Document ID: EPA-HQ-OPP-2009-0268-0008
Agency: epa
Document Type: Supporting & Related Material
Title: 
Posted Date: 2010-05-28T04:00Z

UNITED STATES ENVIRONMENTAL PROTECTION AGENCY

WASHINGTON D.C., 20460

							     

PC Code: 128008

 DP Barcode: 367184

 Date: September 24, 2009

MEMORANDUM	

SUBJECT:	Drinking Water Exposure Assessment for New Uses of Boscalid on
Alfalfa Forage and Hay, Citrus group 10, and an Increase in Tolerance on
Stone Fruit group 12.

TO:		Bryant Crowe, Risk Manager Reviewer (RM Team 22)

		Fungicide Branch/Registration Division (7505P)

			Tony Kish, Risk Manager (RM Team 22)

			Fungicide Branch/Registration Division (7505P)

FROM:			David Lieu, Chemist Trainee

			Environmental Risk Branch IV

			Environmental Fate and Effects Division (7507P)

REVIEWED

BY:		R. David Jones, Ph.D. Senior Agronomist

		Environmental Risk Branch IV

		Environmental Fate and Effects Division (7507P)

APPROVED

BY:		Elizabeth Behl, Branch Chief

		Environmental Risk Branch IV

		Environmental Fate and Effects Division (7507P)

Executive Summary

This memo includes a drinking water exposure assessment for proposed new
uses of boscalid (PC code: 128008) on alfalfa forage and hay, and citrus
group 10.  The petition also requested an increase in tolerance on stone
fruit (crop group 12) based on residues exceeding the 1.7 ppm tolerance
found in samples of sweet and tart cherries and in peaches from field
trials conducted by BASF. The proposed increase in tolerance to stone
fruit group does not necessitate a change to the label and therefore
does not trigger the need for a new drinking water assessment.

Previous drinking water assessments have estimated drinking water
concentrations (EDWCs) for boscalid in surface water and groundwater
using the screening models FIRST and the regression model SCI-GROW.
Three previous assessments (D336183, D341459 and D343753) have all used
application to turf as the maximum application rate allowed. The
proposed new uses on alfalfa (forage and hay) and citrus (crop group 10)
have lower maximum rates per application than that on turf.  The
recommended EDWCs based on the existing turf use are listed in Table 1.
The half-life for boscalid was recalculated to include unextractable
residues, which affected the input parameters for calculating EDWCs in
SCIGROW and FIRST. 

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

Drinking Water Source (Model used)	Use/rate Modeled (lb a.i./A)
Estimated Drinking Water Concentration (EDWC; ppb)

Groundwater (SCI-GROW2)	Ground spray/0.35 x 6 applications; annual total
of 2.1	Acute and Chronic	1.51

Surface Water (FIRST)	Ground spray/0.35 x 6 applications; annual total
of 2.1	Acute	105.3

	Ground spray/0.35 x 6 applications; annual total of 2.1	Chronic	30.2

Problem Formulation

This is a Tier I drinking water assessment that uses modeling and
available monitoring data to estimate the ground water and surface water
concentrations of pesticides in drinking water source water
(pre-treatment) resulting from pesticide use on sites that are highly
vulnerable. This initial tier screens out chemicals with low potential
risk.

Analysis

Use Characterization

Boscalid is currently registered for use on alfalfa, dry and succulent
beans, berries, head and stem brassicas, leafy brassica greens, bulb
vegetables, canola, carrots, celery, citrus fruits, cotton, cucurbit
vegetables, fruiting vegetables, grapes, hops, leafy greens, leafy
petioles, lettuce, peanuts, succulent and dried shelled peas,
pistachios, pome fruit, potatoes, root and tuber vegetables, certain
seed treatments, soybeans, spinach, stone fruit, strawberries,
sunflowers, tree nuts, tropical fruits, turf, and ornamentals. Boscalid
is mixed with a second active ingredient, Pyraclostrobin, in Pristine
Reg. No. 7969-199 and Endura Reg. No. 7969-197. Boscalid is applied
aerially or through ground equipment.

