Document ID: EPA-HQ-OPP-2009-1008-0006
Agency: epa
Document Type: Supporting & Related Material
Title: 
Posted Date: 2012-09-14T04:00Z

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\* MERGEFORMAT
                 UNITED STATES ENVIRONMENTAL PROTECTION AGENCY
                            WASHINGTON, D.C.  20460
                                                                      OFFICE OF
                                                            CHEMICAL SAFETY AND
                                                           POLLUTION PREVENTION
MEMORANDUM

Date:	   May 25, 2012 

SUBJECT:	Bifenthrin.  Section 3 Registration for Grass Grown for Seed and Imported Tea; Section 18 Emergency Exemption for Apples, Nectarines, and Peaches.  Summary of Analytical Chemistry and Residue Data. 

            
PC Code:  128825
DP Barcode:  388604
Decision No.:  NA
Registration No.:  279-3313, 279-3108
Petition No.: 9E7652
Regulatory Action: New Use Registration
Risk Assessment Type: NA
Case No.: NA
TXR No.: NA
CAS No.: 82657-04-3
MRID No.: Summary Table Provided Below 
40 CFR: 180.442

FROM:	Peter Savoia, Chemist
		Risk Assessment Branch V/VII
		Health Effects Division (7509P)
		
THRU:	Michael S. Metzger, Branch Chief
		William H. Donovan, Ph.D., Chemist
		Risk Assessment Branch V/VII
		Health Effects Division (7509P)
		
TO:	Laura E. Nollen, Biologist
		Risk Integration, Minor Use & Emergency Response Branch 
		Registration Division (7505P)
		

MRID Summary Table
MRID No.
Study Type
Comments
47920801
860.1500 (Grass, seed crop)
47920801.der.doc
47920802
860.1500 (Tea)
47920802.der.doc
47920803
860.1500 (Tea)
47920803.der.doc
47920804-07 and -09
860.1500 (Tea)
None
47920808
860.1500 (Tea)
47920808.der.doc
47920810
860.1500 (Tea)
47920810.der.doc

The Memorandum was prepared by Versar and has been reviewed by the Health Effects Division (HED) and revised as needed for correctness, language and to reflect current Office of Pesticide Programs (OPP) policies.

Executive Summary

Bifenthrin, (2-methyl[1,1'-biphenyl]-3-yl) methyl-3-(2-chloro-3,3,3,-trifluoro-1-propenyl)-2,2-dimethylcyclopropanecarboxylate, is a broad-spectrum non-systemic insecticide/miticide.   Registered to FMC Corporation, this synthetic pyrethroid carries uses for foliar applications on a variety of field, fruit, and vegetable crops.  Permanent tolerances are established for residues of bifenthrin in/on a number of food commodities listed under 40 CFR §180.442(a)(1).  These tolerances range from 0.05 ppm on various crop and poultry commodities up to 70 ppm for grain, aspirated fractions.  A tolerance of 0.05 ppm is also listed under §180.442(a)(2) for bifenthrin in food/feed handling establishments.  In addition, time-limited tolerances for orchardgrass forage and hay were established under §180.442(b) following Section 18 emergency exemptions with a 12/31/12 expiration date.

In the current petition, the Interregional Research Project No. 4 (IR-4) requests Section 3 registration for the application of bifenthrin to grass grown for seed on behalf of the Agricultural Experiment Station of Oregon.  For this action (PP#9E7652), IR-4 has also included data to support the establishment of a permanent tolerance in/on imported tea which is being requested on behalf of the tea industry.  In a separate petition, Delaware, Maryland, New Jersey, North Carolina, Pennsylvania, Virginia, and West Virginia is requesting an emergency exemption for treating apples, nectarines, and peaches.  The establishment of permanent tolerances is therefore requested in/on grass forage, grass hay, and tea along with time limited emergency exemptions to be set for apples, nectarines, and peaches at the following limits:

            Apple	0.5 ppm
            Grass, forage	2.5 ppm
            Grass, hay 	4.5 ppm
            Nectarine	0.5 ppm
            Peach	0.5 ppm
            Tea, plucked leaves	25 ppm
            
The nature of bifenthrin residues in plants and livestock is understood based on the previously-submitted apple, corn, cotton, potato, hen, and goat metabolism studies.  Based upon these studies, the Metabolism Committee determined that only the parent compound would be the relevant residue of concern for tolerance enforcement and risk assessment (Metabolism Committee Meeting Minutes, M. T. Flood, 07/27/1993).  Further, the nature of the residues in rotational crops is adequately understood.  Based on a confined rotational crop study, HED has concluded that the residue of concern in rotational crops is the parent compound only.  For annual crops evaluated at a maximum seasonal use rate of 0.5 lb ai/A, the confined study and the available field rotational crop study on wheat support the current rotational crop restrictions on the labels.  Crops having bifenthrin tolerances may be replanted at any time, and all other crops may be replanted 30 days following the last application of bifenthrin.  No rotational crop tolerances are required.

Adequate Gas Chromatography/Electron-Capture Detection (GC/ECD) methods are available for enforcing tolerances of bifenthrin in plant and livestock commodities.  The MRM methods are also adequate for the enforcement of bifenthrin tolerances and no additional data are required.  Analytical standards for bifenthrin furnished by FMC Agricultural Products are currently available in the EPA National Pesticide Standards Repository (personal communication with Theresa Cole, 04/26/2012).  Samples from the current grass field trials were analyzed for residues of bifenthrin using FMC method PC-2132M, which is a modification to one of the current enforcement methods (P-2550 M).  The method reports the Limit of Detection (LOD) to be 0.01 ppm for grass forage and 0.03 ppm for grass hay.  It further notes the Limit of Quantitation (LOQ) to be 0.03 ppm in grass forage and 0.08 ppm in grass hay.  The method was adequately validated in conjunction with the analysis of samples from the field trials.  Similarly, the samples from the tea field trials in MRID No. 47920803 were analyzed for residues of bifenthrin using a GC/ECD method.  The method was successfully validated prior to analysis of the field samples.  The method LOD for bifenthrin in tea was reported to be 0.05 ppm and the LOQ was not provided.

The submitted residue data for grass grown for seed are adequate, and the trials conducted reflect the proposed treatment pattern which will be established for use to crops grown only in ID, OR and WA.  They were carried out following the EPA memo entitled "Additional Guidance on the Crop  -  `Grass Grown for Seed'" dated 9/30/2000 which requires the collection of forage and hay data.  In practice, the forage and hay commodities of grass are used as a livestock feedstuff commonly fed to cattle.  Based upon this assessment, HED concludes that the established bifenthrin livestock tolerances remain appropriate.

In support of tea, the petitioner provided nine (9) data submissions depicting residue levels for this imported Raw Agricultural Commodity (RAC).  The majority of these studies are incomplete failing to note experimental field parameters (application rates, PHIs, sample handling procedures), storage duration and conditions, raw data, and concurrent recoveries.  Due to the incompleteness of these submissions, Data Evaluation Records (DERs) could only be completed for four of the nine studies.  In all, only MRID No. 47920803 is considered to be scientifically acceptable though it was found to lack concurrent recovery information.  Residues in these fresh leaf and black tea samples were analyzed by Gas-Liquid Chromatography/Electron Capture Detection (GLC/ECD).  The method was successfully validated as shown by recoveries of fortified samples but no data from concurrent recovery samples were provided.  The application rate used in this study (0.060 kg ai/ha) is less than GAP application rate of 0.080 kg ai/ha.  

To support the establishment of a time limited emergency exemption for apples, nectarines, and peaches, adequate pear data are available for translation to the requested crops.  For pears, use of WP (EPA Reg. No. 279-3108) and EC (EPA Reg. No. 279-3069) formulations have been established.  The application pattern prescribes a seasonal rate of 0.5 lbs.ai/A (0.45 lbs ai/A post-bloom) made as multiple treatments at a 30-day Re-Treatment Interval (RTI) prior to a 14-day Pre-Harvest Interval (PHI).  This use pattern resulted in a 0.5 ppm tolerance (DP. Nos. D274839 & D280288, S. Levy, 08/15/2002).  Thus, this level may be translated to apples, nectarines, and peaches.

There are adequate storage stability data to validate the storage conditions and durations of RACs collected from the grass field trials.  These data indicate that residues decline by 35% in forage and 55% in hay, requiring the correction of residues from the grass field trial data.  For imported tea, no storage stability data were provided, however, the longest storage interval was only 67 days in the trials from India.  In addition to the storage stability data on grass, previously submitted data indicate that bifenthrin residues are stable when stored frozen for 12 months in corn flour, 36 months in lettuce, pecans and potatoes along with durations up to 49 months in apple (DP Nos. D274839 & D280288, S. J. Levy, 08/15/2002).    

Regulatory Recommendations and Residue Chemistry Deficiencies

Pending revision of Sections B and F, there are no residue chemistry deficiencies that would preclude granting a regional registration of bifenthrin for use on grass grown for seed and the establishment of a tolerance on imported tea.  There are also adequate data to support a time limited emergency exemption for apples, nectarines, and peaches.  Tolerances are established for residues of bifenthrin, including its metabolites and degradates, in or on the commodities listed below.  Compliance with the tolerance levels specified below is to be determined by measuring only bifenthrin, (2-methyl[1,1′-biphenyl]-3-yl)methyl (1R,3R)-rel-3-[(1Z)-2-chloro-3,3,3-trifluoro-1-propenyl]-2,2-dimethylcyclopropanecarboxylate in or on the commodity:

            (a) General. 
            Tea, dried 	30 ppm

            (b) Section 18 emergency exemptions. 
            Apple	0.5 ppm
            Nectarine	0.5 ppm
            Peach	0.5 ppm
            
            (c) Tolerances with regional registrations.
            Grass, forage	4.0 ppm
            Grass, hay	15 ppm

A new human health risk assessment which includes these new crop uses and the amended tolerance levels for the pertinent livestock commodities is forthcoming in a separate document.

860.1200  Directions for Use

An amended Section B is required for grass grown for seed by noting this use is restricted to ID, OR, and WA on product labels 279-3108 and 279-3313.  The grass crop group should be removed from the proposed product labels since the data provided only support the use of bifenthrin on grass grown for seed in the Pacific Northwest.  

Sufficient information was provided on the Good Agricultural Practices (GAP) followed for the cultivation of tea in India.  The data are adequate to establish a tolerance for bifenthrin on imported tea. 

Application directions for treating apples, nectarines, and peaches as an emergency exemption in the states of Delaware, Maryland, New Jersey, North Carolina, Pennsylvania, Virginia, and West Virginia must be provided.  Amended product labels for the 10% WP (EPA Reg. No. 279-3108) and 2 lb/gal EC (EPA Reg. No. 279-3069) formulations of bifenthrin are needed.

860.1550  Proposed Tolerances

The registrant is required to submit a revised Section F to amend all the proposed tolerances relevant to this petition and to reflect correct commodity definition as reflected in Table 10.

International Harmonization

There are no Maximum Residue Limits (MRLs) established by Codex, Canada, or Mexico for any of the proposed commodities in the current registration action (see Attachment 1).  However, Codex has proposed a 30 ppm MRL for Tea, Green and Black (black, fermented and dried).  In order to harmonize with the Codex MRL, a U.S. tolerance level of 30 ppm is recommended for tea, dried.  
 
Background

Bifenthrin is a broad-spectrum, non-systemic insecticide/miticide classified as a synthetic pyrethroid. Like many other insecticides, bifenthrin controls insects by paralyzing the central nervous system upon contact and ingestion.  Applications of bifenthrin are made at the labeled use rates when insect populations reach locally determined economic thresholds.  Follow-up treatments should be made as needed to control insect populations for the purposes of forming a comprehensive integrated pest management program.  Registered to FMC Corporation, permanent tolerances are established for residues of bifenthrin in/on several food commodities listed under 40 CFR §180.442(a)(1).  These tolerances range from 0.05 ppm on various crop and poultry commodities up to 70 ppm for grain, aspirated fractions.  A tolerance of 0.05 ppm is also listed under §180.442(a)(2) for bifenthrin in food/feed handling establishments.  In addition, time-limited tolerances for orchardgrass forage and hay were established under §180.442(b) following Section 18 emergency exemptions with a 12/31/12 expiration date.  The nomenclature and physiochemical properties of bifenthrin are presented below in Tables 1 and 2 for review.  

