Tolclofos

- methyl Human Health Risk Assessment DP No. D406797

Page 3 of 50 1.0 Executive Summary

................................ ................................ ................................ ................. 4
2.0 HED Recommendations

................................ ................................ ................................ .......... 7
2.1 Data Deficiencies

................................ ................................ ................................ .................. 7
2.2 Tolerance Considerations

................................ ................................ ................................ .... 8
2.2.1 International Harmonization

................................ ................................ ........................... 8
2.2.2 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 Ingredient Profile

................................ ................................ ................................ ..................... 9
3.1 Structure a nd Nomenclature

................................ ................................ ............................... 9
3.2 Physical/Chemical Characteristics

................................ ................................ ..................... 9
3.3 Summary of Existing/Proposed Uses

................................ ................................ ................ 10
3.4 Anticipated Exposure Pathways

................................ ................................ ....................... 11
3.5 Consideration of Environmental Justice

................................ ................................ .......... 11
4.0 Hazard Characterization/Assessment

................................ ................................ .................. 11
4.1 Toxicology Studies Available for Analysis

................................ ................................ ....... 11
4.2 Absorption, Distribution, Metabolism, and E limination (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 Neu rotoxicity

................................ ................................ ............................ 15
4.4.3 Evidence of Sensitivity/Susceptibility in the Developing or Young Animal

............... 15
4.4.4 Residual Uncertainty in th e Exposure Database

................................ ........................... 16
4.4 Toxicity Endpoints and Points of Departure Selections

................................ ................. 16
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 Recommendatio ns

................................ .. 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 Exposu re/Risk Characterization

................................ ................................ ........ 19
8.0 Cumulative Exposure/Risk Characterization

................................ ................................ ..... 19
9.0 Occupational Exposure/Risk Characterization

................................ ................................ .. 21
9.1 Short

- and Intermediate

- Term Handler Risk

................................ ................................ . 21
9.2 Short

- and Intermediate

- Term Post

- Application Risk

................................ ................... 26 Appendix A: Toxicology Profile and Updated Executive Summaries

................................ ...... 27 Appendix B: Review of Human Research

................................ ................................ ................... 50Tolclofos

- methyl Human Health Risk Assessment DP No. D406797

Page 4 of 50 1.0 Execut ive 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 contain s the human health exposure and risk assessment for the requested use s

.

Use Profile : Tolclofos

- methyl ( O

- (2,6

- dichloro

- 4

- methylphenyl) O,O

- dimethyl phosphorothioate )
is a organophosphate fung icide used to protect plants from soil borne and seed borne f ungal 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 toxicity 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.414 22904 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

- evalua tion 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 pursues food uses in the future additional studies relevant to the food use will be r equired.

Tolclofos

- methyl is not acutely toxic and is a poor inhibitor of cholinesterase (ChE) compared to other organophosphate compounds. Systemic toxicity from repeat exposure to tolclofos

- methyl is primarily 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, thyroid) observed at high doses typically did not correlate with histopathological changes. Neurotoxicity data from the recently subm itted acute and subchronic neurotoxicity studies indicate 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 neuroto xicity 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 mutagenicity

concern.

In risk assessments for non

- food uses that do not result in residential exposures, points of departure ( POD s ) are selected for the dermal and inhalation routes of occupational exposure only. In the case
of tolclofos

- methyl, there is no dermal or systemic 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, quantif ication of dermal risk is not required. Quantification of inhalation risks was performed using two oral toxicity studies since inhalation data are currently unavailable.Tolclofos

- methyl Human Health Risk Assessment DP No. D406797

Page 5 of 50 The 90

- day rat and 6

- month dog studies provided the most appropriate PoDs for consi derations and
were used as co

- critical studies since they yielded similar NOAELs and LOAELs for use in risk assessment. These NOAELs are considered are protective of the endpoints of concern since the recently submitted acute and subchronic neurotoxicity studies resulted in no cholinesterase ( 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 red blood cell ( 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 applied to the POD.

Food Quality Protection Act (FQPA) considerations do not apply to tolclofos

- methyl as the proposed
seed treatment uses have been deemed non

- food uses. However, t here are three outstanding studies according to revised 40 CFR Part 158 Toxicology Data Requi rements. 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 any 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 a s tolclofos

- methyl has potential to volatilize off of treated fields based on its vapor pressure (D390269, TXR0055976). However, the Agency is not requiring a n inhalation study at this 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.

There are no currently registered or proposed food uses for tolclofos

- methyl . Carcinogenicity
studies ar e not required for non

- food use chemicals. Carcinogenicity 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 Rev ised Part 158 Guidelines should a
food use for tolclofos

- meth yl be requested in the future.

The acute toxicity profile of tolclofos

- methyl consists of low toxicity via the oral

, dermal , and
inhalation routes of exposure (Category III and IV)

. Tolclofos

- m ethyl is not a n eye or skin irritant (Category I V ) and it is not a dermal sensitizer.

Food Residue Profile : The submitted total radioactive residues (TRR) data for soybean, corn, lettuce, cucumber, radish and cotton seeds are adequate to satisfy data r equirements 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 toxicolo gy data requirements which were based on Valent’s review of existing data and their interpretation of the 40 CFR Part 158 requirements for nonfood uses. Subsequently, HED’s Chemistry Science Advisory Council (ChemSAC) met on December 3, 2008
to discuss Va lent’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, soybean and cotton can be classified as non

- food

. A dditionally

, 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 resultsTolclofos

- methyl Human Health Risk Assessment DP No. D406797

Page 6 of 50 showed that the lettuce, cucumbe r and radish plants grown for seeds treated with [phenyl

14 C]tolclofos

- methyl did not take up the radiolabele d test substance residue.

Dietary Exposure and Risk: A dietary exposu re assessment is not required, since it is a non

- food
use chemical and the A gency does not expect the proposed seed treatment uses of tolclofos

- methyl to adversely impact ground water or surface water

.

Residential Exposure : There are currently no registered residential uses associated with tolclofos

methyl ; therefore, a reside ntial/non

- occupational exposure assessment is not required at this time

.

Aggregate Risk: T here are currently no registered food or residential uses for tolclofos

- methyl and the Agency does not expect the proposed seed treatment uses of tolclofos

- methyl to adversely 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 types of occupationa l 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 : Occupati onal 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 tolcl ofos

methyl label has the appropriate REI of 12 hours based on the acute toxicity of tolclofos

- methyl.

Review of Human Research: This risk assessment relies in part on data from studies in which adult human subjects were intentionally exposed to a pestic ide 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. D406797

Page 7 of 50 2.0 HED Recommendations

HED has evalu ated 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.

