UNITED STATES ENVIRONMENTAL PROTECTION AGENCY WASHINGTON D. C., 20460 OFFICE OF PREVENTION, PESTICIDES AND TOXIC SUBSTANCES PC Code 128825 DP Barcode D311012 MEMORANDUM DATE: February 7, 2006 SUBJECT: Tier I Estimated Environmental Concentrations of Bifenthrin for the Use in the Human Health Risk Assessment.

TO: Shaja Brothers, Risk Manager Reviewer Sidney Jackson, Risk Manager Reviewer BeWanda Alexander, Risk Manager Reviewer Daniel Rosenblatt, Risk Manager # 5 George LaRocca, Risk Manager # 13 Registration Division ( 7505C)

AND: Karen Whitby, Branch Chief Registration Action Branch I Health Effects Division ( 7509C)

FROM: José Luis Meléndez, Chemist ERBV, Environmental Fate and Effects Division ( 7507C)

THROUGH: Jean Holmes, DVM, Acting Chief Environmental Risk Branch V Environmental Fate and Effects Division ( 7507C)

This memo presents the Tier I Estimated Surface Drinking Water Concentrations and Estimated Ground Water Concentrations ( EDWCs) for Bifenthrin, calculated using the Tier I aquatic models FIRST and SCI GROW, respectively, for use in the human health risk assessment.

The Estimated Drinking Water Concentrations ( EDWCs) for bifenthrin were calculated based on a maximum application rate of 0.5 lb a. i./ A/ season. The acute drinking water concentration in surface water is 0.0140 ppb of bifenthrin, based on applications of the chemical to lettuce. The cancer/ chronic drinking water concentration is 0.0140 ppb ( based on applications of lettuce, highest application rate). The SCI GROW generated EDWC is 0.00300 ppb of bifenthrin, which is recommended for use, both for acute and chronic exposures. Because of the very low solubility of bifenthrin, the EDWCs did not exceed 0.0140 ppb ( the solubility of bifenthrin). Table 1 provides a summary of the Tier I modeled drinking water concentrations. Should there be a need for additional refinements, the EFED can perform a Tier II aquatic assessment, for surface waters.

EXECUTIVE SUMMARY Bifenthrin ( chemical name 2 methylbiphenyl 3 ylmethyl ( Z)( 1RS, 3RS) 3( 2 chloro 3,3,3 trifluoroprop 1 enyl) 2,2 dimethylcyclopropanecarboxylate, CAS# 82657 04 03, PC code 128825) is a synthetic pyrethroid insecticide. Its structure has three rings, two phenyl rings attached to each other by a single bond, and a cyclopropyl ring. The chemistry of bifenthrin may be dictated by its ester moiety; however, laboratory studies show that it is relatively stable. The molecule has some chiral centers, and a double bond that brings isomer possibilities.

Bifenthrin is a neural toxic insecticide acting through direct contact and ingestion, having a slight repellent effect. The primary biological effects of bifenthrin and other pyrethroids on insects and vertebrates reflect an inhibition of the correct firing of neurotransmitter deliver signals from one cell to another via nerve membrane inhibition of the voltage gated Ca2+ channels coupled with a stimulatory effect on the voltage gated Na+ channels ( sodium ion channels). All pyrethroids act as axonic poisons, affecting both the peripheral and central nervous systems, and share similar modes of action. Pyrethroids, including bifenthrin, stimulate repetitive action in the nervous system by binding to voltage gated sodium channels, prolonging the sodium ion permeability during the excitatory phase of the action potential. This action leads to spontaneous depolarizations, augmented neurotransmitter secretion rate and neuromuscular block, which ultimately results in paralysis of the insect.

This is a Tier I screening assessment using Tier 1 aquatic models SCI GROW and FIRST, and maximum application rates for bifenthrin, with minimum application intervals. It was found that the worse case scenario was lettuce for bifenthrin, with the highest application rate, and the highest PCA. There are no major degradates for bifenthrin; therefore, no degradates were modeled in this assessment. The major uncertainty with respect to this assessment appears to be the problem with the extremely low solubility of bifenthrin. The hydrolysis, aqueous photolysis and batch equilibrium studies were performed in the presence of unusually high concentrations of acetonitrile.

The proposed uses involved in this action are the following IR4 tolerance petitions: leafy brassica greens, tuberous and corm vegetables, dried shelled peas and beans, cilantro and okra, and an application to amend the label to include tobacco ( refer to highlighted section of Table 2).