Table 1.		Bifenthrin Nomenclature.
Chemical structure
                                       
                                       
Common name
Bifenthrin
Company experimental name
FMC 54800
IUPAC name
2-methylbiphenyl-3-ylmethyl (1RS,3RS)-3-[(Z)-2-chloro-3,3,3-trifluoroprop-1-enyl]-2,2-dimethylcyclopropanecarboxylate
or
2-methylbiphenyl-3-ylmethyl (1RS)-cis-3-[(Z)-2-chloro-3,3,3-trifluoroprop-1-enyl]-2,2-dimethylcyclopropanecarboxylate
CAS name
(2-methyl[1,1′-biphenyl]-3-yl)methyl (1R,3R)-rel-3-[(1Z)-2-chloro-3,3,3-trifluoro-1-propenyl]-2,2-dimethylcyclopropanecarboxylate
CAS registry number
82657-04-03
End-use product (EP)
2.0 lb ai/gal emulsifiable-concentrate formulation (Capture(R) 2EC; EPA Reg. No. 279-3069 and Brigade(R) 2EC; EPA Reg. No. 279-3313)
10% wettable-powder formulation  (Brigade(R) WSB, EPA Reg. No. 279-3108)

Table 2.		Physicochemical Properties of Bifenthrin.
Parameter
Value
Reference
Melting range
                                  68-70.6°C
Product Chemistry Chapter of the Bifenthrin Tolerance Reassessment Eligibility Decision (TRED), (DP No. 283808, 8/21/02, S. Levy)
pH
                                     NA[1]

Density
                                   1.26 g/mL

Water solubility
                                 <0.1 μg/L

Solvent solubility
                          8.9 in heptane and methanol
      125 in acetone, chloroform, ether, methylene chloride, and toluene 

Vapor pressure
                                 2.41 x 10[-5]

Dissociation constant, pKa
                                Not applicable

Octanol/water partition coefficient, Log(KOW)
                                >1 x 10 [6]

UV/visible absorption spectrum
                                      NA

[1] NA = information not available.

860.1200  Directions for Use

Grass (grown for seed)

IR-4 submitted proposed supplemental labels for Brigade WSB Insecticide/Miticide (EPA Reg. No.: 279-3108) and Brigade 2EC Insecticide/Miticide (EPA Reg. No.: 279-3313).  The petitioner also states that the label for Capture 2 EC Insecticide/Miticide (EPA Reg No.: 279-3069) supports this tolerance petition, but this label was not provided.  The proposed grass use pattern is detailed below in Table 3 which allows two 0.1 lb ai/A treatments to be made for a maximum seasonal rate of 0.2 lb ai/A as appropriately demonstrated by the field trials supporting this petition.

Table 3.  Summary of Directions for Use of Bifenthrin on Grass.
                                   Commodity
                           Trade Name (EPA Reg. No.)
                    Application Timing, Type, and Equipment
Maximum Application Rate (lb ai/A)
                    Maximum Number Applications per Season
                    Maximum Total Seasonal Application Rate
                                   (lb ai/A)
                                      PHI
                                    (days)
                        Use Directions and Limitations
PP# 9F7602
Grass grown for seed
Brigade WSB Insecticide/Miticide (279-3108)
Ground and aerial
                                      0.1
                                    Two (2)
                                      0.2
30 days for forage and hay
RTI:  14 days. Min. spray volume:  10 GPA ground, 2 GPA aerial.

Brigade 2EC Insecticide/Miticide (279-3313)
Ground and aerial
Not reported
                                 Not reported
                                      0.2
30 days for forage and hay
RTI:  14 days. Min. spray volume:  10 GPA ground, 2 GPA aerial.

Tea 

GAP information was provided for the products Talstar 8SC and Brigade 8 SC for use on tea grown in India.  Talstar 8SC is an 80 g ai/L SC formulation of bifenthrin.  One foliar application is made to tea using a spray volume of 400 L/ha and a 7-day PHI.  The application rate was not provided.  For Brigade 8 SC, an 80 g ai/L SC formulation, one foliar application is made at 0.08 kg ai/ha (0.07 lb ai/A) using a spray volume of 400 L/ha which specifies a PHI of 7 days.
Apples, nectarines, and peaches

The bifenthrin products relevant for carrying this use as a time limited emergency exemption are the 10% WP (EPA Reg. No. 279-3108) and the 2 lb/gal EC (EPA Reg. No. 279-3069) formulations.  These end use products were examined through studies made in treating pears at the seasonal rate of 0.5 lbs.ai/A (0.45 lbs ai/A post-bloom) following a 14 day PHI.  This envisioned pattern of use based upon the pear data obtained is delineated below in Table 4 for review.

Table 4.  Summary of Directions for Use of Bifenthrin on Pears to be used for treating Apples, Nectarines, and Peaches.
                                   Commodity
                           Trade Name (EPA Reg. No.)
                    Application Timing, Type, and Equipment
Application Rate (lb ai/A)
                    Maximum Number Applications per Season
                       Maximum Seasonal Application Rate
                                   (lb ai/A)
                                      PHI
                                    (days)
                        Use Directions and Limitations
Section 18 Emergency Exemption
Apples, Nectarines & Peaches
Brigade WSB Insecticide/Miticide (279-3108)
Ground and aerial
                                  0.04 - 0.2
                                 Not Reported
                                      0.5
14 days 
RTI:  30 days. Min. spray vol.:  200 GPA.
Apply no more than 0.45 lbs ai/A after petal fall

Capture 2EC Insecticide/Miticide (279-3069)
Ground and aerial
                                 0.04  -  0.2
                                 Not Reported
                                      0.5
14 days 
RTI:  30 days. Min. spray vol.:  200 GPA.
Apply no more than 0.45 lbs ai/A after petal fall

Conclusions:  A revised Section B is needed specifying all applicable directions for the proposed new uses of bifenthrin.  For grass, label 279-3108 is adequate to allow evaluation of the residue data relative to this intended new use.  The field trial data provided appropriately reflect the proposed use pattern in supporting two (2) applications made at 0.1 lb ai/A with an RTI of 14-days for a seasonal total of 0.2 lb ai/A.  However, product label 279-3313 is inadequate due to the fact that the application rate is not specified.  Additionally, both labels are to include that this proposed use carries a regional restriction for only the Pacific Northwest States of Oregon, Washington, and Idaho.  The data provided for this petition only support treating grass grown for seed in the Pacific Northwest.  The proposed labels inappropriately indicate that the products can be used on "Grass Forage, Fodder, and Hay Group and Grass Grown for Seed, Pasture and Rangeland."  This listing should be replaced with "Grass Grown for Seed."  For imported tea, GAP information on its cultivation in India was appropriately provided so that the data furnished could be evaluated for establishing a tolerance on this commodity.  For treating apples, nectarines, and peaches carried as an emergency exemption in the states of Delaware, Maryland, New Jersey, North Carolina, Pennsylvania, Virginia, and West Virginia application directions must be provided.  Amended product labels for the 10% WP (EPA Reg. No. 279-3108) and 2 lb/gal EC (EPA Reg. No. 279-3069) formulations of bifenthrin are needed.

860.1300 Nature of the Residue  -  Plants and Livestock

Bifenthrin TRED; DP No. 283808, 8/21/02, S. Levy

Adequate studies are available depicting the relevant residues of concern for bifenthrin tolerance enforcement and risk assessment.  As such, adequate metabolism studies made on apples, corn, and cotton were previously reviewed in conjunction with earlier bifenthrin petitions (PP#5G3201, PP#6F3453 & PP#7F3546).  Based upon these studies, the Metabolism Committee determined that only the parent compound would be the relevant residue of concern to be established for the tolerance enforcement and risk assessment of crops (Metabolism Committee Meeting Minutes, M. T. Flood, 07/27/1993). 

Adequate ruminant and poultry metabolism studies were likewise reviewed in conjunction with earlier bifenthrin petitions (PP#5G3201 & PP#6F3453).  Based upon these studies, the Metabolism Committee subsequently determined that bifenthrin per se would be the relevant residue of concern established for the tolerance enforcement and risk assessment of livestock (Metabolism Committee Meeting Minutes, M. T. Flood, 07/27/1993). 

Conclusions.  For the purposes of this action, the available metabolism data will also support the end-use product labeling request for grass and tea, as well as apple, nectarine, and peach.  

860.1340 Residue Analytical Methods

Bifenthrin TRED; DP No. 283808, S. Levy, 08/21/2002
DER for MRID 47920801, S. Tadayon, 03/22/2010
DER for MRID 47920803, P. Savoia, 09/XX/2010  
ACB Tolerance Enforcement Method Review; DP No. D384283, C. J. Stafford, 12/22/2010  

Enforcement Methods  

The registrant has developed adequate tolerance enforcement methods which rely on GC/ECD analyses for determining bifenthrin residues in both plant and livestock commodities.  The available method for plant commodities works by performing the extraction of the sample with acetone, partitioning with hexane, purification using a Florisil column, and analysis of residues by GC/ECD.  A modified version of the protocol for tree nuts has been provided which enables it to determine bifenthrin residues in walnut nutmeat.  It was initially concluded that the supporting validation data provided with the revised GC/ECD tree nut procedure are adequate but a rewritten version of the method should be provided by the registrant.  Final review by ACB notes that the revised tree nut enforcement method meets OPPTS 860.1340 test guidelines and rewriting the protocol is no longer considered necessary (DP No. D384283, C. J. Stafford, 12/22/2010).

For ruminant commodities, an established method is available to perform these analyses.  FMC method P-1031 is another GC/ECD procedure which has been developed by the registrant and proven to be adequate for enforcing bifenthrin tolerances in milk and ruminant tissues.  The reported LOQ for these methods is 0.05 ppm and in some cases sample extracts may be analyzed by GC/MSD instead of GC/ECD for the purpose of quantitation.    

Data Collection Methods 

For this petition, field trials acquiring samples of grass forage and hay were analyzed for residues of bifenthrin using FMC method P-2132M.  In using this method, residues are extracted with hexane using an accelerated solvent extraction system and concentrated.  The resulting sample extracts are cleaned up using a Florisil column and subsequently quantitated by GC/ECD analysis.  For grass forage, the calculated LOD of the method is 0.01 ppm and the LOQ is 0.03 ppm.  The method similarly reports an LOD of 0.03 ppm along with an LOQ of 0.08 ppm for grass hay.  The method was adequately validated in conjunction with analysis of samples from the field trials.

In regard to the residue chemistry data provided to establish a tolerance on imported tea, many of the submissions provided by the petitioner to support this action were found to be incomplete.  However, the data provided in MRID No. 47920803 for determining the magnitude of residue in tea cultivated in India was adequate.  For this study, data were acquired using a Gas-Liquid Chromatograph/Electron Capture Detection (GLC/ECD) instrumental technique.  Although no reference number was given for the protocol, it was successfully validated prior to the analysis of field samples.  

This method works by macerating a 15-g aliquot of tea sample at moderate speed with acetone, followed by evaporation and re-constituting it back to a final volume of 250 mL with acetone.  An aliquot of the extract was then purified by "silica gel" adsorption column clean up using an 18 mm x 450 mm column packed with anhydrous sodium sulphate and silica gel in tandem using 100 mL of hexane.  The column in then washed using a 100 mL solvent mixture of hexane:diethyl ether (97:3 v/v) followed by 50 mL of hexane with all of the washings being discarded.  The sample residue is then dissolved in 10 mL of hexane and loaded onto a "silica gel" column using another 10 mL of hexane and then washed with a 100 mL solvent mixture of hexane:diethyl ether (97.5:2.5 v/v).  Afterwards, the resulting eluate is then concentrated to near dryness in a rotary evaporator.  The residue that is acquired is then dissolved in a suitable volume of hexane and quantitated using GLC/ECD analysis.  An LOD of 0.05 ppm for bifenthrin in tea was reported for the method but no LOQ was given.

