Tolclofos - methyl Human Health Risk Assessment DP No. 387242

Page 1 of 49 **UNITED STA TES ENVIRONMENTA**  **L PROTECTION A GENCY** 

**WA SHINGTON, D.C. 20460**  **OFFICE OF CHEMICAL SAFETY AND POLLUTION PREVENTION** 

**MEMORANDUM** Date : March 22 , 2012 **SUBJECT:** Tolclofos - methyl : Human Heal th Risk Assessment for Proposed New Seed Treatment Uses **PC Code:** 128905 **DP Barcode:** D387242 **Decision No.:** 443921 **Registration No. :**  **Petition No.: Regulatory**  **Action:** Section 3 Registration **Risk A**  **ss essment Type:**  Single Chemical/ No Aggregate **Case No.:** None **T XR No.:**  None **CAS No.:** 57018 - 04 - 9 **MRID No.:** None **40 CFR: FROM:**  Charles Smith , Senior Environmental Scientist/Risk Assessor

Elissa Reaves , Ph.D., Senior Toxicologist Sheila Piper , Senior Chemist Shalu Shelat , In dustrial Hygienist Risk Assessment Branch VI Health Effects Division (7509P) **THROUGH:** Felecia Fort , Chief

Risk Assessment Branch V I Health Effects Division (7509P) and P.V. Shah, Ph.D. Margarita Collantes Risk Assessment Review Committee Health Effects Division **TO:** Lisa Jones /Mary Waller , Risk Management Team 21 Herbicide Branch Registration Division (7505P) Risk Management DivisionTolclofos - methyl Human Health Risk Assessment DP No. 387242

Page 2 of 49 The Health Effects Division (HED) of the Office of Pesticide Programs (OPP) is charged with estimating the risk to human health from exposure to pesticides. Valent U.S.A. Corporation has requested registrati on of the new active ingredient (ai) tolclofos - methyl for seed treatment use on various crops, turf grass, ornamental flower, and conifers . The Registration Division (RD) of OPP has requested that HED evaluate hazard and exposure data and conduct dietary , occupational, and aggregate exposure assessments, as needed, to estimate the risk to human health that will result from the proposed seed treatment use s of tolclofos - methyl . HED has evaluated the toxicity and exposure databases for the new active ingredient, tolclofos methyl , and has conducted a human health risk assessment in support of the proposed use s . Based on this assessment, HED has determined that there are no potential risk estimates of concern for the proposed uses of tolclofos - me thyl. **HED recommends that the requested uses be granted.** A summary

of the findings and an assessment of human health risk resulting from the proposed use s for tolclofos - methyl are provided in this document. The HED team members contributing to this risk assessment include Shalu Shelat (occupational/residential assessments), Sheila Piper ( residue chemistry assessment), Elissa Reaves (hazard evaluation ) , and Charles Smith (risk assessment) .Tolclofos - methyl Human Health Risk Assessment DP No. 387242

Page 3 of 49 1.0 Executive Summary ................................ ................................ ................................ ................... 4 2.0 HED Recommendations ................................ ................................ ................................ ............ 7 2.1 Data Deficiencies ................................ ................................ ................................ ................... 7 2.2 Tolerance Considerations ................................ ................................ ................................ ....... 8 2.2.1 Enforcement Anal yt ical Method ................................ ................................ ..................... 8 2.2.2 International Harmonization ................................ ................................ ........................... 8 2.2.3 Recommended Tolerances ................................ ................................ .............................. 8 2.3 Label Recommendations ................................ ................................ ................................ ........ 8 2.3.1 Recommendations from Residue Reviews ................................ ................................ ..... 8 2.3.2 Recommendations from Occupational Assessment ................................ ........................ 8 3.0 In gredient Profile ................................ ................................ ................................ ....................... 9 3.1 Structure and Nomenclature ................................ ................................ ................................ ... 9 3.2 Phy sical/Chemical Characteristics ................................ ................................ ......................... 9 3.3 Summary

of Existing/Proposed Uses ................................ ................................ ................... 10 3.4 Anticipated Exposure Pathway s ................................ ................................ ........................... 11 3.5 Consideration of Environmental Justice ................................ ................................ .............. 11 4.0 Hazard Characterization/Assessment ................................ ................................ ...................... 11 4.1 Toxicology

Studies Available for Analy sis ................................ ................................ ......... 11 4.2 Absorption, Distribution, Metabolism, and Elimination (ADME) ................................ ...... 12 4.2.1 Dermal Absorption ................................ ................................ ................................ ........ 13 4.3 Toxicological Effects ................................ ................................ ................................ ........... 13 4.4 Consideration of Toxicity to Children ................................ ................................ ................. 14 4.4.1 Completeness of the Toxicology Database ................................ ................................ ... 14 4.4.2 Evidence of Neurotoxicity ................................ ................................ ............................ 15 4.4.3 Evidence of Sensitivity /Susceptibility

in the Developing or Young Animal ............... 15 4.4.4 Residual Uncertaint y in the Exposure Database ................................ ........................... 16 4.4 Toxicity

Endpoints and Points of Departure Selections ................................ ....................... 1 6 4.5.1 Dose Response Assessment ................................ ................................ .......................... 16 4.5.2 Recommendation for Combining Routes of Exposure for Risk Assessment ............... 17 4.5.3 Cancer Classification and Risk Assessment Recommendations ................................ .. 17 4.5.4 Summary

of Points of Departure and Toxicity Endpoints Used in Human Risk Assessment ................................ ................................ ................................ ................................ .. 17 5.0 Dietary

Exposure and Risk Assessment ................................ ................................ .................. 18 5.1 Food Residue Profile ................................ ................................ ................................ ............ 18 5.2 Water Residue Profile ................................ ................................ ................................ .......... 19 5.3 Dietary

Risk Assessment ................................ ................................ ................................ ...... 19 6.0 Residential (Non - Occupational) Exposure/Risk Characterization ................................ .......... 19 7.0 Aggregate Exposure/Risk Characterization ................................ ................................ ............. 19 8.0 Cumulative Exp osure/Risk Characterization ................................ ................................ ........... 19 9.0 Occupational Exposure/Risk Characterization ................................ ................................ ........ 20 9.1 Short - and Intermediate - Term Handler Risk ................................ ................................ ........ 20 9.2 Short - and Intermediate - Term Post - Application Risk ................................ ......................... 25 Appendix A: Toxicology Profile and Updated Executive Summari es ................................ ........... 26 Appendix B: Review of Human Research ................................ ................................ ...................... 49Tolclofos - methyl Human Health Risk Assessment DP No. 387242

Page 4 of 49 **1.0 Executive Summary**  Valent U.S.A. Corporation has requested registration of the active ingredient (ai) tolclofos - methyl for seed treatment use on various crops, turf grass, ornamental flower, and conifers. The Registration Division (RD) of OPP has requested that HED evaluate hazard and exposure data and conduct dietary , occupational, and aggregate exposure assessments, as needed, to estimate the risk to human health that will result from the proposed seed treatment uses of tolclofos - methyl. This document contains the human health exposure and risk assessment for the requested use s . **Use Profile** : Tolclofos - methyl ( O - (2,6 - dichloro - 4 - methylphen yl ) O,O - dimethyl phosphorothioate ) is a organophosphate fung icide used to protect plants from soil borne and seed borne fungal pathogens. Tolclofos - methyl is being proposed for seed treatment use on various crops, turf grass, ornamental flower, and conifers. The proposed formulated product is a liquid containing 42.0 % tolclofos - methyl active ingredient (4.17 lbs tolclofos - methyl per gallon). The proposed label is for both commercial and on - farm seed treatment. **Hazard Assessment**  : Tolclofos - methyl is an organophosphate with several older toxic ity studies (dating back to 1970s) submitted for consideration in risk assessment. Upon re - evaluation of these old toxicity

studies conducted in the 1970 to 1980 period, several studies are now considered **unacceptable:** 90 - day

oral rat (MRID No. 00156135) (1982); developmental rat (MRID No.00156142 - (1979); developmental rat MRID No.41422904 is acceptable)); developmental rabbit (MRID No. 00156143) (1982); 3 - generation reproduction (MRID No.00156145) (1985); carcinogenicity

mouse (MRID No.00156139) (1983), and chronic/carcinogenicity rat (MRID No.00156140) (1982). Based on the re - evaluation of these old toxicity studies, the toxicity

database for tolclofos - methyl is not complete but adequate for the current non - food seed treatment use. If the registrant purs ues food uses in the future additional studies relevant to the food use will be required. Sy stemic toxicity

from repeat exposure to tolclofos - methyl is primaril y characterized by decreases in body weight, body weight gain, and reduced food consumption and /or efficiency

in rats and dogs. Organ weight changes (kidney , liver, th yr oid) observed at high doses t ypically did not correlate with histopathological changes. Neurotoxicity data from the recentl y submitted acute and subchronic neurotoxicity

studies in dicate tolclofos - methyl is not a potent neurotoxicant. The acute neurotoxicity

study resulted in decreased locomotor activity (total and ambulatory

counts) near the limit dose while the subchronic neurotoxicity study resulted only

in decreased body

weight/gain and food utilization. There was no evidence of increased susceptibility in the pre - natal study with rats. The mouse immunotoxicity study did not indicate immunotoxicity and tolclofos - methyl has not been associated with a genetic toxicity or mutageni cit y concern. In risk assessments for non - food uses that do not result in residential exposures, PoDs are selected for the dermal and inhalation routes of occupational exposure only . In the case of tolclofos - methyl, there is no dermal or sy stemic toxicity at the limit dose and there is low concern for the minimal developmental toxicity

(i.e . , a variation n ot a malformation) seen at the l imit d ose in the offspring . Therefore, quantification of dermal risk is not required. Quantification of inhalation risks was performed using two oral toxicity studies since inhalation data are currentl y unavailable. The 90 - day rat and 6 - month dog studies provided the most appropriate PoDs for considerations and were used as co - critical studies since they yielded similar NOAELs and LOAELs for use in risk assessment.Tolclofos - methyl Human Health Risk Assessment DP No. 387242

Page 5 of 49 These NOAELs are considered are protective of the endpoints of concern since the recentl y submitted acute and subchronic neurotoxicity studies resulted in no ChE inhibition or toxicity near the limit dose (1,000 mg/kg/day). Therefore, the NOAEL of 23 mg/kg/day from the 6 - month dog study , which is similar to the RBC BMDL 10 of 34 mg/kg/day from the 90 - day

rat study , is the most appropriate POD and protective of the short - term and intermediate - term durations of exposure. An uncertaint y factor of 100x (10x to account for interspecies extrapolation and 10x for intraspecies variation) was applied to the POD. Food Qualit y Protection Act (FQPA) considerations do not apply to tolclofo s - methyl as the proposed seed treatment uses have been deemed non - food uses. However, there are three outstanding studies according to revised 40 CFR Part 158 Toxicology Data Requirements. These studies include a development toxicity

study in rabbits, a reproduction study in rats, and an adequate in vivo mammalian cell assay . The Agency is not requesting an y of these studies at this time and does not believe a UF DB is required for the lack of these studies. Based on the proposed uses, quantification of risk is limited to short - and intermediate - term inhalation exposure for workers. A waiver request for a 28 - day

inhalation study

was denied to protect for any future proposed uses as tolclofos - methyl has potential to volatilize off of treated fields based on its vapor pressure (D390269, TXR0055976). However, the Agency

is not requiring an inhalation study at this time since the proposed uses and the risk estimates for occupational handlers are sufficientl y protective ( MOES = 16,000 to 26,000,000 ; see Sect ion 9.0) . T his decision will be reevaluated based on future use requests. There are no currently

registered or proposed food uses for tolclofos - methyl . Carcinogenicit y studies are not required for non - food use chemicals. Carcinogenicit y studies in mice and rats are available for tolclofos - methyl and both of these studies were deemed unacceptable for use in the risk assessment . These cancer studies wo uld be required under the Revised Part 158 Guidelines should a food use for tolclofos - methylbe requested in the future. The acute toxicity

profile of tolclofos - methyl consists of low toxicity via the oral , dermal , and inhalation routes of exposure (Categ ory I II and IV) . Tolclofos - methyl is not an eye or skin irritant (Category IV ) and it is not a dermal sensitizer. **Food Residue Profile :**  The submitted total radioactive residues (TRR) data for soy bean, corn, lettuce, cucumber, radish and cotton seeds are adequate to satisfy data requirements and support the seed treatment uses being classified as non - food uses . V alent met with EPA on October 2, 2008 to discuss tolclofos - methyl radiotracer studies which were conducted to support the non - food classification and the required toxicology data requirements which were based on Valent’s review of existing data and their interpretation of the 40 CFR Part 158 requirements for nonf ood uses. Subsequently , HED’s Chemistry Science Advisory

Council (ChemSAC) met on December 3, 2008 to discuss Valent’s proposal for non - food use classification of the seed treatment uses of tolclofos methyl on various crops and crop groups . A s a result, the proposed seed treatment use of tolclofos methyl on corn, so yb ean and cotton can be classified as non - food . Additionally , the registrant submitted radiotracer studies on lettuce and cucumber at 10 g.ai/100kg, and radish at 50 g.ai/100kg f or a non - food use classification if the TRR are determined to be less than 5 ppb . The results showed that the lettuce, cucumber and radish plants grown for seeds treated with [phenyl 14 C]tolclofos - methyl did not take up the radiolabele d test substance residue.Tolclofos - methyl Human Health Risk Assessment DP No. 387242

Page 6 of 49 **Dietary Exposure and Risk:**  A dietary exposure assessment is not required, since it is a non - food use chemical and the Agency does not expect the proposed seed treatment uses of tolclofos - methyl to adversel y impact ground water or surface water . **Residential Exposure**  : There are currently no registered residential uses associated with tolclofos methyl ; therefore, a residential/non - occupational exposure assessment is not required at this time . **Aggregate Risk:** T here are currentl y no registered food or residential uses for tolclofos - methyl and the Agency

does not expect the proposed seed treatment uses of tolclofos - methyl to adversel y impact ground water or surface water ; therefore , an aggregate risk assessment is not required at this time . **Occupational Exposure/Risk:**  Handler Exposure: Based on the proposed seed treatment uses of tolclofos - methyl, two t ypes of occupational handler exposure are expected: 1) primary handler exposure is expected to result for handlers involved in commercial seed treatment and on - farm seed treatment and 2) secondary handler exposure is expected to result from planting tolclofos - methyl treated seeds. The short - and intermediate - term inhalation risk estimates for all primary and secondary

handler scenarios do not exceed HED’s level of concern (MOEs > 100) at some level of personal protective equipment (PPE) . Post - application Exposure : Occupational post - application exposure is not expected for the proposed seed treatment uses of tolclofos - methyl. As a result, no quantitative post - application assessment is required for exposure to treated seeds that have already been planted. The proposed tolclofos methyl label has the appropriate REI of 12 hours based on the acute toxicity of tolclofos - methyl. **Re view of Human Research:**  This risk assessment relies in part on data from studies in which adult human subjects were intentionally exposed to a pesticide or other chemical. These studies (listed in Appendix B ) have been determined to require a r eview of their ethical conduct and a ll of the studies utilized in this assessment have received the appropriate review.Tolclofos - methyl Human Health Risk Assessment DP No. 387242

Page 7 of 49 **2.0 HED**  **Recommendations** HED has evaluated the toxicity and exposure databases for the active ingredient, tolclofos - methyl, and has conducted a human health risk assessment in support of the proposed uses. Based on this assessment, HED has determined that there are no potential risk estimates of concern for the proposed uses of tolclofos - methyl. **HED recommends that the requested uses be granted. 2**  **.1 Data Deficiencies**  TOXICOLOGY The existing toxicology

database is not complete but is adequate for characterizing tolclofos - methyl toxicity and quantification of risk for a non - food seed treatment use. In accordance with the revised 40 CFR Part 158 Toxicity Data Requirements, the tolclofos - methyl database lacks a development toxicity study in rabbits , a reproduction study in rats, and an adequate in vivo mammalian cell assay. The Agency

is not request ing the developmental toxicity study in rabbits at this time for the following reasons: 1) it is unlikely that the use of this product at the low application rate (range 0.000489 to 0.00000077 lb ai/lb seed) will result in significant human exposure over a portion of the human lifespan in terms of frequency , magnitude or duration of exposure (sub - bullet #26 from 40 CFR Part 158 Toxicity