Table 1. Maximum Tier I Estimated Drinking Water Concentrations ( EDWCs) for drinking water risk assessment based on aerial application of bifenthrin on lettuce.

DRINKING WATER SOURCE ( MODEL USED) USE ( rate modeled) MAXIMUM ESTIMATED DRINKING WATER CONCENTRATION ( EDWC) ( ppb)

Groundwater ( SCI GROW) Lettuce ( 0.5 lb. a. i./ A/ season) Acute and Chronic 0.00300 Lettuce ( 0.5 lb. a. i./ A/ season) Acute 0.0140 Surface water ( FIRST)

Lettuce ( 0.5 lb. a. i./ A/ season) Chronic 0.0140 PROBLEM FORMULATION This is a Tier I drinking water assessment that uses modeling and available monitoring data to estimate the groundwater and surface water concentrations in drinking water source water ( pretreatment resulting from pesticide use on sites that are highly vulnerable. This initial tier screens out chemicals with low potential risk and allows OPP to focus resources on more refined risk assessments for chemicals which potentially present more significant risks. This drinking water assessment will report potential exposure concentrations for the human health dietary risk assessment and provide a clear and transparent description of how those concentrations were determined.

ANALYSIS Use Characterization Table 2 is a summary of all agricultural use patterns for bifenthrin. The highlighted uses are those proposed new ones. The use information was obtained from the current label for Capture 2EC Insecticide/ Miticide and the proposed labels for the same product.

Table 2. Summary use information for bifenthrin, based on Capture 2EC Insecticide/ Miticide label ( EPA Reg. No. 279 3069)

USE SINGLE APP. RATE ( lbs. a. i./ A) NUMBER OF APPS. SEASONAL APP. RATE ( lbs. a. i./ A) INTERVAL BETWEEN APPS. ( days) APP. METHOD INCORPORATION DEPTH ( inches) PHI Cotton 0.1 5 0.5 3 Ground or aerial 0 14 Corn 0.1 3 0.3 As necessary Ground or aerial 0 30 Sweet corn 0.1 2 0.2 As necessary Ground or aerial 0 1 Succulent peas and beans 0.1 2 0.2 Not specified Ground or aerial 0 3 Brassicas 0.1 5 0.5 7 Ground or aerial 0 7 Canola, Crambe, Rapeseed 0.04 2 0.08 14 Ground or aerial 0 35 Cucurbits 0.1 3 0.3 7 Ground or aerial 0 3 Eggplant 0.1 2 0.2 7 Ground or aerial 0 7 USE SINGLE APP. RATE ( lbs. a. i./ A) NUMBER OF APPS. SEASONAL APP. RATE ( lbs. a. i./ A) INTERVAL BETWEEN APPS. ( days) APP. METHOD INCORPORATION DEPTH ( inches) PHI Lettuce, head 0.1 5 0.5 7 Ground or aerial 0 7 Caneberries 0.1 2 0.2 One prebloom and one postbloom Ground or aerial 0 3 Artichoke 0.1 Not specified 15 Ground or aerial 0 5 Peppers 0.1 2 0.2 7 Ground or aerial 0 7 Hops 0.1 3 0.3 21 Ground or aerial 0 14 Pears 0.2 3 0.5 30 Ground or aerial 0 14 Citrus 0.25 2 0.5 Early and late season Ground 0 1 Tomatoes 0.08 4 0.32 10 Ground 0 1 Spinach 0.1 4 0.4 7 Ground or aerial 0 40 Grapes 0.1 1 0.1 N/ A Ground or aerial 0 30 Leafy Brassica Greens 0.1 4 0.4 7 Ground or aerial 0 7 Tuberous and corm vegetables 0.3 in furrow at planting and 0.1 foliar 3 0.5 21 Foliar treatment not specified 0 21 Dried shelled peas 0.1 2 0.2 Not specified Ground or aerial 0 14 Dried shelled beans 0.1 3 0.3 Not specified Ground or aerial 0 14 Tobacco 0.1 at transplant, and 0.05 foliar Not specified 0 N/ A Cilantro ( coriander) 0.1 5 0.5 7 Ground or aerial 0 3 USE SINGLE APP. RATE ( lbs. a. i./ A) NUMBER OF APPS. SEASONAL APP. RATE ( lbs. a. i./ A) INTERVAL BETWEEN APPS. ( days) APP. METHOD INCORPORATION DEPTH ( inches) PHI Okra 0.1 2 0.2 7 Ground or aerial 0 7 Capture 2EC Insecticide/ Miticide is an emulsifiable concentrate. It may be applied by ground, air or ULV methods. The label imposes certain restrictions ( buffer zones) to protect bodies of water, accordingly: 25 ft for ground applications, 150 ft for aerial applications and 450 ft for ULV applications. There is also a granular formulation for use on corn at plant ( granules are incorporated into the top one inch of the soil) or foliar ( as granules).

