UNITED STATES ENVIRONMENTAL PROTECTION AGENCY

WASHINGTON D.C., 20460

PC Code: 275100

Chemical: Buprofezin

DP Barcodes: D321843, D321846

January 31. 2007

MEMORANDUM	

SUBJECT:	Drinking Water Assessment for Buprofezin New Uses (R19),
Section 3, and IR-4 Tolerance Petitions.

FROM:	James K. Wolf

		Environmental Scientist

		Environmental Risk Branch 3

		Environmental Fate and Effects Division (7507P)

THRU:	Daniel Rieder, Chief

		Environmental Risk Branch III

		Environmental Fate and Effects Division (7507P)

		Stephanie Syslo, RAPL

		Environmental Risk Branch III

		Environmental Fate and Effects Division (7507P)

 	

TO:  		Barbara Madden, IR-4 Coordinator

		Risk Integration Minor Use, and Emergency Response Branch

		Registration Division 7505P

		Dana Vogel, Acting Branch Chief

		Health Effects Division (7509P)

 

	The Environmental Fate and Effects Division (EFED) was requested to
prepare a drinking water assessment for the insecticide buprofezin for
use in the HED in the Risk Assessment.  This memo summarizes the Tier 2
Surface Drinking Water Assessment for new uses, crop tolerances, and/or
reduced pre-harvest intervals of Applaud® 70WP (70% buprofezin) and
Applaud ® 70DF (70% buprofezin).  Buprofezin is an insect growth
regulator, used to control white flies, leafhoppers, scales, mealybugs,
plant hoppers and related species.  Previously, surface and ground water
assessments were conducted for almonds, bananas, citrus group, cotton,
grapes, and tomatoes (D271561) and for the melons, cucumbers, pumpkins,
squash, and lettuce (D244351) and the New Chemical Review (D244352).  

	The proposed new uses and/or tolerances for buprofezin are summarized
by DP barcode, action, type of registration, and proposed crop in Table
1.  The proposed use of buprofezin on papaya and mango subgroup is
limited to Florida, Hawaii, and Puerto Rico.  The other uses are
assumed, by EFED, to be for national use, as no specific states are
defined. 

Table 1.   DP Barcode, Action, Type of Registration, and Crop for
buprofezin.

DP Barcode	Action	Type of Registration	Crop

D323242	R19 New Use 

Tolerance petition new crop tolerance

Increase tolerance 	Sect. 3

 	Stone fruit crop group 12

Papaya and mango subgroup

Grapes

D323244	R19 New Use 

Tolerance petition 

Increase tolerance 

with reduce PHI	Sect. 3

	Stone fruit crop group

Grapes

D323245	R19 New Use

Tolerance petition

Increase tolerance	Sect, 3

New use

Increase	Papaya and Mango Subgroup

Limited to FL, HI, PR.

Grapes

D321843

	 Tolerance petition

(petition # 5E6979)	IR-4 

Tolerance Petition	Stone fruit group 12, except peaches

D321846

	R19 New Use

Tolerance petition

(petition # 5E6980)	IR-4 

Tolerance Petition	Papaya, star apple, black sapote, mango, sapodilla,
canistel, mamaey sapote

Limit to FL, HI, PR.



 	The recommended drinking water concentrations for the Tier 2 surface
water and Tier 1 ground water drinking water exposures assessments for
buprofezin are summarized in Table 2.   Estimates are for parent
buprofezin.  The buprofezin concentrations in surface water were
simulated in an Index Reservoir, with 30 years of scenario specific
weather data, using the linked PRZM/EXAMS.  The national default PCA of
0.87 was used for all crops except for the papaya and mango subgroup
which used the South Atlantic Gulf regional PCA of 0.38.  The maximum
peak concentration estimate was associated with New York grapes (Table
2).  The highest chronic and long term average concentrations were
estimated with the Michigan cherry scenario (Tables 2).  The other
scenarios considered were Florida avocados and Georgia peaches (Tables 5
and 6).  Although, the grape scenario resulted in the highest peak EDWC,
the concentrations for GA peaches and MI cherries were similar to the
New York grapes.  For ground water, the SCI-GROW model is not scenario
specific, although, it represents a site vulnerable to ground-water
contamination.

									

	Buprofezin is a relatively new chemical, thus, there are no monitoring
data available.  The water resource assessment is based solely on
model-estimated exposure concentrations.  