The proposed new uses for alfalfa (forage and hay) and citrus group 10
have a maximum seasonal application rate less than that previously
allowed for turf (1.44 lbs a.i./A/season for Alfalfa, Endura Reg. #
7969-197, compared to 2.1 lbs a.i./A/season for turf). This information
is summarized in Table 2. 

Table 2. Application rates for the proposed new uses of boscalid on
alfalfa, citrus (group 10) and the maximum current use rate for turf.

Crop Type	Single Maximum Application Rate (lbs a.i./A)	Maximum Number of
Application	Maximum Seasonal Application Rate (lbs a.i./A/season)
Minimum Interval Between Applications (days)	Application Method

Alfalfa (Pristine, Reg. # 7969-199)	0.28	3	0.85	14	Aerial Spray

Alfalfa (Endura, Reg. #7969-197)	0.48	3	1.44	14	Aerial Spray

Citrus, group 10 (Pristine, Reg. # 7969-199)	0.29	4	1.17	10	Aerial Spray

Turf (reference DP Barcode: D343753)	0.35	6	2.1	14	Ground Spray

Environmental Fate and Transport Characterization

Boscalid, o (2-chloro-N-(4´-chlorobiphenyl-2-yl)-nicotinamide
nicotinamide -IUPAC name)

2-chloro-N-(4’chloro(1,1’-biphenyl)2-yl-3-pyridinecarboxamide - CAS
name) is a persistent compound with low mobility in most soils. The
primary degradation pathway is aerobic soil metabolism, which proceeds
slowly and results in the formation of intermediates which are
relatively rapidly transformed into CO2 or were in unextracted
unidentified soil residues. In anaerobic soil, boscalid is degraded very
slowly and is considered to be stable to microbial degradation as the
disappearance of the parent compound was mainly due to conversion to
unextracted, unidentified residues. There is no significant degradation
of boscalid and by photolysis on soil and in water. The compound is also
not transformed to any significant extent in either aerobic or anaerobic
aquatic systems. Boscalid is also no significant hydrolysis at
environmentally relevant pHs and temperatures. Boscalid may sorb to
aquatic sediments given its moderate soil mobility (Koc ranges from 507
to 1110mL/g). Terrestrial field dissipation studies show that the
maximum leaching depth for boscalid ranged from 0-7.5 cm (MRIDs
454052-19, -20, -21, -22;EPA, 2003). These data support results from
batch equilibrium studies that indicate moderate mobility in soil. A
higher potential for leaching exists for the compound in soils which are
low in organic matter content, as is often the case with coarse-textured
soils. Boscalid is likely to reach surface water through spray drift
when applied using ground and aerial spray. Given its persistence,
transport of boscalid to surface water via runoff water is probably. The
slow biodegradation of boscalid in most soils will increase the
potential for both groundwater and surface water contamination. Because
boscalid does not biodegrade in aquatic systems, but can bind to
sediments, the compound may accumulate in the sediment phase of these
environments (MRIDs 45405213 and 45405214). The boscalid degradate
2-chloronicotinic acid is very mobile in soil and is not expected to
bind to aquatic sediments. However, the degradate is metabolized rapidly
in aerobic soil, and is mineralized to CO2 or transformed to bound
residues. A summary of the fate and transport properties can be found
below in Table 3.  More details on the environmental fate and transport
of boscalid can be found in the original environmental fate and
ecological risk assessment performed for registration, titled
“Environmental Fate and Ecological Risk Assessment for the
Registration of BAS 510F (Nicobifen):
2-chloro-N-(4’chloro(1,1’-biphenyl)-2-yl-3-pyridinecarboxamide”.

