				

UNITED STATES ENVIRONMENTAL PROTECTION AGENCY

WASHINGTON, D.C.  20460

OFFICE OF

PREVENTION, PESTICIDES AND

TOXIC SUBSTANCES

THIS DOCUMENT IN ON THE H:\ DRIVE

MEMORANDUM

DATE:		September 3, 2008

SUBJECT:		Tier I Estimated Drinking Water Concentrations of
Fenpropathrin: IR-4 Tolerance Petition for the Use of Fenpropathrin on
Tree Nuts and Pistachio, Barley, Tropical and Sub Tropical Fruits,
Bushberries, Fruiting Vegetables, Peas, Caneberries and Olives (PC Code
127901, DP Barcodes D313331, D333118,  D342501 and D347897).

FROM:	José Luis Meléndez, Chemist

				Environmental Risk Branch V

				Environmental Fate and Effects Division (7507P)

TO:				Sidney Jackson, Risk Manager

				Daniel Rosenblatt, Branch Chief

				Risk Integration, Minor Use and Emergency Response Branch

				Registration Division (7505P)

				Olga Odiot, Risk Manager Reviewer

				George LaRocca, Risk Manager

				Marion Johnson, Branch Chief

				Insecticide Branch

				Registration Division (7505P)

AND				Christina Swartz, Branch Chief

				Registration Action Branch II

				Health Effects Division (7509P)

THROUGH:	Mah T. Shamim, Ph.D., Chief

Environmental Risk Branch V

				Environmental Fate and Effects Division (7507P)

This memo presents the Tier I Estimated Drinking Water Concentrations
(EDWCs) for fenpropathrin, calculated using FIRST (surface water) and
SCI-GROW (ground water) for use in the human health risk assessment. 
The registrant seeks to establish tolerances for use on tree nuts and
pistachio, barley, tropical and sub tropical fruits, bushberries,
fruiting vegetables, peas, caneberries and olives.

The EFED has found that the scenario with the highest rate and minimum
interval between applications is grapes.  This scenario was assessed in
the previous drinking waters assessment (D295472) and the Division is
relying on it to cover the new uses.

For surface water, the acute (peak) value is 10.3 ppb and the chronic
(annual average) value is 1.81 ppb.  The groundwater screening
concentration is 0.00480 ppb.  These values generally represent
upper-bound estimates of the concentrations that might be found in
surface water and groundwater due to the use of fenpropathrin on grapes.
 Both models provide estimates suitable for screening purposes. 
Additional refinements can be developed should they be needed by HED. 
Should any questions arise, please, contact José Meléndez (EFED).

Data gaps:

The database for fenpropathrin is substantially complete.  The mobility
(batch equilibrium) study was found to be supplemental because
Freundlich KF’s and KFOC’s could only be determined for the loam. 
Kd’s and KOC’s could not be determined for the silt loam sediment,
and sandy loam, silt loam, sandy loam and clay loam soils at all
concentrations.  However, at this time, no additional data are required.

EXECUTIVE SUMMARY 

)-α-cyano-3-phenoxybenzyl 2,2,3,3-tetramethylcyclopropanecarboxylate]
is a Type II synthetic pyrethroid insecticide and miticide (IRAC’s
classification Group 3 – includes pyrethroids and pyrethrins). 
Fenpropathrin has two chiral centers, one in the carbon attached to the
cyano group and one in a carbon of the cyclopropyl moiety (refer to
structure in the appendix).

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

Fenpropathrin is currently used on a variety of crops, including cotton,
head and stem brassica, bushberries and currant, citrus, cucurbits,
fruiting vegetables, grapes, peanuts, pome fruits, strawberries and
peas.  The registrant seeks to establish tolerances for use on tree nuts
and pistachio, barley, tropical and sub tropical fruits, bushberries,
fruiting vegetables, peas, caneberries crop and olives (Section 3 –
new use or IR-4 requests).  Fenpropathrin may be applied by ground,
airblast or aerial methods.

This is a Tier 1 screening-level drinking water analysis (DWA) as a
result of a Section 3 and IR-4 requests for tolerances.  The Tier 1
models utilized were FIRST and SCI-GROW for surface and ground waters,
respectively.  There are no major degradates for fenpropathrin;
therefore, no degradates were modeled in this assessment.  Only the
parent compound was included in the drinking water expression.  A source
of uncertainty for the results of fenpropathrin is that Kd’s and
KOC’s could not be determined for four of the soils and sediments at
all concentrations.  Table 1 provides a summary of the EDWCs obtained in
the assessment.  The EFED relied on the previous DWA since the scenario
of highest exposure is grapes, which was assessed in the previous DWA. 
Please, refer to the appendix, which contains an electronic copy of the
Tier 1 DWA that was performed earlier.  Additional refinements are
available using higher tier aquatic models, should it be needed by HED.

