25 ° C. Dicloran is a member of the substituted aromatics group of fungicides. Additional physicochemical properties can be found in Table 2.3. 15 of 84 Table 2.3 Physicochemical Properties of Dicloran ( DCNA)

Parameter Value Reference Melting point 193.3 194.8 ° C RD D223330, 5/ 22/ 96, S. Mathur PH 6.16 ( ± 0.03) at 24.7 ° C RD D223330, 5/ 22/ 96, S. Mathur Density, bulk density, or specific gravity 0.277 ( ± 0.002) g/ mL ( bulk density) RD D223330, 5/ 22/ 96, S. Mathur Water solubility Practically insoluble; 6 x 10 3 g/ L at 20 ° C DEB # 5866, 1/ 23/ 90, M. Nelson Solvent solubility At 20 EC: ethanol 0.2% chloroform 1.2% ethyl acetate 1.9% ethanol, 2 ethoxy 2.8% 2 butanone 3.3% acetone 4.3% dioxane 4.0% Product Chemistry Chapter of the Reregistration Standard, 8/ 15/ 83 Vapor pressure 2.61 x 10 4 Pa at 25 ° C DEB # 5866, 1/ 23/ 90, M. Nelson Dissociation constant, pKa Not applicable due to low water solubility Octanol/ water partition coefficient 572 at 25 ° C DEB # 5866, 1/ 23/ 90, M. Nelson UV/ visible absorption spectrum Not available 3.0 Metabolism Assessment 3.1 Rat Metabolism Oral metabolism studies in rats showed that dicloran is rapidly absorbed and metabolized in rats. Approximately 96% of the administered dose was excreted in 24 hours. The urine was the major route of excretion ( 86.3% of the administered dose), and smaller amounts in feces ( 8.7% of the administered dose). Dicloran does not appear to accumulate in tissues. The major urine metabolites were DCHA sulfate, and DCHA glucuronide, which accounted for 45.5% to 79% of the total dose. Other metabolites detected were DCHA ( 3.3 to 22.8%), DCAP ( 0.3% to 8.5%), and DCNAP (< 0.1% to 1.0%). A small amount of dicloran was detected in feces. The metabolites DCHA and DCAP were detected in plant and livestock metabolism studies.

3.2 Nature of the Residue in Foods 3.2.1. Description of Primary Crop Metabolism The nature of the residue in plants is adequately understood based on acceptable metabolism studies with dicloran on peaches, potatoes, and lettuce. The salient features of these plant metabolism studies were presented to the HED Metabolism Assessment Review Committee ( MARC) on May 8, 2001. The MARC concluded that only the parent compound should be included in the tolerance expression for primary crops. The Committee also recommended that one major metabolite, 2,6 dichloro 4 16 of 84 hydroxyaniline ( DCHA), should be included in the risk assessments for all presently registered crops ( excluding potato). The residues of concern in potatoes, for the purpose of risk assessment, are dicloran, DCHA, and a group of metabolites designated as Unknown 1, which comprised approximately half of the residues characterized in the potato study. The registrant tentatively concluded that Unknown 1 was most likely composed of glutathione conjugated dicloran metabolites that had been deaminated, dechlorinated, and/ or hydroxylated, and/ or in which the nitro group had been reduced and acetylated.

3.2.2 Description of Livestock Metabolism The nature of the residue in livestock is adequately understood provided the petitioner could provide supporting storage stability data to validate the integrity of samples from the goat and hen metabolism studies submitted in conjunction with PP# 7F04879. The salient features of these livestock metabolism studies were presented to the HED MARC on May 8, 2001. The MARC concluded that the terminal residues of concern ( or residues that need to be included in the tolerance expression for livestock commodities) will include dicloran and 4 amino 2,6 dichlorophenol ( DCAP). DCAP is included since dicloran was not identified in the liver and kidneys of ruminants. For risk assessment purposes, the HED MARC determined that the residues of concern in livestock commodities are dicloran, DCAA, DCHA, DCAP, DCNP, and the A 1 metabolite, which was detected in milk and ruminant liver and kidney. Based on NMR and LC/ MS analyses, the petitioner proposed that A 1 was partially comprised of 2,6 dichloro 3 glutathione 4 nitroaniline and 4 amino 3 chloro 5 glutathioneacetanilide. Residues of A 1 in milk will be estimated based on the ratio of A 1 to dicloran in the metabolism study ( 1.6x). Residues of A 1 in ruminant liver and ruminant kidney will be estimated based on the ratio of A 1 to DCAP in the metabolism study ( liver  5.1x; kidney  104x). Because the MARC concluded that the metabolic pathways of dicloran in livestock and rats are likely to be qualitatively similar, a swine metabolism study need not be conducted.

3.2.3 Description of Rotational Crop Metabolism, including identification of major metabolites and specific routes of biotransformation Field and confined accumulation rotational crop studies ( D270711, 5/ 22/ 01, T. Bloem and D246807, 3/ 1/ 05, C. Olinger) were submitted for dicloran. The limited field rotational crops study only included analysis for the parent compound and did not include the aniline containing metabolites. The study was conducted at 0.9x the maximum single application rate. Current product labels do not specify a maximum number of applications per season, so these residues could underestimate the actual residues in rotational crops. For these reasons, additional limited field rotational crop studies are required at the maximum seasonal application rate and analyzing for the total dichloroanilinecontaining residues.

For the confined study, uniformly ring labeled [ 14C] dicloran was mixed with nonlabeled dicloran and dissolved in a combination of water, acetonitrile, and methanol to produce a test substance. The prepared test substance was applied as a broadcast spray ( without any further incorporation) to the soil surface of sandy loam soil. Application of the test substance was made using a plastic manual trigger sprayer at a field equivalent rate of 13.2 lb ai/ A ( 3.3x the maximum single application rate). Lettuce, turnips, and wheat were planted 30, 120, and 365 days after treatment ( DAT). All samples 17 of 84 were harvested at maturity with the exception of the wheat crop. Approximately one half of the wheat was sampled at the immature stage to yield forage samples. Samples were analyzed using HPLC and TLC. No further residue characterization and identification are required from the confined rotational crop study. See Table 3.2.3 for the results of this study.

The MARC concluded that dicloran per se is the residue of concern in/ on rotational crops for tolerance expression. For risk assessment, the residues of concern are dicloran and the dichloroaniline containing metabolites, which are DCHA, DCAA, 3,5 DCHA, DCPD, DCAP, DCNP, 2,6 DCP, 2,6 DCA, Unknown 1.

Table 3.2.3 Major Residues Found in Confined Rotational Crop Study Analyte Plantback Interval ( days) Commodities % TRR Found 30 Lettuce, Turnip Foliage, Turnip Root, Wheat Forage, Wheat Straw 12 76 Dicloran 120 Lettuce, Turnip Foliage, Turnip Root, Wheat Forage 16 23 DCAP 2 120 Wheat Forage 11 DCPD 2 120 Wheat Forage 11 30 Lettuce, Turnip Foliage, Wheat Forage, Wheat Grain 21 29 Unknown 1 3 120 Turnip Root, Wheat Forage, Wheat Grain 15 20 120 Turnip Foliage, Turnip Root, Wheat Grain 10 17 Unknown 2 365 Lettuce, Turnip Foliage, Turnip Root, Wheat Forage 14 42 Unknown 4 120 Wheat Grain 30 Unknown 11 120 Wheat Straw 12 Unknown 22 30 Wheat Straw 12 30 Lettuce, Turnip Foliage, Turnip Root, Wheat Forage, Wheat Straw 20 78 ( 0.4  1.7 ppm)

120 Lettuce, Turnip Foliage, Turnip Root, Wheat Forage, Wheat Straw, Wheat Grain 8  66 ( 0.2  0.9 ppm) Total Dicloran plus Unknown 1 360 Lettuce, Turnip Foliage, Turnip Root, Wheat Forage, Wheat Straw 3.1  12 (< 0.01  0.04 ppm)

30 Lettuce, Turnip Foliage, Turnip Root, Wheat Forage, Wheat Straw 47 85 ( 0.5  4.1 ppm) Total Known Dichloranilinecontaining Residues 4 120 Lettuce, Turnip Foliage, Turnip Root, Wheat Forage, Wheat Straw, Wheat Grain 15  66 ( 0.2  1.8 ppm) 18 of 84 360 Lettuce, Turnip Foliage, Turnip Root, Wheat Forage, Wheat Straw 3.1  23 (< 0.01  0.04 ppm)

1 Major residues are defined as those comprising greater than 10% of the TRR. 2 DCAP = 4 amino 2,6 dichlorophenol; DCDP = 4 amino 2,6 dichloroaniline 3 Unknown 1 was characterized as a polar multi component species derived from glutathione conjugation of dicloran at one or both of the chlorine substitution sites. 4 Includes dicloran, DCHA, DCAA, 3,5 DCHA, DCPD, DCAP, DCNP, 2,6 DCP, 2,6 DCA and Unknown 1.

3.3 Environmental Degradation DCNA is a low volatility compound that is expected to be persistent and to have low or almost no mobility in most soils. However, dicloran may have slightly higher mobility in coarser ( sandy) soils, particularly those that are low in organic matter. DCNA is expected to undergo faster degradation under anaerobic conditions ( t1/ 2' s of 0.5  10 days in anaerobic aquatic systems and t1/ 2' s of 24 38 days in anaerobic soil) than under aerobic conditions ( t1/ 2' s of approximately 6 18 months in aerobic soil), with much of the apparent loss of the compound attributed to the formation of non extractable residues.

In the field, DCNA is expected to be moderately persistent in soil based on a first order dissipation half life of 95 days. The compound is stable to hydrolysis, but does undergo both aqueous ( t1/ 2 of approximately 2 days) and soil photodegradation ( t1/ 2 of approximately 11 days). However, the photolysis rates were determined under optimal conditions in the laboratory and caution must be used in extrapolating laboratory photolysis data to the environment.

There is a potential for DCNA to reach surface water through spray drift when applied using ground spray or aerial spray, which are common application methods for many of the DCNA labeled uses. Since DCNA is generally persistent under field conditions, over time the compound may be present in field runoff and could thus reach surface water bodies. The slow biodegradation of DCNA in most soils will increase the potential for both groundwater and surface water contamination. However, the potential for groundwater contamination should be decreased by the tendency of the compound to adsorb to most types of surface soils. While DCNA is likely to adsorb to aquatic sediments, the potential for the compound to accumulate in such environments may be decreased by the more rapid degradation of the compound in anaerobic conditions.

There were no major degradates of DCNA in the laboratory studies ( i. e. none accounted for as much as 10% of radioactivity measured at any point in the studies), with the exception of the transformed chemical present as nonextractable residues. The minor degradates of DCNA expected in the environment are: DCPD, DCAA, DCHA, and 3,5HA. An additional degradate, 2,6 dicholorbenzoic acid, was identified in one study only ( aerobic aquatic metabolism) at maximums of 12.8% ( day 7) and 9.4% ( day 7) of the applied in the two water/ sediment systems studied, with the majority present in the water phase of each. However, that study was classified as unacceptable and consequently not included in this risk assessment.

3.4 Toxicity Profile of Major Metabolites and Degradates Plant and livestock metabolites of DCNA are structurally similar to the parent compound. 19 of 84 All metabolites belong to the chemical class common to the parent of substituted aromatics. There is no specific toxicity data available for any metabolite; therefore, it is assumed that the metabolites and the parent compound share similar toxicity.