The use pattern selected for drinking water modeling was lettuce. It has the maximum application rate ( maximum number of applications) with the maximum PCA.

Fate and Transport Characterization Table 3 provides a summary of the major physical, chemical, environmental fate and transport properties of bifenthrin.

Table 3. Summary of physical/ chemical and environmental fate and transport properties of bifenthrin.

PARAMETER VALUE( S) ( units) SOURCE COMMENT Chemical Name 2 methylbiphenyl 3 ylmethyl ( Z) ( 1RS, 3RS) 3( 2 chloro 3,3,3 trifluoroprop 1 enyl) 2,2 dimethylcyclopropanecarboxylate   IUPAC name Molecular Weight 422.87 g/ mol

Solubility ( 22 oC) 1.4x10 5 mg/ L Laskowski 2002

Vapor Pressure ( 25 oC) 1.8 x 10 7 mmHg Tomlin, C. editor 1994.

Henry's Law constant 7.2 x 10 3 Atm m3/ mol   Estimated from vapor pressure and water solubility.

pKa ( 20 oC) NA

Octanol Water Partition Coefficient ( KOW) 3.00x106 Laskowski 2002

Hydrolysis Half life [ pH 5, 7, 9; ( 25 oC)] Stable ACC: 251728, MRID: 132539. Stable at all pHs.

Aqueous Photolysis Half life Relatively stable ACC: 264642. Samples were not buffered and contained 30% acetonitrile as cosolvent. Natural sunlight was used. PARAMETER VALUE( S) ( units) SOURCE COMMENT Soil Photolysis Half life t1/ 2 = 147 days and 98.5 days for cyclopropyl and phenyl labels, respectively.

Corrected half lives are 147 days and 106 days ( no significant degradation in dark control for cyclopropyl label) ACC: 264642. Natural sunlight in New Jersey, silt loam soil used.

Aerobic Soil Metabolism Half life ( days) Soil Cyclopropyl Phenyl SL 132 115 SiL 250 156 SiCL 129 96.8 MRID: 141202, 254411, 532540, 251728, 254401, 073225, 073174, 251278.

Anaerobic Soil Metabolism Stable MRID: 264642

Anaerobic Aquatic Metabolism Half life NA

Aerobic Aquatic Metabolism Half life NA

Organic Carbon Partition Coefficient ( KOC) 131,000, 239,000, 302,000, 275,000 mL/ gOC for the S, SL, SiL and SiCL, respectively MRID: 254401.

Soil Partition Coefficient ( Kd) 992, 4192, 5430, 3690 mL/ g for the S, SL, SiL and SiCL, respectively MRID: 254401.

Terrestrial Field Dissipation Half life Site Half lives Champaign, IL 192 days Fresco, CA 345 Madera, CA 155 Imperial County, CA 228 Tifton, GA 122 Marion, AR 78 Fresno, CA 193 Champaign, IL 118 Champaign, IL 126 Marion, AR 121 San Joaquin, Fresno DT50 35 MRID: 264642, 42339203, 42339201, 42334167, 41673103, 41673101, 41671302.

Aquatic Field Dissipation Half life Dallas County, Orville, Alabama Residues of bifenthrin were found in the sediments of the pond during the 12 months period after application; there was no discernable pattern of decay. MRID: 40981803, 40981805, 40981808, 40981812, 40981814, 40981815, 40981816, 40981817, 40981818, 40981819.

Bifenthrin is a synthetic pyrethroid. Its structure has three rings, two phenyl rings attached to each other by a single bond, and a cyclopropyl ring. The molecule has some chiral centers, and a double bond that bring isomer possibilities. According to the Capture 2EC Insecticide/ Miticide label, a minimum of 97% consists of cis isomers ( see figure in the Appendix).

