UNITED STATES ENVIRONMENTAL PROTECTION AGENCY WASHINGTON, D. C. 20460 OFFICE OF PREVENTION, PESTICIDES AND TOXIC SUBSTANCES May 5, 2004 MEMORANDUM SUBJECT: Residential Exposure Assessment and Recommendations for the Tolerance Reassessment Evaluation Decision ( TRED) Document for Trifluralin FROM: Shanna Recore, Industrial Hygienist Reregistration Branch II Health Effects Division ( 7509C)

TO: Richard Griffin, Biologist Risk Assessor Reregistration Branch II Health Effects Division ( 7509C)

THROUGH: Alan Nielsen, Branch Senior Scientist Reregistration Branch II Health Effects Division ( 7509C)

Please find the review of Trifluralin.

DP Barcode: D296625 Pesticide Chemical Codes: 036101 EPA Reg Numbers: Residential Labels: 228 208, 228 209, 228 254, 228 255, 228 257, 572 200, 961 280, 961 283, 961 335, 961 348, 1812 430, 5887 171, 7401 349, 8378 41, 8660 143, 8660 149, 8660 165, 8660 166, 9198 60, 9198 79, 9198 91, 9198 94, 9198 98, 9198 101, 9198 149, 9688 133, 32802 35, 32802 40, 32802 77, 49585 25, 54705 6, 59823 3, 62719 137, 62719 280, 62719 327, 62719 331, 62719 332, 72620 1 2 Occupational Labels: 228 207, 228 256, 961 370, 8378 37, 10404 57, 32802 35, 32802 40, 62719 97, 62719 150, 62719 151, 62719 152, 62719 175, 32719 192 PHED: Yes, Version 1.1 3 Table of Contents Executive Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 1.0 Residential Exposure/ Risk Assessment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 1.1 Purpose . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 1.2 Criteria for Conducting Exposure Assessments . . . . . . . . . . . . . . . . . . . . . . . . . . 6 1.3 Summary of Hazard Concerns . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 1.4 Summary of Use Patterns and Formulations . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 1.4.1 End Use Products . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 1.4.2 Mode of Action and Targets Controlled . . . . . . . . . . . . . . . . . . . . . . . . 10 1.4.3 Registered Use Categories and Sites . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 2.0 Residential and Other Non Occupational Exposures and Risks . . . . . . . . . . . . . . . . . . . 11 2.1 Residential Handler Exposures and Risks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 2.1.1 Handler Exposure Scenarios . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 2.1.2 Data and Assumptions For Handler Exposure Scenarios . . . . . . . . . . . . 12 2.1.3 Residential Handler Exposure and Non Cancer Risk Estimates . . . . . . . 18 2.1.4 Summary of Non Cancer Risk Concerns for Residential Handlers . . . . . 20 2.2 Residential Cancer Trifluralin Handler Exposure and Risk Assessment . . . . . . . 22 2.2.1 Data and Assumptions For Residential Cancer Handler Exposure Scenarios 22 2.2.2 Residential Cancer Trifluralin Handler Exposure and Risk Calculations . 22 2.3 Residential Postapplication Exposures and Risks . . . . . . . . . . . . . . . . . . . . . . . 26 2.3.1 Residential Postapplication Exposure Scenarios . . . . . . . . . . . . . . . . . . 26 2.3.2 Data & Assumptions for Residential Noncancer Postapplication Exposure Scenarios . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27 2.3.3 Residential Postapplication Exposure and Noncancer Risk Estimates . . . 29 2.4 Combined Residential Handler and Postapplication Exposures and Risks . . . . . 38 3.0 Trifluralin Poisoning Incidents Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38 Appendices . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41 4 RESIDENTIAL EXPOSURE/ RISK ASSESSMENT AND CHARACTERIZATION Executive Summary The Federal Food, Drug, and Cosmetic Act ( FFDCA), as amended, requires the U. S. Environmental Protection Agency to reassess all the tolerances for the registered chemicals in effect on or before August 3, 1996, the date of the enactment of the Food Quality Protection Act ( FQPA), against the new safety standard adopted in the FQPA. A reregistration eligibility decision ( RED) for trifluralin was completed in April 1996, prior to the enactment of FQPA. Therefore, EPA is issuing a tolerance reassessment evaluation decision ( TRED) to reassess the tolerances under the FQPA standard. Occupational exposure assessments are not included in TRED documents; however, potential occupational exposure to trifluralin was assessed in the April 1996 RED document.

At this time, products containing trifluralin are intended for both occupational and nonoccupational uses. Trifluralin is a pre emergent herbicide used to control annual grasses and broadleaf weeds on a variety of residential food and non food uses. There are also several occupational uses which will not be addressed in this TRED. For residential uses, trifluralin is formulated as a granular ( 0.17  2.0 percent active ingredient) and an emulsifiable concentrate liquid ( 43 percent active ingredient).

In May 2003, the Hazard Identification Assessment and Review Committee ( HIARC) reassessed toxicological endpoints for non dietary exposures to trifluralin. The duration of exposure for residential populations is assumed to be short term ( 1 30 days) only. No exposure or risk assessment is required for short term dermal exposures, since there was no systemic toxicity at the limit dose in the dermal toxicity study and there are no developmental toxicity concerns. The short term ( 1 30 days) inhalation toxicological endpoint was established at 81 mg/ kg/ day, based on the no observed adverse effect level ( NOAEL) from a 30 day inhalation rat study. Trifluralin is classified as a " Group C," possible human carcinogen with a Q* of 0.00579 ( mg/ kg/ day) 1. HED notes that the HIARC recommends that products containing trifluralin should be labeled as a dermal sensitizer and should state that skin contact should be avoided.

Short term inhalation risks to residential handlers and dermal and inhalation cancer risks to residential handlers were calculated using surrogate data from the Pesticide Handler Exposure Database ( PHED), the Outdoor Residential Exposure Task Force ( ORETF), and a proprietary study using fipronil1 with MRID 452507 01 .

HED has determined that there are potential exposures to residential handlers ( i. e., mixer/ loader/ applicators) during the usual use patterns associated with trifluralin. Based on the use patterns, seven major residential exposures were identified for trifluralin: ( 1) loading/ applying granulars with a belly grinder; ( 2) loading/ applying granulars with a push type spreader; ( 3) loading/ applying granulars with a spoon, measuring scoop, shaker can, or by hand; ( 4) mixing/ loading/ applying liquids with a hose end sprayer; ( 5) mixing/ loading/ applying liquids with a low 5 pressure handwand; ( 6) mixing/ loading/ applying liquids with a backpack sprayer; and ( 7) applying trifluralin impregnated fabric squares to soil.

For short term noncancer risks to residential handlers, a margin of exposure ( MOE) of less than 100 exceeds the Agency's level of concern. For residential handlers, the calculations of shortterm inhalation noncancer risk indicate that the MOEs are greater than 100 for all residential handler scenarios.

For residential handler scenarios, cancer risks greater than 1x10 6 are considered to be of concern. The calculations of residential handler cancer risk indicate that all scenarios have a cancer risk of less than 1x10 6.

HED has determined that there are potential postapplication exposures to adults and children in residential settings during the usual use patterns associated with trifluralin. Based on the use patterns, seven potential residential postapplication exposures were identified for trifluralin: ( 1) dermal exposure from residue on lawns ( adult and toddler); ( 2) dermal exposure from residue on golf course turfgrass ( adult and youth); ( 3) dermal exposure from residue on home gardens ( adult and youth); ( 4) hand to mouth transfer of residue on lawns ( toddler); ( 5) object to mouth transfer of residues on lawns ( toddler); ( 6) incidental ingestion of soil from pesticide treated residential areas ( toddler); and ( 7) incidental ingestion of granules from pesticide treated residential areas.

For noncancer postapplication risks, since there is no short term dermal toxicological endpoint of concern for trifluralin and no intermediate term dermal exposure is anticipated, the only assessment is for incidental ingestion by toddlers.

For short term noncancer residential postapplication risks, a margin of exposure ( MOE) of less than 100 exceeds the Agency's level of concern. For residential postapplication, the calculations of noncancer risk based on the incidental oral NOAEL endpoint indicate that the MOEs were more than 100 for the following residential postapplication scenarios:

$ hand to mouth transfer of residues on lawns ( toddler), ° object to mouth transfer of residues on lawns ( toddler), and ° incidental ingestion of residues of soil from pesticide treated residential areas ( toddler).

In addition, HED determined that a combined risk assessment was necessary for the following noncancer residential postapplication scenarios listed above. The combined MOE for these scenarios is greater than 100 and is not considered a risk concern.

The Agency also assesses the exposure and risk to toddlers from incidental ingestion of granules in pesticide treated residential areas. Since this exposure is episodic and likely to occur, at most, only once following an application, an acute dietary NOAEL endpoint is used to assess the risks. Since 6 no acute dietary endpoint for trifluralin has been identified for the general population, including infants and children, acute dietary risks from ingestion of pesticide granules were not assessed.

HED has determined that there are potential postapplication cancer risks for adults in residential areas treated with trifluralin. The following scenarios were assessed: ( 1) dermal exposure to residue on lawns, ( 2) dermal exposure to golf course turfgrass, and ( 3) dermal exposure to residue on home gardens. For residential postapplication scenarios, cancer risks greater than 1x10 6 are considered to be of concern. The calculation of residential postapplication cancer risk indicate that all scenarios have a cancer risk of less than 1 x10 6 and are not considered a risk concern.

For the residential turfgrass scenario, HED combined the cancer risks for residential handlers applying granular formulation to lawns with postapplication cancer risks to adults from exercising on just treated lawns. This combined two screening level calculations. The combined risks are less than 1 x10 6 and are not considered a risk concern.

1.0 Residential Exposure/ Risk Assessment 1.1 Purpose The Federal Food, Drug, and Cosmetic Act ( FFDCA), as amended, requires the U. S. Environmental Protection Agency to reassess all the tolerances for the registered chemicals in effect on or before August 3, 1996, the date of the enactment of the Food Quality Protection Act ( FQPA), against the new safety standard adopted in the FQPA. A reregistration eligibility decision ( RED) for trifluralin was completed in April 1996, prior to the enactment of FQPA. Therefore, EPA has issued a tolerance reassessment evaluation decision ( TRED) to reassess the tolerances under the FQPA standard.

In this document, which is for use in EPA's development of the trifluralin TRED Document, EPA presents the results of its review of the potential human health effects of residential/ non occupational exposure to trifluralin. Occupational exposure assessments are not included in TRED documents; however, potential occupational exposure to trifluralin was briefly assessed in the April 1996 RED document.

1.2 Criteria for Conducting Exposure Assessments An occupational and/ or residential exposure assessment is required for an active ingredient if ( 1) certain toxicological criteria are triggered and ( 2) there is a potential for exposure to handlers ( mixers, loaders, applicators) during use or to persons entering treated sites after application is complete. Toxicological endpoints were identified for short term inhalation exposures and for short term incidental ingestion. In addition, trifluralin has been classified as a Category C possible human carcinogen with a Q 1* of 0.00579 ( mg/ kg/ day) 1.2 Handler and postapplication exposure scenarios have been identified. 7 1.3 Summary of Hazard Concerns The toxicological endpoints that were used to complete the residential risk assessments are summarized below and in Table 1 which has been extracted from the latest HIARC document dated May 2, 2003. Adverse effect were identified at different durations of exposure ranging from short term ( up to 30 days) to chronic durations ( every working day). However, for residential exposure assessments, only short term exposures and risks are evaluated because trifluralin is a pre emergent herbicide where the use patterns in residential settings are limited to a few widely spaced applications each year. No short term dermal endpoint was identified, since there was no systemic toxicity at the limit dose in the dermal toxicity study and there are no developmental toxicity concerns. The short term inhalation risk assessment for trifluralin is based on an NOAEL of 81 mg/ kg/ day, which was defined in a 30 day inhalation study in rats. The short term incidental oral risk assessments for trifluralin are based on an NOAEL of 10 mg/ kg/ day, which was defined in a two generation reproductive study in rats. The acute dietary ( toddler ingestion of granules) risks for trifluralin were not assessed, since no acute dietary endpoint of concern was identified for the general population, including infants and toddlers.

The Agency's level of concern for noncancer risks ( i. e., target level for MOEs or Margins of Exposure) is defined by the uncertainty factors that are applied to the assessment. The Agency applies a factor of 100 to account for inter species extrapolation to humans from the animal test species and to account for intra species sensitivity. Based on the requirements of the 1996 Food Quality Protection Act, the Agency must also consider sensitive populations in its nonoccupational risk assessments. The Agency has reduced the FQPA safety factor for trifluralin to 1x for all residential populations. 2 The total uncertainty factors that have been applied to noncancer risk assessments is 100 for the residential assessment.