3.5 Summary of Residues for Tolerance Expression and Risk Assessment 3.5.1 Tabular Summary Table 3.5 Summary of Metabolites and Degradates to be included in the Risk Assessment and Tolerance Expression Matrix Residues included in Risk Assessment Residues included in Tolerance Expression All Primary Crops except Potatoes Parent, DCHA Parent Potatoes Parent, DCHA, Unknown 1 Parent Plants Rotational Crop Parent, DCHA, DCAA, 3,5 DCHA, DCPD, DCAP, DCNP, 2,6 DCP, 2,6 DCA, Unknown 1 Parent Livestock Ruminant & Poultry Parent, DCAP, DCAA, DCHA, DCNP, A 1 metabolite Parent, DCAP Drinking Water Parent Not Applicable 3.5.2 Rationale for Inclusion of Metabolites and Degradates Metabolites and degradates included in this risk assessment are based on recommendations from the HED Metabolism Assessment Review Committee and the Dicloran Drinking Water Assessment memo provided by EFED.

Plant and livestock metabolites of DCNA are structurally similar to the parent compound. All metabolites belong to the chemical class common to the parent of substituted aromatics. There is no specific toxicity data available for any metabolite. Therefore, in absence of evidence to the contrary, it is assumed that the metabolites and the parent compound share similar toxicity.

As illustrated in the above table, more metabolites are included in the risk assessment than in the tolerance expression. However, the Metabolism Committee concluded that the residues of the parent alone are sufficient to serve as a measure of misuse for tolerance purposes, with the exception of livestock commodities. The DCAP metabolite was included in the tolerance expression because the parent, DCNA, was not identified in the liver and kidneys of ruminants. 20 of 84 4.0 Hazard Characterization/ Assessment 4.1 Hazard and Dose Response Characterization 4.1.1 Database Summary The toxicological database on dicloran is complete, with the exception of a developmental neurotoxicity study in rats and a 28 day inhalation toxicity study in rats.

<IP_ADDRESS>. Studies Available and Considered ° Subchronic: 21 day dermal toxicity, 21 day inhalation toxicity, 90 day oral toxicity ( dog); plus others ° Developmental: rat developmental toxicity study, rabbit developmental toxicity study ° Reproduction: 2 generation reproduction study in rats ° Chronic: combined oral chronic toxicity/ carcinogenicity ( rat); carcinogenicity ( mouse); chronic toxicity ( dog) ° Other: mutagenicity battery; metabolism study;

<IP_ADDRESS>. Mode of action, metabolism, toxicokinetic data The major commercial use of 2,6 dichloro 4 nitroaniline is as a fungicide and as an intermediate in the manufacture of dye. As a fungicide, it delays germination and causes a severe check to hyphal growth. It is suggested that dicloran is a structurally non specific toxicant exerting its effect by disorganizing cell growth and division in particular plant pathogens. The mode of action in test animals is not clear.

Oral metabolism studies in rats showed that dicloran is rapidly absorbed and metabolized in rats. Approximately 96 % of the administered dose was excreted in 24 hours. The urine was the major route of excretion ( 86.3% of the administered dose), and smaller amounts in feces ( 8.7% of the administered dose). Dicloran does not appear to accumulate in tissues. The major urine metabolites were DCHA sulfate and DCHA glucuronide which accounted for 45.5% to 79% of the total dose. Other metabolites detected were DCHA ( 3.3 to 22.8%), DCAP ( 0.3% to 8.5%), and DCNAP (< 0.1% to 1.0%). A small amount of dicloran was detected in feces.

<IP_ADDRESS>. Sufficiency of studies/ data Data are sufficient for each exposure scenario, FQPA evaluation, dose response evaluation and endpoint selection.

4.1.2. Toxicological Effects ° Dicloran has low acute toxicity. It is a potential skin sensitizer. The toxicological database for dicloran is adequate. The target organs include the liver, kidney, spleen and hematopoietic 21 of 84 system ( anemia) particularly the destruction of red blood cells. It is positive in the Ames test both in the presence and the absence of S9 activation and negative in both the in vitro chromosome aberration assay in human lymphocytes and primary rat hepatocyte unscheduled DNA synthesis assay. It does not appear to be a reproductive toxicant. The developmental toxicity study in rats showed increased incidences of supernumerary rudimentary ribs and also decreased fetal weights in the presence of maternal toxic dose. Although no neurotoxicity studies are available, the available data did not demonstrate neurotoxicity with subchronic dosing at doses lower than 25 mg/ kg. However, neuropathology was seen in the long term rat study ( NOAEL = 11.3 mg/ kg/ day; LOAEL = 71 mg/ kg/ day) with chronic dosing. Neuropathology was seen in the dogs at lower levels ( NOAEL = 2.5 mg/ kg/ day; LOAEL = 25 mg/ kg/ day) than the neuropathology seen in the long term rat study.

° The chronic toxicity study in rats showed that dicloran caused reduced body weight, reduced body weight gain, and histopathologic lesions in the brain and spinal cord of both sexes, optic nerve in females and Leydig cell hyperplasia in the testes in males. The incidence of Leydig cell tumors was significantly increased in high dose male rats compared with the control incidence and the incidence of endometrial adenocarcinoma was marginally increased in highdose female rats. The mouse carcinogenicity study showed no treatment related increase in tumor incidence. The chronic toxicity study in dogs showed that dicloran caused changes in clinical chemistry, increased liver weights, hepatocyte hypertrophy, vacuolar alterations of the brain and spinal cord, prostate atrophy, degeneration of the seminiferous tubules, and hypospermia in the epididymides.

° The committee members of CARC evaluated the carcinogenicity studies in rats and mice and related toxicity data on dicloran and concluded that this chemical can be classified as " Suggestive Evidence of Carcinogenic Potential" and recommended no quantification of cancer risk is required.

4.1.3. Dose response The developmental rat study, one year dog study, and 90 day oral toxicity study in dogs were the primary studies used for the dose response assessment. The dog is the most sensitive species noted from testing dicloran with the effects occurring at considerably lower doses than those noted for the rat or mouse. The developmental rat study was selected for the acute dietary ( females 13 49 years of age) exposure scenario based on increased incidences of supernumerary rudimentary ribs and decreased fetal weights. An acute dietary general population, including infants and children, endpoint was not selected for this population group because there were no effects observed in oral toxicology studies including maternal toxicity in the developmental toxicity studies in rats and rabbits that are attributable to a single exposure ( dose).

For short and intermediate term incidental oral exposures, the 90 day oral toxicity study in dogs was selected based on changes in hematological ( decreased hemoglobin and hematocrit at 4, 8, and 14 weeks) and clinical biochemistry parameters, reduced body weight gain, increased liver, spleen and kidney weights, and histopathological changes in the liver. 22 of 84 In the 21 day dermal toxicity study in rabbits, systemic toxicity [ increased ( 36%) adrenal weights in males ( 260 g treated vs 191 g controls)] was noted at 1200 mg/ kg/ day. Therefore, this endpoint was selected for both short and intermediate term dermal risk assessments. For short and intermediateterm inhalation exposures, the 90 day oral toxicity study in dogs was used.

Endpoints and dose levels for chronic dietary, dermal and inhalation exposures were based on the chronic oral toxicity study in dogs. The effects observed in the chronic dog study were changes in clinical chemistry ( increased alkaline phosphatase in both sexes and increased cholesterol in males), increased liver weights, hepatocyte hypertrophy, vacuolar alterations of the brain and spinal cord, prostate atrophy, degeneration of the seminiferous tubules, and hypospermia in the epididymides.

The committee members of CARC evaluated the carcinogenicity studies in rats and mice and toxicity data on dicloran and concluded that no quantification of cancer risk is required based on the " Suggestive Evidence of Carcinogenic Potential" classification.

The uncertainty factors used in determining the acute and chronic RfDs ( aRfD and cRfD) were 100 ( 10x for intraspecies variation; 10x for interspecies extrapolation).

Acute Toxicity of Technical Dicloran Guideline No. Study Type MRID #( S). Results Toxicity Category 870.1100 Acute Oral 00086879 LD50 = 1,000 mg/ kg IV 870.1200 Acute Dermal 00086894 LD50 = > 2000 mg/ kg mg/ kg III 870.1300 Acute Inhalation Not Available LC50 = m/ L 870.2400 Primary Eye Irritation 00086892 Mild ocular irritant III 870.2500 Primary Skin Irritation 00086893 Not a dermal irritant IV 870.2600 Dermal Sensitization 00082721 Potential dermal sensitizer N/ A 23 of 84 SUBCHRONIC, CHRONIC AND OTHER TOXICITY PROFILE FOR DICLORAN Guideline No./ STUDY TYPE  MRID No. ( year)/ Classification / Doses NOAEL ( mg/ kg/ day) LOAEL ( mg/ kg/ day)

870.4300 2 year combined chronic/ carcino genicity   rat 46360701 ( 2004)

acceptable/ guideline 0, 60, 240 or 1200 ppm for the first 105 days. Dietary concentration was raised from 1200 ppm to 1440 ppm on treatment day 106 because the effects on body weight gains in animals, especially females was less than expected from the 90 day range finding study. The calculated time weighted average dietary concentration for the high dose main group was 1405 ppm. Males: 0, 2.8, 11.3, and 71.0 mg/ kg/ day Females: 0, 3.7, 15.0, and 94.1 mg/ kg / day M/ F: 11.3/ 15.0 M/ F: 71.0/ 94.1 based on reduced body weight, reduced body weight gain, Histopathologic lesions in the brain ( vacuolation in the cerebral cortex including the optic chiasma, cerebellar cortex, and medulla/ pons regions of the brain) and spinal cord of both sexes, optic nerve in females and Leydig cell hyperplasia in testes. In addition, treatmentrelated increase in the relative weights in the liver, brain and testes in males and relative liver weight in females were observed.

Suggestive evidence of carcinogenic potential.

Incidence of Benign Leydig cell tumors was 0/ 50, 1/ 50, 1/ 50, and 5/ 50 ( p# 0.05) in control, low, mid , and high dose males rats. All Leydig tumors were found in animals sacrificed at study termination.

Incidence of malignant endometrial adenocarcinoma was 3/ 50, 7/ 29, 7/ 21, and 9/ 50 ( p= 0.061) in control, low, mid, and high dose females 870.4200b 18 month carcinogenicity   mouse 40977101 ( 1989)

Acceptable/ guideline 0, 50, 175, 600 ppm M/ F: 0/ 0, 7.4/ 10.1, 24.5/ 35.4, 86.5/ 118.8 mg/ kg/ day 24.5/ 35.4 ( M/ F) 86.5/ 118.8 ( M/ F) histopathological changes in liver and uterus: microscopic hepatic lesions in males, centrilobular hepatocyte vacuolation in females, and distended, enlarged uterus with cystic endometrial hyperplasia increased liver weights No evidence of carcinogenicity 24 of 84 SUBCHRONIC, CHRONIC AND OTHER TOXICITY PROFILE FOR DICLORAN Guideline No./ STUDY TYPE  MRID No. ( year)/ Classification / Doses NOAEL ( mg/ kg/ day) LOAEL ( mg/ kg/ day)

870.4100b 2 year chronic study in dog 00029056, 00082718, 00026810 ( 1962, 1964, 1979)

Acceptable/ guideline 0, 20, 100, 3000 ppm 0, 0.5, 2.5, 75 mg/ kg/ day 2.5 75 reduced body weight gain, increased liver, spleen and kidney weights, hematological and clinical biochemistry changes and histopathological changes in the liver.