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

PARAMETER	VALUE(S) (units)	SOURCE	COMMENT

Chemical Name	boscalid	-	-

Molecular Weight	343.2 g/mole	-	-

Solubility (20ºC)	6 mg/L	MRID 45405205	-

Vapor Pressure (25ºC)	<1x10-8 torr (<1x10-6 Pa)	-	-

Hydrolysis Half-life (pH 5, 7, 9; (25ºC)	no signficant degradation	MRID
45405205	Stable at all pHs.

Aqueous Photolysis half-life	no signficant degradation	MRID 45405206	-

Soil Photolysis Half-life	no signficant degradation	MRID 45405207	-

Aerobic Soil Metabolism Half-life for Parent only (days)	182, 

578, 

408, 

289	MRIDs 

45405208(Supplemental)

45405209(Supplemental)

45643802(Acceptable)	-

Aerobic Soil Metabolism Half-life for Parent and unextracted residues
(days)	1000, 

1609, 

848,

2553	MRIDs 

45405208(Supplemental)

45405209(Supplemental)

45643802(Acceptable)	t1/2 were calculated incorporating unextracted
residues to the total extractable residues

Aerobic Aquatic Metabolism Half-life	no signficant degradation	MRID
45405214	Study was classified as supplemental

Anaerobic Aquatic Metabolism Half-life	no signficant degradation	MRID
45405213	-

Organic Carbon Partition Coefficient (Koc) in mL/g	507 (sandy loam)

594 (loamy sand)

655 (soam)

776 (sandy clay loam)

987 (soamy sand)

1110 (sandy/loamy sand)	MRIDs

45405216(Supplemental)

45405217(Supplemental)	Supplemental status due to absence of material
balance data.

Soil Partition Coefficient (Kd) in mL/g	3.3 (loam)

3.9 (loamy sand)

6.5 (loamy sand)

7.6 (sandy loam)

26.4 (sandy clay loam)

27.8 (sandy/loamy sand)	MRIDs

45405216(Supplemental)

45405217(Supplemental)	Supplemental status due to absence of material
balance data.

Drinking Water Exposure Modeling

SCIGROW (Screening Concentration in Ground Water) is a regression model
used as a screening tool to estimate pesticide concentrations found in
ground water used as drinking water. SCIGROW was developed by fitting a
linear model to groundwater concentrations with the Relative Index of
Leaching Potential (RILP) as the independent variable. Groundwater
concentrations were taken from 90-day average high concentrations from
Prospective Ground Water studies; the RILP is a function of aerobic soil
metabolism and the soil-water partition coefficient. The output of
SCIGROW represents the concentrations that might be expected in shallow
unconfined aquifers under sandy soils, which is representative of the
ground water most vulnerable to pesticide contamination likely to serve
as a drinking water source.

	FIRST (FQPA Index Reservoir Screening Tool) is a metamodel of PRZM and
EXAMS used as a screening tool to estimate pesticide concentrations
found in surface water used as drinking water. FIRST was developed by
making multiple runs of PRZM using varying sorption coefficients and
determining the concentration in the EXAMS index reservoir scenario
after a two-inch single storm event. (The Index Reservoir is a standard
water body used by the Office of Pesticide Programs to assess drinking
water exposure (office of Pesticide Programs, 2002). It is based on a
real reservoir (albeit not currently in active use as a drinking water
supply), Shipman City lake in Illinois, that is known to be vulnerable
to pesticide contamination.) The single runoff event moves a maximum of
8% of the applied pesticide into the reservoir. This amount can be
reduced by degradation or effects of binding to soil in the field.
Additionally, FIRST can account for spray drift and adjusts for the area
within a watershed that is planned with the modeled crop (percent
Cropped Area). Spray drift (modeled as direct deposition of the
pesticide into the reservoir) is assumed to be 16% of the applied active
ingredient for aerial application, 6.3% for orchard air blast
application, and 6.4% for other ground spray application. Despite being
a single even model, FIRST can account for spray drift from multiple
applications. The default a Percent Cropped Area (PCA) is 87% for
agricultural crops. The default PCA for turf is 1.0 since turf is often
grown on land that is not agricultural. The PRZM scenario used for FIRST
development was among the most vulnerable, and thus resulting surface
water concentration represents the upper bound values on the
concentrations that might be found in drinking water from the use of a
pesticide.