Data Requirements Table ) ; 2) the available developmental toxicity study in rabbits, in spite of its deficiencies, indicate s that the rabbits are not the most sensitive species; and 3) the risk assessment is based on an endpoint observed in dogs, which is shown to be the most sensitive species for tolclofos - methyl induced toxicity . The Agency

is not requesting the reproduct ion study in rat s at this time because it is unlikely that the use of this product at the low application rate (range 0.000489 to 0.00000077 lb ai/lb seed) will result in significant human exposure over a portion of the human lifespan in terms of frequency , magnitude or duration of exposure (sub - bullet #26 from 40 CFR Part 158 Toxicity Data Requirements Table ) . The Agency

is not requesting the in vivo mammalian cell assay as the Agency

does not expect that the lack of this assay

would impact the quantification of risk based on the other available tolclofos methyl mutagenicit y studies and the fact that organophosphates are not known to be mutagenic. A waiver request for a 28 - day inhalation study

was denied to protect for any future proposed uses as tolclofos - methyl has potential to volatilize off of treated fields based on its vapor pressure (D390269, TXR0055976). However, the A gency is not requiring an inhalation study at this time since the proposed uses and the risk estimates for occupational ha ndlers are sufficientl y protective ( MOES = 16,000 to 26,000,000 ; see Section 9.0) . T his decision will be reevaluated based on future use requests. It is noted that additional toxicity studies would be required to fulfill the Revised Part 158 guidelines fo r an y other use than the seed treatment use, especially for a food use, and the registrant should consult with the Agency

about any

of the outstanding studies before requesting an y additional uses (see Appendix A.1).Tolclofos - methyl Human Health Risk Assessment DP No. 387242

Page 8 of 49 **2 .**  **2 Tolerance Considerations**  **2.2.1 E**  **nforcement Analytical Method** An adequate data collection method is available for tolclofos - methyl. Batches of radish, lettuce and cucumber seeds were treated with appropriate amounts of the test substance, [phenyl 14 C]tolclofos methyl. To determine the t otal radioactive residue (TRR), aliquots of samples were combusted in a biological oxidizer followed b y liquid scintillation counting (LSC) of the aliquot vials. HPL C was used to determine the radiochemical purity of the test substance before and after see d treatment. The limit of quantification (LOQ) is 0.003 ppm. The method was adequate for data collection based on acceptable concurrent method recoveries. **2.2. 2**  **International Harmonization** There are currently

no established or proposed tolerances for tolclofos - methyl in the United States as the proposed seed treatment uses has been deemed non - food uses. There are currentl y no established MRL s in Canada, however, there are currentl y Codex MRL s for lettuce, potato, and radish. Since there are no U.S. t olerances for tolclofos - methyl, there are no issues of compatibility with respect to the Codex MRL s. **2.2. 3**  **Recommended Tolerances** Tolerances are not required for the proposed seed treatment uses of tolclofos - methyl. There are no residue chemistry

issues that would preclude granting the tolcolfos - methyl seed treatment as non food uses (40 CFR Part 158). **2 .**  **3 Label Recommendations**  **2. 3**  **. 1**  **Recommendations from Residue Reviews** No label revisions are needed with respect to residues and no recommendations are being made by HED. **2.3.2 Recommendations from Occupational Assessment**  No label revisions are needed for occupational purposes and no recommendations are being made by HED.Tolclofos - methyl Human Health Risk Assessment DP No. 387242

Page 9 of 49 **3.0 Ingredient Profile**  Tolclofos - methyl is a new organophosphate fungicide active ingredient used to protect plants from soil borne and seed borne fungal pathogens. **3.1 Structure and Nomenclature**  **Table 3.1 :**  **Tolclofos -**  **methyl Nomenclature** 

Chemical Structure

Common Name tolclofos - methyl IUPAC name O - 2,6 - dichloro - p - tolyl O , O - dimethyl phosphorothioate CAS Name O - (2,6 - dichloro - 4 - methylphenyl) O , O - dimethyl phosphorothioate CAS Registry Number 57018 - 04 - 9 Chemical Class Organophosphate **3.2 Physical/Chemical**  **Characteristics**

**Table 3.2: Toclofos -**  **methyl Physical and Chemical Properties Param**  **eter Value**  Molecular Weight 301.12 g/mol. Melting point/range 78 - 80°C Water solubility (25°C) 1.10 ± 0.08 mg/litre

Solvent solubility % w/w (25°C) Acetone 50.2, Methyl isobutyl ketone 36.5 Cyclohexanone 36.0 Methanol 5.9 Ethyl cellosolve 11.8 Ethylene glycol 0.3 Ethyl acetate 38.9 Hexane 3.8 Xylene 36.0 Petroleum ether 2.3 Acetonitrile 33.1 Chloroform 49.0 Dimethyl formamide 48.7 Vapor pressure (25°C) 1.38 x 10 - 5 mm Hg Octanol/water partition coefficient (25°C) 4.56 O P ( O C H 3 ) 2 C l

C l C H 3 STolclofos - methyl Human Health Risk Assessment DP No. 387242

Page 10 of 49 **3.3 S**  **ummary of Existing/Proposed Uses** Tolclofos - methyl is a new active ingredient being proposed for seed treatment use on various crops, turf grass, ornamental flower, and conifers. The proposed formulated product is a liquid containing 42.0% tolclofos - methyl active ingredient (4.17 lbs tolclofos - methyl per gallon). The proposed lab el is for both commercial and on - farm seed treatment. The proposed label restrict s the use of to l clofos methyl in hopper - box or planter - box seed treatment sy stems at planting time. Th e proposed label also states that the product is only to be applied to “true seed s ” and is not to be applied on other propagation parts. The application rates range from 0.000489 to 0.00000977 lb ai / lb seed .

**Table 3.3: Use Profile for Proposed Tolclofos**  **- methyl**  **Uses** Rizolex Flowable Fungicide (Reg. No. XXX - XXX) suspension concentrate (SC), 4.17 lb ai/gallon **Crops Application**  **Equipment Maximum** 

**Application Rate**  **Notes**

- Root and Tuber Vegetables (Crop Group 1 A) Commercial Seed Treatment Facility and On - Farm Standard Slurry or Mist - Ty pe 0.000489 lb

ai/lb seed except Burdock, Chervil, Turnip - Rooted;

Ginseng; Horseradish; Salsify; Skirret;

- Cotton

- Bulb Vegetables (Crop Group 3 - 7 )

Commercial Seed Treatment Facility and On - Farm Standard Slurry or Mist - Ty pe 0.00000977 lb

ai/lb seed except Daylily, Bulb; Elegans Hosta;

Fritillaria, Bulb; Fritillaria, Leaves; Garlic, Bulb; Garlic, Great - Headed, Bulb; Garlic, Serpent, Bulb; Lily, Bulb; Onion, Chinese, Bulb; Onion, Macrostem ; Onion, Tree, Tops; Onion, Welsh, Tops; Shallot, Bulb ; Shallot, Fresh Leaves

- Leafy Vegetables (Crop Group 4) e xcept Brassica Ve getables

- Brassica (Cole) Leafy Vegetables (Crop Group 5)

- Legume Vegetables (Succulent or Dried) (Crop Group 6)

- Fruiting Vegetables (Crop Group 8 - 10)

- Cucurbit Vegetables (Crop Group 9)

- Cereal Grains (Crop Group 15 ) except Rice and W ildrice

- Grass Forage, Fodder, and Hay (Crop Group 17)

- Non - grass Animal Feeds (Forage, Fodder, Straw , and Hay) (Crop Group 18)

- Herbs and Spices (Crop Group 19)

- Oilseeds (Crop Group 20 ) except cotton

- Ornamental Flowers

- ConifersTolclofos - methyl Human Health Risk Assessment DP No. 387242

Page 11 of 49 **3.4 Anticipated Exposure Pathways**  The Registration Division has requested an assessment of human health risk to support the proposed new uses of tolclofos - methyl as a seed treatment use on various crops, turf grass, ornamental flower, and conifers. Humans are not expected to be exposed to tolclofos - methyl in their diet as the proposed uses of tolclofos - methyl for seed treatment have been deemed to be non - f ood uses based on the submitted residue chemistry data. Drinking water exposure is also not expected based on the proposed seed treatment uses of tolclofos - methyl. There are no residential uses of tolclofos - methyl , so exposure in residential and non - occupational settings is not likely . In an occupational setting, applicators may

be exposed while handling the pesticide prior to application to the seed , as well as during the application to the seed . Additionally , there is a potential for exposure for work ers who handle previousl y treated seed during planting activities . These are the first registrations proposed for tolclofos - methyl in the United States ; therefore, this is the first risk assessment prepared b y the Agency to address potential risks assoc iated with the use of this new active ingredient. **3.5 Consideration of Environmental Justice**  Potential areas of environmental justice concerns, to the extent possible, were considered in this human health risk assessment, in accordance with U.S. Executiv e Order 12898, “Federal Actions to Address Environmental Justice in Minority Populations and L ow - Income Populations,” ( http://www.eh.doe.gov/oepa/guidance/justice/eo12898.pdf . As a part of every

pesticide risk assessment, OPP considers a large variet y of consumer subgroups according to well - established procedures. In line with OPP policy , HED estimates risks to population subgroups from pesticide exposures that are based on patterns of that subgroup’s food and water consumption, and activities in and around the home that involve pesticide use in a residential setting. Extensive data on food consumption patterns are compiled by the USDA under the Continuing Survey of Food Intake by Indiv iduals (CSFII) and are used in pesticide risk assessments for all registered food uses of a pesticide. These data are anal yz ed and categorized by soccer20 subgroups based on age, season of the y ear, ethnic group, and region of the country . Additionally , OPP is able to assess dietary exposure to smaller, specialized subgroups and exposure assessments are performed when conditions or circumstances warrant. Whenever a ppropriate, non - dietary exposures based on home use of pesticide products and associated risks for adult applicators and for toddlers, youths, and adults entering or playing on treated areas postapplication are evaluated. Further considerations are currently in development as OPP has committed resources and expertise to the development of specialized software and models that consider exposure to by standers and farm workers as well as lifestyle and traditional dietary patterns among specific subgroups. **4.0 Hazard Characterization/Assessment**  **4.1 Toxicology Studies Available for Analysis**  Tolclofos - methyl is a new active ingredient currently being considered b y the Agency to be registered as a non - food seed treatment use for various crops, turf grass, orname ntal flowers and conifers. Tolclofos - methyl is an organophosphate with several older toxicity studies (dating back toTolclofos - methyl Human Health Risk Assessment DP No. 387242

Page 12 of 49 1970s) submitted for consideration in risk assessment. Upon re - evaluation of these old toxicity studies (1970s to 1980s), several studie s are now considered **unacceptable:** 90 - day oral rat (MRID No. 00156135) (1982); develo pmental rat (MRID No. 00156142) ( 1979); developmental rabbit (MRID No. 00156143) (1982); 3 - generation reproduction (MRID No. 00156145) (1985); carcinogenicity

mouse (MRID No.00156139) (1983), and chronic/carcinogenicity rat (MRID No. 00156140) (1982). In accordance with the revised 40 CFR Part 158 Toxicity Data Requirements, the tolclofos - methyl database lacks a development toxicity study in rabbits , a reproduction study in rats, and an adequate in vivo mammalian cell assay . The Agency is not requesting an y of these studies at this tim e and does not believe a UF DB is required for th e lack of these studies (see Section 4.4.1 for more details). Based on the re - evaluation of these old toxicity studies, the toxicity

database for tolclofos - methyl is not complete but adequate for the propo sed non - food seed treatment use. The available toxicological studies for tolclofos - methyl are listed in Appendix A. Data from the following studies were used to evaluate the hazard potential of tolclofos - methyl:

- Acute lethalit y studies (oral, dermal, inhalation, primary eye and dermal irritation, dermal sensitization)

- Subchronic dietary

(rat, dog)

- 9 - month dietary

(mouse)

- 104 - week special Cholinesterase (rat)

- Developmental (rat, 41422904)

- Neurotoxicity

(acute and subchronic) (rat)

- Metabolism (rat, mouse)

- Immunotoxicity

(rat)

- Mutagenict y battery Tolclofos - methyl is a new active ingredient although it has been registered in other countries (European Union countries) for several y ears. A search in PubMed (August 2011) with tolclofos methyl as a search term resulted in no applicable toxicity studies for risk assessment and no toxicity studies with humans were submitted. **4. 2**  **Absorption, Distribution, Metabolism, and Elimination (ADME)** The absorption, distribution, metabolism and excretion (ADME) of tolclofos - methyl in rats and mice was characterized in a general metabolism study that was administered via stomach intubation in a single dose of 5 mg/kg. In rats, tolclofos - methyl was elim inated mainly in urine (65 - 70%) and feces (17 - 22%) b y 7 day s post - dosing. In mice, approximately 82 - 83% was eliminated in urine and 5 - 7% in the feces at 7 day s post - dosing. Absorption and elimination were rapid with most of the radioactivity

eliminated at 23 hours post - dosing. Tissue residues were small, in the ppb range. Total recovery of radioactivit y was 87% to 91% of the dose. The main metabolite in rat urine was 3,5 - dichloro - 4 - hydrox yb enzoic acid, accounting for 26% of the dose. In mice, 2, 6 - dic hloro - 4 - hydrox yb enzyl - gl ycine, O,O - dimethyl - 1 - O - (2,6 - dichloro - 4 - carbox yphen yl ) phosphate, and O methyl - O - (2,6 - dichloro - 4 - carbox yphen yl ) phosphate each accounted for 8 - 13% of the dose in urine. Unchanged parent compound accounted for 5% and 1.3% of the dos e in the feces of rats and mice, respectivel y. Tolclofos - methyl is metabolized via oxidative desulfuration of the thiophosphorylTolclofos - methyl Human Health Risk Assessment DP No. 387242

Page 13 of 49 group to give the ox yphosphoryl analog (oxon), oxidation at the 4 - methylphenyl group, and hydrol yt ic cleavage of the p - O - aryl and p - O - methyl linkages. This study was not administer ed at a high dose or repeat dosing for 14 day s as required by guideline. **4.2.1 Dermal Absorption**  A dermal absorption study is not available for tolclofos - methyl. However, a non - guideline 21 - day de rmal (rabbit) toxicity

study is available and, therefore, dermal absorption information is not necessary for this assessment. **4. 3**  **T oxicological Effects**  Tolclofos - methyl is not acutely toxic and is a poor inhibitor of cholinesterase (ChE ) compared to other organophosphate compounds. There was no inhibition observed in a time to peak rat study after a single oral dose up to the limit dose (2,000 mg/kg). ChE activity was therefore not measured in the main acute neurotoxicity (ACN) study . In the subchronic neurotoxicty (SCN) study , RBC ChE was not inhibited up to approximately 800 mg/kg/day

in either males or females while the female brain BMDL 10 was 659 mg/kg/day . In a special 104 - week ChE rat study , tolclofos - methyl did not inhibit ChE activity in an y compartment (plasma, RBC, or brain) in either sex up to the limit dose. For the older studies that did measure ChE activity , ChE inhibition was very sporadic with poor dose - response. For example, the female RBC ChE data from the 90 - day rat study were the only data to fit BMD modeling (male RBC and male or female brain ChE did not produce a significant dose - response curve) with a BMDL 10 of 34 mg/kg/day . The 9 - month mouse toxicity study resulted in a female RBC BMDL 10 of 10 mg/kg/day with the male RBC and male or female brain data again not fitting a dose - response curve. Neurotoxicity

data from the newl y submitted acute and subchronic neurotoxicity studies indicate tolclofos - methyl is not a potent neurotoxicant. The acute neurotoxicity stu dy resulted in decreased locomotor activity