Studies conducted on bifenthrin indicate that it is persistent under most conditions and bioaccumulative. It appears that a major route of degradation is aerobic metabolism. Bifenthrin is relatively stable to hydrolysis at all pH's. It is relatively stable to aqueous and soil photolysis and degrades slowly under both aerobic and anaerobic soil metabolism conditions ( half life range 97 250 days in 3 soils, and relatively stable, respectively). Bifenthrin is relatively immobile in four soils tested ( KOC range 131,000 to 275,000). Field studies show a pattern consistent with the laboratory studies, with relatively high persistence ( half lives ranging from 78 to 345 days in 10 field trials) and low mobility of the chemical in soil. In aquatic environments, it appears that residues of bifenthrin persist in pond sediments ( and in the water column) for extended periods ( at least 12 months of monitoring). No major metabolites were observed (> 10% of the applied) in any of the laboratory studies. The high octanol/ water partition coefficient suggests that bifenthrin will bioconcentrate in aquatic organisms. Bifenthrin was highly bioaccumulative in fish with slow depuration. The very low water solubility and hydrophobic nature of bifenthrin leads to strong soil adsorption and a tendency to partition to sediment in aquatic systems.

Bifenthrin has a vapor pressure of 1.8x10  7 mmHg, water solubility of 0.0140 ppb, and an estimated Henry's law constant of 7.2x10 3 atm m3/ mol. Based upon its Henry's law constant and vapor pressure, bifenthrin is expected to have a moderate to low potential for volatilization from soil and water surfaces. Bifenthrin's potential for volatilization is reduced significantly because it adsorbs strongly to soils, suspended solids, sediment and organic matter in the water column. A laboratory volatility study showed a maximum volatility at 40 ° C of 5.07x10 4 µ g/ cm2 hr ( average at 14 days), a relatively low value.

Bifenthrin can be spray applied by ground or aerially on agricultural settings. A buffer region is label recommended; however, under a high end drift scenario, substantial amounts of the chemical can reach adjacent bodies of water via spray drift. Furthermore, substantial fractions of the applied bifenthrin should be available for runoff for several weeks to several months. Due to its low solubility ( 0.014 ppb) and high level of binding it appears that bifenthrin would remain bound to the soils during run off events, and that the chemical would reach surface waters if the run off event is accompanied by erosion. Once bifenthrin reaches surface water, the fate of the chemical is of concern since bifenthrin is very toxic to fish and aquatic invertebrates. The Agency believes that bifenthrin, due to its high level of binding, would remain bound to the sediments and would dissolve only very slowly into the water column. Organisms that live near the sediments may be particularly at risk. The sediments may serve as reservoirs of bifenthrin, where it will persist.

A supplemental aquatic field dissipation study employing a site in Alabama showed that bifenthrin in aquatic environments ( a pond) persists for extended periods of time. It was found throughout the 12 months of monitoring after the last pesticide application, that residues were observed in the water column and in the sediment, with no clear pattern of decline.

On the other hand, bifenthrin is not likely to reach subsurface soil environments or ground waters. Various terrestrial field dissipation studies confirm that bifenthrin remains mostly in the upper soil level.

Due to the slow dissipation pathways for bifenthrin, no transformation products were observed to be higher than 10% of the applied in any of the laboratory studies.

The major uncertainties with respect to the environmental fate studies on bifenthrin are related to the extremely low solubility of bifenthrin and the problems found when the registrant performed these studies. The hydrolysis, aqueous photolysis, and batch equilibrium studies were performed in unusually high concentrations of acetonitrile. The cosolvent may have had an effect on the results. Furthermore, the batch equilibrium studies were performed at a single concentration ( a Freundlich isotherm was not developed). The EFED had to rely on a single point result.

Table 4 is a summary of degradate formation for bifenthrin. Note that, because bifenthrin is relatively stable or dissipates very slowly in all studies, no major transformation products (  10% of the applied) were observed. Table 4. Summary of degradate formation from degradation of bifenthrin.

DEGRADATE and MAXIMUM CONCENTRATION STUDY TYPE SOURCE DEG1 (% applied) DEG2 (% applied) DEG3 (% applied)

Hydrolysis ACC: 251728, MRID: 132539. NO hydrolysis product exceeded 10% of the applied during the study.