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 treatm ent 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 n ot requesting 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 expos ure 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 , 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 ra t 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 mutagenicity 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 a s tolclofos

- methyl has potential to volatilize off of treated fields based on its vapor pressure (D390269, TXR0055976). However, the A gency is not requiring a n inhalation study at this 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.

It is noted that additional toxicity studies would be required to fulfill the Revised Part 158 guidelines for any 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 any additional uses (see Appendix A.1).Tolclofos

- methyl Human Health Risk Assessment DP No. D406797

Page 8 of 50 2

. 2 Tolerance Considerations

2.2. 1 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 currently no established
MRLs in Canada ; however , there are currently Codex MRLs for lettuce, potato, and radish. Since
there are no U.S. tolerances for tolclofos

- methyl, there are no issues of compatibility with respect to
the Codex MRLs.

2.2. 2 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 tolc l ofos

- 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 m ade by
HED.Tolclofos

- methyl Human Health Risk Assessment DP No. D406797

Page 9 of 50 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

Parameter 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) A cetone 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) 4.56Tolclofos

- methyl Human Health Risk Assessment DP No. D406797

Page 10 of 50 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 label
is for both commercial and on

- farm seed treatment. The proposed label restrict s the use of to l clof os

methyl in hopper

- box or planter

- box seed treatment systems 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

- Type 0.000489 lb

ai/lb seed except Burdock, Chervil, Turnip

- Rooted;

Ginseng; Horseradish; Salsify; Skirret;

- Cotton

- Bulb Vegetables (Cr op Group 3

- 7 )

Commercial Seed Treatment Facility
and On

- Farm Standard Slurry or
Mist

- Type 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)

- Legum e Vegetables (Succulent or Dried) (Crop Group 6)

- Fruiting Vegetables (Crop Group 8

- 10)

- Cucurbit Vegetables (Crop Group 9)

- Cereal Grains (Crop Group 15 ) except R ice 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. D406797

Page 11 of 50 3.4 Anticipated Exposure Pathways

The Registration Divisio n 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 the ir diet as the proposed uses of tolclofos

- methyl for seed treatment have been deemed to be non

- food uses based on the submitted residue chemistry data. Drinking water exposure is also not expected based on the proposed seed treatment uses of tolclofos

- met hyl. 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 workers who handle previously treated seed during planting activities

.

These are the first registrations proposed for tolclofos

- methyl in the United States ; ther efore, this is the first risk assessment prepared by the Agency to address potential risks associated 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. Executive Order 12898, “Federal Actions to Address Environmental Justice in Minority Populations and Low

- Income Populations,” ( http://www.eh.doe.gov/oepa/guidance/justice/eo12898.pdf . As a part of every pesticide risk assessment, OPP considers a large variety 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

c onsumption patterns are compiled by the USDA under the Continuing Survey of Food Intake by Individuals (CSFII) and are used in pesticide risk assessments for all registered food uses of a pesticide. These data are analyzed and categorized by subgroups bas ed on age, season of the year, 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 appro priate, 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 bystanders and farm workers as well as lifestyle and traditional dietary patterns among specific subgroups.

4.0 Haz ard Characterization/Assessment

4.1 Toxicology Studies Available for Analysis

Tolclofos

- methyl is a new active ingredient currently being considered by the Agency to be registered as a non

- food seed treatment use for various crops, turf grass, ornamental flowers and
conifers. Tolclofos

- methyl is an organophosphate with several older toxicity studies (dating back toTolclofos

- methyl Human Health Risk Assessment DP No. D406797

Page 12 of 50 1970s) submitted for consideration in risk assessment. Upon re

- evaluation of these old toxicity studies (1970s to 1980s), several studies ar e 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.0 0156139) (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 any of these studies at this time and
does not believe a database uncertainty factor 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 proposed non

- food seed treatment use. The available toxicological studies for tolclofos

- methyl are listed in Appendix A. D ata from the following studies were used to evaluate the hazard potential of tolclofos

- methyl:

- Acute lethality 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)

- Mutagenicty battery

Tolclofos

- methyl is a new active ingredient although it has been registered in other countries (European Union countries) for several years. 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 we re 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 st omach intubation in a single dose of 5 mg/kg. In rats, tolclofos

- methyl was eliminated mainly in urine (65

- 70%) and feces (17

- 22%) by 7 days post

- dosing. In mice, approximately 82

- 83% was eliminated in urine and 5

- 7% in the feces at 7 days 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 radioactivity was 87% to 91% of the dose. The main metabolite in rat urine was 3,5

- d ichloro

- 4

- hydroxybenzoic acid, accounting for 26% of the dose. In mice, 2, 6

- dichloro

- 4

- hydroxybenzyl

- glycine, O,O

- dimethyl

- 1

- O

- (2,6

- dichloro

- 4

- carboxyphenyl) phosphate, and O

methyl

- O

- (2,6

- dichloro

- 4

- carboxyphenyl) phosphate each accounted for 8

- 13% of t he dose in urine. Unchanged parent compound accounted for 5% and 1.3% of the dose in the feces of rats and mice,Tolclofos

- methyl Human Health Risk Assessment DP No. D406797

Page 13 of 50 respectively. Tolclofos

- methyl is metabolized via oxidative desulfuration of the thiophosphoryl group to give the oxyphosphoryl analog (oxon) , oxidation at the 4

- methylphenyl group, and hydrolytic 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 days 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 dermal (rabbit) toxicity study is available and, therefore, dermal absorption information is not necessary for this assessment.

4. 3 T oxicological Effects

Tolclofos

- methyl is n ot 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 there fore

, not measured in the main acute neurotoxicity (ACN) study. In the subchronic neurotoxic i ty (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 spec ial 104

- week ChE rat study, tolclofos

- methyl did not inhibit ChE activity in any 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

- r esponse. 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 toxi city 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 newly submitted acute and subchronic neurotoxicity studies indicate
tolclofos

- m ethyl 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 bodyweight/gain and food util ization.