(total and ambulatory

counts) near the limit dose while the subchronic neurotoxicity

study resulted only

in decreased body

weight/gain and food utilization. Sy stemic toxicity

from repeat exposure to tolclofos - methyl is primaril y characterized by decreases in body weight, body gain, and reduced food consumption and/or efficiency in rats and dogs. Organ weight changes (kidney , liver, thy roid) observed at high doses t ypicall y did not correlate with histopatholog ical changes. The acceptable developmental rat study resulted in marginal decreases in maternal bodywei ght at the limit dose with unossified sternebra of fetuses occurring onl y at the limit dose. Changes in liver weight and liver enzy mes were not consist ent across the database but were sporadic. The rabbit developmental study is downgraded to unacceptable/non - guideline due to numerous critical study design and data reporting issues. The 3 - generation reproduction study is also downgraded to unacceptable due to critical deficiencies resulting in no conclusion regarding the reproductive toxicity

of tolclofos - methyl. The carcinogenicity studies in mouse and rat are unacceptable since the doses tested were determined to be not adequate to assess the carcinog enic potential of tolclofos - methyl. The mouse immunotoxicity study did not indicate immunotoxicity and tolclofos - methyl has not been associated with a genetic toxicity or mutagenicit y concern.Tolclofos - methyl Human Health Risk Assessment DP No. 387242

Page 14 of 49 **4. 4**  **Consideration of Toxicity to Children** Food Qualit y Protec tion Act (FQPA) considerations do not apply to tolclofos - methyl as the proposed seed treatment uses have been deemed non - food uses. However, there are three outstanding studies according to revised 40 CFR Part 158 Toxicology Data Requirements. These stud ies include a development toxicity

study in rabbits, a reproduction study in rats, and an adequate in vivo mammalian cell assay . The Agency is not requesting an y of these studies at this time and does not believe a UF DB is required for the lack of these studies. Based on the proposed uses, quantification of risk is limited to short - and intermediate - term inhalation exposure for workers. The PoD used for assessing repeated inhalation exposure is based on the most sensit ive endpoint in the most sensitive species (dogs) and supported by the observation of similar effects at a comparable dose in the rat. Consequently , the risk assessment does not underestimate potential risks to occupational workers and a total uncertainty factor of 100 is adequate. **4.4.1 Completeness of the Toxicology Database**  The existing toxicology

database is not complete but is adequate for characterizing tolclofos - methyl toxicity and quantification of risk for a non - food seed treatment use. In acc ordance with the revised 40 CFR Part 158 Toxicity Data Requirements, the tolclofos - methyl database lacks a development toxicity study in rabbits , a reproduction study in rats, and an adequate in vivo mammalian cell assay. The Agency

is not requesting th e developmental toxicity study in rabbits at this time for the following reasons: 1) it is unlikely that the use of this product at the low application rate (range 0.000489 to 0.00000077 lb ai/lb seed) will result in significant human exposure over a porti on of the human lifespan in terms of frequency , magnitude or duration of exposure (sub - bullet #26 from 40 CFR Part 158 Toxicity

Data Requirements Table ) ; 2) the available developmental toxicity study in rabbits, in spite of its deficiencies, indicates that the rabbits are not the most sensitive species; and 3) the risk assessment is based on an endpoint observed in dogs, which is shown to be the most sensitive species for tolclofos - methyl induced toxicity . The Agency

is not requesting the reproduction study in rat s at this time because it is unlikely that the use of this product at the low application rate (range 0.000489 to 0.00000077 lb ai/lb seed) will result in significant human exposure over a portion of the human lifespan in terms of frequency , magn itude or duration of exposure (sub - bullet #26 from 40 CFR Part 158 Toxicity Data Requirements Table ) . The Agency

is not requesting the in vivo mammalian cell assay as the Agency

does not expect that the lack of this assay

would impact the quantification of risk based on the other available tolclofos methyl mutagenicit y studies and the fact that organophosphates are not known to be mutagenic. A waiver request for a 28 - day inhalation study

was denied to protect for any future proposed uses as tolclofos - methyl has potential to volatilize off of treated fields based on its vapor pressure (D390269, TXR0055976). However, the A gency is not requesting an inhalation study at th is time since the proposed uses and the risk estimates for occupational handlers are sufficiently protective ( MOES = 16,000 to 26,000,000 ; see Section 9.0 . T his decision will be reevaluated based on future use requests.Tolclofos - methyl Human Health Risk Assessment DP No. 387242

Page 15 of 49 **4.4. 2**  **Evi dence of Neurotoxicity**  The rat acute neurotoxicity study resulted in decreased locomotor activity in both sexes at 700 and 2000 mg/kg. ChE inhibition was not inhibited after a single dose up to 2000 mg/kg. In the subchronic neurotoxicity

study , decreas ed bod yw eight, body weight gain, and food utilization were observed at 735 mg/kg/day with the female brain BMDL 10 of 659 mg/kg/day . There was no effect on brain weight and there were no clinical signs in the subchronic neurotoxicity study following dietary administration. Neurotoxicity was not a clinical sign or pathological feature of the chronic rat, mouse or dog studies. Since cholinesterase inhibition is not a consistent and sensitive endpoint for tolclofos - methyl, a comparative cholinesterase study that evaluates cholinesterase inhibition compared to juvenile rodents is not needed. The tolclofos - methyl risk a ssessment team considered the submission of a data waiver for the developmental neurotoxicity (DNT) study

and determined that a DNT s tudy is not needed at this time for the following reasons: 1) there is no evidence of treatment - related neurological effect s in adult animals (i.e., clinical signs of neurotoxicity , neuropathology or functional or behavioral effects) in the subchronic neurotoxicity study at doses up to 762 m/k/g; 2) there is no evidence of neurotoxicity

in the other studies in the data base; and 3) there is no evidence of treatment - related neurological effects in developing animals following pre natal exposure (i.e., nervous s ys tem malformations or neuropathology) in the developmental rat study . **4.4.3 Evidence of Sensitivity/Susceptibility i**  **n the Developing or Young Animal** Developmental toxicity. There was no clear sensitivity observed in the rat developmental study . The maternal NOAEL was established at the limit dose ( ≥1000 m/kg/day) even though a marginal decrease in bodyw eight gains (28%) was observed from GD6 - 11 at the limit dose. Although there was no fetal mortalit y or external malformations, the developmental LOAEL (1000 mg/kg/day) was established at the limit dose based on a non - dose responsive increased incidence of unossified 6 th sternebra onl y. The developmental rabbit study is consid ered unacceptable due to critical study and data reporting flaws. However, the maternal LOAEL of 1000 mg/kg/day was based on decreased food consumption and food efficiency at the mid (1000 mg/kg/day) and the highest dose (3000 mg/kg/day) tested as well as decreased spleen and kidney weights. Although several key measurements were not provided for the developmental toxicity , based on maternal toxicity seen at doses including and higher than the limit dose it is evident that the rabbits are less sensitive than rats which lessens the concern for potential developmental toxicity in this species. Reproductive toxicity. The rat reproduction study is now considered unacceptable since several factors preclude the characterization of the reproductive potential of tolclofos - methyl. The low pregnancy

rate in the controls precludes a comparison with treatment groups. Although this study is required for a non - food use, the maternal toxicity or developmental/reproductive toxicity will likely not be lower than the POD (23 mg/kg/day) established for the current occupational assessment. Also, it is unlikely

that the use of this product at the low application rate (range 0.000489 to 0.00000077 lb ai/lb seed) will result in significant human exposure over a portion of the humanTolclofos - methyl Human Health Risk Assessment DP No. 387242

Page 16 of 49 lifespan in terms of frequency , magnitude or duration of exposure (sub - bullet #26 from 40 CFR Part 158 Toxicity

Data Requirements Table ) . **4.4.4 Residual Uncertainty in the Exposure Database**  There are no residual uncertainties in the exposure data base based on the following : 1) there are no currentl y registered or proposed residential uses of tolcofos - methyl in the U.S. ; 2) the proposed uses are considered non - food use s; and 3) adequate exposure data are available to assess the occupational exposures res ulting from the proposed uses. **4. 4**  **Toxicity Endpoints and Points of Departure Selections 4.5.1**  **Dose Response Assessment** The details for selecting toxicity endpoints and points of departure (PODs) are presented in Appendix A2. In risk assessments for non - food uses that do not result in residential exposures, PODs are selected for the dermal and inhalation routes of exposure only . In this case, there is no dermal toxicity

and therefore a dermal POD has not been selected and a quantitative dermal assessment not performed. A quantitative assessment was only performed for the inhalation route. PODs for the acute and chronic dietary and incidental oral exposures are not required to assess risk for non - food uses that do not result in residential exposures, and therefore have not been selected. Acute and Chronic Dietary The current proposed use is a non - food seed treatment. Acute and chronic PODs have not been established for this risk assessment. Short/Intermediate Dermal The 21 - day

dermal rabbit study

(non - guideline) was re - evaluated to ensure consistency with current HED policy

and practices. Based upon this re - evaluation, sy stemic toxicity and dermal irritation was not observed at concentrations up to the limit dose (1,000 mg/kg/day) after 3 weeks of exposure (5 day s/week for 3 weeks). Therefore a quantitative short - and intermediate - term dermal assessment has not be en conducted for tolclofos - methyl. Short/Intermediate Inhalat ion The short - and intermediate - term inhalation POD was based on oral toxicity studies since route specific inhalation data are currentl y unavailable. T he 90 - day rat and 6 - month dog studies provide the most appropriate PODs to consider for risk assessment. The 90 - day rat and 6 - month dog studies were selected as co - critical since they yield similar NOAELs and LOAELs for use in risk assessment. T he NOAEL of 23 mg/kg/day from the 6 - month dog study, which is similar to the RBC BMDL 10 of 34 mg/kg/day from the 90 - day rat study , is the most appropriate POD and protective of the short - term and intermediate - term durations of exposure. An uncertainty factor of 100x (10x to account for interspecies extrapolation and 10x for intraspecies variation) was app lied to the POD. This POD is considered health protective since the recently submitted ACN and SCN studies resulted in no ChE inhibition or toxicity near the limit dose of 1,000 mg/kg/day .Tolclofos - methyl Human Health Risk Assessment DP No. 387242

Page 17 of 49 **4.5.2 Recommendation for Combining Routes of Exposure for Risk As**  **sessment** As part of conducting a human health risk assessment process, the Agency considers risks from individual routes of exposure (oral, dermal, and inhalation). Additionally , the Agency must assess aggregate risks from dietary and residential exposur es. In order to conduct an aggregate risk assessment a determination is made if it is appropriate to combine across routes of exposure and aggregate dietary

risks with residential (non - occupational) risks. At this time, there are no residential uses for tolc l ofos - methyl and the proposed uses have been deemed non - food uses, so a discussion of combining routes of exposure is not pertinent to this assessment. **4.5.3 Cancer Classification and Risk Assessment Recommendations**  There are no currently

registered or proposed food uses for tolclofos - methyl . Carcinogenicit y studies are not required for non - food use chemicals. Carcinogenicit y studies in mice and rats are available for tolclofos - methyl and both of these studies were deemed unacceptable for use in the risk assessment . These cancer studies would be required under the Revised Part 158 Guidelines should a food use for tolclofos - methylbe requested in the future. **4.5.4 Summary of Points of De**  **parture and Toxicity Endpoints Used in Human Risk**  **Assessment Table 4.5.4. Summary of Toxicological Doses and Endpoints for Tolclofos**  **- Methyl for Non**  **- Food Use**  **Occupational Risk Assessments Exposure/**  **Scenario Point of** 

**Departure (POD)**  **Uncertainty**

**Factors Level of** 

**Concern Study**  **and Toxicological Effects** Ac ute Dietary (General Population, including Infants and Children) The proposed seed treatment use is non - food. Chronic Dietary (All Populations) The proposed seed treatment use is non - food. Dermal (Short/Intermediate) Sy stemic toxicity was not observed up to the limit dose of 1,000 mg/kg/day.

Inhalation (Short/Intermediate) NOAEL= 23 mg/kg UF A = 10 X

UF H = 1 0X MOE = 100 **Co -**  **Critical: 1. 6**  **- mo**  **nth dog** (00156138); **LOAEL = 70 m g/kg/day**  , based on decreased bodyweight and gain, hematocrit, hemoglobin, and erythrocyte count in both sexes. In addition, ↓relative thyroid weight, ↑ALK and ↑absolute and relative liver wt at high dose. A consistent dose - response for ChE was not observed. 2. **90 -**  **day rat** (41422901) **RBC BMDL 10**  =34 MKD RBC BMD 10 =72 MKD Cancer (oral, dermal, inhalation) Not required for non - food use pesticides. Point of Departure (POD) = A data point or an estimated point that is derived from observed dose - response data and used to mark the beginning of extrapolation to determine risk associated with lower environmentally relevant human exposures. NOAEL = no observed adverse effect level. LOAEL = lowest observed adverse effect level. UF = uncertainty factor. UF A = extrapolation from animal to human (interspecies). UF H = potential variation in sensitivity among members of the human population (intraspecies).Tolclofos - methyl Human Health Risk Assessment DP No. 387242

Page 18 of 49 **5.0 Dietary Exposure and Risk Assessment**  **5.1 Food Residue Profile**  MRIDs 48341956 and 48341957 ; DP 395999 Tolerances are not required for the proposed seed treatment uses of tolclofos - methyl. HED’s Chemistry

Science Advisory

Council (ChemSAC) met on December 3, 2008 to discuss Valent’s proposal for non - food use classification of the seed treatment uses of tolclofos - methyl on various crops and crop groups . ChemSAC concluded that if all TRR results are less than 5 ppb (based on memorandum of Chemistry SAC - HED - 7509C titled “Classification of Seed Treatments as Food or Nonfood Uses ” dated Oct 28, 1999) , then the proposed seed treatment use of tolclofos - methyl on various crops can be classified as non - food (D362358, S.Piper, 2/27/09). Batches of so ybean, corn, lettuce, cucumber, radish and cotton seeds were treated with formulated [ phenyl 14 C]tolclofos - methyl . The target treatment rates were 50 g/100 kg of se eds for cotton and radish, and 10 g/100 kg of seeds for corn, so yb ean, lettuce and cucumber. The results showed that the seeds treated with [phenyl 14 C]tolclofos - methyl did not take up the radiolabeled test substance residue (<5 ppb). Onl y the radish top samples grown from seeds treated at the rate of 51.6 g/100 kg showed TRR level showed residues above 0.005 ppm. The radish tops grown from seeds contained residues at 0.02

– 0.03 ppm and additional characterization of the residues was provided. The treat ed radish top s amples (TRR = 0.029 ppm and TRR = 0.020 ppm) were spiked with radiolabeled tolclofos - methyl and analyzed by HPL C to determine the efficiency of the extraction method. Both acetonitrile and aqueous extracts showed some polar radioactive resid ues, but did not contain any detectable amount of tolclofos - methyl. There are no residue chemistry issues that w ould preclude granting the tolc l o fos - methyl seed treatment as non - food uses (40 CFR Part 158). Table 5. 0 shows the data that was translated fo r the proposed seed treatment use of tolclofos - methyl . **Table 5. 0**  **T ranslation of T**  **olclofos -**  **methyl Seed Treatment as a Nonfood Uses Crop**  **Crop Group Number Crop Group Name**  Corn* 15 Cereal grains 16 Forage, fodder and straw Soy bean* 6 Legume vegetable 7 Foliage 20 Oilseeds Cucumber* 8 Fruiting vegetable (except cucurbits) 9 Cucurbit Lettuce* 4 Leafy vegetable (except Brassica vegetables) 5 Brassica cole leafy vegetables Radish** 1 Root and tuber vegetables (except potatoes) 2 Leaves of root and tuber vegetables (human food and animal feed) 3 Bulb vegetables Cotton** -- *application rate: 10 g ai/100 kg seed **application rate: 50 g ai/100 kg seedTolclofos - methyl Human Health Risk Assessment DP No. 387242