Aqueous Photolysis ACC: 264642. NO aqueous photolysis product exceeded 10% of the applied during the study.

Soil Photolysis ACC: 264642.. NO soil photolysis product exceeded 10% of the applied during the study.

Aerobic Soil Metabolism MRID: 141202, 254411, 532540, 251728, 254401, 073225, 073174, 251278. NO aerobic soil metabolism product exceeded 10% of the applied during the study.

Anaerobic Soil Metabolism . MRID: 264642 NO anaerobic soil metabolism product exceeded 10% of the applied during the study.

Aerobic Aquatic Metabolism . NA

Anaerobic Aquatic Metabolism NA

Terrestrial Field Dissipation MRID: 40981803, 40981805, 40981808, 40981812, 40981814, 40981815, 40981816, 40981817, 40981818, 40981819. 4' OH Bifenthrin detected in certain studies.

No degradates were considered " major" (> 10% of applied in parent equivalents), nor were they flagged for further quantitation. There is uncertainty with respect to the aqueous photolysis study, which was conducted in the presence of 30% acetonitrile. Even though no substantial photolysis was observed, it is not known if the cosolvent may have affected the formation of transformation products.

Drinking Water Exposure Modeling Models SCI GROW ( Screening Concentration in Ground Water) is a regression model used as a screening tool for ground water used as drinking water. SCI GROW was developed by regressing the results of Prospective Ground Water studies against the Relative Index of Leaching Potential ( RILP). The RILP is a function of aerobic soil metabolism and the soil water partition coefficient. The output of SCI GROW represents the concentrations that might be expected in shallow unconfined aquifers under sandy soils, which is representative of the ground water most vulnerable to pesticide contamination likely to serve as a drinking water source. ( Ref. 2)

FIRST ( FQPA Index Reservoir Screening Tool) is a screening model designed by the Environmental Fate and Effects Division ( EFED, 2001a) of the Office of Pesticide Programs to estimate the concentrations found in drinking water from surface water sources for use in human health risk assessment. As such, it provides upper bound values on the concentrations that might be found in drinking water due to the use of a pesticide. FIRST is a single event model ( one runoff event), but can account for spray drift from multiple applications. Spray drift ( resulting in direct deposition of the pesticide into the reservoir) is assumed to be 16% of the applied active ingredient for aerial application, 6.3% for orchard air blast application, and 6.4% for other ground spray application. FIRST is hardwired to represent the Index Reservoir, a standard water body used by the Office of Pesticide Programs to assess drinking water exposure ( Office of Pesticide Programs, 2002). It is based on a real reservoir ( albeit not currently in active use as a drinking water supply), Shipman City Lake in Illinois, that is known to be vulnerable to pesticide contamination. The single runoff event moves a maximum of 8% of the applied pesticide into the reservoir. This amount can be reduced due to degradation on the field and the effects of binding to soil in the field. FIRST also uses a Percent Cropped Area ( PCA) factor to adjust for the area within the watershed that is planted to the modeled crop. The default agricultural PCA is 0.87. ( Ref. 3 and 4)

For volatile and semi volatile compounds, Tier I modeling will tend to over estimate EDWCs because there are no parameters in SCI GROW and FIRST that explicitly take into account volatility ( ie., no vapor pressure input). Therefore, in reality, more of the compound will be volatilizing than Tier I can account for. If drinking water levels of concern are exceeded for overestimated Tier I EDWCs, Tier II modeling will be able to refine these EDWCs by including volatility considerations.

Modeling Approach and Input Parameters Table 5 provides the input parameter values used for modeling of bifenthrin using SCI GROW. Table 6 provides the input parameter values used for modeling of bifenthrin using FIRST. As indicated earlier, no degradates were included in the modeling because none exceded 10% of the applied in the laboratory studies.

Table 5. SCI GROW ( v2.3) input parameter values for bifenthrin use on lettuce1.

PARAMETER ( units) VALUE( S) SOURCE COMMENT Maximum Application Rate ( lb a. i./ A) 0.1 Label.

Number of Applications per Year 5 Label. Represents most conservative scenario in which the total maximum rate per year is applied in one application.

Organic Carbon Partition Coefficient ( Koc; mL/ g) 257,000 MRID: 254401. Represents the median value of four values ranging from 131,000 to 302,000 mL/ g for the parent compound.