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

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

Groundwater (SCI-GROW)	Grapes (0.8 lb a.i./A/season)	Acute and Chronic
0.00480

Surface water  (FIRST)	Grapes (0.8 lb a.i./A/season)	Acute	10.3



Chronic	            1.81



Use Characterization

A summary table of all use patterns, with the new uses shaded, and Tier
I modeled uses in bold font, is illustrated below (Table 2).

  SEQ CHAPTER \h \r 1 

Table 2.  Summary use information for fenpropathrin, based on DANITOL®
2.4 EC Spray (Reg. No. 59639-35) current and proposed labels (shaded). 
The use pattern selected for modeling is bolded. 

USE	SINGLE  APP. RATE             (lbs. a.i./A)	NUMBER OF APPS.	SEASONAL
APP. RATE (lbs. a.i./A)	INTERVAL BETWEEN APPS. (days)	APP. METHOD
PRE-HARVEST INTERVAL (days)

Head and stem brassica (broccoli, brussel sprouts, cabbage, cauliflower,
cavalo broccolo, Chinese broccoli-gal lon, Chinese cabbage-napa, Chinese
mustard cabbage-gal choy, Kohlrabi, Brussels sprouts, cauliflower)
0.2-0.3	3-4	0.8	7	G, A	7

Citrus	0.2-0.4	2-4	0.8	10	G, Airblast, A	1

Cotton	0.15-0.3	3-5	0.8	7	G, A	21

Cucurbits (balsam apple, balsam pear, bitter melon, chayote, Chinese
cucumber, Chinese waxgourd, citron melon, cucumber, edible gourd,
gherkin, honeydew, Momordica spp., muskmelon, pumpkin, summer squash,
watermelon, winter squash)	0.2-0.3	3-4	0.8	7	G, A	7

Fruiting vegetables (bell pepper, chili pepper, cooking pepper,
eggplant, ground cherry-Physalis spp., pepino, pimento, sweet pepper,
tomatillo, tomato)	0.15-0.2	4-5	0.8	7	G, A	3

Grape	0.1-0.4	2-8	0.8	7	G, A	21

Peanut	0.1-0.3	3-8	0.8	7	G, A	14

Pome fruit (apple, crabapple, loquat, mayhaw, quince, oriental pear,
pear)	0.2-0.4	2-8	0.8	10	Airblast	14

Strawberry	0.2-0.4	2-8	0.8	30	G	2

Pea (English pea, garden pea, green pea, pigeon pea)	0.2	4	0.8	7	G, A	7

Currant	0.2-0.3	3	0.8	7	G	21

Bushberries (blueberry-highbush and lowbush, elderberry, gooseberry,
huckleberry, juneberry, lingonberry, rabbiteye, salal)	0.2-0.3	2	0.6	14
G, A	3

Caneberries (blackberry-including bingleberry, boysenberry, dewberry,
lowberry, marionberry, olallieberry and youngberry; loganberry; black
raspberry; red raspberry)	0.2-0.3	2	0.6	14	G, A	3

Olive	0.2-0.3	3-4	0.8	14	G	7

Stone fruits (such as apricot, cherry, nectarine, peach, plum and prune)
0.2-0.4	2-4	0.8	10	Airblast	14

Tree nut (such as almond, beechnut, cashew, chestnut, chinquapin,
filbert (hazelnut), hickory, macadamia, pecan, pistachio, walnut)
0.2-0.4	2-4	0.8	10	Airblast	14

Barley	0.2	1	0.2	N/A	G	14

Tropical and subtropical fruits (inedible peel, including but not
limited to avocado, canistel, mango, papaya, sapodilla, black and mamey
sapote, star apple)	0.3-0.4	2	0.8	14	G	1



APPENDIX A. Chemical Structure of Fenpropathrin

 

Fenpropathrin

APPENDIX B.  Copy of Drinking Water Assessment Dated January 22, 2003

C O P Y

UNITED STATES ENVIRONMENTAL PROTECTION AGENCY

WASHINGTON D.C., 20460

                                                                     
OFFICE  OF 

                                                                 
PREVENTION, PESTICIDES AND

                                                                   
TOXIC SUBSTANCES

January 22, 2003

MEMORANDUM

SUBJECT:	IR-4 Tolerance Petition for the Use of Fenpropathrin (PC #
127901) on Bushberry Crop Subgroup 13-B (DP Bar Code: D295472).  Tier I
Estimated Drinking Water Concentrations of Fenpropathrin.