870.4100b 1 year chronic study in dog 45610801 ( 2002)

Acceptable/ guideline 0, 33, 100, 3000 ppm 3 weeks   Fed in diet at 0/ 0, 1.1/ 1.4, 4.5/ 3.8, and 54.8/ 57.7 mg/ kg/ day. Weeks 4 through 11  Changed to capsule at doses of 0, 0.75, 2.5, or 50 mg/ kg/ day in capsules. After weeks 11   The dosage was reduced from 50 mg/ kg to 25 mg/ kg/ day. 2.5 25 changes in clinical chemistry ( increased alkaline phosphatase in both sexes and increased cholesterol in males), increased liver weights, hepatocyte hypertrophy, vacuolar alterations of the brain and spinal cord, prostate atrophy, degeneration of the seminiferous tubules, and hypospermia in the epididymides 870.3800 2 generation reproduction study  rat 44233803, 44414101 ( 1996, 1997)

Acceptable/ guideline 0, 50, 250, 1250 ppm M/ F: 0/ 0, 3.4/ 4.1, 16.9/ 20.3, 87/ 102 mg/ kg/ day Parental systemic: 16.9/ 20.3 Offspring systemic: 16.9/ 20.3 Reproductive: 87/ 102 Parental systemic: 87/ 102 [ M/ F], reduced body weight gain of P females prior to mating, and in both generations during gestation and lower body weights during lactation; increased liver weights ( both sexes), kidney weights of males and decrease in ovary weights of females in the F1 generation Offspring systemic: 87/ 102 [ M/ F], reduced mean pup weights of both generations Reproductive: Not established 870.3700a Developmental toxicity  rat 46447501 ( 2003)

acceptable/ guideline 0, 50, 100, or 200 mg/ kg/ day Maternal: not established Developmental: 50 Maternal: 50 ( LDT) decreased body weight gains and food consumption Developmental: 100 decreased fetal weights and increased incidences of supernumerary rudimentary ribs 25 of 84 SUBCHRONIC, CHRONIC AND OTHER TOXICITY PROFILE FOR DICLORAN Guideline No./ STUDY TYPE  MRID No. ( year)/ Classification / Doses NOAEL ( mg/ kg/ day) LOAEL ( mg/ kg/ day)

870.3700b Developmental toxicity  rabbit 43952101 ( 1996)

Acceptable1 0, 8, 20, 50 mg/ kg/ day Maternal: 50 ( HDT)

Developmental: 50 ( HDT) Maternal: not established Developmental: not established 870.3100 90 day oral toxicity rat 00029056, 00082718 ( 1962, 1964)

Acceptable/ guideline 0, 20, 100, 3000 ppm 0, 1, 5, 150 mg/ kg/ day 5 150 reduced body weight gain, increased liver and kidney weights, and histopathological changes in the liver and adrenals 870.3100 90 day oral toxicity rat 46360702 ( 2001)

Acceptable/ guideline 0, 300, 1000, 2000, or 4000 ppm M: 0, 19.4, 61.5, 121.2, and 246.8 mg/ kg/ day F: 0, 25.4, 72.4, 133.6, and 264.6 mg/ kg/ day 61.5/ 72.4 ( 121.2/ 133.6 mg/ kg/ day) decreased body weight, weight gain, and food consumption Non guideline Subchronic ( 146 day study) toxicity rat 00082719 ( 1963)

Acceptable/ non guideline 0, 5, 20, 100 mg/ kg/ day 0, 20 mg/ kg/ day in diet 20 100 reduced body weight gain of females NO Hematopoetic Activity: at 100 870.3150 Subchronic toxicity dog 00029056, 00026810, 00082718 ( 1962, 1964, 1979)

Acceptable/ guideline 0, 20, 100, 3000 ppm 0, 0.5, 2.5, 75 mg/ kg/ day 2.5 75 reduced body weight gain, increased liver, spleen and kidney weights, hematological and clinical biochemistry, and histopathological changes in the liver 870.3200 21 Day Dermal Toxicity   rabbit 40555101 ( 1988) Acceptable/ guideline 0, 12, 120, 1200 mg/ kg/ day 120 1200 increased adrenal weights ( 36% over controls) in males. This finding was corroborated by the histopathological changes observed in the adrenals at 150 mg/ kg/ day in the 90 day feeding study in rats ( MRIDs 00029056 and 00082718). 26 of 84 SUBCHRONIC, CHRONIC AND OTHER TOXICITY PROFILE FOR DICLORAN Guideline No./ STUDY TYPE  MRID No. ( year)/ Classification / Doses NOAEL ( mg/ kg/ day) LOAEL ( mg/ kg/ day)

Non guideline Subchronic ( 21 Day) Inhalation toxicity rats, rabbits and dogs 00086896 ( 1980)

Acceptable/ non guideline 2 mg/ L 2 mg/ L Not established This study indicative that the LC50 of dicloran technical is greater than 2 mg/ L.

870.7485 Metabolism study  rat 44061001 ( 1995) Acceptable/ Guideline 5 or 500 mg/ kg Dicloran was rapidly absorbed and metabolized. urine [ 86.3%]; feces [ 8.7%] highest tissue residue levels 7 days post dose in liver and kidneys Urine metabolites DCHA sulfate [ DCHA = 4 amino 3,5 dichlorophenol] and DCHA glucuronide ( 45.5% to 79.0% of the total dose administered) DCHA [ 4 amino 3,5 dichlorophenol ( 3.3% to 22.8%)] DCAP [ 4 amino 2,6 dichlorophenol ( 0.3% to 8.5%)] DCNAP [ 3,5 dichloro 4 hydroxyacetanilide (< 0.1% to 1.0%)].

Fecal Metabolite [ 3.0% to 7.6%] glutathione conjugate The metabolism of Dicloran involved reduction/ deamination/ hydroxylation of the nitro group to yield the DCHA metabolite, then conjugation occurred to form the major metabolites DCHA sulfate and DCHA glucuronide. DCAP was produced through reduction/ deamination/ hydroxylation. Following Nacetylation DCNAP was formed.

A minor metabolic pathway involved dechlorination/ hydroxylation of Dicloran to form 2 hydroxy 4 nitro 6 chloroaniline.

870.7485 Metabolism study  RAT 43255401 and 43255402 ( 1991) Acceptable/ Guideline ( excretion and distribution study only)

5 or 500 mg/ kg/ day 432554 01 > 97% of the dose excreted via both urine and feces within first 24 hours post dose Urine:   78%   /   73%   Feces: > 13% [   ] /> 14% [   ]

432554 02 > 92 excreted via both urine and feces within the first 48 hours post dose Urine:   68% in both sexes Feces:   22% [ both sexes] 27 of 84 SUBCHRONIC, CHRONIC AND OTHER TOXICITY PROFILE FOR DICLORAN Guideline No./ STUDY TYPE  MRID No. ( year)/ Classification / Doses NOAEL ( mg/ kg/ day) LOAEL ( mg/ kg/ day)

870.5265 Reverse gene mutation assay 40508801 ( 1987) Acceptable 50 5000 : g/ plate ( ± S9) Mutagenic 870.5265 Reverse gene mutation assay 00046435, 00046436 and 00087018 ( 1976 1977) Acceptable 16 1000 : g/ plate ( ± S9) Not mutagenic 870.5375 Chromosome aberration assays 40508802 ( 1988) Acceptable 2 20 : g/ plate ( ± S9) Not mutagenic 870.5550 in vitro Unscheduled DNA synthesis ( UDS) assays 40619001 ( 1988) Acceptable 3 10 : g/ mL Not mutagenic 1 No maternal or developmental toxicity was observed at the highest dose ( 50 mg/ kg/ day) tested in this study. However, this study is considered acceptable based on the results of range finding study ( MRID No. 44282901) where doses levels of 100 mg/ kg/ day and greater resulted in deaths and decreased body weight gains.

4.2 FQPA Hazard Considerations 4.2.1 Adequacy of the Toxicity Database The database for evaluating in utero or postnatal susceptibility is adequate and includes developmental toxicity studies in both rats and rabbits and a two generation reproduction study in the rat.

4.2.2 Evidence of Neurotoxicity Although the available data base indicated that this chemical does not induce neurotoxicity in subchronic toxicity study in rats, mice, and dogs, with chronic toxicity study in rats and dogs, vacuolar alterations of the brain and spinal cord was seen at doses of 25 mg/ kg or greater.

4.2.3 Developmental Toxicity Studies Prenatal Developmental Toxicity Study  Rat; OPPTS 870.3700a [ § 83 3a]; OECD 414.

EXECUTIVE SUMMARY:

In a developmental toxicity study ( MRID 46447501), Dicloran ( 97.17% a. i., Batch # 020327) was administered daily via oral gavage to 25 presumed pregnant Wistar rats/ group at dose levels of 0, 50, 28 of 84 100, or 200 mg/ kg/ day from gestation day ( GD) 6 through 20. All dams were killed on GD 21; their fetuses were removed by cesarean section and examined.

Ruffled fur was observed at 100 mg/ kg/ day in one dam from GD 10 13 and 18 21 and in the remaining 24 dams at this dose from GD 18 21. Ruffled fur was noted in all 25 dams at 200 mg/ kg/ day from GD 13 21. Bloody discharge from the vagina was noted between GD 13 and GD 15 in one dam at 100 mg/ kg/ day and 7 dams at 200 mg/ kg/ day. It was stated that this was a normal finding unrelated to treatment, marking the time of transition from yolk sac to placental nutrition. However, the dose relatedness of this finding indicates that it may be due to the test substance.

At >= 100 mg/ kg/ day, body weights were decreased ( p<= 0.05) by 4 9% compared to controls beginning on GD 8 and continuing through the remainder of the study. Body weight gains, expressed as a percentage of the body weight on GD 6, were decreased ( p<= 0.05) in all of the treated groups compared to controls beginning on GD 7 and continuing through the remainder of the study. Body weight gains were dose dependently decreased by 39 106% in all treated groups during GD 6 11, resulting in decreased body weight gains for the overall treatment period ( GD 6 21), both when corrected for gravid uterine weights ( decr. 53 124%; p<= 0.01) and uncorrected for gravid uterine weights ( decr. 11 34%; statistics not performed). Gravid uterine weights were comparable to controls. Additionally in the 200 mg/ kg/ day dams, body weight gains were decreased by 25% during GD 16 21.

Throughout the treatment period, food consumption was dose dependently decreased ( p<= 0.05 or 0.01) by 9 43% at >= 50 mg/ kg/ day.

The maternal LOAEL was 50 mg/ kg/ day based on decreased body weight gains and food consumption. The maternal NOAEL was not established.

At 200 mg/ kg/ day, increases were noted in the numbers of early, late, and total resorptions, both on an absolute basis and on a per dam basis. These increases in resorptions led to an increased ( p<= 0.05) post implantation loss in this group ( 11.0%) compared to controls ( 6.9%).

Fetal body weights were decreased at 100 mg/ kg/ day in the males and at 200 mg/ kg/ day in both sexes. Non ossification of the talus was increased in fetal ( p<= 0.01) and litter ( NS) incidences in all treated groups ( 89 93% fetuses; 100% litters) compared to concurrent controls ( 77% fetuses; 96% litters). Only fetal incidences of the right talus exceeded historical controls and this was not considered a dose related effect.

Incidences of supernumerary rudimentary ribs, a variation, were increased ( p<= 0.05) at >= 100 mg/ kg/ day ( 49 58% fetuses; 92 100% litters) compared to concurrent ( 28 33% fetuses; 68 72% litters) and historical ( 31 40% fetuses; 63 92% litters) controls. Additionally at 200 mg/ kg/ day, increased fetal ( p<= 0.05) and litter ( NS) incidences of one right supernumerary rib were observed ( 5% fetuses; 21% litters) compared to concurrent ( 1% fetuses; 4% litters) and historical ( 1% fetuses; 4 8% litters) controls. Also, the digits of forelimb and hindlimb were affected at 200 mg/ kg/ day.

There were no treatment related external, visceral, or skeletal malformations. 29 of 84 The developmental LOAEL is 100 mg/ kg/ day based on decreased fetal weights and increased incidences of supernumerary rudimentary ribs. The developmental NOAEL is 50 mg/ kg/ day.

This study is classified acceptable/ guideline ( OPPTS 870.3700a) and satisfies the guideline requirements for a developmental study in the rat.