Systemic toxicity from repeat exposure to tolclofos

- methyl is primarily characterized by decreases in body weight, body gain, and reduced food consumption and/or efficiency in rats and dogs. Organ weight changes (kidney, liver, thyroid) observed at high doses typically did not correlate with histopathological changes. The acceptable developmental rat study resulted in marginal decreases in maternal bodyweight at the limit dose with unossified sternebra of fetuses occurring only at the limit
dose . Changes in liver weight and liver enzymes were not consistent 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

- gene ration 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 tes ted were determined to be not adequate to assess the carcinogenic potential of tolclofos

- methyl.Tolclofos

- methyl Human Health Risk Assessment DP No. D406797

Page 14 of 50 The mouse immunotoxicity study did not indicate immunotoxicity and tolclofos

- methyl has not been associated with a genetic toxicity or mutagenicity concern.
4

. 4 Consideration of Toxicity to Children

Food Quality Protection Act (FQPA) considerations do not apply to tolclofos

- methyl as the proposed
seed treatment uses have been deemed non

- food uses. However, t here are three outstanding studies according to revi sed 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 any of these studies at this time an d does not
believe a database uncertainty factor 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 sensitive 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 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 mammalia n cell assay.

The Agency is not requesting 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 r esult 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
rabbi ts, 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 ra t 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 o f 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 mutagenicity studies and the fact that organophosphates are not known to be mutagenic.

A waiver request for a 28

- day inhalation study was denied to protec t 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 a n inhalation study at th is time
since the proposed uses and the risk estimates for occupational handlers are sufficiently protectiveTolclofos

- methyl Human Health Risk Assessment DP No. D406797

Page 15 of 50 ( MOES = 16,000 to 26,000,000 ; see Section 9.0 . T his decision will be reevaluated based on future use requests.

4.4. 2 Evidence of Neurotoxicity

The rat acute neurotoxicity study result ed 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, decreased bodyweight, bodyweight gain, and food utilization were
observe d 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 pathol ogical 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 rode nts is not needed.

The tolclofos

- methyl risk assessment 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 ev idence of treatment

- related neurological effects 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/ d ; 2) there is no evidence of

neuroto xicity 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 system malformations or neuropathology) in the developmental rat study.

4.4.3 Evidence of Sensitivity/Susceptibility in 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 bodyweight gains (28%) was observed from gestation day ( GD ) 6

- 11 at the limit dose. Although there was no fetal mortality 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 only.

The developmental rabbi t study is considered 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 reproduct ive 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 lo wer than the POD (23 mg/kg/day) established for the current occupational assessment.Tolclofos

- methyl Human Health Risk Assessment DP No. D406797

Page 16 of 50 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 human 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 t he exposure data base based on the following : 1) t here are no currently registered or proposed residential uses of tolcofos

- methyl in the U.S. ; 2) t he proposed uses
are considered non

- food use s; and 3) adequate exposure data are available to assess the occ upational

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 quant itative 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 re sidential 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 d ermal rabbit study (non

- guideline) was re

- evaluated to ensure consistency with current HED policy and practices. Based upon this re

- evaluation, systemic toxicity and dermal irritation was not observed at concentrations up to the limit dose (1,000 mg/kg/da y) after 3 weeks of exposure (5 days/week for 3 weeks). Therefore a quantitative short

- and intermediate

- term dermal assessment
has not be en conducted for tolclofos

- methyl.

Short/Intermediate Inhalation
The short

- and intermediate

- term inhalation POD was based on oral toxicity studies since route specific inhalation data are currently 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 selecte d 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 pro tective 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 applied 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. D406797

Page 17 of 50 4.5.2 Recommendation for Combining Routes of Exposure for Risk Assessment

As part of conducting a human health risk assessment p rocess, the Agency considers risks from individual routes of exposure (oral, dermal, and inhalation). Additionally, the Agency must assess aggregate risks from dietary and residential exposures. In order to conduct an aggregate risk
assessment a determin ation 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 . Carcinogenicity

s tudies are not required for non

- food use chemicals. Carcinogenicity 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 unde r the Revised Part 158 Guidelines should a
food use for tolclofos

- meth yl be 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

Acute Dietary (General Population, including Infants and Children) The propos ed seed treatment use is non

- food.

Chronic Dietary (All Populations) The proposed seed treatment use is non

- food.

Dermal (Short/Intermediate) Systemic toxicity was not observed up to the limit dose of 1,000 mg/kg/day.

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

UF H = 1 0X MOE = 100 Co

- Critical:
1. 6

- month dog (00156138); LOAEL = 70 mg/kg/day , based on decreased bodyweight and gain, hematocrit, he moglobin, 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

v ariation in sensitivity among members of the human population (intraspecies).Tolclofos

- methyl Human Health Risk Assessment DP No. D406797

Page 18 of 50 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 t olclofos

- 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 th at 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 soybean, 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 seeds for cotton and

r adish, and 10 g/100 kg of seeds for corn, soybean, 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). Only the radish top samples grown from s eeds 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 treated radish top s ample s (TRR = 0.029 ppm and TRR = 0.020 ppm) were spiked with radiolabeled
tolclofos

- methyl and analyzed by HPLC to determine the efficiency of the extraction method. Both acetonitrile and aqueous extracts showed some polar radioactive residues, but did not con tain 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 for 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 Soybean* 6 Legume vegetable

7 Foliage
20 Oil seeds
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 vegetable s (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. D406797

Page 19 of 50 5. 2 Water Residue Profile

A qualitative drinking water assessment of tolclofos

- methyl was performed for this risk assessment.
Tolclofos

- methyl may transport to nearby surface water through run off and erosion, especially if
tolclofos

- methyl treated seeds are planted coincid ing with or closely followed by a rain event. After discussing 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 adversely impact ground water or
surface w ater.

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 adversely impac t g round 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 involve applications by homeowners or commer cial 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

- occupation al (residential) uses. However, t here are currently no registered food or
residential uses for tolclofos

- methyl and the Agency does not expect the proposed seed treatment
uses of tolclofos

- methyl to adversely impac t ground water or surface water ; therefor e, 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 Quality 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 o ther 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 class of pesticides are numerous and include azinphos methyl

, diazinon, chlorpyrifos, dichlorvos, dicrotophos, dimethoate, disulfoton, methamidophos, methidathion, monocrotophos, naled, oxydemeton

- methyl, phorate, phosmet, pirimiphos

- methyl, and
trichlorfon to name a few. EPA considers organophosphates to express tox icity through a common
biochemical interaction with cholinesterase which may lead to a myriad of cholinergic effects and, consequently the organophosphate pesticides should be considered as a group when performing
cumulative risk assessments.Tolclofos

- methyl Human Health Risk Assessment DP No. D406797

Page 20 of 50 The Agency h as 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/

.

