EPA Registration Division contact: Laura Nollen

Interregional Research Project Number 4 (IR-4)

Petition Number 9E7652

EPA has received a pesticide petition, PP # 9E7652, from IR-4, 500 College Road East, Suite 

201W, Princeton, NJ 08540, proposing, pursuant to section 408(d) of the Federal Food, Drug, 

and Cosmetic Act (FFDCA), 21 U.S.C. 346a(d), to amend 40 CFR part 180.442 by establishing a 

tolerance for residues of bifenthrin, (2-methyl [1,1′-biphenyl]-3-yl) methyl-3-(2-chloro-3,3,3,-

trifluoro-1-propenyl)-2,2-dimethylcyclopropanecarboxylate), in or on tea at 25 ppm (import 

tolerance); and tolerances with regional registrations in or on grass, forage at 2.5 ppm; and grass, 

hay at 4.5 ppm. EPA has determined that the petition contains data or information regarding the 

elements set forth in section 408(d)(2) of the FFDCA; however, EPA has not fully evaluated the 

sufficiency of the submitted data at this time or whether the data supports granting of the 

petition. Additional data may be needed before EPA rules on the petition.

A. Residue Chemistry 

 

1. Plant metabolism. The metabolism of bifenthrin in plants is adequately

understood. Studies have been conducted to delineate the metabolism of radiolabelled bifenthrin in 

various crops all showing similar results. The residue of concern is the parent compound only.

2. Analytical method. There is a practical analytical method for detecting and 

measuring levels of bifenthrin in or on food with a limit of detection that allows monitoring of food 

with residues at or above the levels set in these tolerances (Gas Chromatography with Electron 

Capture Detection (GC/ECD).

3. Magnitude of residues. Field residue trials meeting EPA study requirements have 

been conducted at the maximum label rate for the crops blueberries and celery. Results from the 

studies demonstrate that the highest bifenthrin residues found will not exceed the proposed 

tolerances for Tea at 25 ppm, Grass, forage at 2.5 ppm, and Grass, hay at 4.5 ppm when 

bifenthrin is applied following the proposed use directions.

B. Toxicological Profile

1. Acute toxicity. For the purposes of assessing acute dietary risk, FMC has used 

the results of the 2003 EPA completed risk assessment for bifenthrin. This acute dietary endpoint 

used to determine acute dietary risks to the general population including infants and children is from 

the acute neurotoxicity study in rats, (LOAEL) = 70.3 mg -/kg/day, NOAEL = 32.8 mg -/kg/day, 

UF = 1000, Acute RfD = 0.033 mg/kg/day.
2. Genotoxicty. The mouse lymphoma mutagenesis assay gave a weak positive 

result; however, the weight of the evidence from short-term mutagenicity tests indicate that 

bifenthrin is not mutagenic.

3. Reproductive and developmental toxicity. i. Rat reproduction study. Parental 

toxicity occurred as decreased body weight at 5.0 mg/kg/day with a no observed adverse effect 

level (NOAEL) of 3.0 mg/kg/day. There were no developmental (pup) or reproductive effects up 

to 5.0 mg/kg/day (highest dose tested).

ii. Postnatal Sensitivity. Based on the absence of pup toxicity up to dose levels, which produced 

toxicity in the parental animals, there was no evidence of special postnatal sensitivity to infants 

and children in the rat reproduction study. In a developmental neurotoxicity study, pups were 

not more sensitive than the dams. The NOAELs for maternal and developmental neurotoxicity

were both 50 ppm.

4. Subchronic toxicity. The results of the 21-day dermal toxicity study in rats is used 

for short-term (1-30 days), intermediate-term (1-6 months) and long-term (> 6 months) dermal risk 

calculations. The 21-day dermal toxicity study NOAEL for systemic toxicity is 47 mg ai/kg/day

based on observations of clinical signs (exaggerated hindlimb flexion and staggered gait).

5. Chronic toxicity. The reference dose (RfD) has been established at 0.004 

mg/kg/day. This RfD is based on a one-year oral study in dogs with a LOAEL of 2.7 mg /kg/day 

and a NOAEL of 1.3 mg /kg/day, UF = 300 based on observations of increased incidence of 

tremors in both sexes. 

ii. Bifenthrin is classified as a Group C chemical (possible human carcinogen); No Q1* has been 

derived.

6. Animal metabolism. The metabolism of bifenthrin in animals is adequately 

understood. Metabolism studies in rats with single doses demonstrated that about 90% of the parent 

compound and its hydroxylated metabolites are excreted.

7. Metabolite toxicology. The Agency has previously determined that the 

metabolites of bifenthrin are not of toxicological concern and need not be included in the tolerance 

expression.

8. Endocrine disruption. No special studies investigating potential estrogenic or 

other endocrine effects of bifenthrin have been conducted. However, no evidence of such effects 

was reported in the standard battery of required toxicology studies, which have been completed and 

found acceptable. Based on these studies, there is no evidence to suggest that bifenthrin has an 

adverse effect on the endocrine system..