	

Table 2.  Recommended Estimated Drinking Water Concentrations (EDWCs)
(µg/L) for Tier 2 surface water and Tier 1 ground water for buprofezin

Water Type	1-in-10 year buprofezin concentrations	Long-term average

	Acute	Chronic

	Surface 	23.21	7.82	4.72

Ground	0.07	0.07	0.07

1 based upon New York Grapes

2 based upon Michigan Cherries

SURFACE WATER ASSESSMENT

	Buprofezin can get into surface water via spray drift, in solution in
runoff water, or attached to soil particles eroded during runoff events.
 If it reaches acidic water (pH≤5), buprofezin is expected to slowly
hydrolyze.  In neutral or alkaline water (pH≥7), buprofezin will
likely remain bound to sediment or suspended particles (due to its high
soil/water partitioning coefficients), and could persist for several
months if the water is deep, static, and/or cloudy.     However,
buprofezin persistence may be reduced significantly by photolysis if the
water is shallow and clear.  Based upon the relative persistence of the
buprofezin, i.e., slow aerobic soil metabolism rate, the aquatic
metabolism (aerobic and anaerobic) is also assumed to be slow.  Based on
the Henry's Law constant, buprofezin loss to air is expected to be
minor. 

Models

	The Tier 2 surface water EDWCs (estimated drinking water
concentrations) for buprofezin were generated with several standard
cropping scenarios using PRZM3 (Carsel, 1997) and EXAMS (Burns, 2002). 
PRZM simulates pesticide fate and transport as a result of leaching,
direct spray drift, runoff and erosion from an agricultural field and
EXAMS estimates environmental fate and transport of pesticides in
surface water body for a 30-year period (1961-1990) (Appendix 1).  PRZM
and EXAMS were linked by the program PE4-PL (version 01) which also
summarizes the output.  The EDWCs assessment for surface water uses a
single or multiple sites which typically represent a high-end exposure
scenario from pesticide use on a particular cropped or non-cropped site.

 Scenarios

	Scenarios used were developed according to EFED Scenario Development
Criteria Guidance (Leovey, 2002; U.S. EPA. 2002b.) and are included as
part of the PE4.PL linkage program.  EFED does not have standard
scenarios for all crops or crop groups, thus, several surrogate
scenarios were selected to represent the crops under consideration in
this assessment. The Florida avocado standard scenario was chosen to
represent the papaya and mango subgroup, the Georgia peach (although
peaches not included in the assessment) and Michigan cherry scenarios
were chosen to be representative of the stone fruit group 12, and the
New York grape scenario was selected to represent the grape use. 
Simulations were conducted using the Index Reservoir environment in
EXAMS, which is a surrogate for a drinking water source drawn from
surface water.  Weather and agricultural practices are simulated for 30
years so that the 10-year exceedance probability at the site can be
estimated (90th percentile).  The values generated by the models for
drinking water were multiplied by a default national or regional percent
crop area factor (PCA) which accounts for the fact that is it unlikely
for any basin to be completely planted to agricultural crops (Jones et
al., 2000; U.S. EPA, 2003). 

	Detailed description, documentation, and direct links for running these
models can be found in:   HYPERLINK
"http://www.epa.gov/oppefed1/models/water/index.htm" 
http://www.epa.gov/oppefed1/models/water/index.htm .  Model outputs are
given in Appendix 1.

Pesticide Input Parameters

	The buprofezin fate properties were previously discussed in detail in
the New Chemical Review (D244352).  The appropriate PRZM, EXAMS, and
SCI-GROW input parameters were selected from the environmental fate data
submitted by the petitioner and in accordance with USEPA-OPP-EFED water
model parameter selection guidelines (U.S. EPA., 2002A).  The
environmental fate and cropping input values used for modeling are
summarized in Table 3.

̊C	EXAMS

Solubility in Water	0.382 mg/L at 25 ̊C	EXAMS

Photolysis in Water	38 days	EXAMS

Aerobic Soil Metabolism Half-life	 168      days (90% upper bound on
mean)

   68.75 days (mean)	PRZM

SCI-GROW

Anaerobic Soil Metabolism Half-life	No data	EXAMS

Hydrolysis	stable @ pH = 7	EXAMS

Aerobic Aquatic Metabolism	336 ( 2 * 168)	EXAMS

Anaerobic Aquatic Metabolism	No data	EXAMS

Kads	69	PRZM/ EXAMS

Koc	2791 	SCI-GROW

Spray Drift	0.16 – aerial; 0.064 ground 	EFED guidance

Application Efficiency	0.95; -aerial 0.99 – ground	EFED guidance

First application Date:

(day/month)	FL avocado  - 15/08; GA peach     - 15/07; 

NY grape     -  15/09; MI cherry    -  15/ 07

	