Conclusions.  The existing GC/ECD enforcement methods are adequate for collecting data on residues of bifenthrin in both crop and livestock commodities.  This includes the revised tree nut test procedure submitted by the registrant.  These methods will be adequate for enforcing tolerances established as a result of this petition request.  The data collection methods used were likewise shown to be adequate for determining the magnitude of bifenthrin in grass forage and hay, as well as in imported tea acquired to support this action.  

860.1360 Multiresidue Methods

Bifenthrin TRED; DP No. 283808, S. Levy, 08/21/2002

The Food and Drug Administration's PESTDATA database dated 10/99 (Pesticide Analytical Manual (PAM) Vol. I, Appendix II) indicates that bifenthrin is completely recovered using MRM Section 303 (Mills, Onley, and Gaither Method; Protocol E, non-fatty food) and that recoveries using Section 302 (Luke Method; Protocol D) are variable.  No information pertaining to the recovery of bifenthrin using Section 304 (Mills Method; Protocol E, fatty food) is available.  Additional MRM data for bifenthrin are not required.  The MRM methods are adequate for enforcement of bifenthrin tolerances.  

860.1380 Storage Stability

DER for MRID 46960801:  DP No. 335688, W. Wassell, 07/25/2007
DP Nos. D274839 & D280288, S. J. Levy, 08/15/2002

The maximum storage duration from harvest to analysis was 250 days for grass forage and 244 days for grass hay.  For tea, only one of the submitted field studies (MRID No. 47920803) provided sample storage information.  The storage durations and conditions of samples from the crop field trials submitted to support this petition are presented below in Table 5.

Table 5.   Summary of Storage Conditions and Durations of Samples from Crop Field Trial Studies.  
Matrix 
                           Storage Temperature (°C)
                        Actual Storage Duration (days)
                 Interval of Verified Storage Stability (days)
Grass (Forage)
                                  -29 to -15
                                      250
                                     229 
Grass (Hay)
                                  -29 to -15
                                      244
                                      221
Tea (MRID 47920803)
                                    <-18
                                      67
                           No data available for tea
Tea (other studies)
                                 Not reported
                                 Not reported
                           No data available for tea
Apple, Nectarines & Peaches 
                                 Not reported
                                 Not Reported
                                     1470

Storage stability studies conducted concurrently with grass crop field trial studies indicate bifenthrin is not stable in forge and hay grass when stored frozen for durations greater than 244 to 250 days.  Following correction for laboratory recovery (79% for forage and 77% for hay), average storage stability recovery was 65% for forage and 44% for hay.  Nonetheless, previously submitted data indicate that bifenthrin residues are stable when stored frozen for 12 months in corn flour, 36 months in lettuce, pecans and potatoes along with durations up to 49 months in apple (DP Nos. D274839 & D280288, S. J. Levy, 08/15/2002).  

Conclusions.  The storage conditions and durations of samples from the grass field trials are supported by adequate storage stability data.  The data indicate that residues decline by approximately 35% in forage and 55% in hay, requiring the correction of residues from the grass field trial data.   For tea, stability data were not provided which reflect the storage conditions that were incurred in the crop field trials that were submitted.  However, there are stability studies available or existing data for other similar crops which can be translated to substantiate the storage durations that were incurred for tea samples in this submission.  Similarly, the available apple storage stability data are adequate to support the Section 18 request.  

860.1400 Water, Fish, and Irrigated Crops

For the purpose of this summary, this guideline requirement is not relevant to this evaluation since bifenthrin has no registered or proposed uses on water or aquatic food and feed crops.

860.1460 Food Handling

For the purpose of this summary, this guideline requirement is not relevant to this evaluation since bifenthrin has no food-handling uses which are being proposed.

860.1480 Meat, Milk, Poultry, and Eggs

Residue Chemistry Memorandums DP Nos. D335693, D335688, D335696 & D335695, W. Wassell (PP#s 6E7125, 6E7126, 6E7127, 6E7128), 07/25/2007; DP No. D355743, P.Savoia, 12/08/2008; and DP No. 373487, I. Negrón-Encarnación, 04/30/2010.

For this petition, the registration of bifenthrin in treating grass grown for seed will be established for use to crops grown only in ID, OR, and WA.  The forage and hay commodities of grass are used as a livestock feedstuff commonly fed to cattle.  Although this will be a limited use, there also exists an emergency exemption on orchard grass, which when considered together, necessitates that the secondary transfer of residues to livestock be assessed.  Following current guidelines, dietary burden was subsequently re-calculated for bifenthrin using the maximum reasonably balanced diet to livestock (Table 6).  Because both grass forage and hay are roughage, only grass forage was used in this re-calculation since the percent dry matter of this feed will result in greater levels for a more conservative evaluation.   For this re-assessment, the estimated dietary burden was found to be 1.58 ppm for beef cattle and 3.63 ppm for dairy cattle.  These values are found to be consistent when compared to the prior determination of livestock dietary burden made for bifenthrin pursuant to PP#s 6E7125-6E7128 (DP Nos. D335688, D335693, D335695 & D335696, W. Wassell, 07/25/2007).  Based upon this assessment, HED concludes that the established bifenthrin livestock tolerances remain appropriate and do not need to be changed.
   
Table 6.   Maximum Reasonably Livestock Dietary Burdens (MRDB) for Bifenthrin.
Feedstuff
                                    Type[1]
                                % Dry Matter[2]
                                   % Diet[2]
                                 Tolerance or
                               STMR/HR[3] (PPM)
                         Dietary Contribution (ppm)[4]
                      Beef Cattle:  15% R, 80% CC, 5% PC
Grass, forage                         HR[5]       
                                       R
                                      25
                                      15
                                    1.97[5]
                                     1.18
Grain, aspirated fractions      MR[6]
                                      CC
                                      85
                                       5
                                70.0 (11.2)[7]
                                  4.12 (0.33)
Corn, field, grain                   MR
                                      CC
                                      88
                                      75
                                     0.05
                                     0.043
Cottonseed, meal                   MR
                                      PC
                                      92
                                       5
                                      0.5
                                     0.028
TOTAL BURDEN
                                      --
                                      --
                                      100
                                      --
                                     1.58
                      Dairy Cattle: 45% R, 45% CC, 10% PC
Grass, forage                         HR[5]       
                                       R
                                      25
                                      45
                                    1.97[5]
                                     3.55
Corn, field, grain                   MR 
                                      CC
                                      88
                                      45
                                     0.05
                                     0.026
Cotton, undelinted seed         MR
                                      PC
                                      88
                                      10
                                      0.5
                                     0.057
TOTAL BURDEN
                                      --
                                      --
                                      100
                                      --
                                     3.63
                           Poultry:  75% CC, 25% PC
Corn, field, grain                    MR
                                      CC
                                      88
                                      65
                                     0.05
                                    0.0325
Cowpea/ field pea/lupin seed MR
                                      CC
                                      88
                                      10
                                     0.15
                                     0.015
Cottonseed, meal                    MR
                                      PC
                                      85
                                      20
                                      0.5
                                      0.1
Soybean, meal                        MR
                                      PC
                                      92
                                       5
                                      0.2
                                     0.01
TOTAL BURDEN
                                      --
                                      --
                                      100
                                      --
                                     0.16
                            Swine:  85% CC, 15% PC
Cor, field, grain                     MR
                                      CC
                                      88
                                      85
                                     0.05
                                    0.0425
Cottonseed, meal                   MR
                                      PC
                                      85
                                      15
                                      0.5
                                     0.075
TOTAL BURDEN
                                      --
                                      --
                                      100
                                      --
                                     0.12
[1] R:  roughage; CC:  carbohydrate concentrate; PC:  protein concentrate.
[2] OPPTS 860.1000 Table 1 Feedstuffs (June 2008). 
[3] Supervised Trial Median Residue/Highest Residue (STMR/HR). 
[4] Contribution = ([tolerance /% DM] x % diet) for beef and dairy cattle; contribution = (tolerance x % diet) for poultry and swine.
[5] Highest Residue (HR). 
[6] Median Residue (MR). 
[7] The value in parenthesis represents 16% of the tolerance level for Aspirated Grain Fractions (AGFs).  AGFs are normally a composite of more than one grain (corn (46%), wheat (36%), sorghum (6%), and soybeans (16%)).  Bifenthrin is not registered for use on wheat and sorghum.  Bifenthrin is registered for use on field corn; however, the requirement for data concerning AGFs from corn has been waived as grain samples resulting from the registered use pattern exhibited non-detectable residues of bifenthrin (<0.01 ppm).

Apple wet pomace is a recognized livestock feedstuff for dairy cattle.  This processed commodity is generally produced only within the prominent apple processing states (e.g., MI, NY, OR, PA, VA, WA).  It is a seasonal feed item that is used within a 100 mile radius of the processing plant.  It is not fed to finishing feedlot beef because it would cause digestive problems when fed to an animal that is on high-level grain diet and is therefore only fed to local dairy cattle on occasion.  For this reason, a re-calculation of dietary burden is not being made at this time because the apple use is only being established for a time limited emergency exemption.  However, if a request is made to establish permanent apple tolerances, dietary burden should be re-calculated to consider apple wet pomace.
Conclusions.  Establishing tolerances for the commodities of grass grown for seed have been concluded to not contribute to the secondary transfer of bifenthrin residues to cattle through feeding.  Re-calculation of dietary burden has shown that the tolerances established for bifenthrin on livestock commodities remain appropriate.  In regard to the emergency exemptions which are sought, this a time limited use which may have an effect on an alternative feed that is only consumed in small quantities.  A re-calculation of dietary burden considering apple wet pomace should be made if a permanent apple tolerance is requested.

860.1500 Crop Field Trials

For PP#9E7652, IR-4 is requesting registration for the use of bifenthrin on grass grown for seed and the establishment of a tolerance on imported tea.  To satisfy data requirements, IR-4 has submitted a study for determining the magnitude of bifenthrin residue found in grass forage and hay.  In addition, nine (9) studies/reports were included from India, China, Japan, and Indonesia to characterize the magnitude of bifenthrin residue found in/on imported tea.  No raw data were included in these submissions and all results presented herein are subsequently summarized from the original studies/reports on imported tea provided by IR-4.  Many of these submissions are inadequate due to the lack of information, such as application rate, PHI, storage length and conditions, and analytical methodology.  Nevertheless, MRID No. 47920803 is considered to be scientifically acceptable though it was found to lack concurrent recovery information.  For review, a summary of the residue data acquired from these field trial studies which were undertaken are presented below in Table 7.

Table 7.  Summary of Residue Data from Grass and Tea Data Acquired for Bifenthrin. 
                                   Commodity
                                   Analytes
                         Total App. Rate (lb ai/acre)
                                  PHI (days)
                                       n
                               Residue (ppm)[1]
                                       
                                       
                                       
                                       
                                       
                                     Min.
                                     Max.
                                    HAFT[2]
                                    Median
                                     Mean
                                   Std. Dev.
                             Grass, Grown for Seed
Grass Forage
                                  Bifenthrin
                                  0.199-0.207
                                     29-36
                                      10
                                     0.11
                                     2.18
                                     1.97
                                     0.48
                                     0.73
                                     0.72
Grass Hay
                                       
                                       
                                     29-43
                                      10
                                     0.20
                                     6.66
                                     6.66
                                     0.32
                                     1.62
                                     2.65
                                Imported Tea[3]
                                      Tea
                                 (Fresh leaf)
                                  Bifenthrin
                                     0.053
                                       
                                       7
                                       9
                                     0.88
                                     8.80
                                     8.04
                                     6.40
                                     5.20
                                     3.22
                                      Tea
                             (Processed black tea)
                                       
                                       
                                       
                                       9
                                     0.52
                                     7.78
                                     7.60
                                     6.45
                                     4.86
                                     3.29
[1]  For the determination of the HAFT, median, mean, and standard deviation, the LOQ (0.03 ppm) for forage the LOQ of (0.08 ppm) for hay and were assumed for residues reported as <LOQ.
[2]  HAFT = highest-average field trial.
[3]  Imported tea results are summarized from MRID No. 47920803.  These residue values have been corrected by a factor of 1.33x to provide proportionality between the actual rate of application made at 60g ai/ha not being comparable to the reported GAP maximum of 80 g ai/ha.  