Tolclofos

- methyl shares a similar chemical structure with many organophosphate (OP) pesticides. From the available toxicity studies, however, it is appar ent that tolclofos

- methyl has a low potential to inhibit acetyl cholinesterase (AChE) compared to the other OP pesticides. For example, in the newly submitted subchronic neurotoxicity study (SCN), the brain ChE BMDL 10 1 was 659 mg/kg/day and clinical signs consistent with cholinergic toxicity were not observed in the SCN at any dose and in the acute neurotoxicity study up to a dose of 2000 mg/kg neither AChE nor clinical signs were observed. In comparison, AChE inhibition commonly occurs within a range of 0.04

- 310 mg/kg/day for members of the OP common mechanism group. Also, unlike these organophosphates, AChE
inhibition is not the most sensitive effect across tolclofos

- methyl repeat dose toxicity studies. For example, organ weight effects or decreases in body weight gain were identified as the basis for NOAELs in most studies. The older toxicity studies for tolclofos

- methyl (e.g., 90

- day rat study and
the 9

- month mouse study) that did measure AChE lacked consistent results and only showed sporadic inhibi tion of AChE at high treatment doses. Additionally, tolclofos

- methyl exhibits a very low acute toxicity across many different species ranging from mammals to insects and across all routes of exposure 2 . In general, many of the members of the OP common mec hanism group (CMG) have a high level of acute toxicity in many species and particularly with regard to insects. Furthermore, overt signs of cholinergic toxicity that would result from inhibition of AChE are not observed in the toxicological database on to lclophos

- methyl. The members of the OP CMG show a close relationship between AChE inhibition and overt signs of cholinergic toxicity. The metabolism
data on tolclofos

- methyl show that its absorption is rapid and most of the tolclofos

- methyl and its
metab olites were excreted within 24 hours. With respect to distribution, tolclofos

- methyl predominately remains in the digestive tract (e.g., stomach, liver, intestine, and kidney) and does not distribute extensively throughout the body to other organ systems, including the brain. Most organophosphates included in the CMG are widely distributed in the body, including the brain.

Although tolclofos

- methyl shares a similar chemical structure with many other OPs and metabolism data show production of an oxon meta bolite, structural similarity is only one consideration in determining whether or not to include a chemical in a CMG. As noted in OPP’s Guidance for Identifying Pesticide Chemicals and Other Substances that have a Common Mechanism of Toxicity
and the Comm on Mechanism Grouping (CMG) Determination for the OPs (USEPA, 1999a and b) a weight

- of

- evidence evaluation should be conducted that involves a detailed analysis of several considerations including not only chemical structure but also data on the mechanism of pesticidal activity, the toxicological profile across species(including data on the biochemical event and the adverse outcome), and pharmacokinetic characteristics. Based on all of the weight of evidence considerations, the data weigh against including tolclofos

- methyl in the OP CMG. Unlike the OPs included in the CMG, mammalian toxicity data for tolclofos

- methyl show only scattered findings of

1 BMDL 10 is the lower 95 th confidence limit on the BMD 10 . The BMD 10 is the estimated dose to result in 10% inhibition compared to control

2 http://www.inchem.org/documents/jmpr/jmpmono/v94pr13.htm ; K. Sappington and M. Ruhman, “Revised Section 3 Environmental Fate and Ecological Risk Assessment for Tolclofos

- methyl”; DP Barcodes 404124 and 386992; August 3, 2012.Tolclofos

- methyl Human Health Risk Assessment DP No. D406797

Page 21 of 50 AChE inhibition and that inhibition was only observed at high doses. Moreover, overt cholinergic toxicity co nsistent with AChE inhibition has not been observed in the tolclofos

- methyl database even at limit doses. Additionally, in the case of the pharmacokinetics of tolclofos methyl, it appears based on the metabolism study that the distribution inside the body is limited to the digestive tract until the system is overwhelmed at high doses. Given the distribution pattern within the body which differs from other OPs in the CMG, tolclofos

- methyl would not be expected to inhibit AChE at
lower doses more relevant t o humans, as compared to the organophosphates included in the CMG. Based on the available in vivo data across vertebrate and invertebrate taxa, EPA concludes that the weight of evidence on tolclofos methyl indicates that it should not be considered a memb er of the OP CMG for purposes of cumulative risk assessment.

9.0 Occupational Exposure/Risk Characterization

Based on the proposed seed treatment uses of tolclofos

- methyl, two types of occupational handler exposure is expected: 1) primary handler exposu re 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 exposure is not expe cted 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 conif ers. 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 us e pattern, t here is potential for exposure to to l clofos

- 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 scena rios from the use of tolclofos

- methyl as a commercial seed
treatment include: Mixing, loading, applying liquid formulations; Bagging treated seed; Sewing bags; and Multiple activities.

Typically, for large

- scale commercial seed treatments, workers perform only those specific individual tasks listed above; however, it is assumed that workers also may perform multiple 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 equ ipment. The proposed label restricts use of tolclofos

- methyl inTolclofos

- methyl Human Health Risk Assessment DP No. D406797

Page 2 2 of 50 hopper

- boxes and planter

- boxes thus the commercial 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 ass essing 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 t reated in a day, and the pounds of seed that can be planted in a day, all of which vary depending upon the seed type. Values for the amount of seed treated and planted per day were obtained from a Biological and Economic Analysis Division memo entitled, “

Acres Planted per Day and Seeding Rates of Crops Grown in the United States” (J. Becker and S. Ratnayake; 3/24/11).

Primary and secondary handler exposure is expected to be short

- or intermediate

- term in duration based on information provided on the propo sed label. The short

- and intermediate

- term toxicological endpoints are the same for the respective routes of exposure; therefore, the estimates of
risk for short

- term duration exposures are protective of those for intermediate

- term durations. Long

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 , respectively

. The short

- and intermediate

- term inhalation risk e stimates 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. D406797

Page 23 of 50 Table 9.1. 1 : Summary of Short

- and Intermediate

- Term Primary Handler Exposure and Risk Est i mat e s for Tolclofos

- methyl

Seed Type Inhal UE a Max App Rate b Amt 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

- B ulb Vegetables (Crop Group 3

- 01)

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

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

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

- Fruiting Vegetables (Crop Group 8

- 10)

- Cucurbit Veg etables (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, Stra w, 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 G roup 5)

- Legume 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, ex cept 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. D406797

Page 24 of 50 Table 9.1.1: Summary of Short

- and Intermediate

- Term Primary Handler Exposure and Risk Estimates for Tolclo fos

- methyl

Seed Type Inhal UE a Max App Rate b Amt 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 Gro up 3

- 01)

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

- 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)

- 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)

- L egume Vegetables (Succulent or Dried) (Crop Group 6)

- Fruiting Vegetables (Crop Group 8

- 10)

- Cucurbit Vegetables (Crop Group 9)