In addition, trifluralin has been classified as a Category C B possible human carcinogen, based on increased incidences of combined malignant and benign tumors of the renal pelvis and benign tumors of the urinary bladder. Quantification of human risk using a low dose model extrapolation was recommended. Trifluralin has a Q 1* of 0.00579 ( mg/ kg/ day) 1.2 For residential handler and postapplication scenarios, cancer risks greater than 1x10 6 are considered by EPA to be of concern.

Trifluralin is also classified as a skin sensitizer, but EPA has no method of quantifying risk due to skin sensitization. Therefore, the HIARC recommends that all products containing trifluralin should be labeled as SENSITIZER and also recommend that human contact should be avoided. 8 Table 1. Hazard Endpoints and Uncertainty Factors.

Exposure Scenario Dose Used in Risk Assessment, UF Special FQPA SF* and Level of Concern for Risk Assessment Study and Toxicological Effects Acute Dietary ( General population including infants and children) No appropriate single dose endpoint was found for this population sub group Residential NA No appropriate single dose endpoint was found for this population sub group Short Term Incidental Oral ( 1 30 days) NOAEL= 10 mg/ kg/ day Residential LOC: MOE = 100 Occupational = NA Two generation Reproduction Study  Rat LOAEL = 32.5 mg/ kg/ day based on decreased pup weights in both generations Intermediate Term Incidental Oral ( 1 6 months) NOAEL= 10 mg/ kg/ day Residential LOC: MOE = 100 Occupational = NA Special Urinalysis Study  Rat LOAEL = 40 mg/ kg/ day based on based on the presence of tubular cytoplasmic hyaline droplets; increased total protein, AST, and LDH in the urine; albumin  1 globulin and  2 globulin observed by urine electrophoresis; and increased urinary volume Short Term Dermal ( 1 to 30 days) No quantification required since there was no systemic toxicity at the limit dose in the dermal toxicity study. There are no developmental toxicity concerns. Also, because risk cannot be quantified, the HIARC also recommends that the products containing trifluralin should be labeled as SENSITIZER and should avoid human contact.

Intermediate Term Dermal ( 1 to 6 months) Oral study NOAEL = 10 mg/ kg/ day ( dermal absorption rate = 3 % Residential LOC: MOE = 100 Occupational LOC: MOE = 100 Special Urinalysis Study  Rat LOAEL = 40 mg/ kg/ day based on based on the presence of tubular cytoplasmic hyaline droplets; increased total protein, AST, and LDH in the urine; albumin  1 globulin and  2 globulin observed by urine electrophoresis; and increased urinary volume Long Term Dermal (> 6 months) Oral study NOAEL= 2.4 mg/ kg/ day ( dermal absorption rate = 3 % when appropriate) Residential LOC: MOE = 100 Occupational LOC: MOE = 100 Chronic Toxicity ( capsule)  Dog LOAEL = mg/ kg/ day based on based on increased frequency of abnormal stool, decreased body weights and body weight gains, and on decreased erythrocytes and hemoglobin and increased thrombocytes in males Short Term Inhalation ( 1 to 30 days) Inhalation study NOAEL= 81 mg/ kg/ day Residential LOC: MOE = 100 Occupational LOC: MOE = 100 30 Day Inhalation Study  Rat LOAEL = 270 mg/ kg/ day based on increased methemoglobin and bilirubin in females and incidences of dyspnea and ruffled fur in males and females Table 1. Hazard Endpoints and Uncertainty Factors.

Exposure Scenario Dose Used in Risk Assessment, UF Special FQPA SF* and Level of Concern for Risk Assessment Study and Toxicological Effects 9 Intermediate Term Inhalation ( 1 to 6 months) Oral study NOAEL = 10 mg/ kg/ day ( inhalation absorption rate = 100%) Residential LOC: MOE = 100 Occupational LOC: MOE = 100 Special Urinalysis Study  Rat LOAEL = 40 mg/ kg/ day based on based on the presence of tubular cytoplasmic hyaline droplets; increased total protein, AST, and LDH in the urine; albumin  1 globulin and  2 globulin observed by urine electrophoresis; and increased urinary volume Long Term Inhalation (> 6 months) Oral study NOAEL= 2.4 mg/ kg/ day ( inhalation absorption rate = 100%) Residential LOC: MOE = 100 Occupational LOC: MOE = 100 Chronic Toxicity ( capsule)  Dog LOAEL = mg/ kg/ day based on based on increased frequency of abnormal stool, decreased body weights and body weight gains, and on decreased erythrocytes and hemoglobin and increased thrombocytes in males Cancer ( oral, dermal, inhalation) Q1* = 5.79 X 10 3 ( mg/ kg/ day) 1 " Group C" ( limited evidence of carcinogenicity)

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

A series of acute toxicity tests were also conducted using trifluralin ( see Table 2). The results indicate that trifluralin is a category IV toxicant via the oral route, and category III via the dermal route. It is also a category IV for acute inhalation toxicity and a category III/ IV eye and skin irritant. Results were positive for dermal sensitization and the HIARC document recommends that dermal exposure to trifluralin should be minimized and the products labeled to provide instructions to avoid contact with skin.

Table 2: Acute Toxicity of Trifluralin ( technical)

Guideline No. Study Type MRID No. Results Toxicity Category 81.1 870.1100 Acute Oral ( Rat) 00157486 ( 1985) TXR 006174 Acceptable/ Guideline LD50 > 5000 mg/ kg IV Table 2: Acute Toxicity of Trifluralin ( technical)

Guideline No. Study Type MRID No. Results Toxicity Category 10 81.2 870.1200 Acute Dermal ( Rat) 00157482 ( 1985) TXR 006174 Acceptable/ Guideline LD50 > 2000 mg/ kg III 81.3 870.1300 Acute Inhalation ( Rat) 00155261 ( 1982) TXR 006174 Acceptable/ guideline LC50 > 4660 mg/ m3, 4.66 mg/ L IV 81.4 870.2400 Primary Eye Irritation ( Rabbit) 00157483 ( 1985) TXR 006174 Acceptable/ Guideline Conjunctival redness at 24 hr, cleared by day 4 III 81.5 870.2500 Primary Skin Irritation 00157485 ( 1985) TXR 006174 Acceptable/ Guideline Not an irritant IV 81.6 870.2600 Dermal Sensitization 00157484 ( 1985) TXR 006174 Acceptable/ Guideline Sensitizing agent N/ A 1.4 Summary of Use Patterns and Formulations At this time, products containing trifluralin are intended for both occupational and residential uses. However, in this TRED only residential ( i. e., non occupational) exposures will be assessed. Trifluralin is a pre emergent herbicide registered for weed control on home lawns, vegetable gardens, ornamental gardens ( including planting beds, flowers, shrubs, and trees), and at other residential sites, such as golf courses, recreational parks, bike/ golf cart paths, and cemeteries. Trifluralin has several registrants including, Dow AgroSciences, Griffin LLC and Riverdale Chemical Company.

1.4.1 End Use Products Based on a review of the Office of Pesticide Programs   Pesticide Product Label System ( PPLS), residential trifluralin formulations include liquid concentrates and granular formulations.

1.4.2 Mode of Action and Targets Controlled Trifluralin is a pre emergent herbicide used in commercial/ residential settings for preemergent weed control of annual grasses and broadleaf weeds which include, but are not limited to, the following: 11 ° Grass Weeds: annual bluegrass, barnyardgrass, brachiaria, bromegrass, cheat, crabgrass, foxtail, guineagrass, itchgrass, johnsongrass, junglerice, panicum, ryegrass, Texas panicum, red rice, sandbur, sprangletop, stinkgrass, shattercane, woolly cupgrass; and ° Broadleaf Weeds: carpetweed, chickweed, field bindweed, goosefoot, henbit, knotweed, kochi, lambsquater, pigweed, puncturevine, purslane, Russian thistle, stinging nettle.

Trifluralin is applied during the growing season to established plants and transplants. It is applied one to two weeks prior to the anticipated germination of annual grass weed seeds, since established weeds will not be controlled. Treated areas should be irrigated or soil incorporated soon after application.

1.4.3 Registered Use Categories and Sites An analysis of the current labeling and available use information was completed. Trifluralin is registered for use in a variety of occupational and homeowner/ residential scenarios. This TRED deals only with homeowner/ residential uses.

Homeowner/ Residential Use Sites Trifluralin can be purchased and used by homeowners in residential settings. The following is a list of use sites in the residential environment.

° vegetable gardens ° residential, golf course, and recreational turf ° ornamentals: flowers, trees, and shrubs, preplant ornamentals 2.0 Residential and Other Non Occupational Exposures and Risks It has been determined there is a potential for exposure in residential settings during the application process for homeowners who use products containing trifluralin. There is also a potential for exposure from entering areas treated with trifluralin that could lead to exposures for adults and children. As a result, risk assessments have been completed for both residential handler and postapplication scenarios.

2.1 Residential Handler Exposures and Risks The Agency uses the term " handlers" to describe those individuals who are involved in the pesticide application process. Residential handlers are assumed to complete all elements of an application ( i. e., mixing, loading, and application) without the use of personal protective equipment and are assumed to be attired in short sleeve shirts, short pants, shoes, and socks. 12 2.1.1 Handler Exposure Scenarios Scenarios are used to define risks based on the U. S. EPA Guidelines For Exposure Assessment ( U. S. EPA; Federal Register Volume 57, Number 104; May 29, 1992). The purpose of this section is to describe how the exposure scenarios were defined.

° For residential scenarios, homeowner handlers are expected to complete all tasks associated with the use of a pesticide product, including mixing/ loading as well as application;

° Residential handler exposure scenarios are only considered to be short term in nature due to the episodic uses associated with homeowner products;

° Label use rates and use information specific to residential products serve as the basis for the risk calculations; and ° Area/ volumes of spray or chemical used in the risk assessment are based on Agency guidance specific to residential use patterns.

It has been determined that exposure to pesticide handlers is likely during the residential use of trifluralin in a variety of environments including on turf, vegetable gardens, and ornamentals. The anticipated use patterns and current labeling indicate several major residential exposure scenarios based on the types of equipment and techniques that can potentially be used to make trifluralin applications. The quantitative exposure and risk assessment developed for residential handlers is based on these scenarios. [ Note: The scenario numbers correspond to the tables of risk calculations included in the residential risk calculation aspects of the appendices.]

( 1) loading/ applying granulars with a belly grinder; ( 2) loading/ applying granulars with a push type spreader; ( 3) loading/ applying granulars using a spoon, measuring scoop, shaker can, or via hand; ( 4) mixing/ loading/ applying liquids with a hose end sprayer; ( 5) mixing/ loading/ applying liquids with low pressure handwand sprayer; ( 6) mixing/ loading/ applying liquids with backpack sprayer; and ( 7) applying trifluralin impregnated fabric squares to soil.

2.1.2 Data and Assumptions For Handler Exposure Scenarios A series of assumptions and exposure factors served as the basis for completing the residential handler risk assessments. Each assumption and factor is detailed below. In addition to these factors, unit exposure values were used to calculate risk estimates. These unit exposure values were taken from the Pesticide Handlers Exposure Database 3 ( PHED), from Outdoor Residential Exposure Task Force 4 ( ORETF) data, or from other surrogate data. Both PHED and the individual studies are presented below. 13 Assumptions and Factors: The assumptions and factors used in the risk calculations include:

° For noncancer assessments, the Agency always considers the maximum application rates allowed by labels in its risk assessments:

S Vegetable gardens: The maximum label application rate using a granular formulation is 4.0 lbs a. i./ A and using a liquid formulation is 4.1 lbs a. i./ A or 0.047 lbs ai/ gallon.

S Flowers, shrubs, trees: The maximum label application rate using a granular formulation is 4.0 lbs a. i./ A and using a liquid formulation is 4.1 lbs a. i./ A or 0.047 lbs ai/ gallon.

S Preplant Ornamentals: The maximum label application rate is 20 lbs a. i./ A ( granular only).

S Turf ( residential lawns, golf courses, recreation parks, etc): The maximum label application rate is 3.0 lbs a. i./ A ( granular only).

$ For cancer assessments, the Agency considers the typical application rate for a given use site, if known. The typical application rate is not known for most trifluralin applications in residential settings, therefore B with one exception B the maximum application rate was used in the cancer exposure and risk assessment. However, since the labeled rate for established ornamentals is 2 to 4 pounds active ingredient per acre, EPA used 3 pounds active ingredient per acre as a typical rate for ornamentals in the cancer assessment.

° Average body weight of an adult handler is 70 kilograms. Since the noncancer and cancer endpoints of concern are not sex specific, the body weight of an average adult is used in the assessments.

° PHED values represent a handler wearing typical residential clothing attire of short sleeved shirt, short pants, socks, shoes, and no gloves. Generally, the use of personal protective equipment ( PPE) and engineering controls are not considered acceptable risk mitigation options for products sold for use by homeowners.