Prenatal Developmental Toxicity Study  Rabbit; OPPTS 870.3700b [ § 83 3b]; OECD 414 A rabbit developmental toxicity ( MRID No. 43952101) was tested up to 50 mg/ kg/ day. No maternal or developmental toxicity was seen.

4.2.4 Reproductive Toxicity Study Reproduction and Fertility Effects Study   Rat [ OPPTS 870.3800 ( § 83 4) OECD 416]

EXECUTIVE SUMMARY: In a 2 generation reproduction study ( MRID 44414101, 44233803), dicloran ( 99.2% a. i., lot # WJC1) was administered in the diet continuously to 2 generations of Sprague Dawley rats ( 28 rats/ sex/ dose) at dose levels of 0, 50, 250, or 1250 ppm ( equivalent to 0, 3.4/ 4.1, 16.9/ 20.3, or 87/ 102 mg/ kg/ day [ M/ F] in the P and F1 animals). The P and F1 animals were exposed to the test substance for approximately 10 weeks prior to mating. The F1 animals were mated at approximately 15 week of age. The F1 animals and their F2 litters were sacrificed at the same time of weaning of these litters.

There was no evidence of treatment related mortality in the P or F1 adults. All animals in the high dose ( P or F1) exhibited yellow staining of the traypaper. Staining may have been due to the test material and/ or metabolite since the test material is yellow. Other clinical signs in P or F1 were observed but these signs were considered incidental findings since they did not occur in dose related manner. No treatment related differences in mean body weights were observed in male and female rats of P or F1 compared to corresponding concurrent controls. During the pre mating period, there was a decrease in body weight gain of Fo females ( 88.4% of the controls) at 1250 ppm, compared with control values ( 130 grams vs 147 grams for controls). In the F1 generation, weight gains of both sexes at 1250 ppm were marginally lower than the control and does not appear to be statistically ( standard deviations) significant different from the control values. In both generations, weight gain during gestation at 1250 ppm was lower than control ( F0 animals ,90% of the controls; F1 animals, 93% of the controls). Overall average food consumption, as calculated by the reviewers, did not appear to show any differences of toxicological concern for any generation during premating, gestation or lactation.

There were no adverse effects of dicloran on mating performance or on litter size and survival, but mean pup weights of both generations ( and hence litter weights) at 1250 ppm were lower than controls. At the high dose, decrease in mean litter body weight gain was 80.9% for the F1 generation and 86.6% for the F2 generation compared to corresponding controls. At the high dose, decrease in pup body weight gain was 85.6% for the males and 86.6% for the females in F1 generation and 90.3% for the males and 87.8% for the females in F2 generation compared to corresponding controls. No 30 of 84 statistical analysis except standard deviation of the mean was provided in the study report. Based on the reported standard deviations these differences do not appear to be statistically different from control values.

The number of seminiferous tubules at different stages were essentially comparable in the control and the high dose groups of both generation. The mean values for Stage VII tubule diameter did not indicate any effect of treatment. In the Fo generation at the high dose, the mean number of abnormal sperm, particularly of sperm with tail defects, was greater than the control value, this increase was due to a few animals with a large number of abnormal sperm ( more than 10 sperm with tail acutely folded/ tightly coiled). Based on the historical control data ( not provided in the study report) , together with the absence of a similar response in the F1 generation, the study authors concluded that the increase observed in the Fo generation were unlikely to be of biological significance. Due to unavailability of the historical control data to the reviewer, it is not possible to agree with the conclusion made by the study authors.

No organ weight data were reported for Fo generation. Liver weights ( absolute and adjusted to body weights) were increased ( p# 0.05, 0.01 or 0.001) for the F1 males and females in the high dose group. Increases in absolute and adjusted ( to body weight) liver weights were observed, but were not accompanied by abnormal hepatic histopathology. Kidney weights were increased for the F1 males compared to controls; higher absolute kidney weights were significant at p< 0.05 level and higher kidney weights adjusted to body weight were significant at p< 0.001 level. The mean ovary weights ( absolute and adjusted to body weights) of F1 females at the high dose were lower than controls. At the 1250 ppm dose level, there was a slightly increased incidence of pro oestrous morphology and slightly decreased incidence of metoestrous. This observation was more apparent in the Fo than the F1 generation, and was considered to be probably incidental by the study authors. This reviewer is in agreement with study author's conclusion.

The LOAEL for systemic parental toxicity is 1250 ppm ( equivalent to 87/ 102 mg/ kg/ day [ M/ F]) based on significantly reduced body weight gain of Fo females prior to mating, and in both generations during gestation and lower body weights during lactation; increased liver weights ( both sexes), kidney weights of males and decrease in ovary weights of females in the F1 generation. The NOAEL is 250 ppm ( equivalent to 16.9/ 20.3 mg/ kg/ day [ M/ F]).

The LOAEL for systemic offspring toxicity is 1250 ppm ( equivalent to 87/ 102 mg/ kg/ day [ M/ F]) based on significantly reduced mean pup weights of both generations; increased liver weights ( both sexes), kidney weights of males and decrease in ovary weights of females in the F1 generation. The NOAEL is 250 ppm ( equivalent to 16.9/ 20.3 mg/ kg/ day [ M/ F]).

The NOAEL for reproductive toxicity is 1250 ppm ( equivalent to 87/ 102 mg/ kg/ day [ M/ F]). The LOAEL was not established.

The reproductive study is determined to be acceptable/ guideline ( § 83 4[ a]) and does satisfy the guideline requirement for a multigenerational reproductive toxicity study in rats. 31 of 84 4.2.5 Additional Information from Literature Sources There were no data available from the general literature, including human clinical or exposure data at this time.

4.2.6 Pre and/ or Postnatal Toxicity <IP_ADDRESS> Determination of Susceptibility No qualitative or quantitative evidence for increased susceptibility was seen in the developmental toxicity study in rats. In this study increased incidences of supernumerary rudimentary ribs and decreased fetal weights were observed at a higher dose than maternal toxicity.

There is no quantitative and qualitative evidence of increased susceptibility of rat offspring in the multi generation reproduction study. In this study, offspring toxicity observed was significantly reduced mean pup weights of both generations. This offspring toxicity was observed at a dose which produced also maternal toxicity including reduced body weight gain of Fo females prior to mating, and in both generations during gestation and lower body weights during lactation; increased liver weights ( both sexes), kidney weights of males and decrease in ovary weights of females in the F1 generation.

<IP_ADDRESS> Degree of Concern Analysis and Residual Uncertainties for Pre and/ or Postnatal Susceptibility There are no concerns or residual uncertainties for pre and/ or post natal toxicity following exposure to dicloran from the available data, although a DNT is required ( see Section 4.3 below).

4.3 Recommendation for a Developmental Neurotoxicity Study No acute or subchronic neurotoxicity studies are available in the database. In a rat developmental toxicity study, no clinical signs of neurotoxicity were reported. Paralysis and depression was reported in an acute oral toxicity study at 2500 mg/ kg.

A DNT study is recommended and evidence that supports requiring a DNT study is listed below.

4.3.1 Evidence in favor of retaining the 10X/ requiring further evaluation of neurobehavioral development ° Dicloran appears to be highly neurotoxic ( vacuolation in the brain) at doses of 25 75 mg/ kg following exposures greater than 90 days. Ninety eight percent of animals were affected so this is a true effect.

° Single high doses of aniline produced similar neuropathology. The neuropathological effects, 32 of 84 were greater in four week old rats than seven week old rats, indicating that age could be an important variable in this neurotoxicity.

4.3.2 Evidence against retaining the 10X/ requiring further evaluation of neurobehavioral development ° No neurotoxic signs were seen in any of the studies with dicloran, including studies indicating significant neuropathology.

° Neuropathology was reported only at the highest doses tested in chronic dog and rat studies.

° There was no dose response.

° Regulatory endpoints are based on the NOAEL ( 2.5 mg/ kg) for the dog chronic study, the more sensitive species, is 10 30 times lower than doses producing neuropathology ( 25 27 mg/ kg).

° Neuropathology appears to require either very high doses or exposures greater than 90 days.

° There was no susceptibility evidence in developmental and reproductive studies.

° A study in rats is unlikely to yield a lower NOAEL, as the dog is a more sensitive species.

Although a DNT study is unlikely to result in a more sensitive endpoint than those currently being used for risk assessment, the study is necessary to fully characterize potential fetal neurotoxicity and neuropathology. Therefore, the study is required and the 10X FQPA special safety factor is retained.

4.4 Hazard Identification and Toxicity Endpoint Selection 4.4.1 Acute Reference Dose ( aRfD)  Females age 13 49 Study Selected: Rat developmental toxicity study MRID No.: 46447501 Executive Summary:

In a developmental toxicity study ( MRID 46447501), Dicloran ( 97.17% a. i., Batch # 020327) was administered daily via oral gavage to 25 presumed pregnant Wistar rats/ group at dose levels of 0, 50, 100, or 200 mg/ kg/ day from gestation day ( GD) 6 through 20. All dams were killed on GD 21; their fetuses were removed by cesarean section and examined. 33 of 84 Ruffled fur was observed at 100 mg/ kg/ day in one dam from GD 10 13 and 18 21 and in the remaining 24 dams at this dose from GD 18 21. Ruffled fur was noted in all 25 dams at 200 mg/ kg/ day from GD 13 21. Bloody discharge from the vagina was noted between GD 13 and GD 15 in one dam at 100 mg/ kg/ day and 7 dams at 200 mg/ kg/ day. It was stated that this was a normal finding unrelated to treatment, marking the time of transition from yolk sac to placental nutrition. However, the dose relatedness of this finding indicates that it may be due to the test substance.

At >= 100 mg/ kg/ day, body weights were decreased ( p<= 0.05) by 4 9% compared to controls beginning on GD 8 and continuing through the remainder of the study. Body weight gains, expressed as a percentage of the body weight on GD 6, were decreased ( p<= 0.05) in all of the treated groups compared to controls beginning on GD 7 and continuing through the remainder of the study. Body weight gains were dose dependently decreased by 39 106% in all treated groups during GD 6 11, resulting in decreased body weight gains for the overall treatment period ( GD 6 21), both when corrected for gravid uterine weights ( decr. 53 124%; p<= 0.01) and uncorrected for gravid uterine weights ( decr. 11 34%; statistics not performed). Gravid uterine weights were comparable to controls. Additionally in the 200 mg/ kg/ day dams, body weight gains were decreased by 25% during GD 16 21.

Throughout the treatment period, food consumption was dose dependently decreased ( p<= 0.05 or 0.01) by 9 43% at >= 50 mg/ kg/ day.

The maternal LOAEL was 50 mg/ kg/ day based on decreased body weight gains and food consumption. The maternal NOAEL was not established.

At 200 mg/ kg/ day, increases were noted in the numbers of early, late, and total resorptions, both on an absolute basis and on a per dam basis. These increases in resorptions led to an increased ( p<= 0.05) post implantation loss in this group ( 11.0%) compared to controls ( 6.9%).

Fetal body weights were decreased at 100 mg/ kg/ day in the males and at 200 mg/ kg/ day in both sexes. Non ossification of the talus was increased in fetal ( p<= 0.01) and litter ( NS) incidences in all treated groups ( 89 93% fetuses; 100% litters) compared to concurrent controls ( 77% fetuses; 96% litters). Only fetal incidences of the right talus exceeded historical controls and this was not considered a dose related effect.

Incidences of supernumerary rudimentary ribs, a variation, were increased ( p<= 0.05) at >= 100 mg/ kg/ day ( 49 58% fetuses; 92 100% litters) compared to concurrent ( 28 33% fetuses; 68 72% litters) and historical ( 31 40% fetuses; 63 92% litters) controls. Additionally at 200 mg/ kg/ day, increased fetal ( p<= 0.05) and litter ( NS) incidences of one right supernumerary rib were observed ( 5% fetuses; 21% litters) compared to concurrent ( 1% fetuses; 4% litters) and historical ( 1% fetuses; 4 8% litters) controls. Also, the digits of forelimb and hindlimb were affected at 200 mg/ kg/ day.