Modeling Approach and Input Parameters

The following Tables 4 and 5 represent the input parameters used for the
surface and groundwater modeling applications, SCIGROW and FIRST. The
input parameter for aerobic soil metabolism was calculated both as
parent only and as parent plus unextracted residues. The parent plus
unextracted residue half-life was calculated using the total toxic
residues (TTR) method (Scientific Advisory Panel “White Paper on
Methods for Assessing Ecological Risks of Pesticides with Persistent,
Bioaccumulative and Toxic Characteristics”). The unextracted residues
in some studies were over 50%. There is insufficient information to
verify that the extraction methods used, methanol and then methanol and
water, were efficiently extracted all unbound residues. Then the EECs in
Table 6. are based on the TTR method. The calculations are in Appendix
A.

Table 4. SCI-GROW input parameter values for boscalid use on Alfalfa
(Hay and Forage), Citrus (group 10) and Turf.

Model Input Parameter (units)	Input Values 	Source	Comments

Application Rate (lbs a.i./A/application)	0.28 (Alfalfa, Pristine®)

0.48 (Alfalfa, Endura®)

0.29 (Citrus, Pristine®)

0.35 (Turf, DP D343753)	Proposed Label	-

Maximum No. of Applications/Year	3 (Alfalfa, Pristine®)

3 (Alfalfa, Endura®)

4 (Citrus, Pristine®)

6 (Turf, DP D343753)	Proposed Label	-

Organic Carbon Normalized Partition Coefficient Koc (mL/g)	821	MRID
45405216	Represents the median value for six soils. 

Aerobic Soil Metabolism Half-life (days)	1503 (Parent + Unextracted)*

364 (Parent Only)	MRIDs 

45405208(Supplemental)

45405209(Supplemental)

45405210(Unacceptable)

45643802(Acceptable)	Mean of four values in the acceptable study.

* Value represents total toxic residues which include parent and
unextracted residues which we assume to be unextracted parent residues.

Table 5. FIRST input parameter values for boscalid use on Alfalfa (Hay
and Forage), Citrus (group 10) and Turf.

Parameter (units)	Value(s)	Source	Comments

Application Rate (lb a.i./A)	0.28 (Alfalfa, Pristine®)

0.48 (Alfalfa, Endura®)

0.29 (Citrus, Pristine®)

0.35 (Turf, DP D343753)	Proposed Label	-

Number of Applications	3 (Alfalfa, Pristine®)

3 (Alfalfa, Endura®)

4 (Citrus, Pristine®)

6 (Turf, DP D343753)	Proposed Label	-

Interval between Applications (days)	14 (Alfalfa, Pristine®)

14 (Alfalfa, Endura®)

10 (Citrus, Pristine®)

14 (Turf, DP D343753)	Proposed Label	-

Percent Cropped Area (decimal)	0.87 (Alfalfa & Citrus)

1.0 (Turf)	EFED PCA Guidance	No PCA Factors for Non-agricultural use
sites (Turf)

Organic Carbon Partition Coefficient (Koc; L/kg-oc)	655	MRID 45405216
Represents the lowest non-sand Koc for six soils

Aerobic Soil Metabolism Half-life (days)	2073 (Parent + Unextracted)*

490 (Parent Only)	MRIDs 

45405208(Supplemental)

45405209(Supplemental)

45405210(Unacceptable)

45643802(Acceptable)	90th percentile of the upper confidence bound on
the mean half-life of four soils 

Wetted in:	No	Input parameter guidance	-

Depth of Incorporation (inches)	0	Input parameter guidance	-

Method of Application	Aerial spray (Alfalfa & Citrus)

Ground spray (Turf, DP D343753)	Proposed Label	-

Solubility in water (mg/L or ppm)	6	MRID 45405205	pH 5-7, 20ºC

Aerobic Aquatic Metabolism Half-life (days)	4146 (Parent +
Unextracted)**

980 (Parent Only)	Input parameter guidance	Twice the aerobic soil
metabolism

Hydrolysis half-life (days)	0	MRID 45405205

	Stable

Aquatic Photolysis Half-life @ pH 7 (days)	0	MRID 45405206	Stable

* Value represents total toxic residues which include parent and
unextracted residues.