Grass grown for seed

DER for MRID No. 47920801, S. Tadayon, 03/22/2010.

IR-4 submitted residue data for five grass (seed crop) field trials conducted in NAFTA growing regions Zone 11 (n=2; ID and WA) and Zone 12 (n=3; OR).  Each trial consisted of one untreated control plot and one treated test plot.  The treated plots received two broadcast foliar applications of Capture(R) 2EC (emulsifiable concentrate; 2 lb ai/gallon).  The application rates were made at 0.099-0.104 lb ai/A per application for a total rate of 0.199-0.207 lb ai/A per season with a Re-treatment Interval (RTI) of 13-14 days.  All applications were made using spray equipment in 24-26 gal/A spray volumes without the use of an adjuvant.
Duplicate samples were harvested. Forage samples were harvested 29-36 days after the last application and hay samples were harvested 29-43 days after the last application.  The samples were analyzed for bifenthrin using a working method very similar to the reference method, "Analytical Method for the Determination of Bifenthrin in/on Various Crops and Soils." P-2132M, FMC Corporation, 1989. The method is adequate based on acceptable concurrent and method validation recovery data.

The storage data in MRID No. 47920801 show significant degradation can occur over time (35% decline in forage and 55% decline in hay, following approximately 230 days in frozen storage).  Therefore, residues were corrected for potential declines during frozen storage.  Following two applications of the 2 lb ai/gal EC formulation at a total rate of 0.199-0.207 lb ai/A per season, total residues of bifenthrin in grass forage were in the range 0.11-2.18 ppm in samples taken at 29-36 days PHI.  The total residues of bifenthrin in grass hay were in the range 0.20-6.66 ppm in samples taken at 29-43 days PHI.

Conclusions.  The submitted residue data made for the grass forage and hay commodities are adequate in fulfilling these data requirements.  The number and location of field trials were sufficient in scope having been undertaken in the Pacific Northwest States of Oregon, Washington, and Idaho because this use will be limited to this growing area.  They were made appropriately in line with the additional guidance requirement on this crop, "Grasses Grown for Seed", an Agency memorandum dated 09/30/2000.  This memorandum requires the collection of forage and hay data for this commodity since it is considered to be a subgroup of grass pasture and rangeland.

Use of the Organization for Economic Cooperation and Development (OECD) calculation procedures was made to determine appropriate tolerance levels (Attachment 2).  Thus, tolerances of 3.0 ppm for grass forage and 6.0 ppm for grass hay are recommended when utilizing the uncorrected values from the field trial studies.  After correction for storage stability decline, tolerance levels of 4.0 ppm for grass forage and 15 ppm for grass hay result.  Accordingly, HED recommends a tolerance of 4.0 ppm in/on grass forage and 15 ppm in/on grass hay for residues of bifenthrin based on the residue data from grass grown for seed.  These levels are higher than those proposed by the petitioner and require a revised Section F for this action. 

Tea

DER References:  MRID Nos. 47920802 - 47920810	

To support the establishment of a bifenthrin tolerance on imported tea, nine (9) studies/reports from India, China, Japan, and Indonesia were provided for characterizing the magnitude of residue in/on this commodity.  Many of these submissions were found to lack detailed information concerning application rates, PHI, storage length and conditions, and analytical methodology.  For these submissions, DERs could not be prepared but the key information they is summarized below.    

MRID No. 47920803

IR-4 has submitted a report summarizing the results of two studies for bifenthrin made on tea conducted in India.  No raw data were included in the submission and all results noted in the report are presented herein.

The FMC Corporation Agricultural Products Group sponsored this study to determine the magnitude of bifenthrin residue in black tea and its fresh leaf.  The United Planters Association of Southern India (UPASI) conducted two field trials in Tamil Nadu, India (municipalities of Valparai and Nilgris) and one in Assam, India (municipality of Tocklai).  This study was held in an area which is representative of the major tea-growing regions in southern and northern India, respectively.  One treated test plot and one untreated control field was established at each trial site.  Each treated plot received one application of Talstar 2EC, an emulsifiable concentrate formulation containing 2.0 lb bifenthrin/gal (240 g ai/liter).  Treatment was made using a hand operated knapsack sprayer applied at the targeted rate of 0.053 lb bifenthrin/A (60 g ai/ha).  All applications were made with a spray volume of 53.5 gallons per acre (500 L/ha).  Following the industry practice in India of a 7-day PHI when treating the crop, tea shoots (three leaves and a bud) were collected from the treated plots for testing.  From the harvested tea shoots, a portion was processed into black tea with the remaining sample submitted for testing as fresh leaf.  The samples of black tea and fresh leaf were subsequently analyzed for residues of bifenthrin. 

For this study, the fresh leaf and black tea samples were analyzed using a GLC/ECD method.  Quantitation of the tea samples was carried out following extraction with acetone by maceration and cleanup with adsorption column chromatography.  This method was successfully validated beforehand demonstrated through the analysis of fortified samples.  The mean recovery of bifenthrin ranged from 86.58 to 99.27% using control samples of black tea and fresh leaf fortified at concentrations of 0.0593 to 10.0664 ppm for testing.  The reported LOD of the method for bifenthrin in tea was determined to be 0.05 ppm.

The data submission did note that the maximum storage interval from sampling to completion of analysis was 67 days (2.2 months).  However, the specific times from sample collection to extraction as well as the interval between preparation and final analysis were not reported.  No concurrent storage stability data were submitted in part with this study.  To ensure the integrity of the samples were maintained, it was reported that they were kept frozen (<-18 ºC) after shipment to the analytical laboratory until analysis.  In all, the bifenthrin residues obtained from the three field trial locations comprising this study ranged from 0.39 to 5.85 ppm in black tea and between 0.66 to 6.62 ppm in the fresh leaf samples.  It is important to note that the actual application of product made at 60 g ai/ha to the tea crop cultivated in this study was approximately 25% less than the reported maximum GAP rate of 80 g ai/ha.  In order to assume proportionality between the actual rate of application and the GAP maximum, a correction factor of 1.33x was applied to this data (Table 7 summary of tea results) for interpreting the magnitude of bifenthrin residue in/on tea.  Although there were a number of minor data deficiencies in both the in-life and analytical phases of the study, it was for the most part compliant with the OPPTS 860.1500 Residue Chemistry Test Guidelines.  This study aptly shows the variation in residue levels which can occur when cultivating tea at different regions following common industry practices.

The following studies provided to support this action were considered but not used for tolerance setting purposes due to the various deficiencies identified in this assessment.

MRID No. 47920802

IR-4 has submitted a report summarizing the results of two studies for bifenthrin made on tea conducted in India.  No raw data were included in the submission and all results noted in the report are presented herein.

The United Planters Association of Southern India (UPASI) Tea Research Foundation conducted two trials at separate locations in Tamil Nadu, India (municipalities of Valparai and Gudalur) investigating the magnitude of bifenthrin residue in black tea.  Each trial site included two treated fields and the use of control plots was not discussed.  The first treated plot received one foliar broadcast spray application of Talstar 8 SC, a soluble concentrate formulation containing 0.668 lb bifenthrin per gallon (80 g ai/L) at a target application rate of 0.018 lb ai/A (0.02 kg ai/ha).  The second treated plot received one foliar broadcast spray application of Talstar 8 SC at a target application rate of 0.036 lb ai/A (0.04 kg ai/ha).  All applications were made with a spray volume of 42.8 gallons per acre (400 L/ha).  Following the industry practice in India of a 7-day PHI when treating the crop, the green tea leaf samples were collected in line with this protocol.  The collection of additional samples also occurred on 0, 10, and 14 days after application.  This was done to enable a residue decline study to be made since other harvesting intervals can occur depending on the season and growth rate of the tea crop.  The harvested green tea leaves were dried and fermented into black tea following standard manufacturing processes for final analysis to determine the extent of bifenthrin residue in this end-product.

In a separate study, the Tea Research Association (TRA) conducted a single trial in Assam, India (municipality of Tocklai) to likewise investigate the magnitude of bifenthrin residue in black tea.  The treated plot received a single foliar broadcast spray application of Brigade 8 SC, a soluble concentrate formulation containing 0.668 lb bifenthrin per gallon (80 g ai/L) at a target application rate of 0.071 lb ai/A (0.08 kg ai/ha).  The application was made with a spray volume of 42.8 gallons per acre (400 L/ha) and the use of control plots was not discussed.  The green tea leaf samples were harvested at a PHI of 7 days following industry protocol with additional samples also being collected on 0, 3, 5, and 14 days after application.  The green tea leaves were then dried and fermented into black tea for final analysis to determine the extent of bifenthrin residue in this end-product.

The dried tea samples from the Tamil Nadu trials were analyzed for residues of bifenthrin using a validated GLC/ECD method.  The method LOD of bifenthrin in/on tea was determined to be 0.01 ppm and no LOQ was reported.  The dried tea samples from the Assam trial were analyzed for residues of bifenthrin using a validated Gas-Liquid Chromatography/Nitrogen Phosphorous Detection/Electron-Capture Detection (GLC/NPD/ECD) procedure.  The determined LOD for this method is reported to be 0.02 ppm.  These analytical procedures are considered to be adequate for data collection based on the acceptable method recovery results that were provided.

Sample storage conditions and durations were not delineated in the submission but the stability of the analytical standards was checked at periodic intervals throughout the study.  For the Tamil Nadu trial, the submission notes that for any field sample held more than 24 hours, residue stability is demonstrated by the recovery studies made to monitor the analytical standards.  As for the Assam trial, the submission states that all samples were extracted immediately upon receipt in the laboratory and did not involve extensive storage prior to analysis.  Although specific storage durations from harvest to extraction could not be determined, storage stability data are not required if the samples were stored for less than 30 days.

Residues of bifenthrin ranged from 0.64 to 4.76 ppm in tea harvested 7 days following a single broadcast foliar application of Talstar 8 SC for a total foliar rate of 0.018 lb ai/A (0.02 kg ai/ha).  Residue levels of 2.92 to 7.62 ppm were found in tea harvested 7 days following a single broadcast foliar application of Talstar 8 SC for a total foliar rate of 0.036 lb ai/A (0.04 kg ai/ha).  Bifenthrin concentrations were likewise observed at 0.83 ppm in tea harvested 7 days following a single broadcast foliar application of Brigade 8 SC for a total foliar rate of 0.071 lb ai/A (0.08 kg ai/ha).
Results from the residue decline study performed at the Tamil Nadu field sites with application rates at 0.018 lb ai/A (0.02 kg ai/ha) and 0.036 lb ai/A (0.04 kg ai/ha) were carried out.  For this determination four sampling intervals corresponding to PHIs of 0, 7, 10, and 14 days indicated that residues of bifenthrin declined when the timeframe to collection increased.  These results showed that residue levels declined rapidly for the first 7 days after application and then continued to diminish at a slower rate to Day 14.  For this determination, all residues were found to remain above the LOD (0.01 ppm) out to Day 14. 

Results from the residue decline study performed at the Assam field site with an application rate of 0.071 lb ai/A (0.08 kg ai/ha) were likewise acquired.  For this determination, five sampling intervals corresponding to PHIs of 0, 3, 5, 7, and 14 days indicated that residues of bifenthrin declined when the timeframe to collection increased.  Residues were observed to decline quickly for the first 3 days after treatment and then continued to lessen at a slower rate to Day 14.  Similarly, residue levels were all observed to remain above the LOD of 0.02 ppm out to Day 14.  The decline rate for the tea crops treated at the two lower application levels was more rapid than those which received treatments at the higher rate.