° Residential risk assessments are based on what would reasonably be treated by homeowners such as the size of a lawn, or the size of a garden. The factors used for the trifluralin assessment were those dictated in the Health Effects Division Science Advisory Committee Standard Operating Procedure 12: Recommended Revisions To The Standard Operating Procedures For Residential Exposure Assessment5 which was completed on February 22, 2001. The following daily volumes handled and area treated, excerpted from the SOP and used in each residential scenario, include:

S The amount of dilute pesticide used per day or area treated per day for liquid formulations: > 5 gallons for a low pressure handwand and a backpack sprayers, and 14 > 1,000 ft2 for applications to gardens ( vegetables and ornamentals) with a hose end sprayer.

S The area treated with granules by a homeowner is assumed to be: > 0.5 acres for broadcast applications with a belly grinder or push type spreader to lawns, > 1,000 ft2 for spot treatments to lawns with a belly grinder, spoon, measuring scoop, shaker can, or by hand; and > 1,000 ft2 for flower or vegetable garden applications with a belly grinder, spoon, measuring scoop, shaker can, or by hand.

Pesticide Handler Exposure Database ( PHED) Version 1.1 ( August 1998): Chemical specific data for assessing human exposures during pesticide handling activities were not submitted to the Agency in support of the reregistration of trifluralin. It is the policy of the HED to use data from the Pesticide Handlers Exposure Database ( PHED) Version 1.1 to assess handler exposures for regulatory actions when chemical specific monitoring data are not available. 6 PHED was designed by a task force of representatives from the U. S. EPA, Health Canada, the California Department of Pesticide Regulation, and member companies of the American Crop Protection Association. PHED is a software system consisting of two parts  a database of measured exposure values for workers involved in the handling of pesticides under actual field conditions and a set of computer algorithms used to subset and statistically summarize the selected data. Currently, the database contains values for over 1,700 monitored individuals ( i. e., replicates)

Users select criteria to subset the PHED database to reflect the exposure scenario being evaluated. The subsetting algorithms in PHED are based on the central assumption that the magnitude of handler exposures to pesticides are primarily a function of activity ( e. g., mixing/ loading/ applying), formulation type ( e. g., liquid concentrates, granulars), application method ( e. g., low pressure handwand sprayer, push type spreader), and clothing scenarios ( e. g., short sleeve shirt and short pants).

Once the data for a given exposure scenario have been selected, the data are normalized ( i. e., divided by) by the amount of pesticide handled resulting in standard unit exposures ( milligrams of exposure per pound of active ingredient handled). Following normalization, the data are statistically summarized. The distribution of exposure values for each body part ( e. g., chest, upper arm) is categorized as normal, lognormal, or " other" ( i. e., neither normal nor lognormal). A central tendency value is then selected from the distribution of the exposure values for each body part. These values are the arithmetic mean for normal distributions, the geometric mean for lognormal distributions, and the median for all " other" distributions. Once selected, the central tendency values for each body part are composited into a " best fit" exposure value representing the entire body. 15 The unit exposure values calculated by PHED generally range from the geometric mean to the median of the selected data set. To add consistency and quality control to the values produced from this system, the PHED Task Force has evaluated all data within the system and has developed a set of grading criteria to characterize the quality of the original study data. The assessment of data quality is based on the number of observations and the available quality control data. These evaluation criteria and the caveats specific to each exposure scenario are summarized in Table 6. While data from PHED provide the best available information on handler exposures, it should be noted that some aspects of the included studies ( e. g., duration, acres treated, pounds of active ingredient handled) may not accurately represent labeled uses in all cases. HED has developed a series of tables of standard unit exposure values for many residential scenarios that can be utilized to ensure consistency in exposure assessments. 5 EPA MRID 449722 01 ( ORETF Handler Studies): A report was submitted by the ORETF ( Outdoor Residential Exposure Task Force4) that presented data in which the application of various products used on turf by homeowners and lawncare operators ( LCOs) was monitored. All of the data submitted in this report were completed in a series of studies. The study that monitored homeowner exposure scenarios using a push type spreader ( ORETF Study OMA003) is summarized below.

Homeowner Push Type Spreader ( OMA003): A mixer/ loader/ applicator study was performed by the Outdoor Residential Exposure Task Force ( ORETF) using Dacthal ( active ingredient DCPA, dimethyl tetrachloroterephthalate) as a surrogate compound to determine " generic" exposures of individuals applying a granular pesticide formulation to residential lawns. A total of 30 volunteers were monitored using passive dosimetry ( inner and outer whole body dosimeters, hand washes, face/ neck wipes, and personal inhalation monitors). Each volunteer carried, loaded, and applied two 25 lb bags of fertilizer ( 0.89% active ingredient) with a rotary type spreader to a lawn covering 10,000 ft2. The target application rate was 2 lb ai/ acre ( actual rate achieved was about 1.9 lbs ai/ acre). The average application time was 22 minutes, including loading the rotary push spreader and disposing of the empty bags. Each replicate handled approximately 0.45 lbs ai. Dermal exposure was measured using inner and outer whole body dosimeters, hand washes, face/ neck washes, and personal air monitoring devices with OVS tubes. The study results are normalized to kg ai handled. The US EPA HED typically assumes that residential applicators wear short pants and short sleeved shirts, as described in the Residential SOPs ( 1997). Therefore, the table reports the dermal exposures for the short pants and shortsleeve shirt clothing scenario only. 16 Table 3: Unit Exposure Values Obtained From ORETF Study MRID 449722 01 Scenario Monitored Push Type Spreader Applied ( lb ai) Dermal ( mg ai/ lb handled) Inhalation (

g ai/ lb handled)

Geometric Mean 0.45 0.67 0.88 EPA MRID 44518501 ( ORETF Handler Studies): A report was submitted by the Outdoor Residential Exposure Task Force ( ORETF) that presented data in which the application of various products used on ornamentals by homeowners was monitored. All of the data submitted in this report were completed in a series of studies. The study that monitored homeowner exposure scenarios using a hose end sprayer and a low pressure handwand are summarized below.

Homeowner Hose end and Hand held Sprayer: Applications of Sevin Liquid ® Carbaryl insecticide [ RP 2 liquid ( 21%)] were made by volunteers to two young citrus trees and two shrubs in each replicate that was monitored in the study. The test field was located only in Florida. Twenty ( 20) replicates were monitored using hose end sprayer ( Ortho ® DIAL or Spray ® hose end sprayer), and 20 replicates were monitored using hand held pump sprayers ( low pressure handwands).

Each replicate opened the end use product, added it to the hose end sprayer or hand held pump and then applied it to the trees and shrubs. After application to two trees and two shrubs dosimeters were collected. Inhalation exposure was monitored with personal air sampling pumps with OVS tubes attached to the shirt collar in the breathing zone. Dermal exposure was assessed by extraction of carbaryl from inner and outer 100 percent cotton dosimeters. The inner and outer dosimeters were segmented into: lower and upper arms, lower and upper legs, front and back torso. No gloves were worn therefore hand exposure was assessed with 400 ml handwash with 0.01 percent Aerosol OT 75 sodium dioctyl sulfosuccinate ( OTS). One hundred percent cotton handkerchiefs wetted with 25 ml OTS were used to wipe face and neck to determine exposure.

Field fortification recoveries for passive dosimeters averaged 88.3 percent for inner and 76.2 percent for outer dosimeters. Face and neck wipe fortifications average 82.5 percent. Handwash and inhalation OVS tube field fortification averaged > 90 percent. Inner and outer dosimeter and face and neck wipe residues were adjusted for field fortification results. Handwash and inhalation residues were not adjusted.

Laboratory method validation for each matrix fell within the acceptable range of 70 to 120 percent. The limit of quantitation ( LOQ) was 1.0

g/ sample for all media except the inhalation monitors where the LOQ was 0.01

g/ sample. The limit of detection ( LOD) was 0.5

g/ sample for all media except the inhalation monitors where the LOQ was 0.005

g/ sample. 17 For use in reregistration documents, the dermal exposure was calculated by adding the values from the hand rinses, face/ neck wipes to the outer dosimeter lower legs and lower arms plus the inner dosimeter front and rear torso, upper legs and upper arms. This accounts for the residential handler wearing short sleeved shirt and short pants. The results for the low pressure handwand are summarized in Table 3 below.

The distribution of the unit exposure values is categorized as normal, lognormal, or " other" ( i. e., neither normal nor lognormal). A central tendency value is selected from the distribution of the exposure values. These values are the arithmetic mean for normal distributions, the geometric mean for lognormal distributions, and the median for all " other" distributions. The dermal exposure had a lognormal distribution so the geometric mean value was used to determine dermal exposure to trifluralin. The inhalation exposure had neither a normal or lognormal distribution so the median was used to determine inhalation exposure to trifluralin.

Table 4: Unit Exposure Values Obtained ORETF Study MRID 44518501)

Scenario Monitored Hose End Pump Sprayer Applied ( lb ai) Dermal ( mg ai/ lb handled) Inhalation (

g ai/ lb handled) Applied ( lb ai) Dermal ( mg ai/ lb handled) Inhalation (

g ai/ lb handled)

Geometric Mean 0.033 39.0 1.6 0.017 56.0 2.6 Proprietary Studies One proprietary study was used to obtain unit exposure values for handlers loading/ applying with a bucket and spoon. This study is summarized below.

Worker Exposure Study During Application of Regent 20GR In Banana Plantation1, EPA MRID 452507 02 ( Fipronil Study): Handler exposure data from a proprietary granular mixer/ loader/ applicator study ( MRID 452507 02) in bananas using fipronil ( Regent 20GR) were used in place of PHED data for the " loading/ applying granulars using a spoon, measuring scoop, shaker can or by hand" scenario. This fipronil study is considered to be an appropriate source of surrogate handler exposure data for trifluralin because formulation types are similar ( granular) and application methods are similar ( applying granulars with a spoon). The study is considered to be of sufficient quality for use in risk assessment. 1 Data compensation for these data should be determined.

Several factors should be considered when using fipronil data in the trifluralin exposure assessment. Protection factors used to calculate trifluralin dermal unit exposure values, based on the fipronil unit exposure values, include a standard 50% protection factor for the torso, a 10% protection factor for legs, based on shorts, and a 10% protection factor for arms, based on a shortsleeved shirt. These protection factors represent the typical attire assumed to be worn by a homeowner during pesticide application ( shorts and short sleeved shirt). The 10% protection factor for shorts and the 10% protection factor for a short sleeved shirt are not standard protection 18 factors used by the Agency; rather, these values are based on the best professional judgement of Agency scientists and are appropriate for calculating range finding estimates only.

Some other issues and limitations to be considered when using the fipronil study include the following:

° Agency guidelines require that 15 replicates be completed in exposure studies in three different locations. In the fipronil study, only ten replicates were completed using spoons, and at only one location. However, the events that were monitored seemed to be reasonable representations of actual agricultural practices, so it is unlikely that additional replicates would significantly alter the final unit exposure results. Additionally, it is unlikely that cultural practices would significantly vary if the study was completed at different locations.

° The individual amounts of chemical applied were not recorded in this study. Instead, the investigators determined how much product was applied by the application teams used. Using this information, the investigators calculated the amount used for each individual by assuming that each was equally productive ( i. e., dividing the total amount used per team by the number of team members).

° One applicator using the spoons had a spoon with no handle. The results for this individual were included with the other spoon applicators as it is a plausible variation of that application method.

Table 5: Unit Exposure Values Obtained From Fipronil Study MRID 452507 02 Scenario Monitored Spoon Applications Handled ( mg exposure/ lb ai handled) Dermal ( mg ai/ lb handled) Inhalation (

g ai/ lb handled)

Geometric Mean 0.045 3.5 45.0 2.1.3 Residential Handler Exposure and Non Cancer Risk Estimates The residential handler exposure and non cancer risk calculations are presented in this section. Non cancer risks were calculated using the Margin of Exposure ( MOE) which is a ratio of the daily dose to the toxicological endpoint of concern. Daily dose values are calculated by first calculating exposures by considering application parameters ( i. e., rate and area treated) along with unit exposure values. Exposures were then normalized by body weight and adjusted for absorption factors as appropriate to calculate dose levels. MOEs were then calculated.

Daily Inhalation Exposure: The daily inhalation exposure, daily inhalation dose and hence the inhalation risks, to handlers were calculated as described below. The first step was to calculate daily exposure ( dermal or inhalation) using the following formula: 19 Daily Inhalation Exposure mg ai day

Unit Exposure

g ai lb ai x Conversion Factor 1mg 1,000

g x Use Rate lb ai Sq ft, Gallons x Amount Treated Sq ft, Gallons day Average Daily Dose mg ai kg/ day

Daily Exposure mg ai day x AbsorptionFactor(%/ 100) Body Weight ( kg) Where:

Daily Exposure = Amount that is inhaled, also referred to as potential dose ( mg ai/ day); Unit Exposure = Normalized exposure value derived from August 1998 PHED Surrogate Exposure Table and various referenced exposure studies noted above ( mg ai/ lb ai); Application Rate = Normalized application rate based on a logical unit treatment such as square feet or gallons, maximum values are generally used ( lb ai/ sq ft, lb ai/ gal) and Daily Area Treated = Normalized application area based on a logical unit treatment such as square feet ( sq ft/ day), or gallons per day ( gal/ day).