Environmental Fate Summary

	Buprofezin is moderately resistant to metabolism and it has low
mobility.  The environmental fate profile for buprofezin, therefore,
suggests no major concerns due to water or fish accumulation.  The EFED
models show that buprofezin residues may reach surface water and ground
water.   Aerobic and anaerobic aquatic metabolism rates are not known.  
Based upon the relative persistence of the buprofezin, i.e., slow
aerobic soil metabolism rate (168 days half-life; the 90% upper-bound on
mean), the aquatic metabolism (aerobic and anaerobic) is also assumed to
be slow (half the aerobic soil metabolism rate) (Table 3).   Limited
losses of buprofezin in rivers and streams would also be expected,
according to the Henry's Law constant, as some volatilization is
expected in shallow and flowing waters.  Additionally, assuming a
first-order decay pattern, the associated half-life may over-predict
longer-term concentrations.  Eleven degradates were identified; but the
environmental fate data for the degradation products have not been
submitted.  However, this is not an issue, since HED has only indicated
a concern for the parent buprofezin.  Since, the contribution of the
degradates did not need to be considered in the drinking water
assessment, the degradates were not modeled,  

 

	The pesticide specific inputs (Table 3) use were the estimated 90
percent upper bound value of the first-order kinetics aerobic soil
metabolism half-lives (T1/2 = 168 days; the 90% upper-bound on mean)), a
maximum aquatic photolysis half-life (T1/2  = 38 days), the lowest
non-sand Kd value of 69 mL/g, and 16% spray drift (aerial application). 
Because the aquatic metabolism rates are not known it was estimated (as
336 days) using EFED guidance (taking the upper 90 percent half-life for
aerobic soil metabolism and multiplying it by 2).

	The limitations and assumptions presented in the previous assessment
(D244352) are still applicable to this assessment.  The sole exception
is that a first-order model has replaced the "bi-phasic 1st period"
model that was used to estimate a "pseudo-half-life" for modeling input
in the previously assessments. The labels did not specify how the
buprofezin is to be applied (aerial vs. ground); these assessments
assumed it will be applied by aerial spray.  

Buprofezin Use

	The rate, number, reapplication interval, and total amount permitted by
the label per period and PHI (pre-harvest interval) are summarized in
Table 4.  The maximum rates and number of applications were used for
this for this assessment.

Table 4.  DP Barcode, Crops, Label, Application rate, number, interval,
and total amount, and pre-harvest interval (PHI).



	Application	Total

	DP Barcode	Crop	Label	Rate/[method]1

lb ai/ac	Number/Interval

#/days	Rate/period2

lb ai/ac	PHI

Days

D323242	Papaya and mango subgroup

stone fruit crop group

grapes	 71711-16

Technical





D323244	Stone fruit crop group

Grapes (reduce PHI)	71711-15 70WP

Applaud	1.50 [a] 

0.38-0.50 [a]	2/14

2/14/crop cycle	3.0/yr

0.76-1.0	14

 7

D323245

Limited to  FL, HI, PR

	Papaya and Mango Subgroup

Grapes	71711-21 70DF

Applaud	0.395 [a]

	

0.395-0.525 [a]	5/14

2/14	2.0

0.78-1.06	 3

 7

D321843

(IR-4)	Stone fruit group 12, except peaches	71711-15 70WP

Applaud	1.5 [a]	2/14	3.0/yr	14

D321846

(IR-4)	Papaya, star apple, black sapote, mango, sapodilla, canistel,
mamaey sapote	71711-21 70DF

Applaud	0.394 [a]

	5/14	2.0/season	3

1 [method] is method of application: a is aerial.

2 The labels use the following terms, crop cycle, season, and year to
limit the amount of buprofezin that can be applied per time period. 

 

Surface Water Concentrations

	The buprofezin concentrations from use on grapes [NY grape scenario],
stone fruit - group 12 [GA peach and MI cherry scenarios], and papaya
and mango [FL avocado scenario] were estimated.  Results are summarized
in Table 5 without applying the PCA and with the PCA applied in Table 6.
 

 

	The highest peak concentration was estimated for the proposed grape
use.  The 90th percent peak EDWCs was 23.2 µg/L.  The annual and long
term mean EDWCs were 7.8 µg/L and 4.7 µg/L, respectively.  The
PRZM/EXAMS outputs are provided in Attachment 1.  These results were
based on the highest proposed rate and number of applications with the
minimum reapplication interval (Table 4) for each crop (or crop group). 


	Shortening the PHI (pre-harvest interval) could indirectly influence
the exposure concentrations.  Differences would be primarily due to
weather differences (precipitation) which occurs between the last
pesticide application and precipitation.