- Herbs and Spices (Crop Group 19) 0.0016 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

- 0 3 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 base d 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 see d) 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. D406797

Page 25 of 50 Table 9.1.2: Summary of Secondary Handler (Planter) Exposures and Risk Estimate s for Tolclofos

- methyl

Seed Type Represented by Max lbs of
seed/acre Inhal UE a Max App Rate b Amt of Seed Planted/Day c Inhalation Dose d Inhalation MOE e

lb seed/acre mg/lb lb ai/lb seed lb seed/da y 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

- 0 4 170,000

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

- 0 5 430,000

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 Flo wers 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 Counc il 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 amoun t planted (lb seed/day) x absorption factor (100%) / body weight (8 0 kg adult).

e Inhalation MOE = 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. D406797

Page 26 of 50 9.2 Short

- and Intermediat e - Term Post

- A pplication 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 expec ted because no routine 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

ass essment is required 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

. It also includes t he appropriate WPS language related to early worker entry if
there will be no worker contact with the soil subsurface or treated seed.Tolclofos

- methyl Human Health Risk Assessment DP No. D406797

Page 27 of 50 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 (n onrodent)

............................. 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

- mammalian

................ 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

Acute Oral (rat)

................................ ........................... Subchronic Oral (rat)

................................ .................. Six

- month 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. D406797

Page 28 of 50 Appendix A.2. Toxicity Profiles

A.2. Toxicity Profiles

Table A.2.1. Acute Toxic ity 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), mic e

>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/no n

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 sligh t conjunctival reaction (24 hrs or less). Not an eye

irritant IV

870.2500 Primary Dermal

irritation

- rabbit 00156131 (1985) PIS=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. D406797

Page 29 of 50 Table A.2.2. Tolclofos

- methyl : Subchronic, Chronic and Other To xicity 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

TXR00693 3 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.

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.
Systemic NOAEL = 69 mg /kg
Systemic LOAEL = 675 m/kg, based on decreased bw gain and increased cholesterol and phosphor lipids.

870.3150 6

- month (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, 18 4, 623
MKD Homogeneity, 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. D406797

Page 30 of 50 Table A.2.2. Tolclofos

- methyl : Subchronic, Chronic and Other To xicity Profile

Guideline
No. Study Type MRID No. (year)/
Classification /Doses Results

870.3150 6 month (26 weeks)

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. T he LOAEL is 2,000 ppm (equivalent to 70/63 mg/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).

N o 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 s tudy 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 Developmental 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) Matern a l NOAEL = >1000 mg/kg/day
Maternal LOAEL = not established. Developmenta 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). Developmenta l NOAEL could not be determined due to critical study design and data reporting issues.Tolclofos

- methyl Human Health Risk Assessment DP No. D406797

Page 31 of 50 Table A.2.2. Tolclofos

- methyl : Subchronic, Chronic and Other To xicity Profile

Guideline
No. Study Type MRID No. (year)/
Classification /Doses Results

870.3800 3

- Gen

Reproduction (rat) Sp rague

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. N umber 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 lesions, which are ge n erally s een in older animal s, 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 cytoplasmic vacuolation of adrenals in the F2 dams of all dosage groups. Although the
inci dence particularly in the high dose group is suggestive of a compound effect, the frequency of this finding was not dosage related.

870.3150 9

- month 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, Homogeneity, 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 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.

ChE BMD 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.

Female RBC BMD 10 = 13.5 mg/kg/day (week 40 only)

Female RBC BMDL 10 = 10.0 mg/kg/day (week 40 only)Tolclofos

- methyl Human Health Risk Assessment DP No. D406797

Page 32 of 50 Table A.2.2. Tolclofos

- methyl : Subchronic, Chronic and Other To xicity Profile

Guideline
No. Study Type MRID No. (year)/
Classification /Doses Results

870.4200 Carcinogenicity

(mouse)

TXR006 933 00156139 (1983)

UNACCEPTABLE

MTD 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 with 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 was 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 p alpable 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 MTD not established.

Special 104

- week 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

TXR 006933 00156147 (1985)

Unacceptable DNA repair: Unacceptable

870.5100 Salmonella

typhimurium. & E.
coli

Reverse gene
mutation

TXR006933 00156147 (1985)

Acceptable Salmonella & E.coli: Acceptable

870.5375 In vitro Chinese

Hamster Lung
Forward Mutation

TX R006933 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. D406797

Page 33 of 50 Table A.2.2. Tolclofos

- methyl : Subchronic, Chronic and Other To xicity 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
Mammali an Cultured Cells

TXR006933 00156148 ( 19 81 )

Unacceptable Inadequate dose, HeLa cells not recommended.

870.6100 Acute delayed

neurotoxicity

(hen)

TXR006933 00156134 (1982)

Acceptable/guideline
10/group
0, 8000 x 2 mg/kg Decreased motor activity observed i mmediately 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 A cute

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 c holinesterase activity significantly different from the control group; a time to peak effect (peak cholinesterase inhibition) of tolclofos

- methyl was not
established.

870.6200a Acute

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 measured.

Doses of 200, 700, and 2000 mg/kg selected for
main ACN.Tolclofos

- methyl Human Health Risk Assessment DP No. D406797

Page 34 of 50 Table A.2.2. Tolclofos

- methyl : Subchronic, Chronic and Other To xicity Profile

Guideline
No. Study Type MRID No. (year)/
Classification /Doses Results

870.6200a Acute 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 = 700 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 fo r 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 Brai n 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
females fai led to provide a dose response and therefore did not provide a reliable fit for BMD analysis.

870.6300 Developmental

Neurotoxicity NA Conditionally Required

Waiver Granted at this time.

870.7485 Metabolism (rat s &

mice )

TXR006933 00156150 ( 19 80 )

A cceptable/ 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. D406797

Page 35 of 50 A.3 HAZARD IDENTIFICATION AND ENDPOINT SELECTION

A.3.1 Acute Reference Dose (aRfD)

– Females age 13

- 49 and
A.3.2 Acute R eference Dose (aRfD) general population, including infants and children

A Study and P O D 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 Exp osure (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 systemic or dermal irritation was observed at concen trations up to the limit dose (1,000 mg/kg/day) after 3 weeks of exposure (5 days/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 Exposu re (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 LOAEL of 2,000 ppm ( equivalent to 70 / 63 mg/kg/day M/F) was based upon decreased body weight gains in males, increased thyroid 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 Endpoin t 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 days) 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 typical species for organosphate compounds.Tolclofos

- methyl Human Health Risk Assessment DP No. D406797

Page 36 of 50 A.3.7 Dermal and Inhalation Exposures (Long

- Te rm)
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 presented here are either fr om 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

me thyl ( 97.7 % a.i. ; Lot 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 days/week for 3 weeks (total 15 days of exposure) . The rabbits were res trained 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 by 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 urinalysis examinations were not performed.