There were no treatment related external, visceral, or skeletal malformations. 34 of 84 The developmental LOAEL is 100 mg/ kg/ day based on decreased fetal weights and increased incidences of supernumerary rudimentary ribs. The developmental NOAEL is 50 mg/ kg/ day. This study is classified acceptable/ guideline ( OPPTS 870.3700a) and satisfies the guideline requirements for a developmental study in the rat.

Dose and Endpoint for Establishing RfD: NOAEL= 50 mg/ kg/ day based on increased incidences of supernumerary rudimentary ribs and also decreased fetal weights at 100 mg/ kg/ day ( LOAEL).

Uncertainty Factor ( UF): 100X [ 10 interspecies; 10X intraspecies]

Comments about Study/ Endpoint/ Uncertainty Factor: The study is appropriate for a single dose exposure with the effects of concern via the oral route and length of exposure for an acute dietary endpoint. The endpoints for risk assessment are based on increased incidences of supernumerary rudimentary ribs. The developmental effects are presumed to occur as a result of a single dose at a critical time during gestation.

4.4.2 Acute Reference Dose ( aRfD)  General Population A dose and endpoint were not selected for this population group because there were no effects observed in oral toxicology studies including maternal toxicity in the developmental toxicity studies in rats and rabbits that could be attributable to a single exposure ( dose).

4.4.3 Chronic Reference Dose ( RfD)

TWO CHRONIC DOG STUDIES WERE CONSIDERED TO SELECT THE ENDPOINT.

NEW STUDY ( 2002)  This new study was conducted because HIARC recommended new chronic toxicity study in dog since the existing dog study appears to drive the risk assessment and NOAEL appears to be artificially low.

Study Selected: One Year Chronic Toxicity Study  dog, OPPTS Number: 870.4100 EXECUTIVE SUMMARY  In a chronic oral toxicity study ( MRID 45610801), Dicloran ( 94.6% a. i., Lot/ Batch # 000313 or 98.3% a. i., Lot/ Batch# QH 1006) was administered to 4 male and female beagle dogs/ group in the diet at concentrations of 0, 33, 100, or 3000 ppm ( equivalent to 0/ 0, 1.1/ 1.4, 4.5/ 3.8, and 54.8/ 57.7 mg/ kg/ day) for the first 3 weeks. Subsequently, dosing was changed from dietary to capsule at doses of 0, 0.75, 2.5, or 50 mg/ kg/ day in capsules for Weeks 4 through 11. Due to poor health conditions in the high doses group, the dosage of this group was reduced from 50 mg/ kg to 25 mg/ kg/ day after Weeks 11. Acute RfD = 50 mg/ kg/ day ( NOAEL) = 0.5 mg/ kg/ day 100 ( UF) 35 of 84 No adverse treatment related effects were noted in mortality, ophthalmology, hematology, or urinalysis.

Food consumption was decreased (  43 72%; p< 0.05 0.01) in both sexes at 3000 ppm ( high dose group) during Weeks 1 3. Decreased food consumption was reflected in decreased body weights (  11 27%; p< 0.05 0.01) at 3000 ppm in males at Weeks 2 6 and in females at Weeks 2 3 and in decreased body weight gains ( p< 0.05) in males at Weeks 2 6 and in females at Weeks 2 3. Slight to moderate thinness or emaciation was observed in a majority of animals at this dose ( high dose group) during Weeks 2 5. The Sponsor stated that these effects were associated with the lack of palatability of the diet and subsequently changed the administration of test compound to capsules after Week 3.

Several weeks following the change to capsule administration, estimated food consumption at 50 mg/ kg/ day ( high dose group) was lower in males ( Weeks 8 11) and females ( Weeks 10 11). At this dose, decreased body weights (  11 19%; p< 0.05) were observed in males during Weeks 6 13. Additionally, weekly body weight gains were decreased ( p< 0.05) in males during Weeks 6 13. Increased incidences of slight thinness or emaciation were observed again in Weeks 10 12 in both sexes at 50 mg/ kg/ day. As a result of these effects, the high dose was lowered from 50 mg/ kg/ day to 25 mg/ kg/ day. No further treatment related decreases in weekly body weight, body weight gain, food consumption, or clinical signs were observed. However, overall ( Weeks 1 13, 1 26, and 1 53) body weight gain was lower in the high dose group males (  12 46%) compared to controls.

In high dose group, alkaline phosphatase was increased (  183 384%; p  0.05 0.01) in the males throughout the study. In females at this dose, alkaline phosphatase was increased at 3 months (  112%; p  0.05) and higher than controls at 6, 9, and 12 months (  55 120%; not significant). Serum cholesterol was increased in males at 6, 9, and 12 months (  47 55%; p  0.01).

Absolute and relative ( body) liver weights were increased (  27 48%; p  0.05 0.01) in both sexes of the high dose group. These increases were consistent with increased incidences of minimal centrilobular hepatocyte hypertrophy observed in all animals of both sexes at this dose.

In high dose group, increased incidences of extensive vacuolation of the white matter of the brain and all three levels of the spinal cord were observed in both sexes. In males, minimal to moderately severe atrophy of the prostate was also observed in all males in this group, and the incidences of grossly observed small prostate were higher than controls ( 2/ 4 treated vs 0/ 4 controls). Additionally, slight/ mild to moderate degeneration of the seminiferous tubules and moderate to moderately severe hypospermia in the epididymides were observed in the two high dose group males.

No effects were observed at the lower doses.

The LOAEL was 25 mg/ kg/ day based on clinical chemistry ( increased alkaline phosphatase in both sexes and increased cholesterol in males), increased liver weights, hepatocyte hypertrophy, 36 of 84 vacuolar alterations of the brain and spinal cord, prostate atrophy, degeneration of the seminiferous tubules, and hypospermia in the epididymides. The NOAEL was 2.5 mg/ kg/ day.

This study is classified as acceptable/ guideline and satisfies the guideline requirements ( OPPTS 870.4100b; OECD 452) for a non rodent chronic oral toxicity study.

OLD STUDY ( 1962, 1964, 1979) Study: Two Year Chronic Toxicity  dog, OPPTS Number: 870.4100 MRID Nos.: 00029056, 00082718, 00026810 Executive Summary: In this chronic ( 104 107 weeks) oral toxicity study ( MRID 00029056, 00082718), dicloran technical grade ( Lot # PS02451, 97.1%) was administered in the diet to beagle dogs ( 4/ sex/ group) for up to 104 weeks at nominal doses of 0, 20, 100, or 3000 ppm ( equivalent to 0, 0.5, 2.5 or 75 mg/ kg/ day). Hematological, clinical chemistry and urinalysis measurements were performed on all dogs at 0, 4, 8, 13, 26, 41, 52, 65, 78, 91, and 104 weeks. During the 14 th week, 1 male and 1 female dog from each group was sacrificed and complete autopsies were performed. Selected organs were weighed and histopathologic examination was performed. At termination ( 104 107 weeks), all surviving dogs were sacrificed, necropsied and selected organs were weighed and histopathological examination was performed.

No mortality was observed in 104 weeks except one female dog from the high dose group died in comatose state during the 74th week. This dog and one dog from the control group experienced a body weight loss. Analysis of variance indicated that there was no difference in body weights between treated dogs and controls at 104 week. All dogs showed normal reflex reactions and appeared normal with the exception of one female dog in the high dose group that died. At the high dose, watery lacrimation was present for all dogs soon after the start of the study and persisted throughout the study. Mild yellowing of the sclera, mucous membranes, and abdominal skin was noted for three dogs in the high dose, which may be due to deposits of the chemical and/ or its metabolite or liver toxicity ( jaundice).

Hemoglobin values were slightly lower for the high dose starting at week 4. Similar trends were observed for the hematocrit values. Hemoglobin and hematocrit values were similar through out the study for the control, 20 ppm and 100 ppm dose group. Hematocrit values for the high dose fluctuated. The erythrocytic series showed immature cells and numerous polychromatophilic macrocytes. Actual thrombocyte ( platelets) counts were not conducted after 13 week because no differences in size or number were seen at the later intervals.

Clinical chemistry consisting of BUN ( blood urea nitrogen), methemoglobin, fasting blood sugar and creatinine remained within control values for all dogs. Statistical analysis of serum chemistry indicated that significant elevation in serum glutamic pyruvic transaminase ( SGPT), and serum alkaline phosphatase ( SAP) values occurred in the high dose group during specific intervals of the study. Increase in the values for these parameters were first noted at week 8. The SGOT, SGPT and SAP values were similar for the controls, 20 ppm and 100 ppm dose group dogs. Results of bromsulphthalein ( BSP) indicated elevated levels for two dogs in the high dose group. The 37 of 84 elevated levels were not sustained indicating that this was probably not related to liver dysfunction.

Urinalysis indicated highly pigmented urine in the high dose group. No remarkable abnormalities in urinalysis were observed between the controls and treated groups.

Organ weight data indicated that the 20 and 100 ppm treatment group organ weights were comparable to those of the control. However, statistically significant increases ( p < 0.05) of kidney, spleen, and liver weights were evident in the high dose group.

Histological examination revealed liver changes at the high dose characterized by irregular hepatic cell size, hepatic cell hypertrophy, increased pigmentation of hepatic cells and of liver macrophages. Changes in gall bladder were observed for the two dogs in the high dose group and one dog in the 20 ppm group.

The LOAEL is 3000 ppm ( equivalent to 75 mg/ kg/ day) based on reduced body weight gain, increased liver, spleen and kidney weights, hematological and clinical biochemistry, and histopathological changes in the liver. The NOAEL is 100 ppm ( equivalent to 2.5 mg/ kg/ day).

The submitted study is classified as acceptable/ guideline ( § 83 1[ b]) and does satisfy the requirements for a chronic toxicity study in dogs.

Dose and Endpoint for Establishing RfD: 2.5 mg/ kg/ day ( NOAEL), based on clinical chemistry ( increased alkaline phosphatase in both sexes and increased cholesterol in males), increased liver weights, hepatocyte hypertrophy, vacuolar alterations of the brain and spinal cord, prostate atrophy, degeneration of the seminiferous tubules, and hypospermia in the epididymides at 25 mg/ kg/ day. The older study ( MRID 00029056, 00082718, 00026810) showed reduced body weight gain, increased liver, spleen and kidney weights, hematological and clinical biochemical changes, and histopathological changes in the liver at 3000 ppm ( LOAEL= 75 mg/ kg/ day).

Uncertainty Factor( s): 100X [ 10 interspecies; 10X intraspecies]

Comments about Study/ Endpoint/ Uncertainty Factor( s): The study duration and route of exposure is appropriate for this risk assessment. The effects of concern ( decreased body weight gain, liver histopathology, increased liver weights and hematological changes) seen in this study were also seen in other subchronic and chronic studies in dogs.

4.4.4 Incidental Oral Exposure ( Short and Intermediate Term)

Study Selected: 90 Day feeding study in dogs Chronic RfD = 2.5 mg/ kg/ day ( NOAEL) = 0.025 mg/ kg/ day 100 ( UF) 38 of 84 MRID No.: MRIDs 00029056, 00026810, 00082718 Executive Summary: In a 90 day toxicity study ( MRID 00029056, 00026810), dicloran technical grade ( Lot # PS02451, 97.1%) was administered in the diet to beagles dogs ( 4/ sex/ group) for up to 104 weeks at nominal doses of 0, 20, 100, or 3000 ppm ( equivalent to 0, 0.5, 2.5 or 75 mg/ kg/ day). This is an interim report ( 13 Weeks) of a 104 week study. Hematological, clinical chemistry and urinalysis measurements were performed on all dogs at 0, 4, 8, and 13 weeks. During the 14th week, 1 male and 1 female dog from each group was sacrificed and complete autopsies were performed. Selected organs were weighed and histopathologic examination was performed.