Daily Inhalation Dose: Daily dose was calculated by normalizing the daily inhalation exposure value by body weight. For adult handlers using trifluralin, an average adult body weight of 70 kg was used for all exposure scenarios. Since there is no specific inhalation absorption factor that is available for trifluralin, a factor of 100 percent has been used for all calculations. Daily dose was calculated using the following formula:

Where:

Average Daily Dose = The amount as absorbed dose received from exposure to a pesticide in a given scenario ( mg pesticide active ingredient/ kg body weight/ day, also referred to as ADD); Daily Exposure = Amount deposited on the surface of the skin that is available for dermal absorption or amount that is inhaled, also referred to as potential dose ( mg ai/ day); Absorption Factor = A measure of the flux or amount of chemical that crosses a biological boundary such as the lungs (% of the total available absorbed); and Body Weight = Body weight determined to represent the population of interest in a risk assessment ( kg).

Margins of Exposure: Finally, the calculations of daily inhalation dose received by handlers were then compared to the appropriate endpoint ( i. e., NOAEL) to assess the total risk to handlers for each exposure route within the scenarios. Inhalation MOEs for all durations were calculated using a NOAEL of 81 mg/ kg/ day ( Table 1). All MOE values were calculated for inhalation exposure levels using the formula below: 20 MOE

NOAEL mg ai kg/ day Average Daily Dose mg ai kg/ day Where:

MOE = Margin of exposure, value used by the Agency to represent risk or how close a chemical exposure is to being a concern ( unitless); ADD = ( Average Daily Dose) or the amount as absorbed dose received from exposure to a pesticide in a given scenario ( mg pesticide active ingredient/ kg body weight/ day); and NOAEL = Dose level in a toxicity study, where no observed adverse effects occurred ( NOAEL) in the study or the lowest dose level where an adverse effect occurred.

A margin of exposure ( MOE) uncertainty factor of 100 is considered an appropriate risk level for the residential risk assessments. 2 Noncancer Risk Summary: All of the noncancer risk calculations for residential trifluralin handlers completed in this assessment are included in Appendix A. A summary of the results for each exposure scenario is also provided below.

Appendix A/ Table A1: Sources of Exposure Data Used in the Short Term Residential Trifluralin Handler Exposure and Risk Calculations Describes the sources and quality of the exposure data used in all of the residential handler calculations.

Appendix A/ Table A2: Margins of Exposure For Short Term Trifluralin Residential Handler Risk Assessment Unit exposure values, daily doses, and risks are presented for residential handlers for short term exposures.

2.1.4 Summary of Non Cancer Risk Concerns for Residential Handlers Short term exposures and risks were not assessed for trifluralin, since no short term dermal endpoint was identified. For the applications in residential settings, the inhalation risks are not a concern for all mixing/ loading/ applying scenarios. Note that there is assumed to be no inhalation risk data for applying ready to use trifluralin impregnated squares to soil. Due to the low vapor pressure of trifluralin ( 4 x 10 5 mm Hg at 25  C), the inhalation risk from this exposure pattern is not expected to be a concern. 21 Table 6. Residential Handler Short Term Inhalation Exposure and Risks to Trifluralin Exposure Scenario ( Scenario #) Use Site Inhalation Unit Exposure (

g/ lb ai) a Application Rateb Amount Used or Area Treated per Dayc Daily Inhalation Dose ( mg/ day/ day) d Inhalation MOEe MIXER/ LOADER/ APPLICATOR EXPOSURE Loading/ applying granulars with a belly grinder ( 1) ornamental ( pre plant) 62 20 lbs ai/ acre 0.023 acres 4.10e 03 2.00e+ 05 ornamental ( post plant) 4.0 lbs ai/ acre 0.023 acres 8.20e 05 9.90e+ 05 turf 3.0 lbs ai/ acre 0.5 acres 1.30e 03 6.10e+ 04 vegetable gardens 4.1 lbs ai/ acre 0.023 acres 8.30e 05 9.70e+ 05 Loading/ applying granulars with a push type spreader ( 2) ornamental ( pre plant) 0.88 20 lbs ai/ acre 0.023 acres 5.80e 06 1.40e+ 07 ornamental ( post plant) 4.0 lbs ai/ acre 0.023 acres 1.20e 06 7.00e+ 07 turf 3.0 lbs ai/ acre 0.5 acres 1.90e 05 4.30e+ 06 vegetable gardens 4.1 lbs ai/ acre 0.023 acres 1.20e 06 6.90e+ 07 Loading/ applying granulars using a spoon, measuring scoop, shaker can,

or by hand( 3) ornamental ( pre plant) 45 20 lbs ai/ acre 0.023 acres 3.00e 04 2.70e+ 05 ornamental ( post plant) 4.0 lbs ai/ acre 0.023 acres 5.90e 05 1.40e+ 07 turf 3.0 lbs ai/ acre 0.023 acres 4.40e 05 1.80e+ 06 vegetable gardens 4.1 lbs ai/ acre 0.023 acres 6.00e 05 1.30e+ 06 rose bushes 0.00043 lbs ai/ bush 50 bushes 1.40e 05 5.90e+ 06 Mixing/ loading/ applying liquids with a hose end sprayer ( 4) flowers, trees and shrubs 1.5 4.1 lbs ai/ acre 0.023 acres 2.00e 06 4.00e+ 07 vegetable gardens 4.1 lbs ai/ acre 0.023 acres 2.00e 06 4.00e+ 07 Mixing/ loading/ applying liquids with low pressure hand wand ( 5) flowers, trees, and shrubs 3.8 0.047 lbs ai/ gallon 5 gallons 1.30e 05 6.30e+ 06 vegetable gardens 0.047 lbs ai/ gallon 5 gallons 1.30e 05 6.30e+ 06 Mixing/ loading/ applying liquids with back pack sprayer ( 6) flowers, trees, and shrubs 30 0.047 lbs ai/ gallon 5 gallons 1.00e 04 8.00e+ 05 vegetable gardens 0.047 lbs ai/ gallon 5 gallons 1.00e 04 8.00e+ 05 Applying trifluralin impregnated fabric squares to soil ( 7) No data are available for this scenario.

Footnotes:

a Inhalation unit exposure values from PHED represent no respirator. 3 b Application Rates are based on the maximum application rates listed on the trifluralin labels. 22 c Amount handled per day are from EPA estimates of acres treated, or square feet treated, in a single day based on the application method. For ready to use formulations, the whole container is assumed to be used in one day.

d Daily Inhalation dose ( mg/ kg/ day) = ( Inhalation Unit Exposure (

g/ lb ai) x ( 1mg/ 1000

g) Conversion Factor x Application Rate ( lb ai/ A or lb ai/ gal or lb ai/ bush) x Area Treated per day ( acres, gallons, or bushes))/ body weight ( 70 kg).

e Short term Inhalation MOE = Inhalation NOAEL ( 81 mg/ kg/ day)/ Daily Inhalation Dose ( mg/ kg/ day). 23 2.2 Residential Cancer Trifluralin Handler Exposure and Risk Assessment This section presents the residential handler exposure and cancer risk assessment for trifluralin.

2.2.1 Data and Assumptions For Residential Cancer Handler Exposure Scenarios A series of assumptions and exposure factors served as the basis for completing the residential handler risk assessments.

Assumptions and Factors: The assumptions and factors used in the risk calculations include:

° The Agency always considers the typical application rates allowed for its cancer risk assessments, however, no typical rates were available for residential trifluralin uses. As a result, the maximum rates were used, except for the post plant applications to ornamentals. The label rates for this use pattern varied from 2 to 4 lb ai/ acre and an average rate of 3 lb ai/ acre was utilized for the cancer assessment.

$ Residential applications per year ( 5 total) for the granular scenarios were as follows:

S one pre plant application to ornamentals ( at 20 lb ai/ acre, treat 1,000 sq ft);

S one post plant application to ornamentals ( at 3 lb ai/ acre, treat 1,000 sq ft  label rates range from 2 to 4 lb ai/ acre);

S one application to vegetable gardens ( 4.1 lb ai/ acre, treat 1,000 sq ft); and S two applications to turf per year for all granular equipment ( 3 lb ai/ acre, treat 0.5 acres).

$ Residential applications per year for the liquid scenarios were set at 5 per year.

2.2.2 Residential Cancer Trifluralin Handler Exposure and Risk Calculations Cancer risks resulting from exposures to trifluralin were calculated using a linear low dose extrapolation approach in which a Lifetime Average Daily Dose ( LADD) is first calculated and then compared with a Q1* that has been calculated for trifluralin based on dose response data ( Q1* = 5.79 x 10 3 ( mg/ kg/ day) 1). Absorbed average daily dose ( ADD) levels were used as the basis for calculating the LADD values. Section 2.1.3 describes how the ADD values for inhalation exposures were calculated for the non cancer MOEs. These values also serve as the basis for the cancer risk estimates. In the cancer assessment both dermal and inhalation ADD values are calculated and then added together to obtain combined dermal plus inhalation ADD values. Dermal ADD values are calculated as described in Section 2.1.3. To assess cancer risks, LADD values are calculated and then compared to the Q1* selected for trifluralin.

Lifetime Average Daily Dose: To calculate the carcinogenic risk from absorbed average daily dose, the values must be amortized over the lifetime of residential handlers. Current use 24 LADD mg ai kg/ day

Total Daily Dose mg ai kg/ day x days exposed 365 days per year x 50 years exposed 70 year lifetime Cancer Risk

LADD mg ai kg/ day x Q 1

patterns indicate that application occurs only a few times per year. HED does not expect homeowner handler exposures to exceed five times per year for this cancer risk assessment:

Finally, a 50 year exposure and a 70 year lifespan were used to complete the calculations. LADD values were calculated using the following equation:

Where:

Lifetime Average Daily Dose = The amount as absorbed dose received from exposure to a pesticide or degradate in a given scenario over a lifetime ( mg/ kg/ day, also referred to as LADD); Average Daily Dose = The amount as absorbed dose received from exposure to a pesticide or degradate in a given scenario on a daily basis ( mg/ kg/ day, also referred to as ADD); Exposure Frequency = The annual frequency of exposure to an individual ( days/ year); Exposure Duration = The amount of a lifetime that an individual is exposed ( 50 years); and Lifetime = The average life expectancy of an individual ( 70 years).

Cancer Risks : Finally, cancer risk calculations were completed by comparing the LADD values to the Q 1* for trifluralin ( Q1* = 5.97 x 10 3 ( mg/ kg/ day) 1). Individual cancer risks were calculated using the following equation:

Where:

Cancer Risk = Probability of excess cancer cases over a lifetime ( unitless); Lifetime Average Daily Dose = The amount as absorbed dose received from exposure to a pesticide or degradate in a given scenario over a lifetime ( mg/ kg/ day); and Q1* = Quantitative dose response factor used for linear, low dose response cancer risk calculations ( mg/ kg/ day) 1.

After calculating all of the individual cancer risks, a total combined cancer risk was calculated by adding together all the individual cancer risks for a particular scenario.

HED has defined a range of acceptable cancer risks based on a policy memorandum issued in 1996 by then Office of Pesticide Programs director, Mr. Dan Barolo. This memo refers to a predetermined quantified " level of concern" for residential carcinogenic risk. In summary, this 25 policy memo indicates risks less than 1 x 10 6 are not considered to be of concern and require no risk management action.

Cancer Risk Summary: A summary of the results for each exposure scenario is provided below in Table 7. In addition, the cancer risk calculations for residential trifluralin handlers completed in this assessment are included in Appendix A: Table A3: Trifluralin Residential Handler Cancer Risk Assessment.