In addition to the field trial data, this submission also included residue data from the Tetley Group, Shanshan Tea, and Finlay Tea.  Data received from The Tetley Group lists the results from bifenthrin residue analyses of tea in commercial shipments from various countries. The highest residue indicated is 0.25 ppm.  A summary of bifenthrin residue results from tea grown and analyzed in China, obtained from Shanshan Tea, indicates that the highest residues were in the range 1-5 ppm.  A list of the results of bifenthrin residue analyses of tea originating in India and Japan, from Finlay Tea, shows that the highest residue was 0.16 ppm. 
Under the conditions and parameters used in this study, the magnitude of bifenthrin residue was demonstrated in the samples of green tea that were acquired.  However, in following the OPPTS 860.1500 Residue Chemistry Test Guidelines, a number of deviations were evident in this data submission.  Most notably, that only one sample was collected for each field trial and no sample storage conditions along with the durations that were incurred are reported.  In addition, there are also a number of minor data deficiencies pertaining to both the in-life and analytical phases of the studies which can be attributed to a lack of detailed information.

MRID No. 47920804

IR-4 submitted residue decline data for seven tea trials conducted in India during 1984 and 1985.   Tea was treated with one application of FMC54800 (10EC) at a dilution rate of 2000X, 3000X, 4000X, or 6000X.  Corresponding application rates were not provided, though the recommended dose was reported as 4000X to 6000X.  Treated tea samples were collected 30 minutes after application and at approximately 1, 3, 7, 10, 14, 17, and 20 days after application.  Samples were extracted using toluene and xylene, concentrated, cleaned up using a Florisil column, and dried using anhydrous sodium sulfate.  Quantitation was made using a GC/ECD protocol with average recoveries ranging from 87.5 to 98.7% for control samples fortified at 0.1, 1, and 5 ppm.  The LOQ of the method was reported to be 0.001 ppm with no information on storage duration and conditions being provided. 

Residues in both fresh tea and dry tea trials declined with increasing pre-harvest intervals with a half-life reported for the study to be 3.2 days.  At a PHI of 7 days, residues of bifenthrin ranged from 1.52 ppm to 4.31 ppm.  Specifically, residues of bifenthrin in fresh tea were 3.71 ppm and 1.52 ppm at the 2000X dilution rate and 2.96 ppm and 3.17 ppm at the 4000X dilution rate.  In dried tea, the residues were 4.31 and 1.22 ppm at the 2000X dilution rate, 1.76 ppm at the 3000X dilution rate, 2.39 ppm and 3.09 ppm at the 4000X dilution rate, and 2.07 ppm at the 6000X dilution rate.  For this study, concentrations were such that no residues reached the LOQ by day 20.

In this study residues of bifenthrin in tea soup were also analyzed.  Tea was treated with bifenthrin and processed on the same day.  The tea was soaked in boiling water three times.  Average residues of bifenthrin were 7.9 ppm in the tea and 0.345 ppm in the tea soup (extraction rate of 4.4%).  No other information was provided, such as application rate and storage information.  In following the OPPTS 860.1500 Residue Chemistry Test Guidelines, a number of deviations were evident in this data submission.  As such, a DER was not completed for this submission because it lacked sufficient information concerning the cultivation of the tea samples used to carry out this study.  

MRID No. 47920805

A paper published in Pesticide Science, Volume 23, 1988, pages 109-118, describes the degradation of pesticides applied to tea.  The paper does not include bifenthrin, but other pyrethroid insecticides are discussed in this journal article.  Consequently, a DER was not prepared for this data submission because it lacked sufficient information. 

MRID No. 47920806

IR-4 submitted residue decline data for tea trials conducted in two locations in China (Xinchang and Yuhang, Zhejiang Province) in 2002.  The product used in the field trials was 2.5% Talstar EC.   Four trials were conducted at each location, which consisted of one, two, or three applications at 450 ml/ha (0.01 kg ai/ha or 0.009 lb ai/A), or one application made at 1200 ml/ha (0.03 kg ai/ha or 0.02 lb ai/A). Tea samples were harvested 7 days after the final application.  In Xinchang, samples consisted of young buds with one leaf, which were stir-fried to Da-fo Longjing tea and stored until analysis.  In Yuhang, young buds were collected and stir-fried.  

Two samples were collected from each treated test plot for analysis.  Samples from the Xinchang test area treated one time at the low rate had a maximum residue of 0.32 ppm.  Those which were treated twice at the low rate had a maximum residue of 0.42 ppm.  The other samples treated three times at the low rate had a mean residue of 0.73 ppm along with those being treated once at the high rate had a maximum residue of 0.52 ppm.  For the Yuhang test area, samples treated one time at the low rate had a maximum residue of 1.70 ppm.  Alternately, samples treated twice at the low rate had a maximum residue of 0.82 ppm.  For the samples treated three times at the low rate, a maximum residue of 1.96 ppm was found.  In regard to the samples treated once at the high rate, maximum residues were observed at a concentration of 2.10 ppm.  

For this submission, no information was provided on the analytical method used or storage duration and conditions that were incurred.  As a result, a DER was not prepared for this study because it lacked many of the data requirements of the OPPTS 860.1500 Residue Chemistry Test Guidelines.

MRID No. 47920807

IR-4 has submitted results of a field trial that was conducted in Indonesia in which Talstar 25 grams/liter EC was applied to fresh, green, and black tea at rates of 0.060 kg a.i./ha (0.054 lb ai/A) and 1.0 kg a.i./ha (0.089 lb ai/A).  Two samples from each treated test plot were collected, as well as two samples from untreated control plots.  No further experimental design information was specified, including the PHI or storage conditions and intervals.  A detailed analytical method for the analysis of the samples was provided.  The samples were analyzed using either a GC/ECD or GC/MS protocol which is referenced as FCC/BIFENTRIN  -  DRY CROPS/96/1.  Briefly, samples were extracted using acetone, partitioned using hexane, and purified using a florisil column.  Acceptable concurrent recoveries were obtained.  Maximum residues of bifenthrin in fresh tea leaves were 0.83 ppm (low rate) and 3.93 ppm (high rate).  Maximum residues in green tea were 3.58 ppm (low rate) and 4.59 ppm (high rate).  Maximum residues in black tea were 1.50 ppm (low rate) and 2.23 ppm (high rate).  For this submission, a DER was not prepared because it for this study because it lacked many of the data requirements of the OPPTS 860.1500 Residue Chemistry Test Guidelines. 

MRID No. 47920808

IR-4 has submitted a report summarizing the results of two studies for bifenthrin made on tea conducted in India.  No raw data were included in the submission and all results noted in the report are presented herein.

For this study, the Institute of Himalayan Bioresource Technology (IHBT) Council of Scientific and Industrial Research carried out two (2) field trials in Banuri, Palampur India.  It was undertaken to investigate the dissipation behavior of bifenthrin residue in tea shoots, processed tea, infused tea (brew) and spent tea leaves.  One field trial was initiated in the dry season (April, 2003) and another in the wet season (July, 2003).  Each trial site was comprised of one control parcel and two treated test plots that were divided into four subplots to enable the collection of four replicate samples to be made at various intervals.  The first treated plot received one foliar broadcast spray application of the Talstar 8 SC soluble concentrate product containing 0.668 lb bifenthrin per gallon (80 g ai/L) made at the rate of 0.036 lb ai/A (40 g ai/ha).  The second treated plot received one foliar broadcast spray application of Talstar 8 SC made at the rate of 0.071 lb ai/A (80 g ai/ha).  

All applications were made with a hand operated knapsack sprayer using a spray volume of 42.8 gallons per acre (400 L/ha).  Following the industry practice in India of a 7-day PHI when treating the crop, tea shoots (three leaves and a bud) were collected from the treated plots for testing.  Green tea leaf samples were also harvested from the treated plots at 0 (1 hour after the application), 3, 5, 9, 11, 14, and 21 days following application to evaluate residue decline.  The harvested tea leaves went through a manufacturing process which involved withering (reduction of moisture in the shoots), rolling, oxidation (fermentation), and drying. The processed tea was further subjected to infusion wherein 5 g of the processed tea was infused in 150 mL of boiling water.     

All of the tea sample matrices comprising this study were analyzed for residues of bifenthrin using a GC/ECD methodology.  The study report notes that the LOD for bifenthrin in all four tea matrices (tea shoots, processed tea, infused tea, and spent tea leaves) is estimated to be 0.05 ppm by combining the values that were obtained.  The study report did not note an LOQ nor were sample storage conditions and durations that were incurred provided in the summary.  

Residues levels of bifenthrin in the green tea shoot samples harvested at a PHI of 7-days were found to average 0.32 +- 0.03 ppm (dry season) and 0.13 +- 0.02 ppm (wet season) for the Talstar 8 SC application made at 0.036 lb ai/A (40 g ai/ha).  Residue levels were found to average 0.50 +- 0.05 ppm (dry season) and 0.23 +- 0.05 ppm (wet season) following application of Talstar 8 SC made at 0.071 lb ai/A (80 g ai/ha).  Average residues in the processed tea harvested at the PHI of 7-days were found to be 0.38 +- 0.05 ppm (dry season) and 0.18 +- 0.02 ppm (wet season) for the 0.036 lb ai/A (40 g ai/ha) treatment rate.  Alternately, residues averaged 0.60 +- 0.06 ppm (dry season) and 0.21 +- 0.02 ppm (wet season) for the application rate made at 0.071 lb ai/A (80 g ai/ha).  Residues of bifenthrin were not detected in brewed tea from samples harvested at the 7-day PHI for both application rates.  For the spent tea leaf samples harvested at a PHI of 7-days, residue levels averaged 0.07 ppm (dry season) and 0.07 ppm (wet season) following treatment made at the 0.036 lb ai/A (40 g ai/ha) rate.  At the 0.071 lb ai/A (80 g ai/ha) application rate, residues were found to average 0.11 ppm (dry season) and 0.05 ppm (wet season) in the spent tea leaves harvested at the PHI of 7-days.

Residue decline studies were made for each application rate using sampling intervals which corresponded to PHIs of 0, 1, 3, 5, 7, 9, 11, 14, and 21 days.  These results indicate that residues of bifenthrin in tea decline with increasing pre-harvest intervals for collection.  The residues declined rapidly for the first 3 days after the application and then continued the decline at a slower rate until they were undetectable.  By Day-11, bifenthrin was undetectable in all matrices for both the dry and wet season trials.  Overall, residues of bifenthrin degraded more rapidly in wet season tea than in dry season tea.  The study also notes that the processing of green tea shoots contributes to a considerable loss of bifenthrin (>= 42%) and only a partial transfer of residues (1.5% to 14%) when brewed.  

Under the conditions and parameters used in this study, the magnitude of bifenthrin residue was shown in the tea samples that were acquired.  However, in following the OPPTS 860.1500 Residue Chemistry Test Guidelines, a number of deviations were evident in this data submission which adversely affects the completeness of this study.  Most notably, the timing of the product applications is not known, it is uncertain if adjuvants were used, meteorological conditions for the field trials were not reported, and the sample storage conditions as well as durations are not provided.  In addition, it is not known if the analytical method was previously validated, no individual data points were reported (only mean values with some standard deviations), and no raw data were provided to support the reproducibility of the method or the lack of potential interferences.

MRID No. 47920809

IR-4 submitted residue decline data for four tea trials conducted in Japan during 1985 and 1987.   Limited experimental design data was provided for three of the trials that were made.  For these three trials, tea was treated with two applications of Talstar 2 WP at a 1,000X dilution (2 g ai/hl), with a final spray volume of 4,000 l/ha.  Based on these parameters, the resulting single application rate was 0.08 kg ai/ha (0.07 lb ai/A), for a total application rate of 0.16 kg ai/ha (0.14 lb ai/A).  Tea was treated at a weekly interval.  Tea was harvested at intervals of approximately 7, 14, 21, and/or 28 days.  The tea tree was covered by shade for 7 to 13 days before harvest.  The number of samples collected per treated test plot was not provided.  Additionally, sample storage conditions and duration were not provided.   