Aerobic Soil Metabolism Half life ( days) 130.5 MRID: 141202, 254411, 532540, 251728, 254401, 073225, 073174, 251278. Represents the median half life of six values available ( 132, 250, 129, 115, 156, 96.8 days).

1 Parameters are selected as per Guidance for Selecting Input Parameters in Modeling the Environmental Fate and Transport of Pesticides; Version I, February 28, 2002.

Table 6. FIRST ( v1.0) input parameter values for bifenthrin use on lettuce1.

PARAMETER ( units) VALUE( S) SOURCE COMMENT Application Rate ( lb a. i./ A) 0.1  Label.

Number of Applications 5 Label.

Interval between Applications ( days) 3 Label.

Percent Cropped Area ( decimal) 0.87   National default. PARAMETER ( units) VALUE( S) SOURCE COMMENT Soil Partition Coefficient ( Kd; ( mL/ g) or KOC ( mL/ gOC)) 275,000 MRID: 254401. Represents the lowest non sand KOC value among four values ranging from 131,000 to 302,000 mL/ g; the KOC model was utilized as per recommendation of the SAP..

Aerobic Soil Metabolism Half life ( days) 176.4 MRID: 141202, 254411, 532540, 251728, 254401, 073225, 073174, 251278. Represents the 90th percentile of the upper confidence bound on the mean of six half life values: 132, 250, 129, 115, 156, 96.8 days; mean = 146.5 days; std. dev.= 49.6 days Wetted in? No Label.

Depth of Incorporation ( inches) 0 Label.

Method of Application Aerial spray Label.

Solubility in Water @ 22 OC, unbuffered ( mg/ L or ppm) 0.000014 Laskowski 2002

Aerobic Aquatic Metabolism Half life ( days) 352.8 MRID: 141202, 254411, 532540, 251728, 254401, 073225, 073174, 251278. No aerobic aquatic metabolism data are available and the pesticide is hydrolytically stable, 2X the aerobic soil metabolism half life input value is used.

Hydrolysis Half life @ pH 7 ( days) 0 ACC: 251728, MRID: 132539 Stable.

Aquatic Photolysis Half life @ pH 7 ( days) 0 ACC: 264642

1 Parameters are selected as per Guidance for Selecting Input Parameters in Modeling the Environmental Fate and Transport of Pesticides; Version I, February 28, 2002 Modeling Results Table 7. Maximum Tier I Estimated Drinking Water Concentrations ( EDWCs) for drinking water risk assessment based on aerial application of bifenthrin.

DRINKING WATER SOURCE ( MODEL USED) USE ( rate modeled) MAXIMUM ESTIMATED DRINKING WATER CONCENTRATION ( EDWC) ( ppb)

Groundwater ( SCI GROW) Lettuce ( 0.5 lb a. i./ A/ season) Acute and Chronic 0.0140 Lettuce ( 0.5 lb a. i./ A/ season) Acute 0.0140 Surface water ( FIRST)

Lettuce ( 0.5 lb a. i./ A/ season) Chronic 0.00300 SCI GROW concentration ( ppb) represents the groundwater concentration that might be expected in shallow unconfined aquifers under sandy soils. Output is used for both acute and chronic endpoints.

FIRST concentrations ( ppb) represent untreated surface water concentrations. The peak day concentration ( over 30 years) is used for acute endpoints and the annual average concentration ( over 30 years) is used for chronic endpoints.

The estimated concentrations provided in this assessment are conservative estimates of concentrations in drinking water. If dietary risks require refinement, higher tiered cropspecific and location specific models and modeling scenarios can be utilized. Monitoring Data Monitoring data usually provide different kinds of information than modeling ( e. g., monitoring reflects current use pattern, underestimates frequency of occurrence, often misses peaks, inputs cannot be adjusted as modeled ones can, usually done for purposes other than characterizing exposure from a particular pesticide), and, consequently, tend to complement the modeling rather than refine it. In general, a useful interpretation of monitoring values requires in depth assessment of the data, which is beyond the scope of a Tier I assessment.

Drinking Water Treatment It is likely that primary treatment may reduce the levels of cypermethrin due to its tendency to bind. However, there is no information available at this time to determine the levels of reduction ( Ref. 7).