Summary of Risk Concerns for Cancer The target risk for cancer is 1 x 10 6. Risks greater than 1 x 10 6 for the general population are considered to be of concern and risks less than 1 x 10 6 are not considered to be of concern. Homeowner exposure to trifluralin is not expected to occur more than five days per year. All scenarios have cancer risks of less than 1 x 10 6. Note that there is no inhalation risk data for applying ready to use trifluralin impregnated squares to soil, but inhalation exposure is expected to be negligible. HED expects the cancer risks for this scenario to be far less than applying granular formulations using a spoon, measuring scoop, shaker can, or by hand. 26 Table 7. Baseline Residential Handler Dermal and Inhalation Cancer Exposure to Trifluralin Exposure Scenario ( Scenario #) Use Site Application Rate a Area Treated Dermal Unit Exposure ( mg/ lb ai) Inhalation Unit Exposure ( ug/ lb ai) Residential Handler Treatments / Year b Daily Total Dose ( mg/ kg/ day) c Residential Handler Total LADD ( mg/ kg/ day) d Residential Handler Cancer Risk e Combined Residential Handler Cancer Riskf MIXER/ LOADER/ APPLICATOR EXPOSURE Loading/ applying granulars with a belly grinder ( 1) ornamental ( pre) 20 lb ai/ acre 0.023 acres 110 62 1 0.022 4.4E 05 2.5E 07 8.85E 07 ornamental ( post) 3 lb ai/ acre 0.023 acres 110 62 1 0.0033 6.5E 06 3.8E 08 turf 3 lb ai/ acre 0.5 acres 110 62 2 0.024 9.4E 05 5.4E 07 vegetable gardens 4.1 lb ai/ acre 0.023 acres 110 62 1 0.0045 8.8E 06 5.1E 08 Loading/ applying granulars with a push type spreader ( 2) ornamental ( pre) 20 lb ai/ acre 0.023 acres 0.67 0.88 1 0.00014 2.7E 07 1.6E 09 5.52E 09 ornamental ( post) 3 lb ai/ acre 0.023 acres 0.67 0.88 1 0.000021 4.0E 08 2.3E 10 turf 3 lb ai/ acre 0.5 acres 0.67 0.88 2 0.00015 5.9E 07 3.4E 09 vegetable gardens 4.1 lb ai/ acre 0.023 acres 0.67 0.88 1 0.000028 5.5E 08 3.2E 10 Loading/ applying granulars using a spoon, measuring scoop, shaker can, or by hand( 3) ornamental ( pre) 20 lb ai/ acre 0.023 acres 3.5 45 1 0.00099 1.9E 06 1.1E 08 1.68E 08 ornamental ( post) 3 lb ai/ acre 0.023 acres 3.5 45 1 0.00015 2.9E 07 1.7E 09 turf 3 lb ai/ acre 0.023 acres 3.5 45 2 0.000049 1.9E 07 1.1E 09 vegetable gardens 4.1 lb ai/ acre 0.023 acres 3.5 45 1 0.0002 3.9E 07 2.3E 09 Mixing/ loading/ applying liquids with a hose end sprayer ( 4) flowers, trees, shrubs,

vegetable gardens 4.1 lb ai/ acre 0.023 acres 39 1.5 5 0.0016 1.5E 05 8.9E 08 Mixing/ loading/ applying liquids with low pressure hand wand ( 5) flowers, trees, shrubs,

vegetable gardens 0.047 lb ai/ gal 5 gallons 56 3.8 5 0.0057 5.5E 05 3.2E 07 Mixing/ loading/ applying liquids with back pack sprayer ( 6) flowers, trees, shrubs,

vegetable gardens 0.047 lb ai/ gal 5 gallons 100 30 5 0.01 1.0E 04 5.8E 07 Applying trifluralin impregnated fabric squares to soil ( 7) No data are available for this scenario.

Footnotes:

a Maximum application rates were utilized for all use sites except for the granular, post plant application. The label rates for this use ranged from 2 to 4 lb ai/ acre so the average rate of 3 lb ai/ acre was utilized for the cancer assessment.

b The number of exposures per year are based on the label recommendations.

c Total Daily Dose ( mg/ kg/ day) = Daily Dermal Dose ( mg/ kg/ day) * Dermal Absorption ( 3%) + Daily Inhalation Dose ( mg/ kg/ day).

d LADD ( mg/ kg/ day) = Total Daily Dose ( mg/ kg/ day) * (# days of exposure per year/ 365 days/ year) * ( 50 years exposed/ 70 years in a lifetime).

e Cancer Risk = LADD ( mg/ kg/ day) * Q1* ( 0.00579)

f Combined Cancer Risk by Equipment Type = Cancer risks for each crop in the equipment scenario added to one another. 27 2.3 Residential Postapplication Exposures and Risks 2.3.1 Residential Postapplication Exposure Scenarios Trifluralin residential uses ( vegetable gardens, ornamentals, and turf) indicate that individuals of varying ages potentially can be exposed during activities in areas that have been previously treated. The Agency is concerned about these kinds of postapplication exposures. Postapplication exposure scenarios were developed for each residential setting where trifluralin can be used.

The Agency considered a number of residential postapplication exposure scenarios for different segments of the population including toddlers, youth aged children, and adults. Noncancer risks were calculated for only a few scenarios, since no short term dermal endpoint of concern has been identified. In general, postapplication inhalation risks following outdoor applications are considered negligible. Therefore, at this time, EPA is only assessing non dietary ingestion exposures for toddlers ( i. e., soil ingestion, hand/ object to mouth, and granule ingestion).

The Agency relies on a standardized approach for completing residential risk assessments that is based on current trifluralin labels and guidance contained in the following four documents:

° Series 875, Residential and Residential Exposure Test Guidelines: Group B  Postapplication Exposure Monitoring Test Guidelines ( V 5.4, Feb. 1998) This document provides general risk assessment guidance and criteria for analysis of residue dissipation data.

° Standard Operating Procedures For Residential Exposure Assessment ( Dec. 1997) This document provides the overarching guidance for developing residential risk assessments including scenario development, algorithms, and values for inputs.

° Science Advisory Council For Exposure Policy 12 ( Feb. 2001): Recommended Revisions To The Standard Operating Procedures ( SOPs) For Residential Exposure Assessment This document provides additional, revised guidance for completing residential exposure assessments.

° Overview of Issues Related To The Standard Operating Procedures For Residential Exposure Assessment ( August 1999 Presentation To The FIFRA SAP) This document provides rationale for Agency changes in SOPs.

When the guidance in current labels and these documents is considered, it is clear that the Agency should consider children of differing ages as well as adults in its assessments. However, since no short term dermal endpoint of concern has been identified, the only population that was considered in the assessment was: 28

Residential Children: children are members of the general population that can also be exposed in their residences ( e. g., on lawns or in gardens), as well as other areas treated with a pesticide ( e. g., parks). These kinds of exposures are attributable to a variety of activities such as playing outside, or playing indoors on carpet or hard flooring. Toddlers have been selected as a sentinel ( or representative) population for turf.

The SOPs For Residential Exposure Assessment define several scenarios that apply to uses specified in current labels. These scenarios served as the basis for the residential postapplication assessment along with the modifications to them and the additional data/ approaches described above. The Agency used this guidance to define the postapplication exposure scenarios as only toddler nondietary ingestion exposure on treated lawns. The SOPs and the associated scenarios are presented below:

Dose from incidental ingestion of granulars from treated turf calculated using SOP 1.3.1: Postapplication dose among toddlers from incidental nondietary ingestion of granulars in a treated turf area ( i. e., those granular particles that end up in the mouth from a child touching treated turf then putting their hands in their mouth).

Dose from hand to mouth activity from treated turf calculated using SOP 1.3.2: Postapplication dose among toddlers from incidental nondietary ingestion of pesticide residues on treated turf from hand to mouth transfer ( i. e., those residues that end up in the mouth from a child touching turf and then putting their hands in their mouth);

Dose from object to mouth activity from treated turf calculated using SOP 1.3.3: Postapplication dose among toddlers from incidental nondietary ingestion of pesticide residues on treated turf from object to mouth transfer ( i. e., those residues that end up in the mouth from a child mouthing a handful of treated turf); and

Dose from soil ingestion activity from treated turf calculated using SOP 1.3.4: Postapplication dose among toddlers from incidental nondietary ingestion of pesticide residues from ingesting soil in a treated turf area ( i. e., those soil residues that end up in the mouth from a child touching treated soil and turf then putting their hands in their mouth).

The detailed residential postapplication calculations are presented in Appendix B of this document.

2.3.2 Data & Assumptions for Residential Noncancer Postapplication Exposure Scenarios 29 A series of assumptions and exposure factors served as the basis for completing the residential noncancer postapplication risk assessments. Each assumption and factor are detailed below.

The assumptions and factors used in the risk calculations are consistent with current Agency Standard Operating Procedures for completing residential exposure assessments ( i. e., SOPs For Residential Exposure Assessment5). [ Note: More detail about the origin of each factor can be obtained in the SOP document and associated documents such as the Agency's 1999 Overview document presented to the FIFRA SAP.] The values used in this assessment include:

° The Agency combines risks resulting from exposures to individual chemicals when it is likely they can occur simultaneously based on the use pattern and the behavior associated with the exposed population. For this residential postapplication assessment, risks from individual exposure scenarios resulting from an application to turf are combined for the toddler hand to mouth, object to mouth, and soil ingestion scenarios, because they can cooccur

° Exposures to children playing on treated turf have been addressed using the latest Agency approaches for this scenario including:

S the TTR value at day zero from the trifluralin specific turf transferable residue study7 ( MRID # 457456 01) was used in each scenario;

S 3 year old toddlers are expected to weigh 15 kg;

S short term hand to mouth exposures are based on a frequency of 20 events/ hour;

S a surface area per event of 20 cm2 representing the palmar surfaces of three fingers is used for short term exposure durations;

S saliva extraction efficiency7 is 50 percent   meaning that every time the hand goes in the mouth approximately ½ of the residues on the hand are removed;

S object to mouth exposures are based on a 25 cm2 surface area;

S exposure durations are expected to be 2 hours based on information in the Agency's Exposure Factors Handbook;

S soil residues are contained in the top centimeter and soil density is 0.67 mL/ gram;

S The assumed ingestion rate of dry pesticide formulations ( i. e., pellets and granules) is 0.3 grams/ day for children ( age 3 years);

S hand and object to mouth, and soil ingestion are added together to represent an overall risk from exposure to turf; and S Postapplication noncancer residential risks are based generally on maximum application rates or values specified in the SOPs For Residential Exposure Assessment.

Dissipation of Transferable Residues of Benefin and Trifluralin on Turf Treated with a Formulation of the Pesticides8   EPA MRID 457456 01: The registrant submitted a transferable residue study of benefin and trifluralin on turf. The study is designed to fulfill the 30 requirements of the EPA Series 875: Occupational and Residential Exposure Test Guidelines in accordance with EPA FIFRA Good Laboratory Practices Standards. The study was conducted from June to September, 1997 at three geographical locations ( California, Indiana, and Mississippi) that are said to be representative of the climatic and turf growing conditions expected in the intended use areas. Turf varieties used were common bermuda in California, tall fescue in Indiana, and a mixture of bermuda and barnyard grasses in Mississippi. The turf was mowed to its normal cutting height prior to pesticide application and no irrigation, mowing, or maintenance chemical applications were performed for the duration of the study. A granular product containing 1.33% benefin and 0.67% trifluralin was applied to the turf in a single application at the maximum label rate of two pounds benefin active ingredient per acre and one pound trifluralin active ingredient per acre using a drop granule spreader or an air powered granular applicator. Sampling was performed using the California Roller technique and the sampling medium was a percale cloth sheet. Samples were collected at days 0, 1, 2, 4, and 7 following application. For trifluralin, the study limit of detection ( LOD) was 0.001  g/ cm2 and the limit of quantitation ( LOQ) was 0.003  g/ cm2. Initial transferable residues of trifluralin were less than the LOQ and ranged from not detectable to 0.002  g/ cm2. The average transferable residues at day 0 were 0.0011  g/ cm2, just slightly higher than the limit of detection. After day 0, no residues were detectable.

2.3.3 Residential Postapplication Exposure and Noncancer Risk Estimates The residential postapplication exposure and noncancer risk calculations are presented in this section. Noncancer risks were calculated using the Margin of Exposure ( MOE), which is a ratio of the daily dose to the toxicological endpoint of concern. Exposures were calculated by considering the potential sources of exposure then calculating nondietary ingestion exposures to toddlers. The major difference with residential risk assessments is that the uncertainty factor which defines the level of risk concern also has to consider application of the additional FQPA safety factor specified by the legislation. The overall uncertainty factor applied to trifluralin for residential postapplication risk assessments is 100.

Nondietary Ingestion Exposure From Treated Turf: Nondietary ingestion exposure levels from turf are calculated using the following equations.