Briefly, the method works by extracting the samples using acetone.  After removal of acetone, NaCl solution was added and the sample is extracted again with dichloromethane.  The water and organic solvent was removed from the dichloromethane layer and the fraction is concentrated.  The sample fraction is purified with florisil column chromatography and partitioned with a mixture of acetonitrile and hexane.  The residues are then quantitated using GC/ECD analysis with concurrent recovery data (two samples at one fortification level) provided to show the proficiency of the procedure.  The LOQ for the method was reported to be 0.005 ppm to 0.01 ppm respectively for each tea matrix analyzed.

Processed tea leaves from the four trials had mean residues in the ranges 5.12-36.0 ppm after a PHI of one-week, 0.976-17.8 ppm at two weeks, and 0.442-4.97 ppm after three weeks.  At a PHI of 6 days, the maximum individual residue from all four trials was 36.2 ppm in processed tea.  However, in brewed tea, the respective residue ranges were 0.014-0.04 ppm, <0.005-0.04 ppm, and <0.005-0.01 ppm.  The maximum individual bifenthrin residue was 0.074 ppm.  For this submission, a DER was not prepared because it for this study because it lacked many of the data requirements of the OPPTS 860.1500 Residue Chemistry Test Guidelines. 

MRID No. 479208010 

IR-4 has submitted a report summarizing the results of two studies which total 16 field trials made for bifenthrin on tea that were conducted in China during the 2006 and 2007 growing seasons.  No raw data were included in the submission and all results noted in the report are presented herein.

The FMC Plant Protection Company held sixteen (16) trials at two locations in the Guangdong and Zhejiang Provinces of China.  It was carried out to investigate the magnitude of bifenthrin and imidacloprid residues found in fresh green tea leaves, processed tea, and soil occurring in these regions.  As such, only the findings pertaining to the use of bifenthrin for cultivating fresh tea leaves and the occurrence of any residues retained in its processed end-product are addressed in this summation.    

For the field trials conducted in 2006, five (5) established plots in Yingde City of the Guangdong Province and Zhuji City of the Zhejiang Province were utilized in this portion of the study.  The first plot in each province received one foliar spray application of 15% imidacloprid-bifenthrin SC soluble concentrate formulation made at the target application rate of 60 ml/mu.  The second plot in each province received two foliar spray applications of this test product made at 60 ml/mu treatments for a total application rate of 120 ml/mu.  The third plot in each province received one treatment of the test product made at 90 ml/mu with the forth parcel in each province receiving two sprays at the 90 ml/mu rate for a total application of 180 ml/mu.  The fifth plot did not receive any treatments of the test product and was used for the collecting control samples.  The report did not provide enough information about the test product to allow for a calculation of the application rate specific to bifenthrin to be made as the active ingredient.  The petition submitted by the registrant only notes that the application rates of bifenthrin used in this study were 22.5 g ai/ha and 33.75 grams ai/ha made using a spray volume of 600 liters/ha.  No supporting data were likewise provided in the petition to enable the targeted application rates for study to be verified as well.  
  
The study was again repeated during the 2007 growing season held at the same locations using the same number of test plots.  For this phase of the study, the same test product was again applied using the same targeted treatment rates to provide an additional eight field trials for evaluation.  It was noted that all applications were made with a spray volume of 64.1 gallons per acre (600 L/ha).  In regard to the test plots which were designated to receive two spray treatments, the intervals for application were reported to range from 5 to 7 days.  Triplicate tea leaf samples were harvested at 3, 7 and 10 day PHIs.  The harvested tea leaves were collected from the field and subsequently manufactured into the processed end-product.     

All of the tea sample matrices comprising this study were analyzed for residues of bifenthrin using a GC/ECD methodology.  The reported LOD for bifenthrin in/on fresh tea leaves and the processed tea end-product was determined to be 0.01 ppm for both sample matrices.  The study report did not note an LOQ but acceptable method recovery results were provided demonstrating the test procedure was adequate for data collection.  The submission did note that all fresh tea leaf and processed tea samples were stored at -20[o]C.  However, the sample storage durations that were incurred for this study are not noted and no discussion of the stability of bifenthrin in tea held under similar conditions is given in the submission. 

For the fresh green tea leaf samples, mean residues of bifenthrin were found to decrease from 0.038 (Day-3) to 0.012 ppm (Day-10) following a single application of 15% SC test product made at the 60 ml/mu rate.  Following two treatments made at the total application rate of 120 ml/mu, mean residues of bifenthrin were observed to decrease from 0.066 (Day-3) to 0.015 ppm (Day-10) in the fresh green tea leaf samples.  Alternately, after a single application of 15% SC test product made at the 90 ml/mu rate, mean residues of bifenthrin were found to decrease from 0.068 (Day-3) to 0.018 ppm (Day-10) in the fresh green tea leaves.  For the treatments made at the total application rate of 180 ml/mu, mean residues of bifenthrin were similarly observed to decrease from 0.092 (Day-3) to 0.024 ppm (Day-10) in the fresh green tea leaves. 

In regard to the processed tea samples, mean residues of bifenthrin were found to decrease from 0.086 (Day-3) to 0.023 ppm (Day-10) following a single application of 15% SC test product made at the 60 ml/mu rate.  Following two treatments made at the total application rate of 120 ml/mu, mean residues of bifenthrin were observed to decrease from 0.068 (Day-3) to 0.013 ppm (Day-10) in the processed tea samples.  After a single application of 15% SC test product made at the 90 ml/mu rate, mean residues of bifenthrin were found to decrease from 0.117 (Day-3) to 0.026 ppm (Day-10) in the processed tea samples.  For the treatments made at the total application rate of 180 ml/mu, mean residues of bifenthrin were similarly observed to decrease from 0.111 (Day-3) to 0.031 ppm (Day-10) in the processed tea samples. 

Mean residues of bifenthrin did not exceed 0.13 ppm in either the fresh green tea leaves or processed tea samples for any number of applications or treatment rates tested in this study.  Under the conditions and parameters used in this study, the magnitude of bifenthrin residue was shown in the tea samples that were acquired.  However, in following the OPPTS 860.1500 Residue Chemistry Test Guidelines, a number of deviations were evident in this data submission which adversely affects the completeness of this study.  Most notably, there was not enough information provided to calculate the rate of application, the timing of the treatments made are not known, application intervals were not reported, meteorological conditions for the field trials were not reported, and whether adjuvants were used are not noted.  In addition, there was no discussion supporting the stability of bifenthrin in samples stored at -20[o]C, and no raw data were provided to support the reproducibility of the method or the lack of potential interferences.

Conclusions.  For the purpose of establishing a tolerance on imported tea, many of the submissions provided are inadequate because they fail to provide application rates, PHIs, storage length and conditions, and raw data to support the analyses that were made.  Nevertheless, MRID No. 47920803 is considered to be scientifically acceptable for demonstrating the magnitude of bifenthrin residue found in tea.  In a prior action made for Ethiprole, three tea field trials were considered sufficient for registration since tea contributes to <0.05% of the diet for any one population subgroup relevant to the United States (DP No. D382875, S. Piper, 11/29/2010).  Similarly, the three (3) tea field trials contained in MRID No. 47920803 support the establishment of a bifenthrin tolerance on imported tea.   

In general, all tea which is consumed domestically is imported with the major exporters of tea to the United States from 2004-2008 being Argentina, (20.2%), Canada (24.6%), Mexico (13.5%), China (11.5%), and India (5.2%).  However, Canada and Mexico are not major tea producers, but rather they simply import product for re-packaging and export into the United States.  Based on the relative amounts imported from countries that are actually major producers, the three (3) trials provided in MRID No. 47920803 are representative in showing the magnitude of bifenthrin residue in/on imported tea.

Apples, Nectarines, and Peaches (Section 18 Emergency Exemption)

Residue Chemistry Memo DP No. D274839 and D280288, 08/15/2002, S. Levy (includes a review of MRID Nos. 45377302 and 45377303 submitted for determining the magnitude of the residue in Pears).

For depicting the magnitude of bifenthrin residues in/on apples, nectarines, and peaches, field trial studies made on pears are available which support prior actions undertaken for this active ingredient.  The most recent data submission for pears was acquired in a 1998 to evaluate the use of different spray volumes (MRID Nos. 45377302 and 45377303).  In establishing this emergency exemption, the same use pattern supported by the representative pear crop data was proposed for treating apples, nectarines, and peaches.   A summary of the residue data are presented below in Table 8.

Table 8.	Summary of Residue Data from the Pear Crop Field Trials with Bifenthrin.
Commodity
                              Total Applic. Rate
                                   (lb ai/A)
                                  PHI (days)
                                Residue Levels
                                     (ppm)

                                       n
                                     Min.
                                     Max.
                                    HAFT[2]
                                    Median
                                     Mean
                                   Std. Dev.
Pears
                                      0.5
                                      14
                                       3
                                     0.10
                                     0.38
                                     0.32
                                     0.18
                                     0.21
                                     0.10
[1]  Except for sample min/max, values reflect per trial averages; n = no. of field trials.  For calculation of median, mean, and standard deviation, the LOQ (0.05 ppm) was used for any results reported as <LOQ or between the LOQ and LOD in the table.
[2]  HAFT = highest-average-field-trial.

Previously submitted crop field trial data for pears have been determined to be adequate to support the proposed tolerance for residues of bifenthrin per se in/on pears at 0.5 ppm (PP#6F3454; CB Nos. 6715 and 7036-7044, 10-JAN-1991, N. Dodd).  The results from the most current crop field trial studies made in pears have shown that residues of bifenthrin to range between 0.10-0.38 ppm.  These were the residue levels found in/on pears harvested 14 days following the last of three foliar applications of the 10% WP formulation of bifenthrin at 0.1, 0.2, and 0.2 lb ai/A in a spray volume of ~400 GPA for a total rate of 0.5 lb ai/A (1x the maximum proposed seasonal rate for pears).  The submitted pear field trial data are classified as acceptable and satisfy the guideline requirement for crop field trials (Residue Chemistry Guidelines OPPTS 860.1500) in conjunction with previously submitted pear field trial data.  However, the field trial data were concluded to be insufficient in supporting the petitioner's request to add lower spray volumes to the proposed label for pears.  For this data collection effort, the petitioner was instructed to submit a revised Section F for "pear" at 0.50 ppm.

Conclusions.  For the purpose of establishing a time limited emergency exemption on apples, nectarines, and peaches, studies are available which examine the use of the 10% WP (EPA Reg. No. 279-3108) and 2 lb/gal EC (EPA Reg. No. 279-3069) formulations in treating pears.  In support of the use made on pears, applications were administered at the seasonal rate of 0.5 lbs.ai/A (0.45 lbs ai/A post-bloom) following a 14 day PHI.  The submitted pear data were found to be adequate in satisfying the OPPTS 860.1500 test guideline requirements used in a establishing a permanent tolerance limit of 0.5 ppm on this commodity (DP Nos. D274839 & D280288, S. J. Levy, 08/15/2002).  This dataset is therefore concluded to be appropriate for translation to apples, nectarines, and peaches for this Section 18 action only.  

860.1520 Processed Food and Feed

Grass grown for seed

HED does not require residue data for any processed commodities associated with grass grown for seed.  Therefore, data requirements for processed food and feed are not relevant to this tolerance petition.

Tea

In support of this petition request, a formal processing study for tea was not provided but the testing of the black tea processed end-product was made in part with each of the field trials which were carried out.  Following the industry practice of adhering to a 7-day PHI when treating the crop, tea shoots (three leaves and a bud) were collected from the treated plots for testing.  From the harvested tea shoots, a portion was processed into black tea with the remaining sample submitted for testing as fresh leaf.  The samples of black tea and fresh leaf were subsequently analyzed for residues of bifenthrin.