The stability and c oncentration of the material in the solutions were not analyzed 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 bodyweight or food consumption. Re

- evaluation of the hematology data suggest that there was not a biologically 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 thi s 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 kidneys, however , and therefore not of biological significance.

The ChE data were submitted for BMD analysis and the data were not fit for analysis since a dose

response was lacking for both males and females. Therefore the ChE data are not appropriate for establishing a systemic LOAEL.

Based on the lack of biologically significant effects, the systemic 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 report and were re

evalu ated for establishment of the irritation NOAEL and LOAEL. Very slight erythema was observed in some animals of every treatment group (Table 3). However, the incidence of theTolclofos

- methyl Human Health Risk Assessment DP No. D406797

Page 37 of 50 erythema decreased with increasing dose. Likewise, the compound was observed to build up on the skin in every treatment group with the first signs in the HDT (6 days) followed by the mid

- dose (8 days) and low

- dose (14 days). This slight erythema, however, does not constitute an adverse
irritation effect.

The 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 continuously in the diet for 90

- days to 12 /sex/ dose Crj:CD (SD) rats, at dose levels of 0, 100, 1,000, and 10,000 ppm (equivalent t o 0, 6.8, 68.6, 674.5 mg/kg/day, respectively). Food consumption was determined for 48 hours each week throughout the treatment period and mean daily diet consumption was calculated. Animals were inspected once daily for signs of toxicity and mortality. Animals were weighed on the day 1, 3, and once weekly thereafter and before necropsy. Blood was collected on the day of sacrifice for hematology, clinical analysis and cholinesterase determinations from all animals. Brain
cholinesterase levels were dete rmined 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 kidneys). The ovaries, adrenals, thyroid (parathyroid) and pituitary were weighed after 23 hour fixation in 10% neutral
buffered formalin.

No mortality or clinica l signs of toxicity were observed. Body weight gains of males (25

- 65%) and females (27

- 61%) were significantly (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 by approximately 25% and 27% (P ≤ 0.01) respectively, when

compa red to the controls (Table 2). The food consumption also decreased significantly (P ≤ 0.01) in the males (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 parti al thromboplastin time (APTT) was increased (8.5% or 5 minutes) and the MCHC was decreased (1.5%) significantly, 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% respectively, when compared to controls. Although these decreases were significant statistically, they do not represent biologically meaningful changes to consider as adverse
effects.

Males and females at the 10,000 ppm exhibited statis tically 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. Also total protein, GGT, SGOT and ALP significantly increased/decreased in males
and females.Tolclofos

- methyl Human Health Risk Assessment DP No. D406797

Page 38 of 50 Males and females in the 10,000 ppm group exhibited significant decreases in RBC, plasma and brain cholinesterase levels. A BMD analysis resulted only in female RBC data fitting a dose

response model. The male ChE data not provide a reliable fit for modeling a s 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 analysis

.

The histopathology and weight of organs (spleen, brain, heart, and kidney) did not change significantly due exposu re to tolclofos

- methyl. Treatment related effects on liver were evidenced by dark, discolored livers grossly and hypertrophy of hepatocytes microscopically.

The above information supports a L OA EL of 10, 000 ppm (674.5 mg/kg/day), based on significantly 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 rel iable 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 study (MRID 00156138), tolclof os

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 sac rifices 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 examinat ions 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 thyroid (23%, 31%) w eights were increased in HDT males compared to controls, respectively (Table 1). In females, absolute (30%) and relative (39%) liver weights were also increased as well as relative thyroid weight (18%). However, histopathological findings did not reveal changes in the liver or thyroid.

Unlike the previous review of the hematology, the hematocrit, hemoglobin, and erythrocyte values for the treated groups were similar to controls in males and females. Therefore, there are no biologically significant chang es in hematology parameters (Table 2).Tolclofos

- methyl Human Health Risk Assessment DP No. D406797

Page 39 of 50 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 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).

It is noted that the increased liver weights and increased ALK values are co nsidered 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, a nd 513/564 mg/kg/day, respectively for male and female mice) for 9 months

. The highest dose level of 3,000 ppm was the maximum tolerable dose determined by 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 weekly. Clinical signs and mortality were observed daily. Organs and tissues were fixed with 10% formol

- saline, embedded in paraffin wax, sliced at 5μ in thickness, stained with hematoxylin and eosin and examined under light

- microscope.

Neither abnormal clinical signs nor dead animals 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%) had significantly less weight gain (p<0.01). Although weight gain appeared lower in the other dose groups, the control males we re small at the beginning of the study. For females, body weight gain did not follow a dose

- response up to 100 ppm.

Ophthalmological examinations were performed on all surviving animals at termination of exposure (week 41) to the test compound and did n ot 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 analysis found statistically significant decrease s in leucocytes f or all treated male
mice , however in a reverse dose

- response with ↓57% at the lowest dose to ↓25% at the highest dose

. For treated female mice, an increase in leucocytes (lymphocytes) was found but with no dose

response pattern.

Cholinesterase levels were measured on 5 mice/se x/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 any timeTolclofos

- methyl Human Health Risk Assessment DP No. D406797

Page 40 of 50 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, hyperplasia of mesenteric lymph node and spleen, and rough

- surfaced liver in some of the mice. Heart (10%, 13%)
and liver (12%, 16%) weight were significantly lower in high dose males and females , respectively.
K idney weight was significantly lower in hig h dose females (20%) while testes weight (11%) was significantly lower in high dose males (p≤0.05). Ovarian weight was increased in 100 ppm females (19%) , but not at any other dosage level . P ituitary weight was increased in 10 ppm (47%) and 30

ppm (23%) males, but not in any other dosage groups . Pitu itary weight was increased in 10 (31%)

, 30 (31%)

, 100 (22%) and 3000 (37%) ppm females.