No mortality was observed in 13 weeks. With the exception of one female dog receiving 100 ppm, all dogs on the 100 and 20 ppm levels gained body weight comparable with control dogs. In the high dose group, two male dogs showed significant body weight loss( 28 and 18% of their initial body weights) and one female showed slight weight loss. All dogs showed normal reflex reactions and appeared normal with the exception of one male dog in the high dose group and one female dog in the 100 ppm dose group. The female dog receiving 100 ppm in the diet showed hair loss around the ears, neck, and anal regions and male dog in the high dose group appeared emaciated and icterit.

Clinical chemistry consisting of BUN ( blood urea nitrogen), methemoglobin, fasting blood sugar and creatinine remained within control values for all dogs. Hematological examination revealed that the dogs receiving 20 and 100 ppm of dicloran in the diet could not be distinguished from control dogs. However, the dogs in the 3000 ppm dose group showed evidence of anemia. All males and two females at this level showed a decrease in hemoglobin and packed cell volume; the most marked reduction being in one male dog whose initial hemoglobin was 14.3 and at 13 week was 8.1 grams. Three of the four males showed leukocytosis. Thrombocyte counts were slightly elevated in the dogs receiving 3000 ppm than in the control dogs at 9 and 13 week measurements. The thrombocyte counts of the high dose level dogs ranged from 342,500 to 575,000 whereas the control dogs ranged from 241,500 to 315,000. Urinalysis indicated highly pigmented urine and more cast in the high dose level dogs compared to urine of the control dogs.

Biochemical values likewise on the dogs receiving 100 and 20 ppm levels in the diet could not be distinguished from control values. Two males and one female dog in the high dose group showed increase in serum alkaline phosphatase, serum glutamic pyruvic transaminase ( SGPT), serum glutamic oxalacetic transaminase ( SGOT), prothrombin time and slight reduction in serum protein.

Gross autopsy did not show any changes except tissue coloring of high dose dogs. Organ weights expressed relative to body weight suggest slightly enlarged livers and kidneys at the high dose. There was increase in spleen weights at the high dose, which may be due to destruction of red blood cells as indicated by decreases in hemoglobin and hematocrit values. Statistically analysis ( MRID 00086902) indicates that there was no difference in hemoglobin values, hematocrit values, and absolute and adjusted ( to body weight) liver weights at 100 ppm dose level. 39 of 84 Histological examination of the tissues revealed no changes related to compound administration other than some moderate degenerative and chronic inflamatory hepatic changes in the 3000 ppm level.

The LOAEL is 3000 ppm ( equivalent to 75 mg/ kg/ day) based on reduced body weight gain, increased liver, spleen and kidney weights, hematological and clinical biochemistry, and histopathological changes in the liver. The NOAEL is 100 ( equivalent to 2.5 mg/ kg/ day).

The submitted study is classified as acceptable/ guideline ( § 82 2[ b]) and does satisfy the requirements for a subchronic toxicity study in dogs.

Dose and Endpoint for Risk Assessment: LOAEL = 75 mg/ kg/ day based on changes in hematological ( decreased hemoglobin and hematocrit at 4, 8, and 14 weeks) and clinical biochemistry parameters, reduced body weight gain, increased liver, spleen and kidney weights, and histopathological changes in the liver.

Comments about Study/ Endpoint: The selected dose/ endpoints are appropriate for the route and duration of exposure and are supported by the 1 and 2 year chronic toxicity studies in dogs with a NOAEL of 2.5 mg/ kg/ day.

4.4.5 Dermal Absorption No dermal absorption studies are available on dicloran. Dermal absorption of structurally related compounds varied. A comparison of the rabbit 21 day dermal toxicity NOAEL [ 120 mg/ kg/ day] and the rabbit developmental toxicity NOAEL [ 50 mg/ kg/ day] provides an upper bound estimate of 42% dermal absorption.

4.4.6 Dermal Exposure ( Short, Intermediate and Long Term)

Short and Intermediate Term Study Selected: 21 day dermal toxicity study MRID No.: 40555101 Executive Summary: In a repeated dose dermal toxicity study ( MRID 40555101), dicloran ( 96.2 97.5% purity, Lot/ Batch #: CR 20642/ 3) was applied to the clipped intact skin of five New Zealand White albino rabbits/ sex/ dose at nominal doses of 0 ( distilled water), 12, 120, or 1,200 mg/ kg/ day for 6 hours/ day, 7 days/ week, for a total of 21 applications during a 21 day period.

No rabbits died during the course of the study as a result of treatment and no treatment related clinical signs of systemic toxicity were observed. No differences were reported for either body weight or food consumption. Slight transient erythema was observed in 2/ 10 rabbits at low dose. All of the mid dose rabbits displayed slight erythema ( most displaying this reaction by second week), and slight edema was observed in 7/ 10 animals during the third week. At the high dose, 40 of 84 slight erythema was observed during the second week, but by days 12 or 16, yellow staining ( test compound) of the treated skin precluded the assessment of erythema. Slight edema observed on day 8 in one high dose female, and two high dose males and all high dose females displayed edema from days 13 to 17, which persisted to the study termination. Statistically significant lower methemoglobin levels were recorded for all treated females, but the increase was not dose related. In male rabbits, statistically significant higher adrenal weights ( 260 g treated vs 191 g controls) were recorded for high dose group. For female rabbits in the high dose group adrenal weights were higher than controls ( 211 g treated vs 190 g controls) but they were not statistically significant.

The LOAEL can be set at 1,200 mg/ kg/ day based on increased adrenal weights ( 36% over controls) in males. The NOAEL is 120 mg/ kg/ day. Slight dermal irritation at the site of application was observed at the mid and high dose levels.

This study is classified acceptable ( § 82 2)/ Guideline and does satisfy the requirement for a repeated dose dermal toxicity study.

Dose and Endpoint for Risk Assessment: NOAEL = 120 mg/ kg/ day based on increased ( 36%) adrenal weights in males ( 260 g treated vs. 191 g controls) at 1200 mg/ kg/ day.

Comments about Study/ Endpoint: The repeated [ 21 day] dermal toxicity study in rabbits was selected for the exposure scenario because the route of exposure is appropriate. The effect observed was increased ( 36%) adrenal weights in males ( 260 g treated vs. 191 g controls). This finding was corroborated by the histopathological changes observed in the adrenals at 150 mg/ kg/ day in the 90 day feeding study in rats ( MRIDs 00029056 and 00082718).

Long Term Study Selected: Same as Chronic Reference Dose ( RfD)

MRID No.: Same as Chronic Reference Dose ( RfD)

Executive Summary: Same as Chronic Reference Dose ( RfD)

Dose and Endpoint for Risk Assessment: 2.5 mg/ kg/ day ( NOAEL), based on reduced body weight gain, increased liver, spleen and kidney weights, hematological and clinical biochemical changes, and histopathological changes in the liver at 3000 ppm ( LOAEL= 75 mg/ kg/ day).

Comments about Study/ Endpoint:. In the absence of dermal toxicity studies, an oral study is selected for this risk assessment. The 100% default value should be used in route to route extrapolation. 41 of 84 4.4.7 Inhalation Exposure ( Short, Intermediate and Long Term)

Short and Intermediate Term Study Selected: Same as short term incidental oral MRID No.: Same as short term incidental oral Executive Summary: Same as short term incidental oral Dose and Endpoint for Risk Assessment: Same as short term incidental oral Uncertainty Factor( s): 100X [ 10 interspecies; 10X intraspecies]

Comments about Study/ Endpoint: The selected dose/ endpoints are appropriate for the duration of exposure. In the absence of inhalation toxicity studies, an oral study is selected for this risk assessment. The 100% default value should be used in route to route extrapolation.

Long Term Study Selected: Same as Chronic Reference Dose ( RfD)

MRID No.: Same as Chronic Reference Dose ( RfD)

Executive Summary: Same as Chronic Reference Dose ( RfD)

Dose and Endpoint for Risk Assessment: Same as Chronic Reference Dose ( RfD)

Comments about Study/ Endpoint: The selected dose/ endpoints are appropriate for the route and duration of exposure. In the absence of inhalation toxicity studies, an oral study is selected for this risk assessment. The 100% default value should be used in route to route extrapolation.

4.4.8 Margins of Exposure Summary of Target Margins of Exposure ( MOEs) for Risk Assessment is shown below:

Route Duration Short Term ( 1 30 Days) Intermediate Term ( 1  6 Months) Long Term (> 6 Months)

Occupational ( Worker) Exposure Dermal 100 100 100 Inhalation 100 100 100 * Since DCNA has no residential uses, only the target MOEs for occupational exposure are presented. 42 of 84 For Occupational exposure: This is based on the conventional uncertainty factor of 100X ( 10X for intraspecies variation and 10X for interspecies extrapolation).

4.4.9 Recommendation for Aggregate Exposure Risk Assessments 4.4.10 Classification of Carcinogenic Potential The committee members of CARC evaluated the carcinogenicity studies in rats and mice and other toxicity data on dicloran and placed DCNA under the classification of " Suggestive Evidence of Carcinogenic Potential." No quantification of cancer was recommended. This classification is based on the following:

° There was a statistically significant pairwise increase in benign testicular tumors in the male rats the high dose. This dose was considered adequate and not excessive.

° The high dose's response was outside of the laboratory's historical control and also showed an increase in testicular hyperplasia.

° There was a borderline increase ( p= 0.06) in endometrial adenocarcinomas in the female rats and was also accompanied by some increase in hyperplasia.

° The tumor response analysis for the low and mid dose endometrial adenocarcinomas was confounded by limited numbers of tissue examined e. g. 29 and 21 instead of 50.

° There was a positive Ames test that was repeated as positive.

° There was some evidence that a plant metabolite, but not a livestock metabolite, had carcinogenic activity.

° The mouse study was negative and tested at adequate doses.

<IP_ADDRESS> Combined Chronic Toxicity/ Carcinogenicity Study in Rats MRID No.: 46360701 Executive Summary: In a combined chronic toxicity/ carcinogenicity study ( MRID 46360701), dicloran ( 94.9% a. i.; batch/ lot # 000313) was administered in the diet to groups of 50 male and 50 female Wistar ( HsdCpb: WU) rats at concentrations of 0, 60, 240 or 1200 ppm for the first 105 days. The dietary concentration was raised from 1200 ppm to 1440 ppm on treatment day 106 because the effects on body weight gains in animals, especially females was less than expected from the 90 day range finding study. Therefore, the calculated time weighted average dietary concentration for the high dose main group was 1405 ppm. The dietary concentrations were equivalent to 0, 2.8, 11.3, and 71.0 mg/ kg/ day, respectively, for males and 0, 3.7, 15.0, and 94.1 mg/ kg / day, respectively, for 43 of 84 females. Additional groups of 10 male and 10 female rats were administered the same diets for 12 months for interim evaluations.

No treatment related signs of toxicity were observed during daily observations, weekly physical examinations, or monthly examinations. No adverse neurological effects were observed as assessed by the functional observational battery ( FOB) conducted at 12 months. Survival was not affected by treatment with the test material, and no eye abnormalities were observed during ophthalmoscopic examinations. High dose male and female rats gained 48% and 31% less weight, respectively, than controls during the first week of treatment resulting in body weights 16% and 8% ( both p  0.05) less than that of controls. Mean body weight of high dose males remained 8 13% ( p  0.05) less than that of controls for the remainder of the study, and mean body weight of high dose females was 10 14% ( p  0.05) less than that of controls during the second year of the study. High dose males and females gained 13% ( p  0.05) and 20% ( p  0.05) less weight, respectively, than controls for the entire study. High dose rats consumed significantly less food than controls during the first 17 weeks ( males) and 73 weeks ( females); total food consumption was not affected and food efficiency for the entire study was similar for high dose and control rats. Body weight, weight gain, and food consumption were not significantly and adversely affected in low and mid dose rats of either sex.