Each of the field trial sites used for study were comprised of both untreated control and treated test plots.  The treated plots received application at accepted industry GAP rates using foliar spray bifenthrin products.  Seven days after treatment, a sample of tea shoots (three leaves and a bud) was harvested from each plot and divided into two parts.  One part was taken as the fresh leaf sample and the other was processed into the black tea end-product following the cut-turn-curl production method, or CTC, as described in the original studies.  In general, black tea is processed by first withering it to reduce the moisture in the shoots at ambient temperature for a period of 20-22 hours.  It is then rolled for 30 minutes mechanically followed by maceration of the leaf with 2 additional passes through the CTC machine's sharp cutting ridges.  Finally, it is fermented at 90-95% relative humidity for 60-75 minutes and then dried for 30 minutes at 90-95 ºC to form the black tea end-product.

For these studies, data were acquired using GLC/ECD instrumental techniques.  Quantitation of the tea samples was carried out following extraction with acetone by maceration and cleanup with adsorption column chromatography. Reference numbers were not given for these protocols, but all the procedures were successfully validated prior to the analysis of field samples.  Mean residue values of bifenthrin were found to range from 0.031 to 3.91 ppm in/on the fresh tea leaf samples analyzed in the three subject field trial studies which tested tea both commodities in this manner.  Following processing into the dried black tea end-product, the resulting mean residue values which were obtained in these studies were observed ranging from 0.041 to 3.66 ppm.  Further evaluation of the data acquired for processed black tea indicates that bifenthrin residues do not concentrate significantly in this dried end-product:  an average processing factor of 1.12x was determined as shown in Table 9. 

Table 9. 	Residue Data for the Black Tea Processed End-Product with Bifenthrin.
Field Trial Study 
                                 Tea Commodity
                                     PHI 
                                    (days)
                              Mean Residues (ppm)
                             Processing Factor[1]
MRID No. 47920803
                                  Fresh Leaf
                                       7
                                     3.91
                                     0.94

                              Processed Black Tea
                                       
                                     3.66
                                       
MRID No. 47920808
                                  Fresh Leaf
                                       
                                     0.36
                                     1.11

                              Processed Black Tea
                                       
                                     0.40
                                       
MRID No. 47920808
                                  Fresh Leaf
                                       
                                     0.031
                                     1.32

                              Processed Black Tea
                                       
                                     0.041
                                       
                                    AVERAGE
                                       
                                     1.12
   1 The processing factor was calculated by the study reviewer by dividing the residues in the processed sample by the residues in the fresh leaf. 

Apples, Nectarines, and Peaches (Section 18 Emergency Exemption)

The Agency requires a processing study for wet apple pomace.   However, For the purposes of this Section 18 only, no apple processing study is required.  

860.1650 Submittal of Analytical Reference Standards

Analytical standards for bifenthrin furnished by FMC Agricultural Products are currently available in the EPA National Pesticide Standards Repository (personal communication with Theresa Cole, BEAD, 04/26/2012).  However, this stock of standards is noted to begin expiring in 2013.  Analytical reference standards of bifenthrin must be supplied and supplies replenished as requested by the Repository.  The reference standards should be sent to the Analytical Chemistry Lab, which is located at Fort Meade, to the attention of either Theresa Cole or Thuy Nguyen at the following address:

	USEPA
	National Pesticide Standards Repository/Analytical Chemistry Branch/OPP
	701 Mapes Road
	Fort George G. Meade, MD  20755-5350

(Note that the mail will be returned if the extended zip code is not used.)

860.1850 and 860.1900 Confined/Field Accumulation in Rotational Crops

Bifenthrin TRED; DP# 283808, 8/21/02, S. Levy

An adequate confined rotational crop study was reviewed by the Environmental Fate and Effects Division (EFED) in conjunction with an earlier bifenthrin petition (Memo, E. Regelman, 08/07/1987).  From this data it was concluded that a 30-day Plant-Back Interval (PBI) would be appropriate for leafy vegetables and root crops with additional data being needed for an assessment of grain crops to be made.  A field rotational crop study made with wheat was subsequently provided by the registrant to fulfill data requirements for grain crops.  In this study, residues of bifenthrin were found to be <0.01 ppm in/on grain, forage, hay and straw from wheat planted 30 days following the last of five treatments made to a primary crop at 0.1 lb ai/A/application.  Based on the available confined and field rotational crop data, HED concluded that all existing rotational crop restrictions are appropriate for bifenthrin (DP No. D283808, S. J. Levy, 08/21/2002).  Crops with established bifenthrin tolerances may be rotated at any time with all others holding to a 30-day PBI following a final application of bifenthrin.  No rotational crop tolerances are required.       

860.1550 Proposed Tolerances 

Tolerances for residues of bifenthrin are currently expressed in terms of the parent compound only.  Permanent tolerances are established for bifenthrin residues in/on several food commodities under 40 CFR §180.442(a)(1).  The established tolerances for plant and livestock commodities, under §180.442(a)(1), range from 0.05 ppm (various plant and poultry commodities) to 70 ppm (grain, aspirated fractions).  A tolerance of 0.05 ppm is also established for residues of bifenthrin in food/feed handling establishments under §180.442(a)(2).  In addition, time-limited tolerances for residues of bifenthrin have been established under §180.442(b) in connection with Section 18 emergency exemptions; these include tolerances for orchardgrass, forage and hay at 2.5 ppm and 4.5 ppm, respectively, with a 12/31/12 expiration date.  

IR-4 has submitted a study for determining the magnitude of bifenthrin residue found in grass forage and hay.  These data were entered into the OECD calculation procedures to determine appropriate tolerance levels (Appendix 1).  Using the OECD calculation procedures, a tolerance of 3.0 ppm for residues in/on grass forage and 6.0 ppm in/on grass hay are recommended when utilizing the uncorrected values from the field trial studies.  After correction for storage stability decline, tolerance levels are 4.0 ppm in/on grass forage and 15 ppm in/on grass hay.  HED recommends a tolerance of 4.0 ppm in/on grass forage and 15 ppm in/on grass hay for residues of bifenthrin based on the residue data obtained from the field trials that were provided.  

For this petition, the registration of bifenthrin for treating grass grown for seed will limit this use only to ID, OR and WA.  The forage and hay commodities of grass are often used as a livestock feedstuff typically fed to cattle.  For this reason, dietary burden was subsequently re-calculated for bifenthrin following current guidelines using the maximum reasonably balanced diet to livestock.  Because both grass forage and hay are roughage, only grass forage was used in this re-calculation since the percent dry matter of this feed will yield greater levels for a more conservative evaluation.   For this re-calculation, the values which were found are consistent when compared to the prior determination of livestock dietary burden made for bifenthrin pursuant to PP#s 6E7125-6E7128 (DP Nos. D335688, D335693, D335695 & D335696, W. Wassell, 07/25/2007).  HED concludes that the established bifenthrin livestock tolerances would remain appropriate and do not need to be increased.

For the purpose of establishing an appropriate tolerance on imported tea, nine (9) studies/reports completed abroad were provided to show the magnitude of bifenthrin residue in/on this commodity.  However, many of the submissions provided were inadequate because they fail to provide application rates, PHIs, storage lengths and conditions, and raw data to support the analyses that were made.  Nevertheless, MRID No. 47920803 is considered to be scientifically acceptable for demonstrating the magnitude of bifenthrin residue found in tea.  Although the registrant requests the tolerance for tea be established on plucked leaves, the fresh tea leaf is not imported into the United States which necessitates that any level be set only on dried tea.  

Based on an examination of all the study data provided to support this petition, residues of bifenthrin were found not to concentrate in the processed dried tea end-product.  Using the OECD calculation procedures, a rounded MRL of 20 ppm was determined for dried tea (Attachment 2).  These residue values were first corrected for the deficit that was apparent in the rate of application (1.33x) because the subject study was approximately 25% less than the reported maximum GAP rate.  However, to harmonize with Codex, HED recommends a tolerance level of 30 ppm for dried tea.    

For determining the magnitude of the residue in/on apples, nectarines, and peaches, the OECD calculation procedures were not used because pear data supporting prior actions made for this representative commodity were considered.  The most recent data submission for pears was acquired in a 1998 to evaluate the use of different spray volumes (MRID Nos. 45377302 and 45377303).  The application pattern for this use on pears prescribes a seasonal rate of 0.5 lbs.ai/A (0.45 lbs ai/A post-bloom) made as multiple treatments at a 30-day RTI following a 14 day PHI.  From this dataset acquired with this use pattern, it was concluded that a 0.5 ppm tolerance would be appropriate for the use of 10% WP bifenthrin product in treating this representative crop (DP. Nos. D274839 & D280288, S. Levy, 08/15/2002).  In establishing this emergency exemption, the same use pattern supported by the representative pear crop data will be put forward for treating apples, nectarines, and peaches to mitigate stink bug infestation in these affected states.   

Table 10. 	Tolerance Summary for Bifenthrin
Crop Group or Commodity
                           Proposed Tolerance (ppm)
                          Recommended Tolerance (ppm)
Comments; Correct Commodity Definition
Apple
                                      --
                                      0.5
Specified in (b) Section 18 emergency exemption;  Apple
Grass, forage 
                                      2.5
                                      4.0
Specified in (c) Tolerances with regional registrations; 
Grass, hay
                                      4.5
                                      15
Specified in (c) Tolerances with regional registrations; 
Nectarine
                                      --
                                      0.5
Specified in (b) Section 18 emergency exemption;  Nectarine
Peach
                                      --
                                      0.5
Specified in (b) Section 18 emergency exemption;  Peach
Tea
                                      25
                                      30
Specified in (a) General; Tea, dried

References

DP Nos.:	274839 and 280288
Subject:	PP#6F03454.  Bifenthrin On Pear and Nut, Tree, Group.  Evaluation of Residue Data and Analytical Methods.  
From:	S. J. Levy and G. Kramer
To:	G. LaRocca
Dated:	08/12/2002
MRID Nos:	45377301-45377305

DP No.:	283808
Subject:	Bifenthrin.  Residue and Product Chemistry Considerations for the Tolerance Reassessment Eligibility Decision (TRED)  
From:	S. J. Levy
To:	T. Myers
Dated:	08/21/2002
MRID Nos:	None

DP No.:	384283
Subject:	Review of Tolerance Enforcement Method for Bifenthrin.  DP Barcode #384283.  ACB Project # B11-10.  
From:	C. J. Stafford
To:	J. Arthur
Dated:	12/22/2010
MRID No.:	45377301

DP No.:	286230
Subject:	Bifenthrin (PC Code: 128825).  Petitioner's Responses to HED Residue Chemistry Deficiencies Identified in the Tolerance Reassessment Eligibility Decision (TRED) Document (Memo, S. Levy, 21-AUG-2002; D283808).  
From:	S. J. Levy
To:	T. Myers
Dated:	10/17/2002
MRID Nos.:	None

DP Nos.:	335693, 335688, 335696, 335695
Subject:	Bifenthrin (Chemical No. 128825).  PP#6E7125, PP#6E7126, PP#6E7127, PP#6E7128; Section 3 Registration for Application of Bifenthrin to Mayhaw, Root Vegetables, (Except Sugar Beets, Crop Subgroup 1B), Peanut, Pistachio, Soybean, and Fruiting Vegetables (Crop Group 8).  Summary of Residue Chemistry Data.  
From:	W. Wassell
To:	D. Rosenblatt and S. Brothers
Dated:	07/25/2007
MRID Nos:	46098701, 46960801, 46961101-46961103, 46960401-46960404

DP No.:	355743
Subject:	Bifenthrin.  Bridging Study Supporting Use of an Emulsifiable Concentrate Formulation on Tree Nuts.  Summary of Analytical Chemistry and Residue Data.
From:	P. Savoia
To:	G. LaRocca
Dated:	12/08/2008
MRID No.:	47433601

DP No.:	382875
Subject:	Ethiprole.  Request for Tolerance without U.S. Registration in/on Imported Rice and Tea.  Summary of Analytical Chemistry and Residue Data.
From:	S. Piper
To:	C. Rodia
Dated:	11/29/2010
MRID Nos.: 	47622720-47622727

Attachments:  
   1.  International Residue Limit Status sheet
   2. Tolerance Assessment Calculations

Attachment 1.  International Residue Limits

                   Bifenthrin (128825; 04/03/2012)
Summary of US and International Tolerances and Maximum Residue Limits 
Residue Definition:
US
Canada
Mexico[2]
Codex[3]
40 CFR 180.442:
Plants/Livestock: Bifenthrin (2-methyl [1,1′-biphenyl]-3-yl) methyl-3-(2-chloro-3,3,3,-trifluoro-1-propenyl)-2,2-dimethylcyclopropanecarboxylate
None

bifenthrin (sum of isomers). The residue is fat-soluble.
Commodity[1]
Tolerance (ppm) /Maximum Residue Limit (mg/kg)

US
Canada
Mexico[2]
Codex[3]
Apple
0.5

Grass, forage
4.0

Grass, hay
15

Nectarine
0.5

Peach
0.5

Tea, dried
10

30 (proposed) Tea, Green, Black (black, fermented and dried) 

Completed:  M. Negussie; 04/03/2012
[1] Includes only commodities of interest for this action.  Tolerance values should be the HED recommendations and not those proposed by the applicant.
2 Mexico adopts US tolerances and/or Codex MRLs for its export purposes.