Page 19 of 49 **5. 2**  **Water Residue Profile**  A qualitative drinking water assessment of tolclofos - methyl was performed for this risk assessment. Tolclofos - methyl may

transport to nearb y surface water through runoff and erosion, especially if tolclofos - methyl treated seeds are planted coinciding with or closely followed by

a rain event. After discuss ing the very

low proposed seed treatment application rates, environmental fate data, and modeling estimates with the Ecological Fate and Effects Division (EFED) ; the Agency does not expect the proposed seed treatment uses of tolclofos - methyl to adversel y i mpact ground water or surface water . **5. 3**  **Dietary Risk Assessment** Dietary exposure (food + drinking water) is not expected for tolclofos - methyl, since it is a non - food use chemical and the Agency does not expect the proposed seed treatment uses of tolclofos - methyl to adversel y impac t ground water or surface water. **6.0 Residential (Non**  **- Occupational) Exposure/Risk Characterization**  Residential exposures and risk are not assessed in this document because the proposed uses of tolclofos - methyl do not involv e applications by homeowners or commercial applicators in residential settings at this time and there are no existing residential uses. **7.0 Aggregate Exposure/Risk Characterization**  Aggregate risk assessments evaluate the combined risk from dietary exposure ( food and water) and any non - occupational (residential) uses. However, there are currentl y no registered food or residential uses for tolclofos - methyl and the Agency does not expect the proposed seed treatment uses of tolclofos - methyl to adversel y impac t g round water or surface water ; therefore, an aggregate risk assessment is not required at this time. **8.0 Cumulative Exposure/Risk Characterization**  Section 408(b)(2)(D)(v) of the Federal Food, Drug, and Cosmetic Act (FFDCA), as amended by the Food Qualit y Protection Act (1996) stipulates that when determining the safety of a pesticide chemical, EPA shall base its assessment of the risk posed by the chemical on, among other things, available information concerning the cumulative effects to human health that may result from dietary , residential, or other non - occupational exposure to other substances that have a common mechanism of toxicity . Tolclofos - methyl is a member of the organophosphate (OP) class of pesticides. Other members of this cl ass of pesticides are numerous and include azinphos methyl , diazinon, chlorpy

rifos, dichlorvos, dicrotophos, dimethoate, disulfoton, methamidophos, methidathion, monocrotophos, naled, ox ydemeton - methyl, phorate, phosmet, pirimiphos - methyl, and trichlorfon to name a few. EPA considers organophosphates to express toxicity through a common biochemical interaction with cholinesterase which may lead to a m yriad of cholinergic effects and,Tolclofos - methyl Human Health Risk Assessment DP No. 387242

Page 20 of 49 consequentl y the organophosphate pesticides should be considered as a group when performing cumulative risk assessments. The Agency

has completed a cumulative risk assessment for OPs, (US EPA, 2001), a revised cumulative risk assessment for OPs, (US EPA, 2002), and an updated OP cumulative risk assessment (US EPA, August 2006) which can be found on the Agency 's web site http://www.epa.gov/pesticides/cumulative/rra - op/ . As the proposed uses of tolclofos - methyl are the first United States registrations of the chemical , tolclofos - methyl was not considered or included in the previous OP cumulative assessment. O PP is in the process of evaluating the most current methods and data for suitability of use in the next version of the OP cumulative risk assessment. Tolclofos - m eth ylwill be considered for inclusion in any revised OP cumulative risk assessment. **9.0 Occupational Exposure/Risk Characterization**  Based on the proposed seed treatment uses of tolclofos - methyl, two t ypes of occupational handler exposure is expected: 1) pri mary handler exposure is expected to result for handlers involved in commercial seed treatment and on - farm seed treatment and 2) secondary handler exposure is expected to result from planting tolclofos - methyl treated seeds. Occupational post - application e xposure is not expected for the proposed seed treatment uses of tolclofos - methyl. **9.1 Short**  **- and**  **Intermediate -**  **Term Handler Risk**  Tolclofos - methyl is being proposed for both commercial and on - farm seed treatment use on various crops, turf grass, ornamental flower, and conifers. The proposed formulated product is a liquid containing 42.0% tolclofos - methyl active ingredient (4.17 lbs tolclofos - methyl per gallon). The proposed maximum application rates and use sites are summarized above in Table 3.3. Based on the proposed use pattern, there is potential for exposure to toclofos - methyl to primary handlers (i.e., activities related to treating the seed) and secondary handlers (i.e., planting treated seed). Primary Handler (Treating Seed ) Potential occupational exposure scenarios from the use of tolclofos - methyl as a commercial seed treatment include:  Mixing, loading, appl yi ng liquid formulations;  Bagging treated seed;  Sewing bags; and  Multiple activities. Ty pically , for large - scale commercial seed treatments, workers perform only those specific individual tasks listed above; however, it is assumed that workers also may perform multip le activities throughout the day . As a result a “multiple activities” scenario (i.e. where one worker performs all seed treatment tasks such as loading/applying, sewing, bagging, cleaning, calibration, repair, forklift driver, etc.) was addressed. On - farm seed treatment utilizes similar machinery as commercial seed treatment with the only difference being the size of the equipment. The proposed label restricts use of tolclofos - methyl inTolclofos - methyl Human Health Risk Assessment DP No. 387242

Page 21 of 49 hopper - boxes and planter - boxes thus the commer cial seed treatment risk estimates should be considered protective of any on - farm seed treatment scenarios. Secondary

Handler (Planting Treated Seed) Potential occupational exposure scenarios from the use of tolclofos - methyl as a commercial seed treatment include planting treated seed (secondary handler). It is the policy

of HED to use the best available data to assess handler exposure. For assessing commercial seed treatment and seed planting activities, unit exposure data were taken from HED ExpoSAC Policy

14: SOPs for Seed Treatment. The amount of active ingredient handled depends on the application rate (lb ai/lb seed), the pounds of seed treated in a day , and the pounds of seed that can be planted in a day , all of which vary depending upon the se ed t ype. Values for the amount of seed treated and planted per day were obtained from a Biological and Economic Analy sis Division memo entitled, “

Acres Planted per Day and Seeding Rates of Crops Grown in the United States” (J. Becker and S. Ratnayake; 3/2 4/11). Primary and secondary

handler exposure is expected to be short - or intermediate - term in duration based on information provided on the proposed label. The short - and intermediate - term toxicological endpoints are the same for the respective routes o f exposure; therefore, the estimates of risk for short - term duration exposures are protective of those for intermediate - term durations. L ong term exposures are not expected; therefore, a long - term assessment was not conducted. Summaries of the risk estimates for primary and secondary

handlers are included in Table s 9.1. 1 and 9.1. 2 , respectivel y . The short - and intermediate - term inhalation risk estimates for all primary and secondary handler scenarios do not exceed HED’s level of concern (MOEs > 10 0) at some level of personal protective equipment ( PPE ) .Tolclofos - methyl Human Health Risk Assessment DP No. 387242

Page 22 of 49 **Table 9.1.**  **1 :**  **Summary of Short**  **- and Intermediate**  **- Term**  **Primary Handler Exposure and Risk**  **Est i**  **mate s for Tolclofos**  **- methyl**  **Seed Type Inhal UE**  a **Ma x App Rate**  b **Am t Treated**  c **Inhal Dose d**  **Inhal MOE** e mg/lb lb ai/lb seed lb seed/day mg/kg/day LOC = 100 **LOADER/APPLICATOR** Root and Tuber Vegetables (Crop Group 1) 0.00034 0.000489 5,500 1.14E - 05 2,000,000

- Bulb Vegetables (Crop Group 3 - 01)

- Leafy Vegetables (except brassica vegetables) (Crop Group 4)

- Brassica (Cole) Leafy Vegetables (Crop Group 5)

- Legu me Vegetables (Succulent or Dried) (Crop Group 6)

- Fruiting Vegetables (Crop Group 8 - 10)

- Cucurbit Vegetables (Crop Group 9)

- Herbs and Spices (Crop Group 19) 0.00034 0.00009773 5,500 2.28E - 06 10,000,000

- Cereal Grains (Crop Group 15, except rice and wildrice)

- Grass Forage, Fodder, and Hay (Crop Group 17)

- Non - grass Animal Feeds (Forage, Fodder, Straw, and Hay) (Crop Group 18)

- Oilseeds (Crop Group 20, except Cotton) 0.00034 0.00009773 718,000 2.98E - 04 77,000 Cotton 0.00034 0.000489 160,000 3.33E - 04 69,000 Conifers 0.00034 0.00009773 2,000 8.31E - 07 28,000,000 Ornamental Flowers 0.00034 0.00009773 5,500 6.65E - 05 350,000 **SEWER** Root and Tuber Vegetables (Crop Group 1) 0.00023 0.000489 5,500 7.73E - 06 3,000,000

- Bulb Vegetables (Crop Group 3 - 01)

- Leafy Vegetables (except brassica vegetables) (Crop Group 4)

- Brassica (Cole) Leafy Vegetables (Crop Group 5)

- Legu me Vegetables (Succulent or Dried) (Crop Group 6)

- Fruiting Vegetables (Crop Group 8 - 10)

- Cucurbit Vegetables (Crop Group 9)

- Herbs and Spices (Crop Group 19) 0.00023 0.00009773 5,500 1.55E - 06 15,000,000

- Cereal Grains (Crop Group 15, except rice and wildrice)

- Grass Forage, Fodder, and Hay (Crop Group 17)

- Non - grass Animal Feeds (Forage, Fodder, Straw, and Hay) (Crop Group 18)

- Oilseeds (Crop Group 20, except Cotton) 0.00023 0.00009773 718,000 2.02E - 04 110,000 Cotton 0.00023 0.000489 160,000 2.25E - 04 100,000 Conifers 0.00023 0.00009773 2,000 5.62E - 07 41,000,000 Ornamental Flowers 0.00023 0.00009773 5,500 4.50E - 05 510,000Tolclofos - methyl Human Health Risk Assessment DP No. 387242

Page 23 of 49 **Table 9.1.1: Summary of Short**  **- and Intermediate**  **- Term Primary Handler Exposure and Risk Estimates for Tolclofos**  **- methyl**  **Seed Type Inhal UE**  a **Ma x App Rate**  b **Am t Treated**  c **Inhal Dose d**  **Inhal MOE** e mg/lb lb ai/lb seed lb seed/day mg/kg/day LOC = 100 **BAGGER** Root and Tuber Vegetables (Crop Group 1) 0.00016 0.000489 5,500 5.38E - 06 4,300,000

- Bulb Vegetables (Crop Group 3 - 01)

- Leafy Vegetables (except brassica vegetables) (Crop Group 4)

- Brassica (Cole) Leafy Vegetables (Crop Group 5)

- Legu me Vegetables (Succulent or Dried) (Crop Group 6)

- Fruiting Vegetables (Crop Group 8 - 10)

- Cucurbit Vegetables (Crop Group 9)

- Herbs and Spices (Crop Group 19) 0.00016 0.00009773 5,500 1.08E - 06 21,000,000

- Cereal Grains (Crop Group 15, except rice and wildrice)

- Grass Forage, Fodder, and Hay (Crop Group 17)

- Non - grass Animal Feeds (Forage, Fodder, Straw, and Hay) (Crop Group 18)

- Oilseeds (Crop Group 20, except Cotton) 0.00016 0.00009773 718,000 1.40E - 04 160,000 Cotton 0.00016 0.000489 160,000 1.56E - 04 150,000 Conifers 0.00016 0.00009773 2,000 3.91E - 07 59,000,000 Ornamental Flowers 0.00016 0.00009773 5,500 3.13E - 05 740,000 **MULTIPLE ACTIVITIES** Root and Tuber Vegetables (Crop Group 1) 0.0016 0.000489 5,500 5.38E - 05 430,000

- Bulb Vegetables (Crop Group 3 - 01)

- Leafy Vegetables (except brassica vegetables) (Crop Group 4)

- Brassica (Cole) Leafy Vegetables (Crop Group 5)

- Legu me Vegetables (Succulent or Dried) (Crop Group 6)

- Fruiting Vegetables (Crop Group 8 - 10)

- Cucurbit Vegetables (Crop Group 9)

- Herbs an d Spices (Crop Group 19) 0.0016 0.00009773 5,500 1.08E - 05 2,100,000

- Cereal Grains (Crop Group 15, except rice and wildrice)

- Grass Forage, Fodder, and Hay (Crop Group 17)

- Non - grass Animal Feeds (Forage, Fodder, Straw, and Hay) (Crop Group 18)

- Oilseeds (Crop Group 20, except Cotton) 0.0016 0.00009773 718,000 1.40E - 03 16,000 Cotton 0.0016 0.000489 160,000 1.56E - 03 15,000 Conifers 0.0016 0.00009773 2,000 3.91E - 06 5,900,000 Ornamental Flowers 0.0016 0.00009773 5,500 3.13E - 04 74,000 a Unit Exposures from HED Exposure Science Advisory Council Policy 14 (baseline inhalation = no respirator). b Application Rates based on proposed label uses for tolclofos - methyl. c HED default for lb seed treated per day from HED Exposure Science Advisory Council Policy 15. d Daily Inhalation Dose (mg/kg/day) = daily inhalation unit exposure (mg/ lb ai) x application rate (lb ai/lb seed) x amount treated (lb seed/day) x absorption factor (100%) / body weight (8 0 kg adult). e Inhalation MOE = NOAEL (23.0 mg/kg/day for short - and intermediate - term exposure ) / Inhalation Dose (mg/kg/day) . Level of concern = 100.Tolclofos - methyl Human Health Risk Assessment DP No. 387242

Page 24 of 49 **Table 9.1.2: Summary of Secondary Handler (Planter) Exposures and Risk**  **Estimate s for Tolclofos**  **- methyl**  **Seed Type Represented by**  **Ma x**  **lbs of seed/acre**  **Inhal UE** a **Ma x App Rate**  b **Am t of Seed**  **Planted/Day** c **Inhalation Dose** d **Inhalation MOE** e lb seed/acre mg/lb lb ai/lb seed lb seed/day mg/kg/day LOC = 100 Root and Tuber Vegetables (Crop Group 1) radish 33 3.4 0.000489 2,614 5.43E - 05 420,000 Bulb Vegetables (Crop Group 3 - 01) onion, dry blub 13 3.4 0.00009773 1,004 4.17E - 06 5,500,000 Leafy Vegetables (except brassica vegetables)

(Crop Group 4) spinach 9 3.4 0.00009773 697 2.89E - 06 8,000,000 Brassica (Cole) Leafy Vegetables (Crop Group

5) broccoli 3 3.4 0.00009773 211 8.76E - 07 26,000,00 Legume Vegetables (Succulent or Dried) (Crop

Group 6) pea, garden 412 3.4 0.00009773 32,920 1.37E - 04 170,000 Fruiting Vegetables (Crop Group 8 - 10) pepper 3 3.4 0.00009773 209 8.68E - 07 26,000,000 Cucurbit Vegetables (Crop Group 9) watermelon 9 3.4 0.00009773 726 3.02E - 06 7,600,000 Cereal Grains (Crop Group 15, except rice and

wildrice) wheat 188 3.4 0.00009773 37,500 1.56E - 04 150,000 Grass Forage, Fodder, and Hay (Crop Group 17) bluegrass, kentucky 35 3.4 0.00009773 2,800 1.16E - 05 2,000,000 Non - grass Animal Feeds (Forage, Fodder, Straw,

and Hay) (Crop Group 18) lupin 160 3.4 0.00009773 12,800 5.32E - 05 430,000 Herbs and Spices (Crop Group 19) parsely 10 3.4 0.00009773 836 3.47E - 06 6,600,000 Oilseeds (Crop Group 20, except Cotton) safflower 35 3.4 0.00009773 2,800 1.16E - 05 2,000,000

Cotton cotton 13 3.4 0.000489 2,667 5.54E - 05 420,000 Ornamental Flowers flowers - varied 11 3.4 0.00009773 440 1.83E - 06 12,600,000 Conifers dust 10 3.4 0.00009773 2,000 8.31E - 06 2,770,000 a Information from “

Acres Planted per Day and Seeding Rates of Crops Grown in the United States” (J. Becker and S. Ratnayake; 3/24/11).: Number of seeds per acre (Table 10) ÷ Number of seeds per lb (Table B - 1) = Max lbs of seed per acre b Application Rates based on proposed label uses for tolclofos - methyl. c Incorporation of acres treated per day from HED Exposure Science Advisory Council Policy 15 and “ Acres Planted per Day and Seeding Rates of Crops Grown in the United States” (J. Becker and S. Ratnayake; 3/24/11) d Daily Inhalation Dose (mg/kg/day) = daily inhalation unit exposure (mg/ lb ai) x application rate (lb ai/lb seed) x amount planted (lb seed/day) x absorption factor (100%) / body weight (8 0 kg adult). e Inhalation M OE = NOAEL (23 mg/kg/day for short - and intermediate - term exposure ) / Inhalation Dose (mg/kg/day). Level of concern = 100.Tolclofos - methyl Human Health Risk Assessment DP No. 387242