Hand to mouth Transfer of Pesticide Residues on Lawns ( toddler)

ADD = ( TTR 0 * SA * FQ * ET * SE * CF1) / BW Where: ADD = average daily dose ( mg/ kg/ day) TTRt = turf transferable residue on day " 0" ( 0.0033

g/ cm2 ) SA = surface area of the hands ( 20 cm2/ event) FQ = frequency of hand to mouth activity ( 20 events/ hr) ET = exposure time ( 2 hr/ day) SE = extraction by saliva ( 50%) 31 CF1 = weight unit conversion factor to convert

g units in the DFR value to mg for the daily exposure ( 0.001 mg/

g) BW = body weight ( 15 kg)

Object to mouth Transfer of Pesticide Residues on Lawns ( toddler)

ADD = ( TTR 0 * IgR* CF1) / BW Where: ADD = average daily dose ( mg/ kg/ day) TTRt = turf transferable residue on day " 0" ( 0.0033

g/ cm2) IgR = ingestion rate of grass ( 25 cm2/ day) CF1 = weight unit conversion factor to convert the

g of residues on the grass to mg to provide units of mg/ day ( 1E 3 mg/

g) BW = body weight ( 15 kg)

Incidental Ingestion of Soil from Pesticide Treated Residential Areas ( toddler)

ADD = ( SR 0 * IgR * CF1) / BW Where: ADD = average daily dose ( mg/ kg/ day) SR0t = soil residue on day " 0" ( 0.0022

g/ g) IgR = ingestion rate of soil ( 100 mg/ day) CF1 = weight unit conversion factor to convert the

g of residues on the soil to grams to provide units of mg/ day ( 1E 6 g/

g) BW = body weight ( 15 kg)

and SRt = TTRt * F * CF2 Where: TTRt = turf transferable residue on day " 0" ( 0.0033

g/ cm2) F = fraction of ai available in uppermost cm of soil ( 1 fraction/ cm) CF2 = volume to weight unit conversion factor to convert the volume units ( cm3) to weight units for the SR value ( U. S. EPA, 1992) ( 0.67 cm3/ g soil)

Residential Postapplication Noncancer Short Term Oral Risk Calculations: For postapplication oral exposures to toddlers from contact with treated turfgrass and soil, the margin of exposure ( MOE) is calculated as follows:

Oral MOE = Short Term Incidental Oral NOAEL Exposure Dose 32 Episodic Exposure From Ingesting Granules or Pellets: The Agency assesses risks to toddlers resulting from incidental ingestion of pesticide granules or pellets in pesticide treated residential areas. Since this exposure is likely to occur, at most, only once following a residential application, the acute dietary NOAEL toxicological endpoint of concern is used to assess the risks. The following illustrates the approach used to calculate the nondietary ingestion exposures that are attributable to toddlers ingesting pesticide granules or pellets:

Incidental ingestion of granules from pesticide treated residential areas ( toddler)

ADD = IgR* F* CF1/ BW Where: ADD = average daily dose ( mg/ kg/ day) IgR = ingestion rate of dry pesticide formulation ( 0.3 g/ day) F = fraction of ai in dry formulation ( 0.0175 unitless) CF1 = weight unit conversion factor to convert g units in the ingestion rate value to mg for the daily exposure ( 1,000 mg/ g) BW = body weight ( 15 kg)

Residential Postapplication Noncancer Acute Oral Risk Calculations: For postapplication exposures to toddlers from a one time incident involving ingestion of pesticide granules, the margin of exposure ( MOE) is calculated as follows:

Oral MOE = Acute Dietary NOAEL Exposure Dose However, no acute dietary endpoint of concern for trifluralin was identified for the general population, including infants and toddlers, therefore no acute oral risks were assessed for toddlers ingesting pesticide granules.

Noncancer Postapplication Risk Summary: A summary of the results for each exposure scenario is also provided below in Table 8. In addition, the noncancer residential risk calculations for the trifluralin assessment are included in Appendix A: Table A4: NonCancer Postapplication Risk Assessment for Trifluralin.

The Agency has addressed residential postapplication exposures to trifluralin using the standard set of scenarios that are prescribed in current guidance. There are many issues associated with the development of these scenarios and, in general, residential exposure methods. The shortterm incidental oral endpoint of 10 mg/ kg/ day was used for the hand to mouth, object to mouth, soil ingestion scenarios, granular ingestion since these are oral exposures. The FQPA safety factor was reduced to 1x for all residential populations2. The target MOE for the oral short term exposures is 100. 33 The calculations of short term oral risk indicate that oral MOEs are more than 100 for all of the assessed exposure scenarios.

Table 8: Residential Risk Estimates for Postapplication Exposure to Trifluralin Exposure Scenario Route of Exposure Population Application Ratea MOEb Short term Postapplication Exposures Outdoors Hand to Mouth Activity on Turfc Oral Toddler 3.0 lb ai/ acre 110,000 Object to Mouth Activity on Turfd Oral Toddler 3.0 lb ai/ acre 1,800,000 Incidental Soil Ingestione Oral Toddler 3.0 lb ai/ acre 680,000,000 Incidental Ingestion of Granulesf Oral Toddler 1.75 % ai NA Footnotes:

a Application rates represent maximum label rates from current EPA registered labels ( Granular rate is 3.0 lb ai/ acre), except for ingestion of granules where the highest percent active ingredient product is utilized. b MOEs calculated using residues which would be found on day of treatment. Short term Oral MOE ( S T) = Short term Incidental Oral NOAEL ( 10 mg/ kg/ day / short term Oral Dose ( mg/ kg/ day) with a target MOE of 100; c Hand to mouth Dose Calculation: oral dose to child ( 1 6 year old) on the day of treatment ( mg/ kg/ day) = TTR at day 0 normalized to application rate ( 0.0033 ug/ cm2) x median surface area for 1 3 fingers ( 20 cm2/ event) x hand tomouth rate ( 20 events/ hour) x exposure. time ( 2 hr/ day) x 50% saliva extraction factor x 0.001 mg/ µ g] / bw ( 15 kg child). d Object to Mouth Activity on  Turf Dose Calculation: oral dose to child ( 1 6 year old) on the day of treatment = TTR at day 0 normalized to application rate ( 0.0033 ug/ cm2) x median surface area for 1 3 fingers ( 25 cm2/ event) x hand tomouth rate ( 20 events/ hour) x 0.001 mg/ µ g]] / bw ( 15 kg child). e Incidental Soil ingestion  Dose Calculation: oral dose to child ( 1 6 year old) on the day of treatment ( mg/ kg/ day) = [ TTR at day 0 normalized to application rate ( 0.0033 ug/ cm2) x fraction of residue retained on uppermost 1 cm of soil ( 100% or 1.0/ cm) x 0.67 cm3/ g soil conversion factor] x 100 mg/ day ingestion rate x 1.0E 06 g/

g conversion factor] / bw ( 15 kg). Note: Assumptions used in dose calculations ( e. g., transfer coefficients) are from Residential SOPs ( revised 2/ 01).

Combined Risk Assessment for Residential Scenarios The Agency combines risk values resulting from separate postapplication exposure scenarios when it is likely they can occur simultaneously based on the use pattern and the behavior associated with the exposed population. For trifluralin, HED combined risk values ( i. e., MOEs) for postapplication exposures to toddlers associated with turf applications by combining risks from oral exposures via transfer of residues from turf to hands to mouth with risks from oral exposures via transfer from turf to directly to mouth, and risks from oral exposures via incidental soil ingestion.

The combined risk assessment was calculated as follows:

Combined MOE = NOAEL/( ADD hand to mouth + ADD object to mouth + ADD incidental soil ingestion) 34 The combined MOE for the above scenario is 180 ( see Table 9) and is greater than the target MOE of 100 and thus is not a risk concern.

Table 9: Trifluralin Residential Scenarios for Combined Risk Estimates Postapplication Exposure Scenario Margins of Exposure ( MOEs) ( UF= 100) Short Term Oral ( Non Dietary) Total Non Dietary Riska Toddler Turf: granules on turf ( 3 lb ai/ acre) Hand to Mouth 110,000 110,000 Object to Mouth 1,800,000 Incidental Soil Ingestion 680,000,000 2.4 Residential Postapplication Cancer Exposures and Risks 2.4.1 Residential Postapplication Cancer Exposure Scenarios HED has determined that there are potential postapplication exposures to residents entering the areas where trifluralin has been applied. Although postapplication exposures to youths and toddlers are expected, when assessing cancer risk, the only postapplication residential scenarios that are applicable, using the current methods, are the following:

S Dermal exposure to residues on lawns ( adults);

S Dermal exposure to golf course turfgrass ( adults); and S Dermal exposure in home vegetable gardens.

2.4.2 Residential Postapplication Cancer Trifluralin Exposure and Risk Calculations The Agency has trifluralin specific turf transferrable residue data upon which to base the postapplication cancer assessment resulting from dermal exposures to adults in residential settings.

For cancer assessments, it is necessary to estimate the number of days per year an adult would be exposed to a treated surface. Trifluralin specific turf transferable residue data indicate that residues are not detectable after the day of application and two applications are permitted each year. Therefore for postapplication exposures to residential turfgrass and golf course turfgrass, and for postapplication exposures to residential vegetable gardens, EPA estimated cancer risks to adults using the assumption that adults might be exposed on the day of application ( day zero) following both the permitted applications each year.

For the exposure duration, standard default values5 were used:

S Two hours of exposure while exercising on a treated lawn; 35 S Four hours of exposure while playing golf; and S Forty minutes of exposure while working in a vegetable garden.

Exposure duration was assumed to be 50 years in a 70 year lifespan.

The exposure length ( hours/ day) and exposure frequency ( days/ year) assumptions are assumed to be worst case, since it is unlikely that B for 50 years B an adult would spend:

S two hours exercising on a treated lawn on day 0 for two applications per year;

S 4 hours playing golf on a treated golf course on day 0 for two applications per year; or S 2/ 3 hours working in the vegetable garden on day 0 for two applications per year.

In addition, the label recommends watering in following application, which would further reduce the potential exposure in treated areas.

For the postapplication cancer risk assessment, EPA used the following transfer coeffients:

S 7300 for exposures to lawns while exercising; ( This is the transfer coefficient in the revised Residential Standard Operating Procedures for intermediate term B and presumably long term B exposures by adults to turfgrass. 5)

S 500 for exposures to treated turfgrass while golfing; ( This is the transfer coefficient in the draft standard operating procedure for golfer exposure assessment for adults and children and has been used in other golfer exposure assessments.)

S 1000 for exposures to treated vegetables in a residential garden. ( This is the transfer coefficient in the Agricultural Default Transfer Coefficient SOP10 as high exposure to fruiting vegetables.)

Postapplication cancer risks resulting from exposures to trifluralin were calculated using a linear low dose extrapolation approach in which a Lifetime Average Daily Dermal Dose ( LADD) is first calculated and then compared with a Q1* that has been calculated for trifluralin based on dose response data ( Q1* = 5.79 x 10 3 ( mg/ kg/ day) 1). Absorbed average daily dermal dose ( ADD) levels were used as the basis for calculating the LADD values. LADD values were then calculated and compared to the Q1* to obtain cancer risk estimates.

Lifetime Average Daily Dose: To calculate the carcinogenic risk from absorbed average daily dermal dose, the values must be amortized over the lifetime of residential handlers. Current use patterns indicate that application occurs only a few times per year. 36 LADD mg ai kg/ day

Total Daily Dose mg ai kg/ day x days exposed 365 days per year x 50 years exposed 70 year lifetime Cancer Risk

LADD mg ai kg/ day x Q 1

LADD values were calculated using the following equation:

Where:

Lifetime Average Daily Dose = The amount as absorbed dose received from exposure to a pesticide or degradate in a given scenario over a lifetime ( mg/ kg/ day, also referred to as LADD); Average Daily Dermal Dose = The amount as absorbed dose received from dermal and inhalation exposure to a pesticide or degradate in a given scenario on a daily basis ( mg/ kg/ day, also referred to as ADD); Exposure Frequency = The annual frequency of exposure to an individual ( days/ year); Exposure Duration = The amount of a lifetime that an individual is exposed ( 50 years); and Lifetime = The average life expectancy of an individual ( 70 years).

Cancer Risks : Cancer risk calculations were completed by comparing the LADD values to the Q1* for trifluralin ( Q1* = 5.97 x 10 3 ( mg/ kg/ day) 1). Individual cancer risks were calculated using the following equation:

Where:

Cancer Risk = Probability of excess cancer cases over a lifetime ( unitless); Lifetime Average Daily Dose = The amount as absorbed dermal dose received from exposure to a pesticide or degradate in a given scenario over a lifetime ( mg// kg/ day); and Q1* = Quantitative dose response factor used for linear, lowdose response cancer risk calculations ( mg/ kg/ day) 1.

Table 10 presents the residential lifetime average daily doses and cancer risks associated with postapplication exposures to trifluralin.