			

Table 5.  Tier 2 Surface Water Concentrations (µg/L) for Buprofezin
concentration in drinking water (Index Reservoir concentrations are not
corrected for PCA).

	1-in-10 year buprofezin concentrations

	Crop/file	Acute	Chronic	Long term average

GA Peach	23.99	6.39	5.31

MI Cherry	22.44	9.0	5.43

NY Grapes	26.76	6.22	4.76

FL Avocado	8.67	2.57	2.29



	The regional percent crop area (PCA) for the papaya and mango [FL
Avocado] subgroup is 0.38, the others used the national PCA (0.87).  

It is necessary to characterize EDWCs generated from the FL Avocado
scenario which was used to represent the papaya and mango use.  Avocado
trees require soils that are well-drained, thus would be limited to
soils of Hydrologic Group A and perhaps some soils in Hydrologic Group
B.  About 98 percent of the avocado acreage in Florida is located in
Miami-Dade County.  The remaining acreage, in Florida, is located in the
following Counties: Brevard, Broward, Collier, Hillsborough, Palm Beach,
and others.  This scenario represents the most likely site conditions
that avocados will be grown on in southern Florida and therefore should
only be used for avocado grown in southern Florida.  This site is not
highly vulnerable to runoff, because the soils are well drained
(Hydrologic Group A) and site is relatively level (0 to 2 percent slope,
but up to 5 percent).  

	The peak concentration for grapes in this assessment is somewhat less
(23.6 µg/L; Table 6) than the concentration (34.2 µg/L) predicted (by
GENEEC) for grapes in a previous assessment (D271561), which was based
upon the standard pond rather than an Index Reservoir and did not
include a PCA. 

Table 6.  Tier 2 Surface Water Concentrations (µg/L) for Buprofezin
concentration in drinking water (Index Reservoir concentrations
corrected for the national PCA1 and regional PCA2). Bold values are
recommended for use in the drinking water assessment.

	1-in-10 year buprofezin concentrations	30-years

	State/Scenario (crop)	Acute	Chronic	Long term average	Applicable

PCAs

GA Peach	20.9	5.6	4.6	0.871

MI Cherry	19.5	7.8	4.7	0.871

NY Grapes	23.2	5.4	4.1	0.871

FL Avocado	3.3	0.98	0.87	0.382



GROUND WATER ASSESSMENT

	Buprofezin concentrations in ground water were estimated using the Tier
1 SCI-GROW (Screening Concentration in Ground Water) model (USEPA,
2003c). 

	SCI-GROW is generic and represents a site vulnerable to ground-water
contamination. Although moderately persistent in soils, the use rates
and the mobility/leaching data indicated that buprofezin will have low
propensity to leach into ground water.  Using the mean first-order
aerobic soil half life (T1/2 = 68.75 days), the median value Koc of 2791
mL/g, and the highest proposed application rate (2 applications per year
at  the rate of 1.5 lb ai/A/application  with a 14 -day interval), the
SCI-GROW model estimates a ground water concentration of less than 0.07
µg/L.  The SCI-GROW output is shown in Attachment 2.  These results are
supported by the absence of buprofezin residues in the deep soil
profiles of the terrestrial field dissipation studies.

Detailed description, documentation, and direct links for running these
models can be found at:

	  HYPERLINK http://www.epa.gov/oppefed1/models/water/index.htm 

http://www.epa.gov/oppefed1/models/water/index.htm 

Label Clarification Issues:

	The labels limit the number of applications and the maximum amount of
buprofezin that can be applied per period.  Unfortunately, the labels
use several terms (crop cycle, season, and year) to limit the amount of
buprofezin that can be applied per time period.  Clarification is
required, i.e., the number of crop cycles per year and “seasons” per
year should be specified.   

	This assessment assumed that there was only 1 crop cycle (plant to
harvest per year).  This could be calendar year (plant 5-11 and harvest
9-15) or crop year (plant 9-15 and harvest 4-10).  If there are multiple
crops per year then the pesticide concentrations are underestimated
because the amount of pesticide applied is not correct.  

	The Applaud 70DF Insect Growth Regulator label (APPLAUD 70WD,
APP21b-072905, EPA Reg. No.) uses the terminology “crop cycle” for
the grape use (Page 4 of 6).  Is there more than one cycle per year?  
Additionally, some locations have multiple crops or crops per year. 
Does “per season” indicate one crop per year, or multiple seasons
per year?  The scales use (page 5 of 6) limits the application on a
yearly basis.  The Applaud 70 WP Insect Growth Regulator label (APPLAUD
70WP, APP15r-072905) EPA Reg. No. 71711-15) also uses the terms “per
season” and “per year.”