Page 25 of 49 **9.2 Short**  **- and**  **Intermediat e**  **- Term**  **Post -**  **Application Risk** Occupational post - application exposure is not expected for the proposed seed treatment uses of tolclofos - methyl. S ustained levels of contact with treated seed after it has been placed in the soil or other planting media would not be expected because no ro utine cultural practice required for the production of agricultural commodities involves such an activity as defined in the no/low contact criteria in the Worker Protection Standard (WPS). As a result, no quantitative post - application assessment is requir ed for exposure to treated seeds that have already been planted. Restricted - Entry

Interval (REI) The proposed tolclofos - methyl label ha s the appropriate REI of 12 hours based on the acute toxicity of tolclofos - methyl . Italso includes the appropriate WP S language related to earl y worker entry if there will be no worker contact with the soil subsurface or treated seed.Tolclofos - methyl Human Health Risk Assessment DP No. 387242

Page 26 of 49 **Appendix A: Toxicology Profile and Updated Executive Summaries**  **A.1 Toxicology Data Requirements**  The requirements (40 CFR 158.340) for non - food use of tolclofos - methyl are shown in the table below. Use of the new guideline numbers does not imply that the new (1998) guideline protocols were used. **Test Technical**  **Required Satisfied**  870.1100 Acute Oral Toxicity ................................ ....................... 870.1200 Acute Dermal Toxicity ................................ .................. 870.1300 Acute Inhalation Toxicity ................................ .............. 870.2400 Primary Eye Irritation ................................ .................... 870.2500 Primary Dermal Irritation ................................ .............. 870.2600 Dermal Sensitization ................................ ...................... yes yes yes yes yes yes Y es

yes yes yes yes yes 870.3100 Oral Subchronic (rodent) ................................ ............... 870.3150 Oral Subchronic (nonrodent) ................................ ......... 870.3200 21/28 - Day Dermal ................................ ......................... 870.3250 90 - Day

Dermal ................................ .............................. 870.3465 90 - Day

Inhalation ................................ .......................... CR CR no yes CR Y es

yes yes yes

**--** 870.3700a Developmental Toxicity (rodent) ................................ ... 870.3700b Developmental Toxicity (nonrodent) ............................. 870.3800 Reproduction ................................ ................................ . yes yes yes yes

NO 1 NO 1 870.4100a Chronic Toxicity (rodent) ................................ .............. 870.4100b Chronic Toxicity (nonrodent) ................................ ........ 870.4200a Oncogenicity (rat) ................................ .......................... 870.4200b Oncogenicity (mouse) ................................ .................... 870.4300 Chronic/ Oncogenicity ................................ .................... CR no CR CR CR NO 1

--

--

--

-- 870.5100 Mutagenicity

— Gene Mutation - bacterial ..................... 870.5300 Mutagenicity

— Gene Mutation - ma mmalian ................ 870.5375 Mutagenicity

— Structural Chromosomal Aberrations ... 870.5550 Mutagenicity

— Other Genotoxic Effects ....................... yes yes yes yes NO 1

NO 1 yes NO 1 870.6100a Acute Delayed Neurotox. (hen) ................................ ..... 870.6100b 90 - Day

Neurotoxicity (hen) ................................ ........... 870.6200a Acute Neurotox. Screening Battery (rat) ....................... 870.6200b 90 - Day

Neuro. Screening Battery (rat) .......................... 870.6300 Develop. Neuro ................................ .............................. CR CR yes yes CR Yes

-- Yes Yes

-- 870.7485 General Metabolism ................................ ...................... 870.7600 Dermal Penetration ................................ ........................ 870.7800 Immunotoxicity............................................... CR CR yes No

**--** Yes Special Studies for Ocular Effects

Ac ute Oral (rat) ................................ ........................... Subchronic Oral (rat) ................................ .................. Six - mo nth Oral (dog) ................................ .................. no no no --

--

--

--Not applicable 1 The Agency is not requesting any of these studies at this time and does not believe a UF DB is required for the lack of these studies (see Section 4.4.1) .Tolclofos - methyl Human Health Risk Assessment DP No. 387242

Page 27 of 49 **Appendix A.2. Toxicity Profiles A.2. Toxicity**  **Profiles**

**Table A.2.1. Acute Toxicity Profile for Tolclofos -**  **methyl*** **Guideline No.**  **Study Type MRID**  **Results Toxicity**  **Category** 870.1100 Acute oral - rat

Acute oral - mouse Acute oral - dog 00156124 (1985)

00156128 (1978) 00156125 (1978) Combined LD 50 > 5 g/kg, rats # 3500 mg/kg (2760 - 4800), mice >1000 mg/kg/day IV III III 870.1200 Acute dermal rabbit 00156126 (1985)

Water vehicle 1/5 died by day 5

No clinical signs after dosing of surviving rabbits. LD 50 > 2 g/kg III

870.1300 Acute inhalation

- rat 41410501 (1986) @

Powder,non acceptable/non guideline 41445702 (1983) @ 25% flowable, unacceptable/non guideline LC 50 ≥ 3.32 mg/L Particles 0.3 - 5.5μm %MMAD 1μm or less not met LC 50 ≥ 0.146 mg/L MMAD not determined III NA

870.2400 Primary eye

irritation - rabbit 00156129 (1985) Transient slight conjunctival reaction (24 hrs or less). Not an eye

irritant IV 870.2500 Primary Dermal

irritation - rabbit 00156131 (1985) PI S=0, not an irritant IV 870.2600 Skin

sensitization guinea pig 00156131 (1985) Not a contact sensitizer N/A *Acute summaries found in TXR006933 # Clinical signs (piloerection, hunched posture) in all animals were observed shortly after dosing with complete recovery by 5 days post - dosing. @ Studies found in TXR008856Tolclofos - methyl Human Health Risk Assessment DP No. 387242

Page 28 of 49 **Table A.2.2.**  **Tolclofos -**  **methyl : Subchronic, Chronic and Other Toxicity Profile**  **Guideline No.**  **Study Type MRID No. (year)/**  **Classification /Doses Results**  870.3200 21 - Day

dermal (rabbit) 41506302 (1986)

Acceptable/non - guideline 0 (acetone), 30, 300, 1000 mg/kg 5/sex/dose (previous TXR008890) **Systemic NOAEL** ≥ 1000 mg/kg/day **Systemic LOAEL** not established. *A dose - response of the ChE data resulted in No reliable fit for BMD analysis.* **Irritation NOAEL** ≥ 1000 mg/kg/day **Irritation LOAEL** not established. 870.3100 90 - Day

oral toxicity (rat) 4 weeks Sprague - Dawley TXR006933 00156135 ( 1982 )

Purity not reported **Unacceptable** /non guideline 0, 200, 1000, 5000, 20,000 ppm M: 0, 16, 79, 414, 1636 mg/kg/day F: 0, 18, 88, 452, 1829 mg/kg/day No purity information. HDT: Increased kidney and liver wts (males) and females (mid and HDT) as well as increased spleen and thyroid wts, enlarged hepatocytes HDT male and females. Decreased brain ChE at all dose levels.

870.3100 90 - Day

oral toxicity (rat) Sprague - Dawley TXR009047 41796501 (1990)

Acceptable/guideline 0, 100, 1,000, 10,000 ppm 0, 6.8, 69, 675 mg/kg/day, M&F **RBC ChE**  Male RBC ChE data did not provide a reliable fit for modeling. **Fem ale RBC BMD**  **10** = 72.1 mg/kg/day **Fem ale RBC BMDL**  **10** = 34.01 mg/kg/day Male and Female **brain ChE** data did not provide a reliable fit. **Systemic NOAEL =**  69 mg/kg **Systemic LOAEL** = 675 m /kg, based on decreased bw

gain and increased cholesterol and phosphor lipids. 870.3150 6 - mo nth (rat)

TXR006933 00156136 (1985)

**Unacceptable** /non guideline 0, 300, 1000, 3000, 10,000 ppm M:0,16, 51, 164, 540 MKD F:0, 18, 65, 184, 623 MKD **Hom ogeneity, concentration, and stability**  **not provided.** No histopathology provided for mammary gland. NOEL=300 ppm (16/18 mg/kg/day) LOEL=1,000 ppm (51/65 mg/kg/day), based on increased kidney and liver weight, and fatty bone marrow

infiltrates in females at 1,000 ppm and above.Tolclofos - methyl Human Health Risk Assessment DP No. 387242

Page 29 of 49 **Table A.2.2.**  **Tolclofos -**  **methyl : Subchronic, Chronic and Other Toxicity Profile**  **Guideline No.**  **Study Type MRID No. (year)/**  **Classification /Doses Results**  870.3150 6 month (26 w eeks)

diet (dog) Beagle TXR006933 00156138 (19 79 )

Acceptable/guideline 0, 200, 600, 20 00 ppm M: 0, 7 , 23, 70 mg/kg/day F: 0, 6, 20, 63 mg/kg/day RBC & plasma ChE measured at 4, 8, 13 & 26 weeks. The **LOAEL** is **2,000 ppm (equivalent to**  **70/63 m g/kg/day M/F),**  based upon decreased body weight gains in males, increased thyroid weights in males and females, and decreased cholesterol levels in males and females. The **NOAEL** is 600 ppm (23/20 mg/kg/day M/F). No consistent dose - response was observed for any of the ChE parameters. 870.3250 90 - Day

Dermal Fulfilled by 21 - day rabbit 870.3465 90 - Day

Inhalation toxicity (rat) NA Conditionally Required **Data Waiver Denied** - A waiver request for a 28 - day inhalation study was denied to protect for any future proposed uses as tolclofos methyl has potential to volatilize off of treated fields based on its vapor pressure (D390269, TXR0055976). This inhalation study is not required to assess the proposed uses and the risk estimates for occupational handlers are sufficiently protective . 870.3700a Prenatal

developmental in (rat) Fischer 344 TXR006933 00156142 ( 19 79 )

**Unacceptable** /non guideline 0, 5, 15, 50 mg /kg/day **Maternal** NOAEL = HDT (50 mg/kg). LOAEL not established > 50 mg/kg **Developm ental**  NOAEL could not be established since external examination data were not provided. 870.3700 a Prenatal

developmental in (rat) Crl:CD(SD)BR TXR009333 41422901 ( 19 87 )

Acceptable/guideline 0, 100, 300, 1000 mg/kg/day (TXR009333) **Materna** l NOAEL = >1000 mg/kg/day Maternal LOAEL = not established. **Developm enta**  l NOAEL = 300 mg/kg/day Developmental LOAEL = 1,000 mg/kg/day based on increased incidence of unossified 6 th sternebra (p ≤0.01). 870.3700b Prenatal

developmental in (rabbit) New Zealand White TXR006933 00156143 ( 19 82 )

**Unacceptable** /non guideline 0, 300, 1000, 3000 mg/kg/day **Materna** l NOAEL = 300 mg/kg/day Maternal LOAEL = 1000 mg/kg/day based on decreased food consumption and food efficiency at mid and HDT, decreased spleen and kidney wts at HDT (histology not conducted). **Developm enta**  l NOAEL could not be determined due to critical study design and data reporting issues.Tolclofos - methyl Human Health Risk Assessment DP No. 387242

Page 30 of 49 **Table A.2.2.**  **Tolclofos -**  **methyl : Subchronic, Chronic and Other Toxicity Profile**  **Guideline No.**  **Study Type MRID No. (year)/**  **Classification /Doses Results**  870.3800 3 - Gen

Reproduction (rat) Sprague Dawley TXR006933 00156145 ( 19 85 )

**Unacceptable** /non guideline 0, 100, 300, 1000 ppm Study is **UNACCEPTABL** E. 1. Low pregnancy rates in the control s. 2. Num ber of viable litters in these control groups was low (16/generation). 3. The combined effect of low numbers of pregnancies and viable litters precludes an evaluation of test results because of the potential of the inadequate control data masking compound effects. 4. Unusually high incidence of kidney le sions, which are ge n erally s een in older animals, occurred i n weanlings from all groups; the significance of these findings is unclear. Similarly, no conclusion can be reached regarding the increased incidence of cy toplasmic vacuolation of adrenals in the F2 dams of all dosage groups. Although the incidence particularly in the high dose group is suggestive of a compound effect, the frequency of this finding was not dosage related. 870.3150 9 - mo nth oral

toxicity ( mouse ) ddY TXR006933 00156137 (19 78 )

Acceptable/ **non** - guideline 0, 10 , 30 , 100 , 3000 ppm 0, 1.2, 4, 12, 513(M) 0, 1.4, 4, 14, 564 (F) mg/kg/day **Concentration, Hom ogeneity, and Stability**  **data were not submitted. Systemic NOAEL**  = 100 ppm (12M/14F mg/kg/day) **Systemic LOAEL** = 3000 ppm (513/564 mg/kg/day), based on decreased body w eight and lower body weight gains in both males and females, as well as decreased heart and liver wts (males and females), decreased kidney weight (females), and decreased testes weights all at 3,000 ppm. **ChE B MD**  analysis: ChE RBC and brain data at 2, 4, and 13 weeks did not provide a reliable fit. No dose - response. However, female RBC ChE at 40 weeks data did provide a reliable fit. **Fem ale RBC BMD**  **10** = 13.5 mg/kg/day (week 40 only) **Fem ale RBC BMDL**  **10** = 10.0 mg/kg/ day (week 40 only)Tolclofos - methyl Human Health Risk Assessment DP No. 387242

Page 31 of 49 **Table A.2.2.**  **Tolclofos -**  **methyl : Subchronic, Chronic and Other Toxicity Profile**  **Guideline No.**  **Study Type MRID No. (year)/**  **Classification /Doses Results**  870.4200 Carcinogenicity

(mouse) TXR006933 00156139 (1983)

**UNACCEPTABLE MT**  **D not achieved** 0, 10, 50, 250, 1000 ppm M: 0, 1.3, 6.5, 32.2, 134 F: 0, 1.3, 6.9, 34.1, 137 mg/kg/day - Stability and homogeneity analyses of the test diet were not reported.

- Data from the pilot study were not reported.

- The study authors reported that the first two analyses of

the test diet concentration revealed that the control diet was contaminated w ith 1.8 to 3.0 μg/g of S3349; the study authors indicated that these results may not be accurate.

- A large amount of

the individual data wa s handwritten and illegible; therefore, validation of many parameters (body weights, hematology, clinical chemistry, urinalyses, and organ weights) was not possible.

- Individual data were not reported for clinical observations or palpable mass observation. 870.4300 Chronic/

Carcinogenicity (rat) Sprague - Dawley TXR006933 00156140 ( 19 82 )

**UNACCEPTABLE** Acceptable/guideline 0, 100, 300, 1000 ppm mg/kg/day : M: 0, 4.6, 13.8, 47.0 F: 0, 5.4, 16.3, 54.5 **MT D not established.** 

Special 104 - we ek ChE

study (rat) Fischer 344 TXR006933 00156141 (1985)

Acceptable/non - guideline 0, 100, 300, 1000 ppm 4.5/5.2, 13.5/16.7, 45.6/52.7 mg/kg/day NOAEL > 1000 ppm No decrease in plasma, RBC, or brain ChE at any dose in either sex. 870.5100 DNA Repair

TXR006933 00156147 (1985)

**Unacceptable** DNA repair: **Unacceptable** 870.5100 Salmonella

ty phimurium. & E. coli Reverse gene mutation TXR006933 00156147 (1985)

Acceptable Salmonella & E.coli: Acceptable

870.5375 In vitro Chinese

Ham ster Lung Forward Mutation TXR006933 00156148 ( 19 81 )

Acceptable/ guideline Negative in V79 cells with or without S9 activation at doses ranging from 5x10 - 9 to 5x10 - 6 M. 870.5375 In vivo

chromosome aberration TXR006933 00156149 ( 19 81 )

**Unacceptable** / guideline **Unacceptable.**Tolclofos - methyl Human Health Risk Assessment DP No. 387242

Page 32 of 49 **Table A.2.2.**  **Tolclofos -**  **methyl : Subchronic, Chronic and Other Toxicity Profile**  **Guideline No.**  **Study Type MRID No. (year)/**  **Classification /Doses Results**  870.5375 Dominant Lethal

Rats TXR006933 00156515 (1981)

**Unacceptable** MTD not achieved. 870.5375 UDS

TXR006933 41760801 (1990)

Acceptable/guideline Negative to primary rat hepatocytes up to 40 μg/ml. 870.5375 Chromosome

Aberration (CHO K1) TXR006933 41506301 (1990)

Acceptable/guideline Negative with or without metabolic activation.