Summary of Cancer Risk Concerns for Residential Postapplication HED has defined a range of acceptable cancer risks based on a policy memorandum issued in 1996 by then Office of Pesticide Programs director, Mr. Dan Barolo. This memo refers to a predetermined quantified " level of concern" for residential carcinogenic risk. In summary, this policy memo indicates risks less than 1 x 10 6 are not considered to be of concern and require no risk management action. Risks greater than 1 x 10 6 for the general population are considered to be of concern. 37 Dermal contact with residential turf for adults when assessed at two days of exposure per year   each on the day of application   had risks of less than 1 x 10 6 and are not considered to be a risk concern. Dermal contact with golf course turfgrass for adults when assessed at two days of exposure per year   each on the day of application   had risks less than 1 x 10 6 and are not considered to be of concern. Dermal contact with vegetable gardens for adults when assessed at two days of exposure per year   each on the day of application after sprays have dried   had risks of less than 1 x 10 6 and are not considered to be a risk concern. 38 Table 10. Residential Postapplication Scenarios and Cancer Risks from Trifluralin Exposure Scenario Application Rate ( lb ai/ acre) a TTR/ DFR (

g/ cm2) b Transfer Coefficient ( Tc)

( cm2/ hr) Exposure Time ( ET)

( hrs/ day) ADD ( mg/ kg/ day) c Days of Exposure LADD ( mg/ kg/ day) d Cancer Riske Dermal contact with turf ( adults) 3.0 0.0033 ( at day 0) 7300 2 2.06 x 10 5 2 8.08 x 10 8 4.7 x 10 10 Dermal contact with golf course turfgrass ( adults) 0.0033 ( at day 0) 500 4 2.83 x 10 6 2 1.11 x 10 8 6.4 x 10 11 Dermal contact with vegetable gardens ( adults) 4.0 0.0044 ( at day 0) 1000 0.67 1.26 x 10 6 2 7.42 x 10 8 4.3 x 10 10 a Application rate for turf is the maximum label rate for turfgrass use patterns; application rate for vegetable gardens is maximum label rate for use on vegetable gardens.

b Turf transfer residue at day zero (

g/ cm2) = [ AR ( 3 lbs ai/ A) * TTR residue on day 0 from the trifluralin specific study; Dislodgeable foliar residue for vegetable gardens at day zero (

g/ cm2) = [ AR ( 4 lbs ai/ A) * TTR residue on day 0 from the trifluralin specific study;

c Average daily dermal dose ( ADD) ( mg/ kg/ day) = [ DFR/ TTR (

g/ cm2) * TC ( cm2/ hr) * mg/ 1,000

g * ET ( hrs/ day) * Dermal Absorption ( 3%)] / [ BW ( 70 kg)]

d Lifetime average daily dose ( LADD) = Average Daily Dermal Dose ( mg/ kg/ day) * ( number of days of exposure per year / 365 days/ year) * ( 50 years exposed / 70 years in a lifetime).

e Cancer Risk = LADD ( mg/ kg/ day) x Q1* ( mg/ kg/ day) where Q1* = 0.00579. 39 2.4 Combined Residential Handler and Postapplication Exposures and Risks The Agency combines risk values resulting from separate exposure scenarios when it is likely they can occur simultaneously based on the use pattern and the behavior associated with the exposed population. For trifluralin, HED combined cancer risk values for residential handler and residential postapplication exposures associated with turf applications. ( Note that since both the residential handler and residential postapplication exposures were estimated using a worse case rangefinder approach, combining these risk values may result in exaggerated cancer risks.) The combined handler plus postapplication cancer risk associated with applications to residential turfgrass is 5.4 x10 7. This below EPA's level of concern for cancer. Note that combining shortterm risks was not done, since there are no short term postapplication risks because there is no short term dermal endpoint of concern.

3.0 Trifluralin Poisoning Incidents Information HED tracks pesticide related incidents involving humans through four main resources:

$ OPP Incident Data System ( IDS)

$ Poison Control Centers $ California Department of Pesticide Regulation $ National Pesticide Information Center ( NPIC)

OPP Incident Data System ( IDS): The Office of Pesticide Programs ( OPP) Incident Data System consists of reports of incidents from various sources, including registrants, other federal and state health and environmental agencies and individual consumers, submitted to OPP since 1992. Reports submitted to the Incident Data System represent anecdotal reports or allegations only, unless otherwise stated. Typically no conclusions can be drawn implicating the pesticide as a cause of any of the reported health effects. Nevertheless, sometimes with enough cases and/ or enough documentation risk mitigation measures may be suggested. For trifluralin, it appears that the majority of cases involved skin and eye illnesses.

Poison Control Centers: As the result of a data purchase by EPA, Office of Pesticide Programs received Poison Control Center data covering the years 1993 through 1998 for all pesticides. Most of the national Poison Control Centers ( PCCs) participate in a national data collection system, the Toxic Exposure Surveillance System which obtains data from about 65 70 centers at hospitals and universities. PCCs provide telephone consultation for individuals and health care providers on suspected poisonings, involving drugs, household products, pesticides, etc. Poison Control Center data indicates that, in general, trifluralin is less likely to cause minor, moderate, or life threatening symptoms than other pesticides, except among nonoccupational cases where moderate effects are more likely. There were no major or life threatening cases or cases requiring hospitalization or intensive care, except for one case involving a two year old child who ingested trifluralin and was hospitalized even through asymptomatic. It appears likely this case was kept in the hospital overnight for observation. Symptoms most commonly reported in ten or more reports were eye irritation/ pain ( 25 reports), nausea ( 16 reports), vomiting ( 13 reports), and skin irritation/ pain ( 10 reports). Of the symptomatic cases, one quarter involved exposure to residue rather than direct spray or spill. 40 California Department of Pesticide Regulation: California has collected uniform data on suspected pesticide poisonings since 1982. Physicians are required, by statute, to report to their local health officer all occurrences of illness suspected of being related to exposure to pesticides. The majority of the incidents involve workers. Information on exposure ( worker activity), type of illness ( systemic, eye, skin, eye/ skin and respiratory), likelihood of a causal relationship, and number of days off work and in the hospital are provided. Detailed descriptions of 77 trifluralin related cases submitted to the California Pesticide Illness Surveillance Program ( 1982 2001) were reviewed. In 57 of these cases, trifluralin was used alone or was judged to be responsible for the health effects. Only cases with a definite, probable or possible relationship were reviewed. Trifluralin ranked 72nd as a cause of systemic poisoning in California based on data for 1982 through 2001. Pesticide handler ( i. e., mixer/ loader and applicator) were associated with 31 exposure incidents and field workers were associated with 12 incidents. The reported illnesses included symptoms of conjunctivitis, swollen arms, hand, and face and a rash, eye irritation, tearing and red eyes, headache, skin irritation, and abdominal pain.

National Pesticide Information Center ( NPIC): NPIC is a toll free information service supported by the Office of Pesticide Programs. A ranking has been prepared of the top 200 active ingredients for which telephone calls were received during the calendar years of 1984 through 1991. The total number of calls was tabulated for the categories human incidents, animal incidents, calls for information, and others. On the list, trifluralin was ranked 53rd with 75 incidents involving humans and 17 incidents involving animals ( mostly pets).

Incident Reported in the Scientific Literature: Pentel et al. ( 1994) reported that a sixty one year old male laboratory supervisor at a chemical pesticide company since 1951 was patch tested for trifluralin along with eight other pesticides. The man had a positive reaction to trifluralin. The authors concluded that exposure to this chemical caused him to have allergic contact dermatitis.

Conclusions: Based on California data and the Incident Data System, it appears that the majority of cases involved skin and eye illnesses. Poison Control Center data would tend to support these results, dermal and ocular effects were some of the most common effects reported. 41 References 1) Dawson, J. ( 2001) Ethoprop. Review of fipronil granular mixer/ loader/ applicator study ( MRID 452507 01) in bananas as a source of surrogate data and accompanying ethoprop risk assessment. Washington, D. C.: U. S. Environmental Protection Agency, Office of Pesticide Programs. January 5, 2001.

2) Fricke, R. F. ( 2003) Trifulralin  Report of the Hazard Identification Assessment Review Committee. Washington, D. C.: U. S. Environmental Protection Agency, Office of Pesticide Programs. May 2, 2003.

3) U. S. EPA ( 1998) PHED Surrogate Exposure Guide. Version 1.1. Health Effects Division, Office of Pesticide Programs, August 1998.

4) Bangs, G. ( 2001) Summary of HED's Reviews of Outdoor Residential Exposure Task Force ( ORETF) Chemical Handler Exposure Studies; MRID 449722 01. Memorandum from Gary Bangs ( HED) to Demson Fuller ( Special Review and Reregistration Division), April 30, 2001.

5) U. S. EPA ( 1997) Draft Standard Operating Procedures ( SOPs) for Residential Exposure Assessments. December 1997 with revisions stated in the HED Science Advisory Council for Exposure, SOP 12. Recommended Revisions to the Standard Operating Procedures ( SOPs) for Residential Exposure Assessments. February 22, 2001.

6) U. S. EPA ( 1998) HED Exposure Science Advisory Council SOP Memo No. 7. Use of Values from the PHED Surrogate Table and Chemical Specific Data. Health Effects Division, Office of Pesticide Programs, December 1998.

7) Clothier, J. M. ( 2000) Dermal Transfer Efficiency of Pesticides from Turf Grass to Dry and Wetted Palms. U. S. Environmental Protection Agency, National Exposure Research Laboratory, Research Triangle Park, NC.

8) Trifluralin. Dissipation of transferable residues of benefin and trifluralin on turf treated with a formulation of the pesticides ( MRID 457456 01). Washington, D. C.: U. S. Environmental Protection Agency, Office of Pesticide Programs. Study completed July 26, 2002.

9) U. S. EPA ( 2000) HED Science Advisory Council for Exposure, SOP 003.1. Agricultural Default Transfer Coefficients. Health Effects Division, Office of Pesticide Programs, August 7, 2000.

10) U. S. EPA ( 2000) HED Science Advisory Council for Exposure, SOP 003.1. Agricultural Default Transfer Coefficients. Health Effects Division, Office of Pesticide Programs, August 7, 2000. 42 Appendices 43 Table A1: Sources of Exposure Data Used in the Short Term Residential Trifluralin Handler Exposure and Risk Calculations Exposure Scenario ( Scenario #) Data Source Standard Assumptiona Commentsb Mixer/ Loader/ Applicator Descriptors Loading/ applying granules with a belly grinder ( 1) PHED V1.1 0.5 acres/ day for use on turf, 1000 ft2/ day for use on ornamentals ( both pre plant and post plant ) and vegetable gardens. Baseline: Dermal data = A, B, C grades; 20 45 replicates ( medium confidence). Hands data = A, B, C grades; 23 replicates ( medium confidence). Inhalation data = A, B grades; 40 replicates ( high confidence).

PPE and Engineering Controls: Not required for assessment.

Loading/ applying granules with a push type spreader ( 2) PHED V1.1 0.5 acres/ day for use on turf, 1000 ft2/ day for use on ornamentals ( both pre plant and post plant ) and vegetable gardens. Baseline: Dermal data = C grade; 0 15 replicates ( low confidence). Hands data = C grades; 15 replicates ( low confidence); Inhalation data = B grades; 15 replicates ( high confidence).

PPE and Engineering Controls: Not required for assessment.

Loading/ applying granules using a spoon, measuring scoop, shaker can, or by hand ( 3) Review of fipronil granular mixer/ loader/ applicator study as a source of surrogate data,

MRID 452507 01. J. Dawson memo, D270065, 1/ 5/ 01. 1000 ft2/ day for use on ornamentals ( both pre plant and post plant ), turf and vegetable gardens. 50 bushes/ day for use on roses. Baseline: A 90% protection factor was applied to gloved hands data to back calculate " no glove" hand exposure. A standard 50% protection factor was used for the torso. A 10% protection factor was used to represent the protection afforded by shorts and a short sleeved shirt.

PPE and Engineering Controls: Not required for assessment.

Mixing/ loading/ applying liquids using a hose end sprayer ( 4) ORETF Chemical Handler Exposure Studies 1000 ft2/ day Baseline: Dermal, inhalation, and hands = A grade. Dermal, inhalation, and hands =

20 replicates each. High confidence in all data.

PPE and Engineering Controls: Not required for assessment.

Mixing/ loading/ applying liquids with a low pressure handwand ( 5) ORETF Chemical Handler Exposure Studies 5 gallons spray/ day Baseline: Dermal, inhalation, and hands = A grade. Dermal, inhalation, and hands =

20 replicates each. High confidence in all data.

PPE and Engineering Controls: Not required for assessment.

Mixing/ loading/ applying liquids with a backpack sprayer ( 6) PHED V1.1 5 gallons spray/ day Baseline: Dermal data = A, B grades; 9 11 replicates ( low confidence). Hands data =

C grade, 11 replicates ( low confidence). Inhalation data = A grade; 11 replicates ( low confidence).

PPE and Engineering Controls: Not required for assessment.

Applying trifluralin impregnated fabric squares to soil ( 7) No data is available for this scenario.