TO:		Shaja Brothers, PM Team Reviewer

Robert Forrest, Chief

Registration Division (7505C)

and		Gary Bangs

Health Effects Division (7509C)

FROM:	José Luis Meléndez, Chemist

Environmental Risk Branch V/EFED

THROUGH:	Mah T. Shamim, Ph.D., Chief

Environmental Risk Branch V

Environmental Fate and Effects Division (7507C)

This memo presents the Tier I Estimated Drinking Water Concentrations
(EDWCs) for fenpropathrin, calculated using FIRST (surface water) and
SCIGROW (ground water) for use in the human health risk assessment.  The
registrant seeks to establish tolerances for use on bushberry crop
(subgroup 13-B).

For surface water, the acute (peak) value is 10.3 ppb and the annual
average value is 1.8 ppb.  The groundwater screening concentration is
<0.006 ppb.  These values generally represent upper-bound estimates of
the concentrations that might be found in surface water and groundwater
due to the use of fenpropathrin on grapes, which represents the scenario
with the highest application rate with the lowest interval between
applications.  Both models provide estimates suitable for screening
purposes.  Additional refinements can be developed should they be needed
by HED.

Use of Fenpropathrin on Bushberry Crops (Subgroup 13-B):

The proposed petition for tolerance for the use of fenpropathrin is for
use in the production of bushberry (subgroup 13B).  The product used is
Danitol 2.4 EC Spray (30.9% a.i.).  It would be used on Blueberries
(highbush and lowbush), Elderberries, Gooseberries, Huckleberries,
Lingonberries, Juneberries, and Salal, for the control of Japanese
Beetle, Blueberry Maggot, and Obliquebanded Leafroller.  Two
applications can be made with 14 day interval at a maximum of 0.3 lb
a.i./A/application, and not to exceed a seasonal application rate of 0.6
lb a.i./A.  According to the submission (section B), the chemical can be
applied by ground methods only.

Background Information on FIRST:

FIRST is a screening model designed to estimate the pesticide
concentrations found in water for use in drinking water assessments.  It
provides high-end values on the concentrations that might be found in a
small drinking water reservoir due to the use of pesticide.  Like
GENEEC, the model previously used for Tier I screening level, FIRST is a
single-event model (one run-off event).  It can also account for spray
drift from multiple applications.  FIRST takes into consideration the so
called Index Drinking Water Reservoir by representing a larger field and
pond than the standard GENEEC scenario.  The FIRST scenario includes a
427 acres field immediately adjacent to a 13 acres reservoir, 9 feet
deep, with continuous flow (two turnovers per year).  The pond receives
a spray drift event from each application plus one runoff event.  The
runoff event moves a maximum of 8% of the applied pesticide into the
pond.  This amount can be reduced due to degradation on field and the
effect of binding to soil.  Spray drift is equal to 6.4% of the applied
concentration from the ground spray application and 16% for aerial
applications.

FIRST also makes adjustments for the percent crop area. While FIRST
assumes that the entire watershed would not be treated, the use of a PCA
is still a screen because it represents the highest percentage of crop
cover of any large watershed in the US, and it assumes that the entire
crop is being treated.  Various other conservative assumptions of FIRST
include the use of a small drinking water reservoir surrounded by a
runoff-prone watershed, the use of the maximum use rate, no buffer zone,
and a single large rainfall.

Background Information on SCIGROW:

SCIGROW  V.2.3 provides a groundwater screening exposure value to be
used in determining the potential risk to human health from drinking
water contaminated with the pesticide.  Since the SCIGROW concentrations
are likely to be approached in only a very small percentage of drinking
water sources, i.e., highly vulnerable aquifers, it is not appropriate
to use SCIGROW for national or regional exposure estimates.

SCIGROW estimates likely groundwater concentrations if the pesticide is
used at the maximum allowable rate in areas where groundwater is
exceptionally vulnerable to contamination.  In most cases, a large
majority of the use area will have groundwater that is less vulnerable
to contamination than the areas used to derive the SCIGROW estimate.

Estimated concentrations of chemicals with Koc values greater than 9995
ml/g are beyond the scope of the regression data used in SCI-GROW
development.  If there are concerns for such chemicals, a higher tier
groundwater exposure assessment should be considered, regardless of the
concentration returned by SCI-GROW.

Modeling Inputs and Results:

Tables 1 and 2 summarize the input values used in the model runs for
FIRST 1.0 and SCIGROW, respectively.  The lowest non-sand KD was used in
FIRST.  The median KOC value was used in SCIGROW.  There was one
available aerobic soil metabolism half-life for fenpropathrin.  Three
times the available half-life was used for the aerobic soil metabolism
input in FIRST.  The modeling results associated with maximum allowable
rate per year (on peanuts, 0.27 lb ai/A applied three times at 7 days
intervals), are presented in Table 3.  Attached to this memo are copies
of the original printouts generated from FIRST and SCIGROW runs.

According to the label, there is a buffer zone of 25 feet between the
treated fields and streams, ponds, lakes, rivers, springs, swamps,
marshes, or irrigation canals containing water year around for ground
applications, and 150 feet for aerial applications.  If ultra low volume
(ULV) application is made, the buffer zone should be increased to 450
feet.