870.5375 Chromosome

Aberration TXR006933 00156149 (1981)

**Unacceptable** Data not presented, corn oil not recommended, both sexes not used. 870.5550 Unscheduled DNA

Synthesis in Mammalian Cultured Cells TXR006933 00156148 ( 19 81 )

**Unacceptable** Inadequate dose, HeLa cells not recommended.

870.6100 Ac ute delayed

neurotoxicity (hen) TXR006933 00156134 (1982)

Acceptable/guideline 10/group 0, 8000 x 2 mg/kg Decreased motor activity observed immediately after dosing but resolved by day 5 or 6. Decreased food consumption. Plasma ChE inhibited 42% by 24 hrs but returned to normal by day 8 on study. Negative for axonal degeneration or demyelination. (Brain and RBC ChE not measured). 870.6200a Ac ute

neurotoxicity : time to peak (rat) Crl:CD(SD) TXR0055856 48341941 (2009)

Acceptable/non - guideline Adults only 2,000 mg/kg 1, 2, 4, 8 hrs A single oral dose of 2000 mg/kg to rats did not produce clinical deficits as well as plasma, RBC and whole brain cholinesterase activity significantly different from the control group; a time to peak effect (peak cholinesterase inhibition) of tolclofos - methyl was not established. 870.6200a Ac ute

neurotoxicity : range - finding (rat) Crl:CD(SD) TXR0055856 48341940 (2010)

Acceptable/guideline 5/sex/dose 0, 1000, 2000 mg/kg Adults only Clinical observations (ease of removal, handling, piloerection, grooming, etc) taken every hr from 1 - 8 hrs. No clinical signs at any dose (thru 8 hrs post - dose). **ChE activity not m easured.**  Doses of 200, 700, and 2000 mg/kg selected for main ACN.Tolclofos - methyl Human Health Risk Assessment DP No. 387242

Page 33 of 49 **Table A.2.2.**  **Tolclofos -**  **methyl : Subchronic, Chronic and Other Toxicity Profile**  **Guideline No.**  **Study Type MRID No. (year)/**  **Classification /Doses Results**  870.6200a Ac ute neurotoxicity

(rat) Crl:CD(SD) TXR0055856 48341951 (2010 )

Acceptable/guideline Adults only 12/sex/dose 0, 200, 700, 2000 mg/kg/day Time to peak: 4 hrs ChE not measured. Clinical observations taken at 4 hrs post - dose **NOAEL** = 200 mg /kg/day **LOAEL** = 70 0 mg/kg/day , based on decreased locomotor activity (total and ambulatory counts) in both sexes as well as in the HDT. ChE not measured since no inhibition in the time to peak inhibition study (48341941). 870.6200b Subchronic

neurotoxicity (rat) (Alpk:AP f

SD) Diet TXR0055856 48341952 ( 2007 )

Acceptable/**Non**   ** guideline** Wistar - derived Adults 12/sex/dose 0, 300, 1800, 10000ppm M:0, 21, 122, 736 mg/kg F:0, 23, 136, 763 mg/kg Satelitte 5/dose for ChE at 2, 5, 9, 14 weeks M:0, 23, 130, 720 mg/kg F:0, 24, 144, 817 mg/kg The **NOAEL** is 122.3 M/135.8 F mg/kg/day. The **LOAEL** is 735.7M /762.7F mg/kg/day, based on decreased bodyweight and bodyweight gain, and food utilization. **Brain ChE Adult Female Brain ChE BMD**  **10 =**  956.4 mg/kg/day **Adult Female Brain ChE BML 10**  **=** 659.2 mg/kg/day The adult male b rain ChE data did not produce a dose - response and therefore did not provide a reliable fit for BMD analysis. **RBC ChE The RBC ChE data in both males and**  **fem ales failed to provide a dose response and**  **therefore did not provide a reli able fit for**  **BM D analysis.**  870.6300 Developmental

Neurotoxicity NA Conditionally Required Waiver Granted at this time. 870.7485 Metabolism (rat s &

mice ) TXR006933 00156150 ( 19 80 )

Acceptable/non - guideline Rats and mice were given a single oral dose of 5 mg/kg. Absorption and elimination was almost complete by 24 hrs post - dosing. 13 metabolites found in mice and rats. Unchanged parent accounted for only 5 and 1.3% of dose in feces of rats and mice, respectively. *Repeat or high doses were not administered. 870.7800 Immunotoxicity

28 - day Diet (mice) TXR0055856 48341954 (2010)

Acceptable/guideline 0, 91, 273, 811 mg/kg/day **Systemic NOAEL** = 273 mg/kg/day **Systemic LOAEL** = 811 mg/kg/day, based on decreased body weights/gains, and food consumption. **Immunotoxicity NOAEL** = HDT (811 mg/kg/day), LOAEL not established.Tolclofos - methyl Human Health Risk Assessment DP No. 387242

Page 34 of 49 **A.3 HAZARD IDENTIFICATION AND ENDPOINT SELECTION**  **A.3.1 Acute Reference Dose (aRfD)**  **– Females age 13**  **- 49**  **and A.3.2 Acute Reference Dose (aRfD) general population, including infants and children**  A Study and PoD is not required for this risk assessment. **A.3. 3**  **. Chronic Reference Dose (cRfD**  ) A Study and PoD is not required for this risk assessment. **A.3.4 Incidental Oral Exposure**  (short and intermediate term) A study and POD is not required for this risk assessment. **A.3.5 Dermal Exposure**  (short and intermediate term) **Study Selected:** None Selected **MRID:** NA **Summary:** No s ys temic or dermal irritation was observed at concentrations up to the limit dose (1,000 mg/kg/day) after 3 weeks of exposure (5 day s/week for 3 weeks; MRID41506302). Therefore, a dermal assessment for the short - and intermediate - term durations is not required for tolclofos - methyl. **A.3.6 Inhalation Exposure**  (short and intermediate term) **Study Selected:** Since an inhalation study is currently

unavailable, an oral study was selected for the short - and intermediate - term inhalation assessment. **MRID: 6**  **- month dog**  (00156138) **Summary:** The **L OAEL of**  **2,000 ppm (equivalent to 70**  **/ 63**  **mg/kg/day M/F)** was based upon decreased body weight gains in males, increased thy roid weights in males and females , and decreased cholesterol levels in dogs of both sexes . The **NOAEL** is 600 ppm (23/20 mg/kg/day M/F). **Dose and Endpoint for Risk Assessment:** 70 mg/kg/day . **Uncertainty Factor(s):** 100x [10x interspecies; 10x intraspecies] **Comments about Study/Endpoint/Uncertainty Factor:** The duration of exposure of this subchronic oral study

is appropriate for both the short (1 - 30 day s) and intermediate (1 - 6 months) durations of exposure. Furthermore, the endpoints identified in the dog are protective of effects observed in the rat, which is the ty pical species for organosphate compounds.Tolclofos - methyl Human Health Risk Assessment DP No. 387242

Page 35 of 49 **A.3.7 Dermal and Inhalatio n Exposures**  (L ong - Term) The current non - food seed treatment use is short and intermediate - term, not long - term. Therefore long - term dermal and inhalation risk assessments were not performed. **A.4 UPDATED**  **EXECUTIVE SUMMARIES** The executive summaries presente d here are either from the critical studies used in the assessment and required an updated executive summary or newly submitted studies which required a data evaluation record (DER). **DERMAL: EXECUTIVE SUMMARY**  **:** In a 21 - day dermal toxicity

study (MRID 41506302 ), tolclofos methyl ( 97.7 % a.i. ; L ot No. 40810 ) was applied to the clipped skin of 5/sex/dose New Zealand White albino rabbits at dose levels of 0, 30, 300, or 1000 mg/kg bw/day for 6 hours/day and 5 day s/week for 3 weeks (total 15 day s of exposure ) . The rabbits were restrained with plexiglass neck collars during exposure. The collars were removed and the test sites wiped clean with gauze after the exposure period. Doses were prepared b y combining the appropriate finely powdered test material with the desired volume of acetone. The low - and mid - dose levels constituted a solution and the high - dose level a suspension. Animals were inspected twice daily for signs of toxicity

and mortality . Ophthalmologic and urinal ys is examinations were not performe d. The stability

and concentration of the material in the solutions were not analy zed but are reported to be on file with the sponsor. No deaths were reported as well as clinical signs of toxicity . There were no treatment related effects on body weight or food consumption. Re - evaluation of the hematology data suggest that there was not a biologicall y significant increase in eosinophil counts in HDT males (Table 1), unlike the previous review. These eosinophil counts are within control ranges and are therefore not considered to be of biological significance. In addition a positive dose - related trend in eosinophil levels was not observed, unlike the previous review. Re - evaluation of the clinical chemistry resulted in all parameters within the normal range published for this species and age of rabbits. Absolute organ weights were not affected by treatment. Relative kidney weights, however, were increased (20%) in HDT females (Table 2). There were no compound - related histopathological changes observed in the kidney s, however, and therefore not of biological significance. The ChE data were submitted for BMD anal ys is and the data were not fit for anal ys is since a dose response was lacking for both males and females. Therefore the ChE data are not approp riate for establishing a s ys temic LOAEL. Based on the lack of biologically significant effects, the sy stemic **LOAEL was not identified** . The **systemic NOAEL** is ≥ 1,000 mg/kg/day . The dermal irritation scores were located in Table 4 of the original study r eport and were re evaluated for establishment of the irritation NOAEL and LOAEL. Very slight ery

thema was observed in some animals of every treatment group (Table 3). However, the incidence of theTolclofos - methyl Human Health Risk Assessment DP No. 387242

Page 36 of 49 erythema decreased with increasing dose. Likewise, the c ompound was observed to build up on the skin in every

treatment group with the first signs in the HDT (6 day s) followed by the mid - dose (8 day s) and low - dose (14 day s). This slight ery thema, however, does not constitute an adverse irritation effect. Th e **irritation LOAEL** was not identified. The **irritation NOAEL** is ≥ 1000 mg/kg/day . This study is classified as **acceptable/guideline** and satisfies the guideline requirement s (OPPTS 870.3200; OECD 410) for a 28 - day dermal toxicity

study in Rabbits . **ORAL: Subchronic Rat**  **EXECUTIVE SUMMARY :**  In a 90 - day study (MRID 41796501 ) Rizolex ( to lclofos - methyl, S 3349) ( 96.6% w/w, lot # 90437 - M ) was administered continuousl y in the diet for 90 - day s to 12 /sex/ dose Crj:CD (SD) rats, at dose levels of 0, 100, 1,000, and 10,000 ppm (equivalent to 0, 6.8, 68.6, 674.5 mg/kg/day , respectivel y). Food consumption was determined for 48 hours each week throughout the treatment period and mean daily diet consumption was calculated. Animals were inspected once dai ly

for signs of toxicity

and mortality . Animals were weighed on the day 1, 3, and once weekl y thereafter and before necrops y. Blood was collected on the day of sacrifice for hematology , clinical analy sis and cholinesterase determinations from all animals . Brain cholinesterase levels were determined in the left half of a mid - line section of the whole brain taken immediately

after death from all rats in each group. All animals that died and sacrificed on schedule were subject to gross pathological examination, but only tissues from the controls and 10,000 ppm groups were subjected to histological examination (only lung, liver, and kidney s). The ovaries, adrenals, th yroid (parathyroid) and pituitary were weighed after 23 hour fixation in 10% neutral buffer ed formalin. No mortality

or clinical signs of toxicity were observed. Body

weight gains of males (25 - 65%) and females (27 - 61%) were significantl y (P ≤ 0.01) reduced, in the 10,000 ppm group, during the entire treatment period when compared to controls. At termination, the mean cumulative body weight gain of males and females was decreased b y approximately 25% and 27% (P ≤ 0.01) respectively , when compared to the controls (Table 2). The food consumption also decreased significantl y (P ≤ 0.01) in the male s (17 - 46%) and females (13 - 19%), throughout the treatment period, at 10,000 ppm, when compared to the controls (Table 3). In males, the activated partial thromboplastin time (APTT) was increased (8.5% or 5 minutes) and the MCHC was decreased (1.5%) sign ificantl y, when compared to the controls. At the same dose in females, the hemoglobin (HGB), mean corpuscular HGB, and prothrombin time were decreased 3.6%, 2.8%, and 2% respectivel y, when compared to controls. Although these decreases were significant s tatisticall y, they do not represent biologically meaningful changes to consider as adverse effects. Males and females at the 10,000 ppm exhibited statistically significant increases in total cholesterol (33% M and 50% F) and phospholipids (27% M and 39% F), which may be due to disturbed fat metabolism ( Table 4). Also total protein, GGT, SGOT and ALP significantly increased/decreased in males and females.Tolclofos - methyl Human Health Risk Assessment DP No. 387242

Page 37 of 49 Males and females in the 10,000 ppm group exhibited significant decreases in RBC, plasma and brain cholinesterase levels. A BMD anal ys is resulted only in female RBC data fitting a dose response model. The male ChE data not provide a reliable fit for mode ling as well as the female brain ChE data. The ChE data are provided in T able 5 as well as the BMD model outputs for the female RBC ChE anal ys is . The histopathology

and weight of organs (spleen, brain, heart, and kidney) did not change significantl y due exposure to tolclofos - methyl. Treatment related effects on liver were evidenced by dark, discolored livers grossly and h ypertroph y of hepatocytes microscopically. The above information supports a **L OA**  **EL of 10, 000 ppm (674.5 mg/kg/day),**  based on signific antl y reduced bodyweight gains and increased total cholesterol and phospholipids. The **NO A**  **EL is**  **1,000 ppm (68.6 mg/kg/day)**  . **Cholinesterase: Female RBC BMD**  **10** = 72.1 mg/kg/day **Female RBC BMDL 10**  = 34.01 mg/kg/day Male and Female **brain ChE** data did not provide a reliable fit. The study is classified as **Acceptable/Guideline** and satisfies the guideline requirement for a subchronic neurotoxicity

study in rats (870.6200b). **Subchronic Dog EXECUTIVE SUMMARY**  **:** In a subchronic oral toxicity stu dy (MRID 00156138), tolclofos methyl (98.7%, white powder, Lot#4, LH No 17,631B) was administered to 6 beagle dogs/sex/dose in the diet at doses of 0, 200, 600, or 2000 ppm (equivalent to 0/0, 7/6, 23/20, and 70/63 mg/kg/day in males/females) for 6 months (26 weeks). No interim sacrifices were performed in this study. Ophthalmological examinations were performed on all dogs prior to study start and at study termination. All animals survived the study and no treatment - related clinical signs were reported. Ophthalmological examinations were normal in all treatment groups. There were no significant differences in body weights or food consumption with the exception of reduced body weight gain in high dose males ( ↓54%). Absolute and relative liver (37%, 44 %) and th yroid (23%, 31%) weights were increased in HDT males compared to controls, respectivel y (Table 1). In females, absolute (30%) and relative (39%) liver weights were also increased as well as relative thy roid weight (18%). However, histopathologic al findings did not reveal changes in the liver or thy roid. Unlike the previous review of the hematology , the hematocrit, hemoglobin, and ery throcy te values for the treated groups were similar to controls in males and females. Therefore, there are no bio logicall y significant changes in hematology parameters (Table 2).Tolclofos - methyl Human Health Risk Assessment DP No. 387242