	The general information, on both labels, indicates that the Applaud
(70WP and 70DF) can be applied by either ground or air.  The application
rate chart for Applaud 70WP indicates that almonds and pistachios,
bananas, citrus, cotton, grapes, stone fruit only allows application by
ground; neither is specified for cucurbits, lettuce, longan, and snap
beans; both air and ground and air are indicated for tomatoes. The
specific request, Section B, (in DP 331843) does not limit the
application by air.

	The application rate chart for Applaud 70DF indicates ground
application for almonds, bananas, citrus, grapes, and 3 multiple crop
groupings (1-acerola, 2-black sapote, and 3-longan).  Thus, it could be
assumed that air application is not allowed under this label.   The
specific request, Section B, (in DP 331846) does not limit the
application by air.

	These inconsistencies should be clarified for both labels.

	 .    

SELECTED CITATIONS 

Burns, L. A.  2002.  EXAMS (Exposure Analysis Modeling System) Version
2.98.04.  (Compiled 07/18/04). Environmental Research Laboratory., U. S.
Environmental Protection Agency. Athens, GA.

Carsel, R. F., J. C. Imhoff, P. R. Hummel,  J.M. Cheplick, and A.S.
Donigian, Jr. 1998. PRZM-3, Version 3.12 beta (Compiled (05/24/01). A
Model for Predicting Pesticide and Nitrogen Fate in the Crop Root and
Unsaturated Soil Zones: Users Manual for Release 3.0.  United State
Environmental Protection Agency. Athens, GA.

Jones, R.D. et al., 2000.  Guidance for use of the Index Reservoir and
Percent Crop Area Factor in Drinking Water Assessments (March 21, 2000).
 Office of Pesticide Programs, Environmental Fate and Effects Division,
U.S. Environmental Protection Agency. Arlington, VA.

Leovey, E.  2002.  PRZM Standard Crop/Location Scenarios, Procedure to
Develop and Approve New Scenarios, and PRZM Turf Modeling Scenarios to
Date (February 27, 2002). Office of Pesticide Programs, Environmental
Fate and Effects Division, U.S. Environmental Protection Agency.
Arlington, VA.

USEPA. 1999. Guidance for Use of the Index Reservoir in Drinking Water
Exposure Assessments. Arlington, VA.

USEPA.   2000. Drinking Water Screening Level Assessment. Part A:
Applying a Percent Crop Area Adjustment to Tier II Surface Water Model
Estimates for Pesticide Drinking Water Exposure Assessments. FQPA
Science Policy Document .Public Comment Draft September 1, 2000. 
Federal Register: October 11, 2000 (volume 65, number 197).  Electronic
copy available at http://www.epa.gov/pesticides/trac/science/ .

USEPA. 2002a. Guidance for Selecting Input Parameters in Modeling the
Environmental Fate and Transport of Pesticides,  Version II (February
28, 2002).   Office of Pesticide Programs, Environmental Fate and
Effects Division, U.S. Environmental Protection Agency. Arlington, VA.

U.S. EPA. 2002b. Pesticide Root Zone Model (PRZM) Field and Orchard Crop
Scenarios: Standard Procedures for Conducting Quality Control and
Quality Assurance. Office of Pesticide Programs, Environmental Fate and
Effects Division, U.S. Environmental Protection Agency. Arlington, VA. 

	

USEPA. 2002b. Pesticide Root Zone Model (PRZM) Field and Orchard Crop
Scenarios: 

Standard Procedures for Conducting Quality Control and Quality
Assurance. Office of Pesticide Programs, Environmental Fate and Effects
Division, U.S. Environmental Protection Agency. Arlington, VA.

USEPA.  2003a.  Report of the Food Quality Protection Act (FQPA)
Tolerance Reassessment Progress and Risk Management Decision (TRED) for
Lactofen.  USEPA. OPPTS, EPA 738-R-04-002.  Washington DC.

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. Use of Regional Percent Crop Area Factors in Refined Drinking Water
Assessments. US EPA Office of Pesticide Programs (OPP), Environmental
Fate and Effects Division (EFED), Water Quality Technical Team (WQTT).
Arlington, VA

USEPA, 2003c.   SCI-GROW 2.3: Windows Version of SCI-GROW. September 30,
2003. Office of Pesticide Programs, Environmental Fate and Effects
Division, U.S. Environmental Protection Agency. Arlington, VA. 

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