Analysis of hematologic parameters showed very mild transient changes in red blood cell ( RBC) count, mean cell volume, and mean cell hemoglobin in high dose male and female rats and was indicative of a mild hyperchromatic macrocytic anemia. These changes are not considered adverse. Other hematologic changes ( total white blood cell ( WBC), neutrophil, and lymphocyte counts in male and female rats and prothrombin time and platelet count in females) were not considered treatment related. Significant changes in clinical chemistry parameters in high dose rats were transient and were not correlated with histopathologic findings.

Statistically significant changes in absolute organ weights and organ: body weight ratios were due to decreased terminal body weight. Postmortem examination showed no treatment related gross findings in male or female rats receiving any dose of the test material. The primary target for microscopic lesions appeared to be the brain and spinal cord. Vacuolation was observed in the cerebral cortex including the optic chiasma, cerebellar cortex, and medulla/ pons regions of the brain and in the cervical, thoracic, and lumbar segments of the spinal cord of high dose males and females at 12 and 24 months. In the main group, vacuolation was observed in the brain of 62 96% of males and 84 98% of females and in the spinal cord of 56 86% of males and 46 86% of females compared with 0 4% of male controls and 0 2% of female controls. In addition, vacuolation in the optic chiasma in the cerebral cortex occurred in 28% of high dose males and 34% of high dose females compared with none of the controls. Vacuolar changes in the optic nerve were observed in 8% ( p= 0.059) of high dose females compared with none of the controls, and the incidence of Leydig cell hyperplasia in the testes was 34% ( p  0.05) in high dose males compared with 8% of controls.

The lowest observed adverse effect level ( LOAEL) for dicloran in rats is 1405 ppm ( 71.0 and 94.1 mg/ kg bw/ day for males and females, respectively) based on reduced body weight, reduced body weight gain, and histopathologic lesions in the brain and spinal cord of both sexes, optic nerve in females and Leydig cell hyperplasia in the testes in males. In addition, treatment related 44 of 84 increase in the relative weights in the liver, brain and testes in males and relative liver weight in females were observed.

The no observed adverse effect level ( NOAEL) is 240 ppm ( 11.3 and 15.0 mg/ kg bw/ day for males and females, respectively).

At the doses tested, the incidence of benign Leydig cell tumors was 0/ 50, 1/ 50, 1/ 50, and 5/ 50 ( p  0.05) in control, low, mid, and high dose males rats, respectively. All Leydig tumors were found in animals sacrificed at study termination. The incidence of malignant endometrial adenocarcinoma was 3/ 50, 7/ 29, 7/ 21, and 9/ 50 ( p= 0.061) in control, low, mid, and high dose females, respectively. Both tumor types occurred in hormone responsive tissues, but there was no other evidence suggesting that dicloran is an endocrine disruptor. The increased incidences of Leydig cell tumors and endometrial adenocarcinoma is considered some evidence of carcinogenicity of dicloran in rats. Dosing was considered to be sufficient for evaluating the carcinogenic potential for this pesticide based on decreased body weight and weight gain in male and female rats in the high dose groups.

This chronic toxicity/ carcinogenicity study in the rat is Acceptable/ Guideline and satisfies the guideline requirement for a chronic toxicity/ carcinogenicity study in the rat [ OPPTS 870.4300); OECD 453].

Discussion of Tumor Data The incidence of Leydig cell tumors was increased in high dose male rats compared with the control incidence and the incidence of endometrial adenocarcinoma was marginally increased in high dose female rats.

Adequacy of the Dose Levels Tested Dosing was considered adequate and not excessive based on reduced body weight, reduced body weight gain, and histopathologic lesions in the brain and spinal cord of both sexes, optic nerve in females and Leydig cell hyperplasia in the testes in males..

<IP_ADDRESS> Carcinogenicity Study in Mice MRID No. 40977101 Executive Summary:

In a carcinogenicity study ( MRID# 40977101), CD 1 ( ICR) BR mice ( 50/ sex/ group) were administered via diets for 80 weeks with dicloran ( 96.2 to 97.2% a. i.) at dose levels of 0, 50, 175 or 600 ppm ( mean compound intake 0, 7.4, 24.5 or 86.5 mg/ kg/ day for males and 0, 10.1, 35.4 or 118.8 mg/ kg/ day for females, respectively). In addition to the above, groups of 5 mice/ sex/ dose were used for microbiological screening and baseline histopathology. 45 of 84 Dicloran was not oncogenic in male or female CD 1 mice when fed at dietary levels of 50, 175, or 600 ppm for 80 weeks. No adverse effects were observed on mortality, clinical signs, body weight, palpable masses, food consumption or conversion, hematology, macroscopic pathology, or tumor incidence. Correlation of gross and microscopic findings was conducted for this study. Histopathologic examination showed the liver to be the principal target organ with changes noted at the high dose. Histopathologic changes in the liver, which were noted at the high dietary level ( 600 ppm), included centrilobular hepatocyte enlargement, centrilobular hemosiderosis, focal necrosis ( males), acute inflammatory cell infiltration ( males), single cell necrosis ( males), and vacuolation of centrilobular hepatocytes ( females). Other organs, in which histopathologic changes were seen in animals administered the high dietary level, were spleen ( increased incidence of erythropoiesis in males) and uterus ( increase in severity and incidence of cystic endometrial hyperplasia). Also, liver weight in females and kidney weight in males were elevated in high dose animals. Since no treatment related changes were evident at the lower dosages ( 50 or 175) ppm, the No Observed Adverse Effect Level ( NOAEL) in this study was 175 ppm ( 24.5 mg/ kg/ day). The Lowest Observed Effect Level ( LOAEL) was 600 ppm ( 86.5 mg/ kg/ day) based on histopathologic changes in organs ( liver, spleen, uterus) and increased in liver and kidney weights.

This study is classified as Acceptable/ Guideline and satisfies the guideline requirement for a carcinogenicity study ( 83 2( b)) in the mice.

Discussion of Tumor Data The administration of dicloran to mice at doses up to 600 ppm ( 86.5 mg/ kg/ day for males, 118.8 mg/ kg/ day for females) in the diet did not result in an overall treatment related increase in incidence of tumor formation.

Adequacy of the Dose Levels Tested Under conditions of this study, dosing is considered adequate to assess the carcinogenic potential of dicloran based upon histopathologic changes in organs ( liver, spleen, uterus) and increased liver and kidney weights seen at 600 ppm ( 86.5 mg/ kg/ day for males, 118.8 mg/ kg/ day for females).

4.4.11 Mutagenicity REVERSE GENE MUTATION ASSAY In independently performed microbial reverse gene mutation assays ( MRID No. 40508801), Salmonella typhimurium strains TA98, TA100, TA1535, TA1537 and TA1538 were exposed to dicloran ( 97.5 % ai) at concentrations of 50 5000 µ g/ plate with and without S9 activation in both trials. The S9 fraction was derived from Aroclor 1254 induced male rat ( strain not specified) livers and the test material was delivered to the test system in dimethyl sulfoxide ( amount not specified).

Dicloran induced reverse mutations when tested at 5000 and 1500 µ g/ plate in strains TA1538 and TA98 ( ± S9) and in TA100 ( S9). Dicloran did not induce reverse mutations in TA1535, TA1537 46 of 84 ( ± S9) or in TA100 (+ S9). Positive controls confirmed the sensitivity of the tester strains. A repeat assay confirmed the results of the first study. Therefore, it is concluded that dicloran is genotoxic in the strains TA1538, TA98 and TA100.

This study is classified as acceptable and satisfies the guideline requirements for a bacterial gene mutation assay ( 84 2).

In a second study, in independently performed microbial reverse gene mutation assays ( MRID No. 00046435, 00046436 and 00087018), Salmonella typhimurium strains TA1535, TA1537, TA1538, TA98 and TA100 and Escherichia coli WP2 uvrA were exposed to dicloran ( 99.9 % ai) at concentrations of 16 1000 µ g/ plate with and without S9 activation in both trials and reversion to histidine or tryptophan prototrophy was determined. The S9 fraction was derived from phenobarbitone treated male Boots Wistar rat livers and the test material was delivered to the test system in dimethyl sulfoxide. It was also tested in Bacillus subtilis strains H17 Rec' and M45 Rec' in the Rec assay.

Dicloran of 99.9% purity proved to be without mutagenic activity in the " Ames Test" using Salmonella typhimurium TA1535, TA1537, TA1538, TA98 and TA100 indicator strains. Semiquantitative assays with Escherichia coli WP2 and WP2 uvrA also gave negative results. Dicloran did not indicate mutagenic activity in the Rec assay using Bacillus subtilis. Therefore, it is concluded that dicloran ( purified) is not genotoxic in the bacterial strains utilized in this study.

CHROMOSOME ABERRATION ASSAY In independently conducted in vitro mammalian cell cytogenetic assays ( MRID No: 40508802), human lymphocytes derived from a unspecified source were exposed for 4 hours to dicloran ( 97.5 % ai) at doses of 2, 10 and 20 µ g/ mL with or without S9 activation using a 22 hour cell harvest. Metaphases were collected and scored for structural chromosome aberrations. The S9 liver homogenate was derived from Aroclor 1254 induced Sprague Dawley rat livers and the test material was delivered to the test system in dimethylsulfoxide ( DMSO).

Two replications were used at each dose level and four replications for controls. Positive controls demonstrated the sensitivity of the test system. In cells tested without metabolic activation, the results were statistically significant increased at the mid and high doses ( 10 and 20 µ g/ mL). The results were slightly increased over the low dose. In cells tested with metabolic activation the study was negative at all doses. Therefore, the EPA review ( TXR No. 006845) concluded that dicloran technical induced a slight increase in aberrations in human lymphocytes in culture. However, a subsequent review ( TXR No. 007841) concluded that dicloran was found to be negative in this in vitro test system. The significantly increased percentage of cells with aberrations in treatment groups exposed to nonactivated 10 and 20 µ g/ mL dicloran resulted from the absence of aberrations in the vehicle control group. However, the percentage of aberrant cells ( 1.5% in the mid dose group and 2.5% in the high dose group) were well within the historical background range observed by the contract reviewers in evaluating other human lymphocytes cytogenetic assays ( 0 3.0%). It is concluded that the slight increases in aberrant cells compared to concurrent solvent control and the types of induced aberrations do not provide sufficient evidence of a clastogenic effects. Therefore, dicloran did not induce a clastogenic effect. 47 of 84 This study is classified as acceptable and satisfies the guideline requirement for an in vitro cytogenetic assay.

UNSCHEDULED DNA SYNTHESIS ASSAY In independently conducted in vitro unscheduled DNA synthesis ( UDS) assays ( MRID No. 40619001), primary rat hepatocytes from normal adult Fischer 344 males were exposed to eight concentrations of dicloran ( 97.5 % ai) ranging from 3.0 10 µ g/ mL in both trials; hepatocytes treated with all doses # 10 µ g/ mL were scored for net nuclear grains to determine UDS. The test material was delivered to the test system in dimethyl sulfoxide.

The results from both assays were in good agreement, and showed that the selected doses were not cytotoxic or genotoxic in the target cell. The presence of test material precipitation at the highest assayed level ( 10 µ g/ mL) indicated that the solubility limit of dicloran was reached. It is concluded that dicloran was adequately tested, and there was no evidence of a genotoxic effect.

The study is classified as acceptable and satisfies the guideline requirement for an unscheduled DNA synthesis ( genotoxicity) assay ( 84 2).

Summary of Toxicological Endpoints The doses and toxicological endpoints selected for various exposure scenarios are summarized below.