Footnotes:

a Standard Assumptions from Residential SOPs.

b " Best Available" grades are defined by HED SOP for meeting Subdivision U Guidelines. Best available grades are assigned as follows: matrices with grades A and B data and a minimum of 15 replicates; if not available, then grades A, B and C data and a minimum of 15 replicates; if not available, then all data regardless of the quality and number of replicates. Data confidence are assigned as follows:

High = grades A and B and 15 or more replicates per body part Medium = grades A, B, and C and 15 or more replicates per body part Low = grades A, B, C, D and E or any combination of grades with less than 15 replicates 44 Table A2: Margins of Exposure For Short Term Trifluralin Residential Handler Risk Assessment Exposure Scenario ( Scenario #) Crop or Target Application Rate a Area Treated Daily b Baseline Inhalation Unit Exposure ( ug/ lb ai) c Baseline Inhalation Exposure d Baseline Inhalation Dose e Baseline Inhalation MOE f Loading/ applying granules with a belly grinder ( 1) ornamental ( pre) 20 lbs ai/ acre 0.023 acres 62 0.029 0.00041 200,000 ornamental ( post) 4.0 lbs ai/ acre 0.023 acres 62 0.0057 0.000082 990,000 turf 1.0 lbs ai/ acre 0.5 acres 62 0.031 0.00044 180,000 vegetable gardens 4.1 lbs ai/ acre 0.023 acres 62 0.0058 0.000083 970,000 Loading/ applying granules with a push type spreader ( 2) ornamental ( pre) 20 lbs ai/ acre 0.023 acres 0.88 0.00041 0.0000058 14,000,000 ornamental ( post) 4.0 lbs ai/ acre 0.023 acres 0.88 0.000081 0.0000012 70,000,000 turf 1.0 lbs ai/ acre 0.5 acres 0.88 0.00044 0.0000063 13,000,000 vegetable gardens 4.1 lbs ai/ acre 0.023 acres 0.88 0.000083 0.0000012 69,000,000 Loading/ applying granules using a spoon, measuring scoop, shaker can, or by hand ( 3) ornamental ( pre) 20 lbs ai/ acre 0.023 acres 45 0.021 0.0003 270,000 ornamental ( post) 4.0 lbs ai/ acre 0.023 acres 45 0.0041 0.000059 1,400,000 turf 1.0 lbs ai/ acre 0.023 acres 45 0.001 0.000015 5,500,000 vegetable gardens 4.1 lbs ai/ acre 0.023 acres 45 0.0042 0.00006 1,300,000 rose bushes 0.000425 lbs ai/ bush 50 bushes 45 0.00096 0.000014 5,900,000 Mixing/ loading/ applying liquids using a hose end sprayer ( 4) flowers, trees, shrubs 4.1 lbs ai/ acre 0.023 acres 1.5 0.00014 0.000002 40,000,000 vegetable gardens 4.1 lbs ai/ acre 0.023 acres 1.5 0.00014 0.000002 40,000,000 Mixing/ loading/ applying liquids with a low pressure handwand ( 5) flowers, trees, shrubs 0.047 lb ai/ gallon 5 gallons 3.8 0.00089 0.000013 6,300,000 vegetable gardens 0.047 lb ai/ gallon 5 gallons 3.8 0.00089 0.000013 6,300,000 Mixing/ loading/ applying liquids with a backpack sprayer ( 6) flowers, trees, shrubs 0.047 lb ai/ gallon 5 gallons 30 0.0071 0.0001 800,000 vegetable gardens 0.047 lb ai/ gallon 5 gallons 30 0.0071 0.0001 800,000 Footnotes:

a Application Rates are based on the maximum application rates listed on the trifluralin labels.

b Amount handled per day are from EPA estimates of acres treated, or square feet treated, in a single day based on the application method. For ready to use formulations, the whole container is assumed to be used in one day.

c Baseline inhalation unit exposure represents no respirator.

d Daily Inhalation Exposure (

g/ day) = ( Inhalation Unit Exposure (

g/ lb ai) x ( 1mg/ 1000

g) Conversion Factor x Application Rate ( lb ai/ A) x Area Treated per day ( acres and square feet)). 45 e Daily Inhalation Exposure (

g/ day) = ( Daily Inhalation Exposure (

g/ day) x Inhalation Absorption Factor (%))/ Body Weight ( 70 kg).

f Short term Inhalation MOE = Inhalation NOAEL ( 81 mg/ kg/ day)/ Daily Inhalation Dose ( mg/ kg/ day). 46 Table A3: Cancer Risks For Trifluralin Residential Handler Risk Assessment Exposure Scenario Crop Type Application Rate a Area Treated Daily b Baseline Dermal Unit Exposure ( mg/ lb ai) Baseline Inhalation Unit Exposure ( ug/ lb ai) Days / Yr Baseline Daily Total Dose ( mg/ kg/ day) Residential Applicator Total Baseline LADD ( mg/ kg/ day) Residential Applicator Baseline Cancer Risk Loading/ applying granules with a belly grinder ( 1) ornamental ( pre) 20 lbs ai/ acre 0.023 acres 110 62 1 0.022 4.4E 05 2.5E 07 ornamental ( post) 4.0 lbs ai/ acre 0.023 acres 110 62 1 0.0033 6.5E 06 3.8E 08 turf 1.0 lbs ai/ acre 0.5 acres 110 62 2 0.024 9.4E 05 5.4E 07 vegetable gardens 4.1 lbs ai/ acre 0.023 acres 110 62 1 0.0045 8.8E 06 5.1E 08 Loading/ applying granules with a push type spreader ( 2) ornamental ( pre) 20 lbs ai/ acre 0.023 acres 0.67 0.88 1 0.00014 2.7E 07 1.6E 09 ornamental ( post) 4.0 lbs ai/ acre 0.023 acres 0.67 0.88 1 0.000021 4.0E 08 2.3E 10 turf 1.0 lbs ai/ acre 0.5 acres 0.67 0.88 2 0.00015 5.9E 07 3.4E 09 vegetable gardens 4.1 lbs ai/ acre 0.023 acres 0.67 0.88 1 0.000028 5.5E 08 3.2E 10 Loading/ applying granules using a spoon, measuring scoop, shaker can, or by hand ( 3) ornamental ( pre) 20 lbs ai/ acre 0.023 acres 3.5 45 1 0.00099 1.9E 06 1.1E 08 ornamental ( post) 4.0 lbs ai/ acre 0.023 acres 3.5 45 1 0.00015 2.9E 07 1.7E 09 turf 1.0 lbs ai/ acre 0.023 acres 3.5 45 2 0.000049 1.9E 07 1.1E 09 vegetable gardens 4.1 lbs ai/ acre 0.023 acres 3.5 45 1 0.0002 3.9E 07 2.3E 09 rose bushes 0.000425 lb ai/ bush 50 bushes 3.5 45 1 0.000046 8.9E 08 5.2E 10 Mixing/ loading/ applying liquids using a hose end sprayer ( 4) flowers, trees, shrubs,

vegetable gardens 4.1 lb ai/ acre 0.023 acres 39 1.5 5 0.0016 1.5E 05 8.9E 08 Mixing/ loading/ applying liquids with a low pressure handwand ( 5) flowers, trees, shrubs 0.047 lb ai/ gal 5 gallons 56 3.8 5 0.0057 5.5E 05 3.2E 07 Mixing/ loading/ applying liquids with a backpack sprayer ( 6) flowers, trees, shrubs 0.047 lb ai/ gal 5 gallons 100 30 5 0.01 1.0E 04 5.8E 07 Footnotes:

a Application Rates are based on the typical application rates listed on the trifluralin labels when available. If no typical rate was provided, maximum applications rates were used.

b Amount handled per day are from EPA estimates of acres treated, or square feet treated, in a single day based on the application method. For ready to use formulations, the whole container is assumed to be used in one day.

c Baseline inhalation unit exposure represents no respirator. 47 Table A4  Short Term Oral Exposure from Hand to Mouth Activity on Trifluralin Treated Turf Exposure Scenario Maximum Application Rate TTR at day 0 ( normalized to max appl. rate) Surface Area ( cm2) Hand to Mouth ( events/ hr) Extraction by Saliva Exposure Time ( hours) Body Weight ( kg) Average Daily Dose ( mg/ kg/ day) MOE Hand to Mouth ( turf) 3.0lb ai/ acre 0.0033

g/ cm2 20 20 50% 2 15 0.000088 110,000 Oral Dose ( mg/ kg/ day) TTR(

g/ cm2) x CF ( 0.001mg/

g) x SA ( cm2) x EXT x FQ ( events/ hr) x ET ( hrs/ day)

BW ( kg)

Where:

Dose = oral dose on day of application ( mg/ kg/ day)

TTR = turf transferable residue normalized to maximum application rate (

g/ cm2)

CF = conversion factor from

g to mg ( 0.001)

F = fraction of residue dislodgeable from wet hands ( unitless)

SA = surface area of 1 to 3 fingers ( cm2)

EXT = extraction rate by saliva ( unitless)

FQ = frequency of hand to mouth events ( events/ hour)

ET = exposure duration ( hours/ day)

BW = body weight ( kg)

Assumptions:

SA  The surface area of 1 to 3 finger is 20 cm2 FQ  The frequency of hand to mouth events is 20 events per hour for short term EXT  The extraction rate by saliva is 50%.

ET  The time spent outdoors is 2 hours/ day Endpoint of Concern = Short Term Incidental Oral NOAEL ( 10 mg/ kg/ day) 48 Table A5  Short Term Oral Exposure from Mouthing Trifluralin Treated Turf Exposure Scenario Application Rate TTR at day 0 ( normalized to max appl. rate) Surface Area ( cm2) Body Weight ( kg) Average Daily Dose ( mg/ kg/ day) MOE Object ( turf) to Mouth 3.0 lb ai/ acre 0.0033

g/ cm2 25 15 0.0000055 1,800,000 Short Term Oral Dose ( mg/ kg/ day) = ( TTRt * IgR* CF1) / BW Where: ADD = average daily dose ( mg/ kg/ day)

TTRt = turf transferable residue on day " 0" (

g/ cm2) normalized to maximum application rate IgR = ingestion rate of grass ( 25 cm2/ day)

CF1 = weight unit conversion factor to convert the

g of residues on the grass to mg to provide units of mg/ day ( 1E 3 mg/

g)

BW = body weight ( 15 kg)

Endpoint of Concern = Short Term Incidental Oral NOAEL ( 10 mg/ kg/ day) 49 Table A6  Short Term Oral Exposure from Incidental Soil Ingestion Exposure Scenario Application Rate Application Rate Units % of Application Rate in Uppermost 1 cm of Soil ( fraction/ cm) Ingestion Rate ( IgR) mg/ day Body Weight ( kg) Average Daily Dose ( mg/ kg/ day) MOE Incidental Soil Ingestion 3.0lb ai/ acre 100% 100 15 1.47 x 10 8 680,000,000 Oral Dose = TTR ( ug/ cm2) x F( 1.0/ cm) x IgR( mg/ day) x ( 0.67 cm3/ g) x ( 1E 6 g/

g)

BW ( kg)

Where:

Dose = oral dose on day of application ( mg/ kg/ day)

AR = application rate ( lb ai/ A)

F = fraction or residue retained on uppermost 1 cm of soil IgR = ingestion rate of soil ( mg/ day)

CF2 = volume to weight unit conversion factor to convert the volume units ( cm3) to weight units for the soil residue value ( 0.67 cm3/ g soil)

CF3 = weight unit conversion factor to convert the

g of residues on the soil to grams to provide units of mg/ day ( 1E 6 g/

g)

BW = body weight ( kg)

Assumptions:

F  The fraction or residue retained on uppermost 1 cm of soil is 100 percent based on soil incorporation into top 1 cm of soil after application ( 1.0/ cm)

IgR  The ingestion rate of soil is 100 mg/ day Endpoint of Concern = Short Term Incidental Oral NOAEL ( 10 mg/ kg/ day) 50 Table A8: Cancer Risks For Trifluralin Residential Postapplication Risk Assessment Scenario TC cm2/ hr Hours of Exposure Days of Exposure TTR/ DFR ug/ cm2 Absorbed Dose ( mg/ kg/ day) LADD Cancer Residential Turfa  adults ( 2 days of exposure using TTR at day 0) 7,300 2 2 0.0033 2.06E 05 8.08E 08 4.7E 10 Golf Course Turfa  adults ( 2 days of exposure using TTR at day 0) 500 4 2 0.0033 2.83E 06 1.11E 08 6.4E 11 Vegetable gardensa  adults ( 2 days of exposure using DFR at day 0) 1,000 0.67 2 0.0044 1.26E 06 7.42E 08 4.3E 10 a Application rate for turf is the maximum label rate for turfgrass use patterns; application rate for vegetable gardens is maximum label rate for use on vegetable gardens.

b Turf transfer residue at day zero (

g/ cm2) = data from the trifluralin specific TTR study normalized to maximum application rate; Dislodgeable foliar residue for vegetable gardens at day zero (

g/ cm2) = data from the trifluralin specific TTR study normalized to maximum application rate;

c Average daily dermal dose ( ADD) ( mg/ kg/ day) = [ DFR/ TTR (

g/ cm2) * TC ( cm2/ hr) * mg/ 1,000

g * ET ( hrs/ day) * Dermal Absorption ( 3%)] / [ BW ( 70 kg)]

d Lifetime average daily dose ( LADD) = Average Daily Dermal Dose ( mg/ kg/ day) * ( number of days of exposure per year / 365 days/ year) * ( 50 years exposed / 70 years in a lifetime).

e Cancer Risk = LADD ( mg/ kg/ day) x Q1* ( mg/ kg/ day) where Q1* = 0.00579.