Page 38 of 49 The clinical chemistry

parameters were also re - evaluated. Alkaline phosphatase (ALK) levels were consistently

increased from week 12 thru week 24 in HDT males (58 - 70%) and females (64 - 72%) . Cholesterol was reduced in HDT males from week12 through week 20 (9 - 21%) but similar to controls at week 24. In females, cholesterol was decreased throughout the entire study and ranged from 4 - 33%. The **LOAEL** is **2,000 ppm (equivalent to 70**  **/ 63**  **mg/kg/day M/F),**  based upon decreased body weight gains in males, increased th yroid weights in males and females , and decreased cholesterol levels in males and females. The **NOAEL** is 600 ppm (23/20 mg/kg/day M/F). It is noted that the increased liver weights and increased ALK values are considered adaptive since no histopathological changes were observed in the liver. This study

is classified as **acceptable/guideline** and satisfies the guideline requirement for a 90 - day oral toxicity

study (OPPTS 870.3150; OECD 409) in dogs. In a **nine -**  **month oral toxicity study** (MRID00156137), tolclofos - methyl ( S 3349 ), (97% a.i, Batch # 524) was administered in diet to 5 week old, ( ddY ) mice 15/sex/group at the dietary levels of 0, 10, 30, 100 and 3,000 ppm (calculated to be 1.2/1.42, 3.78/4.14, 12.2/13.8, and 513/564 mg/kg/day , respectivel y for male and female mice) for 9 months . The highest dose level of 3,000 ppm was the maximum t olerable dose determined b y a preliminary study . There were 3 satellite groups (5 animals/sex/group) to determine time - course changes of plasma, RBC and brain ChE levels. Body weight, food and water consumption were recorded weekl y. Clinical signs and m ortality were observed dail y. Organs and tissues were fixed with 10% formol - saline, embedded in paraffin wax, sliced at 5μ in thickness, stained with hematox yl in and eosin and examined under light - microscope. Neither abnormal clinical signs nor dead anim als were found throughout the feeding period. Body weights of both males (12 - 21%) and females (17 - 28%) treated with the highest dose of tolclofos methyl (3,000 ppm) were lower than controls (week 10

– week 40). Highest dose females (30%) and males (33%) h ad significantly less weight gain (p<0.01). Although weight gain appeared lower in the other dose groups, the control males were small at the beginning of the study . For females, body weight gain did not follow a dose - response up to 100 ppm. Ophthalmol ogical examinations were performed on all surviving animals at termination of exposure (week 41) to the test compound and did not find significant changes in irises, lenses, and retinas. Some of the mice including controls had cornea opacity (1/15, 1/15, 2 /15 and 0/15 HDT compared to 1/15 controls) . Hematological analy sis found statistically significant decrease s in leucocy tes for all treated male mice , however in a reverse dose - response with ↓57% at the lowest dose to ↓25% at the highest dose . For treate d female mice, an increase in leucocy tes (ly mphocy tes) was found but with no dose response pattern. Cholinesterase levels were measured on 5 mice/sex/group of the satellite animals at each time point (2, 4, 13 weeks), and 5 mice/sex/group of the main group at study termination (week 40) (Table 6 B in the report). BMD analyses revealed no reliable fit of the data in males or females at an y timeTolclofos - methyl Human Health Risk Assessment DP No. 387242

Page 39 of 49 point (weeks 2, 4, 13, or 40) expect for female RBC ChE at 40 weeks. Female plasma ChE was inhibited significantly

(p<0.05) at 100 ppm in week 2 and 30 ppm and above in week 40. Gross pathology revealed hydronephrosis, defect of pelvis in kidney , pneumonia, hy perplasia of mesenteric l ymph node and spleen, and rough - surfaced liver in some of the mice. Heart (10% , 13%) and liver (12%, 16%) weight were significantl y lower in high dose males and females , respectivel y. Kidney weight was significantly lower in high dose females (20%) while testes weight (11%) was significantl y lower in high dose males (p ≤0.05). Ovarian weight was increased in 100 ppm females (19%) , but not at an y other dosage level . P ituitary weight was increased in 10 ppm (47%) and 30 ppm (23%) males, but not in any other dosage groups . Pituitary weight was increased in 10 (31%) , 30 (31%) , 100 (22% ) and 3000 (37%) ppm females. Histological evaluation revealed adenomatous h yperplasia and adenocarcinoma of lungs in one male and one female at 3,000 ppm, respectivel y. Lym phocy tic infiltration (one control male) and fatt y change in liver (five control males) were found only in controls and in two of the highest dosed males (one with l ymphocy tic infiltratio n, and one with both fatty change and ly

mphocy tic infiltration) and 7 females (one female with fatty change, two females with focal necrosis, and four female with l ymphocy

tic infiltrates (note: one female had both fatty change and lymphocytic infiltrate)]. Kidney

lesions were found in 4 high dose males (1 hydronephrosis; 1 hy perplasia; and 2 pelvic defects) and none in the other treatment groups while lesions were found in 1 control (atrophy of kidney) and two high dose females (1 cy stic change of tubuli an d 1 glomerular hyalinosis). Fatty change of adrenal medulla was found in 10 control females and 12 females at 3000 ppm group; while none were observed in males. Interstitial nephritis, vacuolation in cy toplasm of epithelial cells were found in a few mice; cy stic changes of tubuli and glomerular hy alinosis were sporadicall y found. Urinary

bladder erosion and edema were found in 3,000 ppm females. Atrophy and hy perplasia of interstitial cells were found in a few animals of both control and the treatment gr oup. Other organs including brain, spinal cord, and sciatic nerve had no remarkable changes. **ChE Inhibition** Tolclofos - methyl in the diet for 9 months did not consistently produce ChE inhibition over the time course of the study in mice. A BMD analy sis p roduced a reliable fit for the 40 week RBC ChE data in females onl y. The female RBC (week 40 onl y) **BMD 10**  is 13.5 mg/kg/day and the **BMDL 10**  is 10.0 mg/kg/day . **Systemic** Sy stemic LOAEL = HDT (3,000 ppm), based on decreased body weight and lower body weight gains in both males and females, as well as decreased heart and liver wts (males and females), decreased kidney

weight (females), and decreased testes weights all at 3,000 ppm. Sy stemic NOAEL = 100 ppm (12.2M/13.8 F mg/kg/day) **This updated Executive Su mmary updates the**  **NOAEL and LOAEL conclusions for the 9 month study for tolclofos**  **- methyl and supersedes the previous conclusions in TXR 006933.**  **Deficiencies:**Tolclofos - methyl Human Health Risk Assessment DP No. 387242

Page 40 of 49 The anal ys is for concentration, homogeneity , and stability w as not provided in the study report . However, since effects were observed in mice at relatively lower concentrations than other studies for tolclofos - methyl, then the mice were exposed to sufficient tolclofos - methyl to elicit these responses . The stud y, however, is considered non - guideline . Th is study

is classified as **A cceptable/** **N on**  **- guideline**  . Th is study do es not satisfy a guideline requirement for tolclofos - methyl . **Chronic/Cancer Rat**  **EXECUTIVE SUMMARY :**  In a chronic toxicity study (MRID 00156140 ) , S - 3349 (three batches were used: batch no. 0523, purity 94.9%; batch no.4, purity : 98.7%; batch no.523, purity : 94.9% ) was administered as a lifetime dietary administration at 100, 300 and 1000 ppm (equivalent to 0, 4.6/5.4, 13.8/16.3, 47/54.4 mg/kg/day for M/F respectivel y) to Fischer 344 rats (until termination , for males at week 122 and 123; females at week 130) . The test material was incorporated on a weight - per - weight basis into the basal diet by adding the appropriate amount to 250 g of basal diet. Diet was prepared weekly. Storage cond itions were not specified. Samples of diets were collected weekl y beginning at week 68 and samples were assayed at 4 - week intervals. Animals were assigned randoml y to the 0, 100, 300, and 1000 ppm test groups. There were 55animals/sex/group in main study group and 10 animals/sex/group in interim sacrifice group (termination at 52 weeks). Animals were inspected twice dail y for signs of toxicity and mortalit y. Observations were recorded weekl y for the first 26 weeks, biweekl y for the next 26 weeks, and e very week for the remainder of the study . Individual food consumption was recorded weekly for the first 26 weeks, biweekl y for the next 26 weeks, and every 4 weeks for the remainder of the study. Individual body weight gains were anal yz ed at weeks 0, 4 , 14, and 50 in male rats and at weeks 0, 4, 16, and 52 in female rats. Growth rates, total food consumption, and clinical pathology data generated through week 52 and organ weight data at week 52 were compared between dosed and control groups of the same sex by Bartlett’s test for homogeneity of variance and the one - way classification anal ys is of variance (ANOVA). Scheffe’s multiple pairwise comparison procedure was used when ANOVA showed significance. Mean body weights at weeks 0 and 52 were also anal yz ed using a multiple pairwise comparison procedure. Ophthalmology examinations were performed on all rats initially and at weeks 26, 52, 78 and 104; on all male rats at week 122, and on all female rats at week 129 . Blood was collected at 1, 4, 13, 26, 52, 78, and 104 weeks for hematology and clinical chemical anal ys i s from 10 rats/sex/group, and from 10 males/group at week 122 and 10 females/group at week 129 . Blood was collected b y s egmental amputation of the tail for hematology determinations and by orbi tal sinus puncture under ether anesthesia for clinical chemistry determinations. Urine samples were collected b y housing rats overnight in metabolism cages and pooling the samples b y sex within each group. Interim sacrifice was done at 52 weeks, and termi nal sacrifice was done at week 122 and week 123 for main study males and at week 130 for main study females. Gross pathology and histology examination s were done on all animals that died and that were sacrificed on schedule. In cidental signs such as hunch ed and/or thin appearance, labored respiration, enlarged testes in males, and/or ocular changes occurred with comparable frequency in control and treated rats. There was no compound related effect on mortality . At 120 weeks, survival ranged from 44 to 59 % in treated male rats, compared to 51% in control male rats. At 128 weeks, survival ranged from 41 to 56% in treated female rats, compared to 48% in control female rats. No dose - related trends in survival or clinical signs were observed.Tolclofos - methyl Human Health Risk Assessment DP No. 387242

Page 41 of 49 Stability an d homogeneity

analy ses conducted on diet samples prepared after study termination showed that stability

ranged from 89.3 to 106.0% of target levels and homogeneity ranged from 87.6 to 110.3% of target levels. Mean food consumption in male rats fed low and mid dose diets, and in female rats fed mid and high dose diets were comparable to control values. An anal ys is of mean efficiency of food utilization for the first year of the study did not reveal any

significant compound effects. Weekly

group water consumption was recorded during weeks 3, 12, 25, 51, 77 and 103. Terminal water consumption values were recorded the first 4 day s of week 122 for males and all of week 124 for females. Individual water consumption values were calculated by dividing group cons umption by

the number of rats/group . Water consumption was consistently higher in high - dose males at all intervals although it was not statistically significant after week 51. There were no compound - related changes in the ocular findings. No compound re lated changes in hematology values were noted. There were some statisticall y significant differences between controls and compound - treated rats at sporadic intervals; however, the changes were not consistent with time or dose. Mean alkaline phosphatase values were lower in treated group than control males; significant decreases were measured at all three dose levels. No consistent significant decrease in alkaline phosphatase was measured in treated female rats. Cholinesterase (ChE) levels were signif icantly lower in 100, 300, and 1,000 ppm males and females at week 52. Also significantly lower ChE levels were found in 300 ppm males (at terminal/week 122); and 100, and 300 ppm females (at terminal/week 129). These changes were, however, not dose related. Itis noted that, standard deviations levels were higher than means in females at all three dose levels at week 52; and females at 100 and 300 ppm at terminal/week 129. No consistent significant changes in plasma or RBC ChE values were detected. At the terminal sacrifice, values for plasma and RBC ChE were similar in dosed and control groups but standard deviations were high. Examination of the individual data in all the groups indicated that 30 - 60% of the blood samples were hemolyzed. Mean alkaline phosphatase values were significantly lower in all three dose levels males and females. No significant compound - related effects were determined by urinal ys is. No significant compound - related organ or tissue changes were observed. There were no differences in organ weights between compound - treated rats and control group at the interim sacrifice and the terminal sacrifice. Decreased spleen weights, increased thy roid weights and decreased adrenal weights were noted for selected dose levels, however , no significant dose - relate pattern was evident. Histopathology

examination at week 52 found areas of interstitial cell hy perplasia of the testes, hy perplasia in the pars anterior of the pituitary , chronic myocarditis and m yocardial degeneration, peribr onchial l ymphoid infiltration, and focal areas of hemorrhage and intimal mineralization of the pulmonary

vessels in the respiratory s ys tem to be among the more frequently occurring lesions. However, their prevalence was comparable between compound - treated groups and control groups.Tolclofos - methyl Human Health Risk Assessment DP No. 387242

Page 42 of 49 In the urinary

s ys tem both groups showed chronic interstitial nephritis, tubular dilatation, and tubular eosinophilic proteinaceous casts with equal frequency . In the digestive s ystem, hemosiderosis of the spleen, ly mphoid hy

p erplasia and l ymphoid necrosis of the Peyer’s patches occurred with comparable frequency

in control and compound - treated rats. A summary tabulation of histologic findings at the 12 - month sacrifice was not presented; however, tabulation of findings for ind ividual animals supported the authors’ descriptive text on findings. No dose - related trends for non neoplastic lesions were apparent. Neoplastic lesions were observed with comparable frequency in control and compound treated rats with a few sporadic exceptions. There were no apparent dose related trends nor was there an y difference in degree of histologic differentiation with increasing dietary compound levels. Neoplastic lesions are summarized in Table ... **Deficiencies** : Examination of individual data in all the groups indicated that 30 - 60% of the blood samples were hemoly zed. Dose levels used were not adequate to produce biologicall y relevant changes in life parameters, pathology findings, or cholinesterase activity . Brain ChE values in all groups including controls had an excess of outl yi ng values (approximately 0.1 of mean value). For example, in females receiving 0, 100, 300, 1000 ppm there were two, seven, seven and seven outliers at 12 months and two, six, six, and three outliers at terminatio n (10rats/group). In addition, mean values in controls were about 5 to 8 times lower than normally expected. The sponsor’s summary

indicted that there was a technical error in the cholinesterase determinations. Th is study

is classified as **Una cceptable/** **N on**  **- guideline**  . Th is study do es not satisfy a guideline requirement for tolclofos - methyl . **Cancer Mouse** In a **Chronic Toxicity/Oncogenicity** Feeding Study in Mice (MRID 00 156139 ), S - 3349, tolclofos methyl (94.3% a.i., Lot # of Batch # not specified ) at dose levels 10, 50, 250 and 10,000 ppm were fed in the diet to male and female B6C3F1 mice for 24 months. There was one week acclimation period and animals were assigned to the above test dose groups b y stratified randomization. Mice were individuall y housed in an environmentall y controlled room with a 12 - hr light/dark cycle. The test compound was mixed monthly with the basal diet at the appropriate test concentrations based on the results of the pilot study . However, data from the pilot study were not reported. The test diet was stored in a cold room of unspecified temperature. Concentration analy ses of the test diet were performed monthl y for 18 months at the Institute for Biological Sciences of Sumitomo Chemical Company . Animals received food an d water ad libitum . There were 50 animals/sex/group in main study groups and 10 animals/sex/group in satellite groups. Animals were inspected twice daily for signs of morbidity

and mortality . All mice were individually examined for palpable masses at week ly intervals. Main study

mice were weighed weekl y at weeks 1 to 13 and monthly thereafter until study

termination. Mice of the satellite group were weighed monthly . Mean dail y diet consumption was calculated at weekl y intervals. Efficiencies of food util ization were determined monthly at months 1 to 6 and biannuall y thereafter to study termination. Efficiency and compound intake were calculated from the consumption and body weight gain data. Water consumption every 48 hours was determined weekl y. Ophtha lmological examinations were performed on controls and high - dose males and females at 12 and 24 months. Blood was collected from the caudal vein orTolclofos - methyl Human Health Risk Assessment DP No. 387242

Page 43 of 49 right ventricle for hematological anal ys is at 12 and 24 months and for clinical chemistry anal ys es at 6, 12 and 24 months from 10animals/sex/group. Urine was collected from 10animals/sex/group at 6 and 12 months from mice of the satellite group, and 10animals/sex/group at 18 months from mice of the main group, and all survivors at 24 months. All animals that d ied and that were sacrificed on schedule were subject to gross pathological examination and the tissues were collected for histological examination. Student’s T test was used to analyze the numerical data: body weight, food consumption, clinical pathology , and organ weight data. Chi - square test was used to anal yz e mortality and gross microscopic pathology . Bod y weights of males receiving 250 and 1000 ppm were found to be slightly but significantly (p<0.01, p<0.001) decreased from weeks 1 to 12 and fro m weeks 1 to 32, respectivel y; thereafter, body weights were found to be similar to those of concurrent controls. Body weights of females receiving 50 ppm were found to be slightly but significantly