Histological evaluation revealed adenomatous hyperplasia and adenocarcinoma of lungs in one male and one female at 3,000 ppm, respectively. Lymphocytic infiltration (one control male) and fatty change in liver (five control males) were found only in controls and in two of the highest dosed males (one with lymphocytic infiltration, and one with both fatty change and lymphocytic infiltration) and 7 females (one female with fatty change, two females with focal necrosis, and four female with lymphocytic infiltrates (note: one female had both fatty change and lymphocytic infiltrate)]. Kidney lesions were found in 4 high dose males (1 hydronephrosis; 1 hyperplasia; and 2

pe lvic defects) and none in the other treatment groups while lesions were found in 1 control (atrophy of kidney) and two high dose females (1 cystic change of tubuli and 1 glomerular hyalinosis). Fatty change of adrenal medulla was found in 10 control femal es and 12 females at 3000 ppm group; while none were observed in males. Interstitial nephritis, vacuolation in cytoplasm of epithelial cells were found in a few mice; cystic changes of tubuli and glomerular hyalinosis were sporadically found. Urinary blad der erosion and edema were found in 3,000 ppm females. Atrophy and hyperplasia of interstitial cells were found in a few animals of both control and the treatment group. Other organs including brain, spinal cord, and sciatic nerve had no remarkable chang es.

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 analysis produced a reliable fit for the 40 week RBC ChE data in females only. The female RBC (week 40 only) BMD 10 is 13.5 mg/kg/day and the BMDL 10 is 10.0 mg/kg/day.

Systemic Systemic 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 femal es), decreased kidney weight (females), and decreased testes weights all at 3,000 ppm.

Systemic NOAEL = 100 ppm (12.2M/13.8 F mg/kg/day)

This updated Executive Summary 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. D406797

Page 41 of 50 The analysis 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 oth er studies
for tolclofos

- methyl, then the mice were exposed to sufficient tolclofos

- methyl to elicit these

responses

. The study, however, is considered non

- guideline.

Th is study is classified as A cceptable/ N on - guideline . Th is study do es not satisfy a gui deline 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 admini stered 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 respectively) to Fischer 344 rats (until termination

, for males at week 122 and 123; females at week 130) . The test materi al 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 conditions were not specified. Samples of diets were collected weekly beginning at week 68 and samples were assayed at 4

- week intervals. Animals were assigned randomly 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).
An imals were inspected twice daily for signs of toxicity and mortality. Observations were recorded weekly for the first 26 weeks, biweekly for the next 26 weeks, and every week for the remainder of the study. Individual food consumption was recorded weekl y for the first 26 weeks, biweekly for the next 26 weeks, and every 4 weeks for the remainder of the study. Individual body weight gains were analyzed at weeks 0, 4, 14, and 50 in male rats and at weeks 0, 4, 16, and 52 in female rats. Growth rates, tota l 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 analysis 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 analyzed using a multiple pairwise comparison procedure. Ophthalmology examinations were perform ed 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 analys i s from 10 rats/sex/group, an d from 10 males/group at week 122 and 10 females/group at week 129

. Blood was collected by segmental amputation of the tail for hematology determinations and by orbital sinus puncture under ether anesthesia for clinical chemistry determinations. Urine sam ples were collected by housing rats overnight in metabolism cages and pooling the samples by sex within each group. Interim sacrifice was done at 52 weeks, and terminal sacrifice was done at week 122 and week 123 for main study males and at week 130 for m ain study females. Gross pathology and histology examination s were done on all animals that died and that were sacrificed on schedule.

Incidental signs such as hunched and/or thin appearance, labored respiration, enlarged testes in males, and/or ocular ch anges 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 rang ed 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. D406797

Page 42 of 50 Stability and homogeneity analyses conducted on diet samples prepared after study termination
showed t hat 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 analysis 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 va lues were recorded the first 4 days of week 122 for males and all of week 124 for females. Individual water consumption values were calculated by dividing group consumption by the number of rats/group

. Water consumption was consistently higher in high

- do se 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 related changes in hematology values were noted. There were some statistically 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 measure d at all three dose levels. No consistent significant decrease in alkaline phosphatase was measured in treated female rats.

Cholinesterase (ChE) levels were significantly 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. It is noted that, standard deviations levels were higher than means in females at al l 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 g roups 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
f emales.

No significant compound

- related effects were determined by urinalysis.

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 interi m sacrifice and the terminal sacrifice. Decreased spleen weights, increased thyroid 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 hyperplasia of the testes, hyperplasia in the pars anterior of the pituitary, chronic myocarditis and myocardial degeneration, peribronchial lymphoid infiltration, and focal areas of hemorrhage and intimal mineralization of the pulmonary vessels in the respiratory system 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. D406797

Page 43 of 50 In the urinary system both groups showed chronic interstitial nephritis, tubular dilatation, and tubular eosinophilic proteinaceous casts with equal frequency. In the digestive system, hemosiderosis of the spleen, lymphoid hyperplasia and lymphoid necrosis of the Peyer’s patches occurred with comparable frequency i n control and compound

- treated rats. A summary tabulation of histologic findings at the 12

- month sacrifice was not presented; however, tabulation of findings for individual animals supported the authors’ descriptive text on findings. No dose

- related tren ds 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 any 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 hemolyzed.
Dose levels used were not adequate to produce biologically relevant changes in life parameters, pathology findings, or cholinesterase activity. Brain ChE values in all groups including controls had an excess of outlying values (approximately 0.1 of mean value). Fo r 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 termination (10rats/group). In addition, mean values in controls were about 5 to 8 times lower th an 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

- methy l

.

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 by stratified randomization. Mice were individually housed in an environmentally 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. Concentratio n analyses of the test diet were performed monthly for 18 months at the Institute for Biological Sciences of Sumitomo Chemical Company. Animals received food and water ad libitum . There were 50 animals/sex/group in main study groups and 10 animals/sex/gro up in satellite groups. Animals were inspected twice daily for signs of morbidity and mortality. All mice were individually examined for palpable masses at weekly intervals. Main study mice were weighed weekly at weeks 1 to 13 and monthly thereafter
until study termination. Mice of the satellite group were weighed monthly. Mean daily diet consumption was calculated at weekly intervals. Efficiencies of food utilization were determined monthly at months 1 to 6 and biannually 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 weekly. Ophthalmological 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. D406797

Page 44 of 50 right ventricle for hematological analysis at 12 and 24 months and for clinical chemistry analyses at 6, 12 and 24 months from 10animals/sex/group. Urine was collected from 10animals/sex/group at 6
and 1 2 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 died 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 analyze mortality and gross microscopic pat hology.

Body 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 from weeks 1 to 32, respectively; thereafter, body weights were found to be similar to those of con current 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, while body weights of females receiving 250 and 1000 ppm were slightly but significantly (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 groups 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, respectively. Mean test compound intake for females receiving 10, 50, 250, and 1000 ppm concentrations was reported to be 1.32, 6.86, 34.10,
and 136.91 mg/kg/day, respectively. 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 were significantly decreased in males and females receiving 250 and 1000 ppm S

- 3349 throughout th e study when compared to concurrent controls; this decreased was more pronounced in females receiving 1000 ppm. Brain ChE activity was significantly 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 activity was most extensively reduced in females receiving 1000 ppm at
28 weeks.