Exposure Scenario Dose Used in Risk Assessment, UF Special FQPA SF* and Level of Concern for Risk Assessment Study and Toxicological Effects Acute Dietary ( females 13 49) NOAEL = 50 mg/ kg/ day UF = 100 Acute RfD = 0.5 mg/ kg/ day FQPA SF = 10X aPAD = acute RfD ( 0.5) FQPA SF ( 10)

= 0.05 mg/ kg/ day Developmental toxicity study in rats LOAEL = 100 mg/ kg/ day based on increased incidences of supernumerary rudimentary ribs and also decreased fetal weights.

Acute Dietary ( general population including infants and children) NOT APPLICABLE. A dose and endpoint were not selected for this population group because there were no effects observed in oral toxicology studies including maternal toxicity in the developmental toxicity studies in rats and rabbits that are attributable to a single exposure ( dose). 48 of 84 Exposure Scenario Dose Used in Risk Assessment, UF Special FQPA SF* and Level of Concern for Risk Assessment Study and Toxicological Effects Chronic Dietary ( All populations) NOAEL= 2.5 mg/ kg/ day UF = 100 Chronic RfD = 0.025 mg/ kg/ day FQPA SF = 10X cPAD = chronic RfD FQPA SF ( 10)

= 0.0025 mg/ kg/ day One Year Chronic Toxicity Study in Dogs LOAEL = 25 mg/ kg/ day based on clinical chemistry ( increased alkaline phosphatase in both sexes and increased cholesterol in males), increased liver weights, hepatocyte hypertrophy, vacuolar alterations of the brain and spinal cord, prostate atrophy, degeneration of the seminiferous tubules, and hypospermia in the epididymides Short Term Incidental Oral ( 1 30 days) NOAEL= 2.5 mg/ kg/ day Occupational = NA 90 Day feeding  Dog LOAEL = 75 mg/ kg/ day based on changes in hematological ( decreased hemoglobin and hematocrit at 4, 8, and 14 weeks) and clinical biochemistry parameters, reduced body weight gain, increased liver, spleen and kidney weights, and histopathological changes in the liver Intermediate Term Incidental Oral ( 1 6 months) NOAEL = 2.5 mg/ kg/ day Occupational = NA Same as for Short Term Incidental Oral Short Term Dermal ( 1 to 30 days) NOAEL= 120 mg/ kg/ day Occupational LOC for MOE = 100 rabbit 21 day dermal toxicity study LOAEL = 1200 mg/ kg/ day based on increased ( 36%) adrenal weights in males. This finding was corroborated by the histopathological changes observed in the adrenals at 150 mg/ kg/ day in the 90 day feeding study in rats ( MRIDs 00029056 and 00082718). 49 of 84 Exposure Scenario Dose Used in Risk Assessment, UF Special FQPA SF* and Level of Concern for Risk Assessment Study and Toxicological Effects Intermediate Term Dermal ( 1 to 6 months) NOAEL = 120 mg/ kg/ day ( a) Occupational LOC for MOE = 100 Same as for Short Term Dermal Long Term Dermal (> 6 months) Oral NOAEL= 2.5 mg/ kg/ day ( dermal absorption rate = 100%) Occupational LOC for MOE = 100 Same as for Chronic RfD Short Term Inhalation ( 1 to 30 days) oral NOAEL= 2.5 mg/ kg/ day ( inhalation absorption rate = 100%) ( a) Occupational LOC for MOE = 100 Same as for Short Term Incidental Oral Intermediate Term Inhalation ( 1 to 6 months) oral NOAEL = 2.5 mg/ kg/ day ( inhalation absorption rate = 100%) ( a) Occupational LOC for MOE = 100 Same as for Short Term Incidental Oral Long Term Inhalation (> 6 months) oral NOAEL= 2.5 mg/ kg/ day ( inhalation absorption rate = 100%)( a) Occupational LOC for MOE = 100 Same as for Chronic RfD Cancer ( oral, dermal, inhalation) " Suggestive Evidence of Carcinogenic Potential"

UF = uncertainty factor, FQPA SF = Special FQPA safety factor, NOAEL = no observed adverse effect level, LOAEL = lowest observed adverse effect level, PAD = population adjusted dose ( a = acute, c = chronic), RfD = reference dose, MOE = margin of exposure, LOC = level of concern, NA = Not Applicable NOTE: The Special FQPA Safety Factor assumes exposure databases ( dietary food, drinking water, and residential) are complete and risk assessment for each potential exposure scenario includes all metabolites and/ or degradates of concern and does not underestimate the potential risk for infants and children.

a: The inhalation exposure limits for all durations were based on the NOAELs from oral studies for each exposure scenario since no route specific study was available. Since no inhalation absorption data are available, toxicity by the inhalation route was considered to be equivalent to toxicity by the oral route of exposure. b: Dicloran does not have any residential uses; therefore, the residential LOC was not included. 50 of 84 4.5 Special FQPA Safety Factor FQPA directs EPA, in setting pesticide tolerances, to use an additional tenfold margin of safety to protect infants and children, taking into account the potential for pre and post natal toxicity and the completeness of the toxicology and exposure databases. The statute authorizes EPA to modify this tenfold FQPA safety factor only if reliable data demonstrate that the resulting level of exposure will be safe for infants and children.

The toxicity database for DCNA includes acceptable developmental and reproductive toxicity studies, and these studies showed no increase in susceptibility in fetuses and pups with in utero and postnatal exposure. However, EPA has determined that all of the FQPA safety factor( 10X) must be retained to account for database uncertainties.

DCNA appears to elicit neuropathology ( vacuolation in the brain) at doses of 25 75 mg/ kg following exposures greater than 90 days. The neuropathological effects were greater in fourweek old rats than seven week old rats, indicating that age could be a variable in this neurotoxicity. The study is necessary to fully characterize potential fetal neuropathology. Since the DCNA database does not include a DNT study, and a DNT study is required, an FQPA safety factor must be retained for exposure scenarios through which exposure to children or pregnant women is expected.

4.6 Endocrine disruption EPA is required under the FFDCA, as amended by FQPA, to develop a screening program to determine whether certain substances ( including all pesticide active and other ingredients) " may have an effect in humans that is similar to an effect produced by a naturally occurring estrogen, or other such endocrine effects as the Administrator may designate." Following the recommendations of its Endocrine Disruptor Screening and Testing Advisory Committee ( EDSTAC), EPA determined that there was scientific bases for including, as part of the program, the androgen and thyroid hormone systems, in addition to the estrogen hormone system. EPA also adopted EDSTAC's recommendation that the Program include evaluations of potential effects in wildlife. For pesticide chemicals, EPA will use FIFRA and, to the extent that effects in wildlife may help determine whether a substance may have an effect in humans, FFDCA authority to require the wildlife evaluations. As the science develops and resources allow, screening of additional hormone systems may be added to the Endocrine Disruptor Screening Program ( EDSP).

When the appropriate screening and/ or testing protocols being considered under the Agency's EDSP have been developed, dicloran may be subjected to additional screening and/ or testing to better characterize effects related to possible endocrine disruption.

It is noted that the results of the chronic dietary feeding study in dogs showed that dicloran produced prostate atrophy, degeneration of the seminiferous tubules, and hypospermia in the epididymides. In addition, dicloran produced increased incidences of Leydig cell tumors and endometrial adenocarcinoma in the chronic dietary feeding study in rats. No data indicates that these findings are related to hormonal effects. 51 of 84 5.0 Public Health Data 5.1 Incident Reports The following databases have been consulted for the poisoning incident data on the active ingredient dicloran: OPP Incident Data System ( IDS), Poison Control Centers, California Department of Pesticide Regulation, National Pesticide Information Center ( NPIC), and the National Institute of Occupational Safety and Health's Sentinel Event Notification System for Occupational Risks ( NIOSH SENSOR).

A total of seven cases were located in the Poison Control Center records from 1993 through 2001. Two involved children under age six, one was exposed in an occupational setting, and the remaining four were adults exposed in a non occupational setting. Only one case has medical outcome determined with dermal symptoms characterized as minor. There was a potentially toxic case that did not receive follow up treatment. Nothing can be concluded from such a small number of cases, except that there is no positive evidence of significant harm in the small number of cases examined. There were no poisoning reports due to DCNA exposure according to the OPP IDS, California Department of Pesticide Regulation ( 1982 2002), NPIC ( 1984 1991), and NIOSH SENSOR ( 1998 2002). Additionally, there were no incidents of poisoning or other human health effects related to DCNA found in scientific literature. Very few incidents of illness have been reported due to DCNA; as a result, no recommendations are warranted.

6.0 Exposure Characterization/ Assessment 6.1 Dietary Exposure/ Risk Pathway 6.1.1 Residue Profile Dicloran is currently registered for preharvest and postharvest uses on various raw agricultural commodities. Tolerances are established under 40 CFR § 180.200 for residues of dicloran per se in/ on the following commodities: apricots, beans ( snap), celery, cherries ( sweet), cucumbers, endive ( escarole), fennel, garlic, grapes, lettuce ( head and leaf), nectarines, onions, peaches, plums ( fresh prunes), potatoes, rhubarb, shallots, and tomatoes. It is also registered for postharvest uses on carrots and sweet potatoes.

The current tolerance expression is in harmony with the MARC's determination that only the parent compound should be included in the tolerance expression for primary crops. It is also compatible with the Codex definition of residues for dicloran. No tolerances have been established for livestock commodities.

The registrant has expressed interest in supporting postharvest uses on stone fruit that were previously registered. A petition, PP# 7F04879, is pending for the establishment of permanent tolerances resulting from proposed uses on peanuts ( preharvest), carrots ( preharvest), and tomatoes ( postharvest). Preharvest treatments are typically made with either aerial or ground 52 of 84 equipment, whereas postharvest treatments are made as sprays and dips. An IR 4 petition, PP# 5E04557, is pending for uses on leafy vegetables subgroup 4a, except spinach.

The nature of the residue in plants is adequately understood based on acceptable metabolism studies with dicloran on peaches, potatoes, and lettuce. The residues of concern for all primary crops are the parent only, DCNA, for the tolerance expression and for risk assessment purposed the residues of concern are the parent plus 2,6 dichloro 4 hydroxyaniline ( DCHA) for all primary crops excluding potatoes. The residues of concern in potatoes, for the purpose of risk assessment, are dicloran, DCHA, and the group of metabolites designated as Unknown 1.

The nature of the residue in livestock is adequately understood provided the petitioner could provide supporting storage stability data to validate the integrity of samples from the goat and hen metabolism studies submitted in conjunction with PP# 7F04879. The residues that need to be included in the tolerance expression for livestock commodities includes dicloran and 4 amino 2,6 dichlorophenol ( DCAP). For risk assessment purposes, the residues of concern in livestock commodities are dicloran, DCAA, DCHA, DCAP, DCNP, and the A 1 metabolite. Since the MARC concluded that the metabolic pathways of dicloran in livestock and rats are likely to be qualitatively similar, a swine metabolism study need not be conducted.

The nature of the residue in rotational crops is adequately understood. Dicloran per se is the residue of concern in/ on rotational crops for tolerance expression. For risk assessment, the residues of concern are dicloran and the dichloroaniline containing metabolites. A limited field rotational crop study is available, however additional data from limited field rotational crop trials are required. The requested trials should be conducted at the maximum seasonal application rate, and samples should be analyzed for the total dichloroaniline containing residues. Extensive rotational crop studies may be required if residues are detected at the desired plantback interval. The required trials will need supporting storage stability data for total dichloroaniline containing residues if samples are stored for more than 30 days prior to sample analysis.

The HED MARC's decisions and recommendations for the residues of concern for tolerance and risk assessment purposes are triggering new sets of data requirements for residue analytical methods, storage stability, magnitude of the residue in plants and livestock, and rotational crops. These new requirements are incorporated in this risk assessment.