3 * = absent at the limit of quantitation; Po = postharvest treatment, such as treatment of stored grains.  PoP = processed postharvest treated commodity, such as processing of treated stored wheat. (fat) = to be measured on the fat portion of the sample. MRLs indicated as proposed have not been finalized by the CCPR and the CAC.

Tea, green and black
Supervised trials on green and black tea (dry) were available from China, India, Indonesia and Japan.
In China, the registered use for bifenthrin in tea is foliar spray treatment at 0.0075 - 
0.053 kg ai/ha and a PHI of 7 days. The Meeting received ten Chinese trials treated with 2 x 0.045 - 
0.048 kg ai/ha and a PHI of 7 days which were considered still consistent with Chinese GAP. The
residues were in dried tea in ranked order (n = 10): 0.04, 0.07, 0.08, 0.08, 0.08, 0.09, 0.09, 0.11, 1.2
and 4.3 mg/kg.

Three trials from India treated with 0.06 kg ai/ha and a PHI of 7 days were submitted. The
application rate was in the limit of +- 25% of Chinese GAP. The residues were in dried tea 0.42, 5.1
and 5.9 mg/kg.

The GAP in Japan is 2 x 0.08 kg ai/ha and a PHI of 14 days. Three Japanese trials according
to GAP were submitted. The residues were in dried tea 1.3, 5.2 and 18 mg/kg.
One Indian (1 x 0.08 kg ai/ha, PHI 14 days) and one Indonesian trial (0.06 and 0.10 kg ai/ha,
PHI 10 days) were considered still consistent with Japanese GAP. The residues were in dried tea 0.47
and 4.6 mg/kg.

The Meeting agreed to use the Japanese trials supported by the results of the Indian and
Indonesian trials to estimate a maximum residue level.
The Meeting estimated a maximum residue level and an STMR for bifenthrin in tea, green
and black, of 30 mg/kg and 5.2 mg/kg, respectively.

Statistical calculations for only three data points were not adequate.

Attachment 2.  Tolerance Assessment Calculations.

Grass (grown for seed)

The dataset used to establish a tolerance for bifenthrin on grass grown for seed forage and hay consisted of field trial data acquired for these commodities.  The data reflect application rates of 0.199-0.207 lb ai/A/season (2 applications at 0.099-0.104 lb ai/A/application) of an EC formulation with a 29- to 36-day PHI for forage and 29- to 43-day PHI for hay.  This field trial data appropriately quantified the expected range of residues in these commodities following treatment according to the Good Agricultural Practice (GAP) proposed for this pattern of use.  In this study, the application rates were all made at the maximum rate following minimum re-treatment and harvest intervals.  It is important to note that the PHIs for three (3) of the five (5) trials did exceed this criterion for hay.  All field trial sample results obtained for grass forage and hay were found to be above the LOQ (LOQ = 0.03 ppm for forage; LOQ = 0.08 ppm for hay). 

To establish appropriate tolerance levels on grass forage and hay, these data were entered into the Organization for Economic Cooperation and Development (OECD) calculation procedures for determination.  For those field trials where sampling replicates were taken, the average or mean value was used for calculation.  The mean residue values corrected for storage stability decline used to calculate the tolerance levels are provided in Table I-1 for forage and Table I-2 for hay.  These field trial results acquired for bifenthrin on grass forage and hay do in fact represent a small dataset of only 3-7 residue values.  In using the OECD calculation procedures with small datasets, there can be a considerable level of uncertainty in the resulting MRL value for this statistical determination.  Nonetheless, for datasets of this size where uncertainty can be high, the results obtained are justifiable 
given the non-distributional approach followed by the OECD calculation procedures and the great variability which exists in the data.

When using the OECD calculation procedures, the resulting MRL value is always found to be greater than or equal to the highest residue within the dataset.  MRLs are displayed without decimal zeros after the last significant figure and are rounded in the last step of calculation to produce a result in the region of the 95[th] percentile.  For grass forage, storage stability loss was found to occur at 35% so the corrected data was appropriately used for calculation.  The MRL estimate calculated at the "Mean + 4 SD" recommends a tolerance level for bifenthrin on grass forage at 4 ppm.  In regard to grass hay, the data entered for calculation were likewise adjusted because storage stability loss was found to occur at 55% for this commodity.   The MRL estimate calculated at the "Mean + 4 SD" recommends a tolerance level for bifenthrin on grass hay at 15 ppm. 

Inputs for calculating statistically based pesticide tolerances.

Table I-1 Inputs for Grass Forage

 
 
 
 
 
                                  BiFenthrin
                                       
 
                            Grass Forage(Corrected)
                                       
 
                      US (Restricted to ID, OR & WA)
                                       
 
                               PHI = 29-36 Days
                                       
 
 
 
 
 
Total number of data (n)
                                       5
                                       
 
Percentage of censored data
                                      0%
                                       
 
Number of non-censored data
                                       5
                                       
 
Lowest residue
                                     0.130
                                       
 
Highest residue
                                     1.960
                                       
 
Median residue
                                     0.480
                                       
 
Mean
                                     0.724
                                       
 
Standard deviation (SD)
                                     0.747
                                       
 
Correction factor for censoring (CF)
                                     1.000
                                       
 
 
                                       
                                       
 
Proposed MRL estimate
 
 
 
 
                                       
 
 
- Highest residue
                                     1.960
 
 
- Mean + 4 SD
                                     3.711
 
 
- CF x 3 Mean
                                     2.172
 
 
Unrounded MRL
                                     3.711
                                       
 
 
                                       
 
 
Rounded MRL
                                       4
                                       
 
 
                                       
                                       
 
 High uncertainty of MRL estimate.
                                       
 
[Small dataset]
 
 
 
 
 

                               Residues (mg/kg)
                                     0.13
                                      0.2
                                     0.48
                                     0.85
                                     1.96

Table I-2 Inputs for Grass Hay

 
 
 
 
 
                                  Bifenthrin
                                       
 
                             Grass Hay (Corrected)
                                       
 
                      US (Restricted to ID, OR & WA)
                                       
 
                               PHI = 29-36 Days
                                       
 
 
 
 
 
Total number of data (n)
                                       5
                                       
 
Percentage of censored data
                                      0%
                                       
 
Number of non-censored data
                                       5
                                       
 
Lowest residue
                                     0.220
                                       
 
Highest residue
                                     6.650
                                       
 
Median residue
                                     0.320
                                       
 
Mean
                                     1.624
                                       
 
Standard deviation (SD)
                                     2.815
                                       
 
Correction factor for censoring (CF)
                                     1.000
                                       
 
 
                                       
                                       
 
Proposed MRL estimate
 
 
 
 
                                       
 
 
- Highest residue
                                     6.650
 
 
- Mean + 4 SD
                                    12.885
 
 
- CF x 3 Mean
                                     4.872
 
 
Unrounded MRL
                                    12.885
                                       
 
 
                                       
 
 
Rounded MRL
                                      15
                                       
 
 
                                       
                                       
 
 High uncertainty of MRL estimate.
                                       
 
[Small dataset]
 
 
 
 
 

                               Residues (mg/kg)
                                     0.22
                                     0.26
                                     0.32
                                     0.67
                                     6.65

Tea, dried

The dataset used to establish a tolerance for bifenthrin on tea (dried) consisted of field trial data acquired for this commodity.  The data reflect one application of Talstar 2EC, an emulsifiable concentrate formulation containing 2.0 lb bifenthrin/gal (240 g ai/liter).  Treatment was made as a foliar spray applied at the targeted rate of 0.053 lb bifenthrin/A (60 g ai/ha).  All applications were made with a spray volume of 53.5 gallons per acre (500 L/ha).  Following the industry practice in India of a 7-day PHI when treating the crop, tea shoots (three leaves and a bud) were collected from the treated plots for testing.  From the harvested tea shoots, a portion was processed into black tea with the remaining sample submitted for testing as fresh leaf.  The samples of black tea and fresh leaf were subsequently analyzed for residues of bifenthrin.

To establish appropriate tolerance levels on tea, the data for the processed dried tea end-product were entered into the Organization for Economic Cooperation and Development (OECD) calculation procedures for determination.  These residue values were first corrected for the deficit that was apparent in the rate of application (1.33x) because the subject study was approximately 25% less than the reported maximum GAP rate.  For those field trials where sampling replicates were taken, the average or mean corrected value was used for calculation.  These field trial results entered on dried tea do in fact represent a small dataset of only 3-7 residue values.  In using the OECD calculation procedures with small datasets, there can be a considerable level of uncertainty in the resulting MRL value for this statistical determination.   Nonetheless, for datasets of this size where uncertainty can be high, the results obtained are justifiable given the non-distributional approach followed by the OECD calculation procedures and the great variability which exists in the data.

When using the OECD calculation procedures, the resulting MRL value is always found to be greater than or equal to the highest residue within the dataset.  MRLs are displayed without decimal zeros after the last significant figure and are rounded in the last step of calculation to produce a result in the region of the 95[th] percentile.  The MRL estimate for bifenthrin on dried tea was 20 ppm (see Table I-3).  For harmonization with Codex, HED recommends a tolerance level of 30 ppm for dried tea.    

Table I-3 Inputs for Tea, dried

 
 
 
 
 
                                  Bifenthrin
                                       
 
                                  Tea, dried
                                       
 
                                Import (India)
                                       
 
                                   7-day PHI
                                       
 
 
 
 
 
Total number of data (n)
                                       3
                                       
 
Percentage of censored data
                                      0%
                                       
 
Number of non-censored data
                                       3
                                       
 
Lowest residue
                                     0.530
                                       
 
Highest residue
                                     7.590
                                       
 
Median residue
                                     6.450
                                       
 
Mean
                                     4.857
                                       
 
Standard deviation (SD)
                                     3.790
                                       
 
Correction factor for censoring (CF)
                                     1.000
                                       
 
 
                                       
                                       
 
Proposed MRL estimate
 
 
 
 
                                       
 
 
- Highest residue
                                     7.590
 
 
- Mean + 4 SD
                                    20.017
 
 
- CF x 3 Mean
                                    14.570
 
 
Unrounded MRL
                                    20.017
                                       
 
 
                                       
 
 
Rounded MRL
                                      20
                                       
 
 
                                       
                                       
 
 High uncertainty of MRL estimate.
                                       
 
[Small dataset]
 
 
 
 
 

                               Residues (mg/kg)
                                       n
                                     0.53
                                       1
                                     6.45
                                       1
                                     7.59
                                       1