** Value was affected by the new aerobic soil metabolism input

Modeling Results

	SCIGROW concentration (ppb) represents the groundwater concentration
that might be expected in shallow unconfined aquifers under sandy soils.
The outputs located in Appendix B are used for both acute and chronic
endpoints. FIRST concentrations (ppb) represent untreated surface water
concentrations. The one-in-10-year peak concentration is used for acute
endpoints and the 1-in-10-year annual average concentration used for
chronic endpoints. The estimated concentrations provided in this
assessment are conservative estimates of concentrations in drinking
water. The output files are located in Appendix C. The summary of EDWCs
for each new use and the existing use on turf is shown below in Table 6
for groundwater using FIRST and Table 7 for surface water using SCIGROW.

.

Table 6. Summary of Tier 1 Surface Water EDWCs based on application of
boscalid on turf and proposed new uses on Alfalfa Forage and hay, and
Citrus Group 10 run with FIRST. 

Estimated Drinking Water Concentration (EDWC; ppb)

Use	Use/rate Modeled (lb a.i./A)	Acute	Chronic

Alfalfa (Pristine)	Aerial spray/0.28 x 3 applications; annual total of
0.85	38.09	11.25

Alfalfa (Endura)	Aerial spray/0.48 x 3 applications; annual total of
1.44	65.30	19.29

Citrus Group 10 (Pristine)	Aerial spray/0.29 x 4 applications; annual
total of 1.17	52.58	15.54

Turf (Parent + Unextracted)	Ground spray/0.35 x 6 applications; annual
total of 2.1	105.3	30.2

Turf (Parent Only)	Ground spray/0.35 x 6 applications; annual total of
2.1	101.4	26.8

Table 7. Summary of Tier 1 Groundwater EDWCs based on application of
boscalid on turf and proposed new uses on Alfalfa Forage and hay, and
Citrus Group 10 run with SCIGROW. 

Estimated Drinking Water Concentration (EDWC; ppb)

Use	Use/rate Modeled (lb a.i./A)	Acute and Chronic

Alfalfa (Pristine)	Aerial spray/0.28 x 3 applications; annual total of
0.85	0.61

Alfalfa (Endura)	Aerial spray/0.48 x 3 applications; annual total of
1.44	1.04

Citrus Group 10 (Pristine)	Aerial spray/0.29 x 4 applications; annual
total of 1.17	0.84

Turf (Parent + Unextracted)	Ground spray/0.35 x 6 applications; annual
total of 2.1	1.51

Turf (Parent Only)	Ground spray/0.35 x 6 applications; annual total of
2.1	0.59

Conclusions

	The EDWCs for boscalid in surface water and groundwater were determined
to be lower than those estimated for the maximum application rate given
by turf. Risks for the new uses should therefore be less than that of
those maximum rates already established by turf. There were a number of
uncertainties in the drinking water exposure assessment. These include
the application method for the new uses. It was assumed that the
applications would be aerial, which would have a higher percentage of
spray drift. The label did not specify which application method is to be
used but mentioned both aerial and ground applications. Another
assumption that was factored into the assessment is the addition of the
unextracted residues in the calculation of the aerobic soil metabolism
half-lives and its associated input parameters for FIRST and SCIGROW.
This value was also used in the determination of aerobic aquatic soil
metabolism input parameter. There is also the uncertainty that comes
with the modeling with FIRST and SCIGROW.