CONCLUSIONS The following can be concluded about bifenthrin:

C This is a Tier I level analysis, refinements may be available should they be needed. The acute levels of surface drinking waters was 0.0140 ppb, the chronic level of drinking waters was 0.0140 ppb of bifenthrin. The groundwater concentration of cypermethrin, suitable for acute and chronic is 0.000300 ppb. All the concentrations were limited by the solubility limit of bifenthrin. It was assumed that the maximum application rate was used on lettuce, with the minimum interval between applications. The major uncertainty is presence of acetonitrile in several of the laboratory experiments. Furthermore, the batch equilibrium constants were obtained at only one concentration ( no Freundlich isotherms).

C Despite the weaknesses of the data, this is considered a conservative ( screening level) analysis. APPENDIX SCI GROW and FIRST model output files.

RUN No. 1 FOR Bifenthrin ON Lettuce * INPUT VALUES *  RATE (#/ AC) No. APPS & SOIL SOLUBIL APPL TYPE % CROPPED INCORP ONE( MULT) INTERVAL Koc ( PPTr) (% DRIFT) AREA ( IN)  .100( .474) 5 7 275000.0 14.0 AERIAL( 16.0) 87.0 .0 FIELD AND RESERVOIR HALFLIFE VALUES ( DAYS)  METABOLIC DAYS UNTIL HYDROLYSIS PHOTOLYSIS METABOLIC COMBINED ( FIELD) RAIN/ RUNOFF ( RESERVOIR) ( RES. EFF) ( RESER.) ( RESER.)  176.40 2 N/ A .00 .00 352.80 352.80 UNTREATED WATER CONC ( NANOGRAMS/ LITER ( PPTr)) Ver 1.0 AUG 1, 2001  PEAK DAY ( ACUTE) ANNUAL AVERAGE ( CHRONIC) CONCENTRATION CONCENTRATION  14.000 14.000 SCIGROW VERSION 2.3 ENVIRONMENTAL FATE AND EFFECTS DIVISION OFFICE OF PESTICIDE PROGRAMS U. S. ENVIRONMENTAL PROTECTION AGENCY SCREENING MODEL FOR AQUATIC PESTICIDE EXPOSURE SciGrow version 2.3 chemical: Bifenthrin time is 1/ 18/ 2006 10: 23: 25  Application Number of Total Use Koc Soil Aerobic rate ( lb/ acre) applications ( lb/ acre/ yr) ( ml/ g) metabolism ( days)  0.100 5.0 0.500 2.57E+ 05 130.5  groundwater screening cond ( ppb) = 3.00E 03* * Estimated concentrations of chemicals with Koc values greater than 9995 ml/ g are beyond the scope of the regression data used in SCI GROW development. If there are concerns for such chemicals, a higher tier groundwater exposure assessment should be considered, regardless of the concentration returned by SCI GROW. ************************************************************************ Molecular structure of BIFENTHRIN.

************************************************************************ References: 1. Policy Establishing Current Versions of Exposure Models and Responsibility for Model Maintenance ( 11/ 06/ 2002) 2. SCIGROW: Users Manual ( 11/ 01/ 2001, revised 08/ 23/ 2002) 3. FIRST Users Manual ( 08/ 01/ 2001) 4. FIRST: A Screening Model to Estimate Pesticide Concentrations in Drinking Water ( 05/ 01/ 2001) 5. Guidance for Selecting Input Parameters in Modeling the Environmental Fate and Transport of Pesticides, Version II ( 02/ 28/ 2002) 6. Use of the Index Reservoir and Percent Crop Area in EFED Drinking Water Assessments ( 12/ 01/ 1999) 7. The Incorporation of Water Treatment Effects on Pesticide Removal and Transformations in Food Quality Protection Act ( FQPA) Drinking Water Assessments ( 10/ 25/ 2001) 8. Laskowski, D. A. 2002. Rev. Environ. Contam. Toxicol. 174: 49 170 9. Tomlin, C. editor. 1994. The Pesticide Manual 10th Edition. British Crop Protection Council and Royal Society of Chemistry, UK.


[Federal Register: April 23, 2009 (Volume 74, Number 77)]
[Notices]
[Page 18604-18605]
[DOCID:fr23ap09-76]

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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

Agency Information Collection Activity Seeking OMB Approval

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Notice.

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SUMMARY: The FAA invites public comments about our intention to request
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FOR FURTHER INFORMATION CONTACT: Carla Mauney at<EMAIL_ADDRESS>
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Federal Aviation Administration (FAA)

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