Other clinical chemistry parameters were similar for control and dosed males a nd 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 significantly (p<0.05) decreased absolute and relative pituitary weights we re found in males receiving 250 ppm. Females receiving 1000 ppm had significantly increase (p<0.05) absolute and relative pituitary weights. Absolute brain weights were significantly (p<0.01) increased in males receiving 1000 ppm at 24 months; absolute a nd relative brain weights were slightly but significantly (p<0.05) increased in females receiving 250 ppm at this time period. Absolute kidney weights were slightly but significantly (p<0.05, p< 0.01) increased at 12 months in males receivingTolclofos

- methyl Human Health Risk Assessment DP No. D406797

Page 45 of 50 250 ppm; abso lute and relative kidney weights were significantly (p<0.05, p<0.01) increased in males receiving 1000 ppm and in females receiving 250 and 1000 ppm. The incidence of kidney discoloration was increased in males receiving 10 and 1000 ppm and in females rec eiving 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, respectively; 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 males and 17, 14, 11 and 13 males receiving 10, 50, 250, and 1000 ppm, respectively.

Histologica l examination found that, at 24 months, the incidences of lymphomas 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 ex ception 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 controls (5/50). Non

- neoplastic lesions such as lymphocytic infiltration of the kidneys were increase d in dosed males when compared to controls, and pyelonephritis of the kidneys was increased in females receiving 10000 ppm when compared to controls. Hemorrhage of the lymph nodes were found in 2 control males and 10, 4, 3, and 7 males receiving 10, 50, 2 50 and 1000 ppm, respectively; 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, respectively; the incidence at 1000 ppm w as significantly (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 hepatocel lular carcinomas and if lung tumors were alveolar bronchiolar pulmonary lesions).

Based on decreased serum, erythrocyte, and brain cholinesterase activities, MTD of 1000 ppm (highest dose tested) for this study was obtained. The systemic LOEL is 250 pp m and the systemic NOEL is 50 ppm S

- 3349, based on decreased serum, erythrocyte, and brain cholinesterase activities. The LOEL and NOEL for histopathology cannot be definitively determined.

Deficiencies : Stability and homogeneity analyses of the test die t 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 with 1.8 to 3.0μg/g of S3349; the study authors
indicate d 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, urinalyses, and organ weights) was not possible.

In dividual 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 parame ters, in fact decreased.Tolclofos

- methyl Human Health Risk Assessment DP No. D406797

Page 46 of 50 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 i n Table 47

- 3

- 1 of the study report).

The numbers of organs with pathology reported in this 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 na rrative in histologic lesions and was unable to differentiate between malignant and benign lesions; as such, histopathology results could not be conclusively determined. The LOEL and NOEL for histopathology cannot be definitively determined.

Based on th e number of deficiencies t h 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 orally by 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 v ehicle on a comparable regimen. The dose volume was 5 ml/kg for all groups. Each group consisted of 20 rats/sex. For analysis 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 following 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 analyzed for cholinesterase act ivity.

All animals survived to the scheduled 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 cholinester ase 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 days. Neurobehavioral assessment (functional observational battery and motor activity test ing) was performed 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 days 7 and 14. Cholinester ase 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. D406797

Page 47 of 50 group were selected randomly and subjected to histopathological evaluation of brain and peripheral nervous system 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 we ights and body 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 c ontrol group on study days 7 and 14. Locomotor 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 by administration of the test compound at any 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 gr oups at the time of peak effect on study day 0 . The NOAEL is 200 mg/kg 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 guid eline 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 d ays 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 (f unctional 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
Path ology) in 5 rats/sex/dose, in brain and erythrocytes (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 euthanized 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 system tissues.

There were no treatment

- related clinical abnormalities recorded during the funct ional obse rvation battery and on motor ac tivity

. Body weight was statistically significantly 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)

. Body 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 weeks 1 to 4 (80

- 98% of control) a nd 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. D406797

Page 48 of 50 A BMD analysis of the ChE data revea led 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. How ever, 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
reli able fit for BMD analysis.

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. The LOAEL is 735.7M /762.7F mg/kg/day , based on decreased bodyweight and bodyweight gain, and food utilization.

The study is classified as Acceptable/Non

- Guideline and satisfies the guideline requirement for a subchronic neurotoxicity study in rats (870.6200b).

Immunotoxicity
In an immun otoxicity 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, respectively) for 28 days. The po sitive control consisted of 8 female mice which were administered 20 mg/kg/day cyclophosphamide via gavage on days 22

- 26. On Day 25, all animals were immunized with a 0.5 mL intravenous injection of sheep red blood cells (SRBCs) at a concentration of 4x10 8 cells/mL. On Day 29, all animals were sacrificed by carbon dioxide asphyxiation. The necropsy included the examinations of all major organs, tissues and body cavities. Spleens from all animals were harvested for evaluation of spleen
anti

- SRBC antibody res ponse with a plaque

- forming cell (PFC) assay. Other parameters evaluated were: clinical observation, mortality, body weight, body weight gain, food consumption, spleen and thymus weights.

There were no unscheduled deaths or treatment

- related clinical sign s. The mean final body weight (Day 29) for animals receiving 4500 ppm was lower (

- 11.2%) than controls

. Overall mean body weight gains (Days 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 b ody weights, body weight gains and food consumption.

For immunotoxicity, t here were no statistically significant changes in the numbers of cells/spleen,
PFC/10 6 viable cel ls or PFC/spleen in any of the t olclofos

- 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. D406797

Page 49 of 50 PFC response. The numbers of PFC/10 6 viable cells and PFC/spleen (both p < 0.001) were significantly reduced when compared to the control. A high inter

- individua l 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 any trend or distribution that would demonstrate significant suppression of anti

SRBC plaque

- forming

- cell r esponse. 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 toxicology database for
tolclofos

- methyl does not sho w any evidence of treatment

- related effects on the immune system. The overall weight of evidence suggests that this chemical does not dire ctly target the immune system. Under the HED guidance, a NK cells activity assay is not required at this time.

Unde r 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 immunot o xicity study (OPPTS 870.7800)

.Tolclofos

- methyl Human Health Risk Assessment DP No. D406797

Page 50 of 50 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 to determine their dermal and inhalation exposure. Thes e 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.