C. Aggregate Exposure
1. Dietary exposure. Tolerances have been established for the residues of 

bifenthrin, in or on a variety of raw agricultural commodities. Tolerances, in support of 

registrations, currently exist for residues of bifenthrin on the following crops: hops, strawberries, 

corn (grain, forage and fodder), sweet corn, eggplant, cottonseed, artichokes, peppers (bell and 

non-bell), lettuce (head), grapes, spinach, cabbage, rapeseed, tomatoes, Food Handling 

Establishments, banana (import), pears, okra, cilantro, mayhaw, peanut, and soybeans. Also for 

the crop groups: vegetables, cucurbit, group 9, fruit, citrus, group 10 and nuts, tree, group 14, 

fruiting vegetables, group 8 and the subgroups: vegetable, legume, edible podded, subgroup 6A, 

pea and bean, succulent shelled, subgroup 6B, caneberry subgroup 13A, and brassica, head and 

stem, subgroup 5A, herb subgroup 19A, leaf petioles subgroup 4B, vegetables tuberous and 

corm, subgroup 1C, pea and bean, dried shelled, except soybeans, subgroup 6C, root crops, 

subgroup 1B, bushberries, subgroup 13B. Also, for the livestock commodities of cattle, goats, 

hogs, horses, sheep, poultry, eggs, and milk. For the purposes of assessing the potential dietary

exposure for these existing and pending tolerances, EPA conducted an exposure estimate using 

Dietary Exposure Evaluation Model – Food Commodity Intake Database TM (DEEM-FCIDTM) 

Version 2.14, results from field trials and processing studies, monitoring data, consumption data 

from the 1989-1992, USDA Continuing Surveys of Food Intakes by Individuals (CSFII), and 

information on the percentages of the crops treated (where available) with bifenthrin were 

utilized.

i. Food. a. Acute Dietary Exposure risk assessments are performed for a food-use 

pesticide if a toxicological study has indicated the possibility of an effect of concern occurring as a 

result of a 1-day or single exposure. For the purposes of assessing acute dietary risk, FMC has used 

the results of the 2003 EPA completed risk assessment for bifenthrin. This acute dietary endpoint 

used to determine acute dietary risks to the general population including infants and children is from 

the acute neurotoxicity study in rats, LOAEL= 70.3 mg/kg/day, NOAEL = 32.8 mg /kg/day, UF = 

100, Acute RfD = 0.328 mg/kg/day. Assumptions of tolerance-level residues and 100 percent crop 

treated were incorporated into a Tier I analysis. The 95

th percentile of exposure for the general U.S. 

Population is estimated to be 0.0127 mg/kg/day (3.88% aPAD). The 95

th percentile of exposure for 

infants <1 year old (most highly exposed population subgroup) is estimated to be 0.0256 mg/kg/day 

(7.80% aPAD). The 95

th percentile of exposure to children 3-5 years old is estimated to be 0.0152

mg/kg/day (4.64% aPAD). Based on the conservatism used in the analyses, actual dietary exposure 

will be less than that presented here. FMC concludes that based on adequate % aPAD for all 

population subgroups there is reasonable certainty that no harm will result from the proposed 

additional uses of bifenthrin.

b. Chronic Exposure. The reference dose (RfD) has been established at 0.013 mg/kg/day. This 

RfD is based on a one-year oral study in dogs with a LOAEL of 2.7 mg /kg/day and a NOAEL of 

1.3 mg /kg/day, UF = 100 based on observations of increased incidence of tremors in both sexes. 

The Tier I chronic exposures for the general U.S. Population are estimated to be 0.0047

mg/kg/day and utilize 34.9% of the cPAD. The chronic exposures for all infants <1 year old

(most highly exposed population subgroup) is estimated to be 0.0118 mg/kg/day and utilizes 

90.6% of the cPAD. Chronic dietary exposure estimates for children 1-2 years old is estimated 

to be 0.0096 mg/kg/day and utilizes 73.3% of the cPAD. Therefore, FMC concludes with 
reasonable certainty that no harm will result from the proposed additional uses of bifenthrin.

ii. Drinking water. US EPA’s draft SOP for Incorporating Estimates of Drinking 

Water Exposure into Aggregate Risk Assessments was used to perform a drinking water analysis. 

This SOP utilizes a variety of tools to conduct drinking water assessment. These tools include water 

models such as FQPA Index Reservoir Screening Tool (FIRST), PRZM/EXAMS, SCIGROW and 

monitoring data. If monitoring data are not available then the models are used to predict potential 

residues in surface water. A comparison of the calculated Drinking Water Level of Concern 

(DWLOC) value to the Estimated Environmental Concentration (EEC) is made. If the DWLOC

exceeds the EEC value then there is reasonable certainty that no harm will result from the short- or 

intermediate-term aggregate exposure. In the case of bifenthrin, monitoring data do not exist, so the 

FIRST model was used to estimate a surface water residue and SCIGROW for the groundwater. 