Table 1.	Environmental Fate and Other Input Parameters for the
Estimation of Fenpropathrin using FIRST

Parameter	

Value	

Source



Water Solubility (25(C)	

0.0103 ppm	

MRID# 44370001



Hydrolysis Half-Life (pH 7) (stable)	

0	

MRID# 42599901



Aerobic Soil Metabolism Half-Life (3X available value)	

456 days	

MRID# 42525902



Aerobic Aquatic Metabolism Half-life (2X aerobic soil input)	

912 days	

NA



Aqueous Photolysis Half-Life (stable)	

0	

MRID# 42546402



Coefficient (Lowest non-sand Kd)	

212	

MRID#.s 42584101 and 44370002



Pesticide is Wetted-In	

No	

Label



Method of Application	

aerial	

Label



PCA	

0.87	

Default for grapes



Depth of Incorporation (Broadcast)	

0.0 in.	

Label



Table 2.	Environmental Fate Input Parameters for the Estimation of
Fenpropathrin using SCIGROW.

Parameter	

Value	

Source



Organic Carbon Partition Coefficient (median KOC)	

293000	

MRID#’s 42584101 and 44370002



Aerobic Soil Metabolism Half-Life (available value)	

152 days	

MRID# 42525902



Table 3.  Modeling Results for Use of Fenpropathrin on Grapes

Parameter	

Grapes	

Source



Application Method	

aerial	

Label



Application Rate	

0.4 lb a.i./A	

Label



Applications Permitted per Year	

2	

Label



Application Interval	

7 days	

N/A



FIRST 1.0 Peak Untreated Water Concentration	

10.3 ppb	

N/A



FIRST 1.0 Annual Average Untreated Water Concentration	

1.8 ppb	

N/A



SCIGROW Ground Water Concentration	

<0.006 ppb	

N/A



Appendix I.	SURFACE WATERS (FIRST) and GROUND WATERS OUTPUT RUNS FOR
GRAPES

	Estimated Surface Water Concentrations for Fenpropathrin

   RUN No.   1 FOR Fenpropathrin    ON   Grapes        * INPUT VALUES * 

   --------------------------------------------------------------------

   RATE (#/AC)   No.APPS &   SOIL  SOLUBIL   APPL TYPE  %CROPPED INCORP

    ONE(MULT)    INTERVAL     Kd   (PPB )    (%DRIFT)     AREA    (IN)

   --------------------------------------------------------------------

   .400(   .796)   2   7     212.0   10.3   AERIAL(16.0)  87.0      .0

   FIELD AND RESERVOIR HALFLIFE VALUES (DAYS) 

   --------------------------------------------------------------------

   METABOLIC  DAYS UNTIL  HYDROLYSIS   PHOTOLYSIS   METABOLIC  COMBINED

    (FIELD)  RAIN/RUNOFF  (RESERVOIR)  (RES.-EFF)   (RESER.)   (RESER.) 

   --------------------------------------------------------------------

    456.00        2          N/A       .00-     .00   912.00    912.00

   UNTREATED WATER CONC (MICROGRAMS/LITER (PPB))    Ver 1.0 AUG 1, 2001

   --------------------------------------------------------------------

        PEAK DAY  (ACUTE)      ANNUAL AVERAGE (CHRONIC)      

          CONCENTRATION             CONCENTRATION            

   --------------------------------------------------------------------

             10.300                      1.811

	Estimated Ground Water Concentrations for Fenpropathrin

                           SCIGROW

                          VERSION 2.3

            ENVIRONMENTAL FATE AND EFFECTS DIVISION

                 OFFICE OF PESTICIDE PROGRAMS

             U.S. ENVIRONMENTAL PROTECTION AGENCY

                        SCREENING MODEL

                FOR AQUATIC PESTICIDE EXPOSURE

 

 SciGrow version 2.3

 chemical:Fenpropathrin

 time is  1/20/2004  10:21:32

 -----------------------------------------------------------------------
-

  Application      Number of       Total Use    Koc      Soil Aerobic

  rate (lb/acre)  applications   (lb/acre/yr)  (ml/g)   metabolism
(days)

 -----------------------------------------------------------------------
-

      0.400           2.0           0.800      2.93E+05      152.0

 -----------------------------------------------------------------------
-

 groundwater screening cond (ppb) =   4.80E-03*

 *Estimated concentrations of chemicals with Koc values greater than
9995 ml/g

 are beyond the scope of the regression data used in SCI-GROW
development.

 If there are concerns for such chemicals, a higher tier groundwater
exposure

 assessment should be considered, regardless of the concentration
returned

 by SCI-GROW.

 ***********************************************************************
*

 

	

  PAGE   1 

	

  PAGE   10 

( PAGE  10 (

	

  PAGE   11 