(p<0.05, p<0.01, p<0.001) decreased from weeks 1 - 52, whi le body weights of females receiving 250 and 1000 ppm were slightly but significantl y (p<0.05, p<0.01, p<0.001) decreased at most weighing intervals throughout the study when compared to concurrent controls. Dosed male and female mice of the satellite gro ups exhibited slight fluctuations in body weights. Mean test compound intake was reported to be 1.28, 6.45, 32.20, and 134.15 mg/kg/day for males receiving 10, 50, 250 and 1000 ppm concentrations, respectivel y. Mean test compound intake for females rec eiving 10, 50, 250, and 1000 ppm concentrations was reported to be 1.32, 6.86, 34.10, and 136.91 mg/kg/day , respectivel y. Food consumption of treated males was similar to concurrent controls. Food consumption of females receiving 1000 ppm was found to be decreased from week 30 to study

termination. The food consumption of other treated females was similar to that of concurrent controls. Ophthalmological findings were similar in dosed and control mice. Serum and RBC cholinesterase (ChE) activities w ere significantl y decreased in males and females receiving 250 and 1000 ppm S - 3349 throughout the study when compared to concurrent controls; this decreased was more pronounced in females receiving 1000 ppm. Brain ChE activity was significantl y decreased in males receiving 250 and 1000 ppm at 52 and 104 weeks and females receiving 50, 250, and 1000 ppm at 28 weeks, 250 and 1000 ppm at 52 weeks, and 1000 ppm at 104 weeks. Brain cholinesterase activit y was most extensively reduced in females receiving 1000 ppm at 28 weeks. Other clinical chemistry

parameters were similar for control and dosed males and females and there were no effects of dosing on any urinary parameter. Organ weights of control and dosed males and females were similar at 28 weeks. At 12 months, slightly but significantl y (p<0.05) decreased absolute and relative pituitary weights were found in males receiving 250 ppm. Females receiving 1000 ppm had significantly increase (p<0.05) absolute and relative pituitary

weights. Absolute brain we ights were significantl y (p<0.01) increased in males receiving 1000 ppm at 24 months; absolute and relative brain weights were slightly but significantl y (p<0.05) increased in females receiving 250 ppm at this time period. Absolute kidney weights were slightly

but significantl y (p<0.05, p< 0.01) increased at 12 months in males receivingTolclofos - methyl Human Health Risk Assessment DP No. 387242

Page 44 of 49 250 ppm; absolute and relative kidney weights were significantl y (p<0.05, p<0.01) increased in males receiving 1000 ppm and in females receiving 250 and 1000 ppm. The incid ence of kidney discoloration was increased in males receiving 10 and 1000 ppm and in females receiving 250 ppm. Hematomas of the pituitary were not found in control females but were found in one, four, and five females receiving 10, 50 and 1000 ppm, respe ctively ; this finding was not exhibited in treated males. At 24 months, the incidence of liver nodules was found to be increased in 50 and 1000 ppm males and females at 1000 ppm when compared to concurrent controls; liver masses were found in 8 control ma les and 17, 14, 11 and 13 males receiving 10, 50, 250, and 1000 ppm, respectivel y. Histological examination found that, at 24 months, the incidences of ly mphomas were higher in females, and incidence of adenomas and adenocarcinomas of the liver and lung were higher in males. However, these findings were similar in dosed and control mice with the exception of adenomas of the liver which were increased in males treated with 10 ppm (9/50), 50 ppm (11/50) and 1000 ppm (9/50) when compared to concurrent contro ls (5/50). Non - neoplastic lesions such as ly mphocy tic infiltration of the kidney s were increased in dosed males when compared to controls, and pyelonephritis of the kidney s was increased in females receiving 10000 ppm when compared to controls. Hemorrhag e of the ly mph nodes were found in 2 control males and 10, 4, 3, and 7 males receiving 10, 50, 250 and 1000 ppm, respectivel y; the incidence at 10 ppm was significantly (p<0.05) increased. Fibrosis of the tongue was reported in 4 control females and 8, 8, 5, and 12 females receiving 10, 50, 250 and 1000 ppm, respectivel y; the incidence at 1000 ppm was significantl y (p<0.05) increased. However, since there was no descriptive narrative in histologic lesions, it was unable to differentiate between malignant and benign lesions (could not determined if adenocarcinomas of the liver were actually hepatocellular carcinomas and if lung tumors were alveolar bronchiolar pulmonary lesions). Based on decreased serum, ery throcy te, and brain cholinesterase activities, MTD of 1000 ppm (highest dose tested) for this study was obtained. The sy stemic LOEL is 250 ppm and the sy stemic NOEL is 50 ppm S - 3349, based on decreased serum, ery throcy te, and brain cholinesterase activities. The LOEL and NOEL for histopathology cann ot be definitively

determined. **Deficiencies** : Stability and homogeneity

analy ses of the test diet were not reported. Data from the pilot study were not reported. The study authors reported that the first two anal ys es of the test diet concentration revealed that the control diet was contaminated with 1.8 to 3.0μg/g of S3349; the study authors indicated that these results may not be accurate. A large amount of the individual data was handwritten and illegible; therefore, validation of many parameters (body weights, hematology , clinical chemistry , urinal ys es, and organ weights) was not possible. Individual data were not reported for, clinical observations or palpable mass observation. The report’s section on conclusions (page#48 of the study report) indicated that ChE activities increased in males and females receiving 1000 ppm, when these parameters, in fact decreased.Tolclofos - methyl Human Health Risk Assessment DP No. 387242

Page 45 of 49 One animal death was incorrectly identified in Table 43 - 3 of the study report (animal no. 1324 was reported with adenocarcinoma of liver when animal no.1334, a male receiving 50 ppm, was reported to have died with this finding in Table 47 - 3 - 1 of the study report). The numbers of organs with pathology reported in th is study

were compared to the number of animals sacrificed rather than the number of organs examined (which is appropriate to do). Also there was no descriptive narrative in histologic lesions and was unable to differentiate between malignant and benign l esions; as such, histopathology results could not be conclusively determined. The LOEL and NOEL for histopathology cannot be definitively

determined. Based on the number of deficiencies th is study is classified as **Una cceptable/** **N on**  **- guideline**  . Th is study do es not satisfy

a guideline requirement for tolclofos - methyl . **Neurotoxicity Rat Time to Peak**  **In a time to peak effect study** (MRID 48341941 ), tolclofos - methyl (t echnical grade 97.5% a.i., Lot no. # 080712G ) in corn oil (vehicle) was administered orall y b y gavage as a single dose (2000 mg/kg) to one group of adult (approximately 7 weeks old) Sprague - Dawley (Crl:CD(SD)) rats. A concurrent control group received the vehicle on a comparable regimen. The dose volume was 5 ml/kg for all groups. Each group consisted of 20 rats/sex. For anal ys is of plasma, red blood cell (RBC) and whole brain cholinesterase activity , 5 animals/sex/group were euthanized by carbon dioxide at approximately 1, 2, 4, and 8 hours followin g dose administration. Blood samples were collected from the inferior vena cava, the whole brains were collected and weighed and plasma, red blood cell, and brain homogenates were anal yz ed for cholinesterase activity . All animals survived to the schedu led euthanasia, there were no test substance - related clinical findings noted. Cholinesterase activity (RBC, plasma, whole brain) was unaffected for males and females in the 2000 mg/kg group at approximately 1, 2, 4 and 8 hours (no different from the control group across all time points observed). The absence of consistent inhibition of cholinesterase through 8 hours following dose administration precluded the determination of a time of peak effect of cholinesterase inhibition. Th is study

is classified as A **cceptable/ N**  **on -**  **guideline** . Th is study do es not satisfy a guideline requirement for tolclofos - methyl . **ACN In an acute neurotoxicity study**  (MRID # 483419 40 ) , groups of non - fasted , six weeks - old, Crl:CD(SD) rats, 12 /sex/dose were given a single oral dose of tolclofos - Methyl ( 97.5% a.i., lot # 080712G ) in corn oil at doses of 0 , 200 , 700, or 2000 mg/kg bw and observed for 14 day s. Neurobehavioral assessment (functional observational battery and motor activity

testing) was perf ormed in 12 animals/sex/group prior to the initiation of dose administration (study day - 8), at the time of peak effect on study day 0 (considered to be approximately 4 hours after dose administration), and on study day s 7 and 14. Cholinesterase activity was not measured. At study termination, 12 animals/sex/group were euthanized and perfused in situ for neuropathological examination. Of the perfused animals, 6 animals/sex from the control group and the 2000 mg/kgTolclofos - methyl Human Health Risk Assessment DP No. 387242

Page 46 of 49 group were selected randomly and subjecte d to histopathological evaluation of brain and peripheral nervous s ys tem tissues. There were no test substance - related clinical findings observed during the study. All animals survived to the scheduled euthanasia (study day 15). Mean body

weights and bod y weight gains were unaffected by treatment. Mean overall locomotor activity (total and ambulatory

counts) was decreased for males and females in the 700 and 2000 mg/kg groups at the time of peak effect on study day 0, but was similar to the control group on study day s 7 and 14. L ocomotor activity was unaffected by

test substance administration at a dose level of 200 mg/kg. There were no test substance - related macroscopic or microscopic changes. Brain weights and measurements were unaffected b y administration of the test compound at an y dose level. **Based on the effects seen in this study, the LOAEL**  **i s**  **700 mg/kg**  **bw/day based on**  **decreases in**  **overall locomotor activity (total and ambulatory counts) in males and females in the 700 and 2000 mg/kg groups at the time of peak effect on study day 0**  **. The NOAEL**  **is 200**  **mg/k g**  **bw/day. P**  **lasma ,**  **erythrocyte , and**  **brain cholinesterase**  **levels were not measured in this study.** This neurotoxicity

study is classified as acceptable, guideline, and satisfies the guideline requirement for an acute neurotoxicity study in rats (870.6200; OECD 424). **SCN In a subchronic neurotoxicity study**  (MRID 48341952 ) tolclofos - methyl (Technical grade) (96.8% w/w, batch # 041128G) was administered continuously in the diet for 90 day s to male and female Alpk:APfSD (Wistar - derived) rats 12 /sex/group at dose levels of 0, 300, 1800, or 10,000 ppm (equivalent to 0, 20.6 , 122.3 , 735.7 mg/kg bw/day for males; 0, 23.1, 135.8, and 762.7 mg/kg/day for females ) . N eurobehavioral assessment (functional observational battery and motor act ivity

testing) was performed in all main study animals 12 rats /sex/group in week - 1, and in weeks 2, 5, 9 and 14 . Cholinesterase (ChE) act ivity was determined at the Central Toxicology Laboratory

(Clinical Pathology) in 5 rats/sex/dose, in brain and ery throcy tes (RBC) at weeks 2, 5 and 9 (satellite phase) and week 14 (main study). Plasma ChE was not evaluated. At study termination (14 weeks), 5 animals/sex/group were euthan ized and perfused with formol saline for n europathological examination. Brain was weighed from all o f the perfused animals as was a histopathological evaluation of brain and peripheral nervous s ys tem tissues. There were no treatment - related clinical abn ormalities recorded during the functional obse rvation battery and on motor ac tivity. Bod y weight was statistically significantl y lower than control for both sexes fed 10 , 000 ppm thro ughout the study (maximum difference of 17% in males and 11% in females , starting from week 2) . Bod y weight gain was also statistically significantly

lower than the controls throughout the study in both sexes fed 10,000 ppm [range 4 - 82%]. Food utilization for both males and females at 10 , 000 ppm was lower than control in week s 1 to 4 (80 - 98% of control) and for males over all (weeks 1 - 13; maximum 84% of controls). There were no effects on brain weights in the main study

animals. There were no treatment - related neuropathology and microscopic findings in the tissues examined.Tolclofos - methyl Human Health Risk Assessment DP No. 387242

Page 47 of 49 A BMD anal ys is of the ChE data revealed a lack of dose response such that a reliable fit was not obtained for adult male RBC and whole brain ChE data. For females, the whole brain ChE data were fit to the exponential model, with a BMD 10 of 956.4 mg/kg/day and BMDL 10 of 659.2 mg/kg/day . However, female RBC did not provide a reliable fit. **Brain ChE Adult Female Brain ChE BMD**  **10 =**  956.4 mg/kg/day **Adult Female Brain ChE BML 10**  **=** 659.2 mg/kg/day The adult male Brain ChE data failed to produce a dose - response and therefore did not provide a reliable fit for BMD analy sis. **RBC ChE The RBC ChE data in both males and females failed to provide a dose response and therefore**  **did not provide a reliable fit for BMD analysis.** The **NOAEL** is 122.3 M/135.8 F mg/kg/day . T he **LOAEL** is 735.7M /762.7F mg/kg/day , based on decreased bodyw eight and body weight gain, and food utilization. The study is classified as **Acceptable/Non -**  **Guideline** and satisfies the guideline requirement for a subchronic neurotoxicity

study in rats (870.6 200b). **Immunotoxicity** In an **immunotoxicity study** (MRID 48341954 ) , tolclofos - methyl (97.5% a.i., lot number: 080712G) was administered to female Crl:CD1(ICR) mice (10/dose) via diet at dose levels of 0, 500, 1500, or 4500 ppm (0, 91, 273, or 811 mg/kg/day , respectivel y) for 28 day s. The positive control consisted of 8 female mice which were administered 20 mg/kg/day cyclophosphamide via gavage on day s 22 - 26. On Day

25, all animals were immunized with a 0.5 mLintravenous injection of sheep red blo od cells (SRBCs) at a concentration of 4x10 8 cells/mL . On Day 29, all animals were sacrificed b y carbon dioxide asphyxiation. The necrops y included the examinations of all major organs, tissues and body cavities. Spleens from all animals were harvested for evaluation of spleen anti - SRBC antibody

response with a plaque - forming cell (PFC) assay . Other parameters evaluated were: clinical observation, mortality , body weight, body

weight gain, food consumption, spleen and thy mus weights. There were no unschedul ed deaths or treatment - related clinical signs. The mean final body weight (Day 29) for animals receiving 4500 ppm was lower ( - 11.2%) than controls . Overall mean body weight gains (Day s 1 to 29) for anima ls receiving 4500 ppm were low er ( - 40%) than the controls . Food consumption for females receiving 4500 ppm was lower ( - 11%) than the control. There was n o treatment - related effect on water consumption , organ weights and macropathology . **The systemic toxicity NOAEL is 1500 ppm (273 mg/kg/day); the LOAEL was 4500 ppm (811**  **mg/kg/day) based on decreased body weights, body weight gains and food consumption.** For immunotoxicity , there were no statistically significant changes in the numbers of cells/spleen, PFC/10 6 viable cel ls or PFC/spleen in an y of the t olclofo s - methyl treated groups when compared to the control. The positive control with Cyclophosphamide resulted in a significant reduction of theTolclofos - methyl Human Health Risk Assessment DP No. 387242

Page 48 of 49 PFC response. The numbers of PFC/10 6 viable cells and PFC/spleen (both p < 0.001) were significantl y reduced when co mpared to the control. A high inter - individual variability was noted in all the treatment groups as well as in the control group. Evaluation of individual animal data of this study did not show an y trend or distribution that would demonstrate significant s uppression of anti SRBC plaque - forming - cell response. The positive control group demonstr ated a statistical decrease in P FC response as compared to the vehicle controls. The Natural Killer (NK) cells activity was not evaluated in this study . The toxicolo gy database for tolclofos - methyl does not show any evidence of treatment - related effects on the immune sy stem. The overall weight of evidence suggests that this chemical does not dire ctly target the immune sy stem. Under the HED guidance, a NK cells activity assay is not required at this time. **Under conditions of this study, t he**  **immunotoxicity NOAEL for anti -**  **SRBC PFC response is 4500 ppm (811 mg/kg/day); the**  **LOAEL was not established .**  This immunotoxicity

study is classified **acceptable /guideline**  and satisfies the guideline requirement for an immunoto xicity

study (OPPTS 870.7800) .Tolclofos - methyl Human Health Risk Assessment DP No. 387242

Page 49 of 49 **Appendix B: Review of Human Research**  This risk assessment relies in part on data from studies in which adult human subjects were intentionally

exposed to a pesticide t o determine their dermal and inhalation exposure. These studies, which have been utilized in the HED Seed Treatment SOPs 14 and 15, have been determined to require a review of their ethical conduct, have received that review, and have been determined to be ethical.