Based on the analyses the acute aggregate exposures to bifenthrin residues, the DWLOC for all 

seasons for the general US population was 11 ppm (11,000 ppb) while the modeled EEC, was 0.1 

and 0.006 ppb for surface water and ground water respectively. For children (1-6 year old), the 

DWLOCs was 2.3 ppm (2300 ppb) while the modeled EEC was the same as that for the whole US 

population. For the chronic aggregate exposures to bifenthrin residues, the DWLOC for all 

seasons for the US population was 291 ppb while the modeled EEC, was 0.1 and 0.006 ppb for 

surface water and ground water respectively. For children (1-6 year old), the DWLOCs was 26 ppb 

while the modeled EEC was the same as that for the whole US population. Since, the calculated 

DWLOC values for all population subgroups exceeded the modeled EEC for surface water and 

ground water residues, there is reasonable certainty that no harm will result from aggregate 

exposures to bifenthrin residues.

2. Non-dietary exposure. The aggregate residential exposure analyses were based 

on conservative screening-level assumptions. The residential risk assessments resulted in 

acceptable MOEs and a clear indication of reasonable certainty of no harm. The short-term 

analyses, all of the route- and product-specific MOEs were greater than 100 and the aggregate 

MOEs were greater than 100 for all population subgroups. Based on the above information, 

FMC concludes that bifenthrin does not pose a risk due to short- and intermediate-term aggregate 

exposure.

D. Cumulative Effects

To our knowledge there are currently no available data or other reliable information 

indicating that any toxic effects produced by bifenthrin would be cumulative with those of other 

chemical compounds; thus only the potential risks of bifenthrin have been considered in this 

assessment of its aggregate exposure.

E. Safety Determination

1. U.S. population. Using the conservative Tier 1 exposure assessment analyses the 

estimated chronic exposure to the U.S. Population is 0.0047 mg/kg/day and utilizes 35.9% of the 

cPAD. In addition, the chronic exposure estimates for all population subgroups (including infants 

and children) are well below the cPAD of 0.013 mg/kg/day. The acute dietary exposure analyses at 

the 95

th percentile for the general U.S. Population is 0.0127 and utilizes 3.88% of the aPAD. In 
addition, the acute exposure estimates for population subgroups of concern (infants and children) 

indicate that the maximum %aPAD or %cPAD utilized is 7.80% (aPAD) and 90.6% (cPAD) . 

Based on this information FMC concludes that there is reasonable certainty that no harm will result 

from acute and chronic exposure to bifenthrin.

2. Infants and children. i. General. In assessing the potential for additional 

sensitivity of infants and children to residues of bifenthrin, FMC considered data from 

developmental toxicity studies in the rat and rabbit, a developmental neurotoxicity study, and a 

two-generation reproduction study in the rat. The developmental toxicity studies are designed to 

evaluate adverse effects on the developing organism resulting from pesticide exposure during 

prenatal development to one or both parents. Reproduction studies provide information relating 

to effects from exposure to the systemic toxicity. FFDCA Section 408 provides that the EPA 

may apply an additional margin of safety for infants and children in the case of threshold effects 

to account for prenatal and postnatal toxicity and completeness of the database. ii. 

Developmental toxicity studies. In the rabbit developmental study, there were no developmental 

effects observed in the fetuses exposed to bifenthrin. The maternal NOAEL was 2.67 mg/kg/day 

based on head and forelimb twitching at the LOAEL of 4 mg/kg/day. In the rat developmental 

study, the maternal NOAEL was 7.4 mg/kg/day, based on treatment-related clinical signs and 

reductions in body weights, adjusted maternal body weights, and corresponding reductions in 

food consumption noted among dams receiving the LOAEL of 16.3 mg/kg/day. The 

developmental NOAEL was greater than 16.3 mg/kg/day based on lack of any adverse fetal 

effects at levels up to and including 16.3 mg/kg/day. iii. Developmental neurotoxicity study. In

a rat developmental neurotoxicity study, pups were not more sensitive than the dams. The 

NOAEL for maternal toxicity was 50 ppm, based on tremors at the LOEL of 100 ppm. The 

NOAEL for developmental neurotoxicity was also 50 ppm. iv. Reproductive toxicity study. In 

the rat reproduction study, parental toxicity occurred as decreased body weight at 5.0 mg/kg/day

with a NOAEL of 3.0 mg/kg/day. There were no developmental (pup) or reproductive effects up 

to 5.0 mg/kg/day (highest dose tested). v. Conclusion. Based on the absence of fetal effects and 

pup toxicity in any of the referenced studies, FMC concludes that reliable data support use of the 

standard 100-fold uncertainty factor, and that an additional uncertainty factor is not needed to 

protect the safety of infants and children. As previously stated, aggregate exposure assessments 

utilized no more than 45.5% of the aPAD or cPAD for either the entire U.S. Population or any of 

the population subgroups including infants and children. Therefore, it may be concluded that 

there is reasonable certainty that no harm will result to infants and children from aggregate 

exposure to bifenthrin residues.

F. International Tolerances

There are tolerances/MRL’s established for tea in other countries as follows: Japan 

25.0 ppm, China 5.0 ppm, India 5.0 ppm, Taiwan 2.0 ppm, European Union 5.0 ppm.