When using the parent plus unextracted to calculated groundwater and
surface water EDWCs the acute EDWC for surface water was least affected,
changing from 101.4 ppb to 105.3 ppb giving a 3.8% change. The chronic
surface water was slightly little more affected than the acute surface
water changing from 26.8 ppb with the parent only to 30.2 ppb with the
parent plus unextracted, which gives a 12.7%. The greatest change came
from the EDWCs calculated from groundwater which went from 0.59 ppb to
1.51 ppb. This is an overall 156% increase in the EDWC for groundwater.
This uncertainty may be resolved with more data or further studies which
could include different extraction solvents or additional physical
characterization techniques such as NMR. 

Appendix A. Aerobic Soil Metabolism Half-life Calculation

	A	B	C	D	E	F	G	H

1	Before Calc

After re-Calc

	2	MRID	Half-life

MRID	Half-life

	3	45643802	182

45643802	1000

	4	45643802	578

45643802	1609

	5	45643802	408

45643802	848

	6	45643802	289

45643802	2553

	7

8

9

10	Mean	364.25

Mean	1502.5	=AVERAGE(G3:G6)

11	STDEV	169.7849

STDEV	773.6858	=STDEV(G3:G6)

12	n^0.5	2

n^0.5	2	=4^0.5

13	t90	1.476

t90	1.476	from input parameter guidance

14

15	tinput	489.5513

tinput	2073.48	=G10+((G13*G11)/G12)

Appendix A. (Continued)

SUMMARY OUTPUT Illinois Silt Loam

Regression Statistics

	Multiple R	0.925907944

	R Square	0.85730552

	Adjusted R Square	0.83946871

	Standard Error	0.037516789

	Observations	10

	ANOVA

 	df	SS	MS	F	Significance F

	Regression	1	0.067650305	0.067650305	48.06383647	0.000120481

	Residual	8	0.011260076	0.001407509

	Total	9	0.078910381	 	 	 

	 	Coefficients	Standard Error	t Stat	P-value	Lower 95%	Upper 95%	Lower
95.0%	Upper 95.0%

Intercept	4.571314246	0.016564229	275.9750727	3.32732E-17	4.533117066
4.609511	4.533117	4.609511

X Variable 1	-0.000693253	9.99959E-05	-6.9328087	0.000120481
-0.000923844	-0.00046	-0.00092	-0.00046

Appendix A. (Continued)

SUMMARY OUTPUT Idaho Clay Loam

Regression Statistics

	Multiple R	0.927848957

	R Square	0.860903687

	Adjusted R Square	0.843516648

	Standard Error	0.022941401

	Observations	10

	ANOVA

 	df	SS	MS	F	Significance F

	Regression	1	0.026059663	0.026059663	49.51410533	0.000108603

	Residual	8	0.004210463	0.000526308

	Total	9	0.030270126	 	 	 

	 	Coefficients	Standard Error	t Stat	P-value	Lower 95%	Upper 95%	Lower
95.0%	Upper 95.0%

Intercept	4.584678672	0.01012496	452.80955	6.33625E-19	4.561330472
4.608027	4.56133	4.608027

X Variable 1	-0.000430665	6.12033E-05	-7.03662599	0.000108603	-0.0005718
-0.00029	-0.00057	-0.00029

Appendix A. (Continued)

SUMMARY OUTPUT California Clay Loam

Regression Statistics

	Multiple R	0.964142142

	R Square	0.929570069

	Adjusted R Square	0.920766328

	Standard Error	0.029828543

	Observations	10

	ANOVA

 	df	SS	MS	F	Significance F

	Regression	1	0.093946142	0.093946142	105.5880712	6.92635E-06

	Residual	8	0.007117936	0.000889742

	Total	9	0.101064078	 	 	 

	 	Coefficients	Standard Error	t Stat	P-value	Lower 95%	Upper 95%	Lower
95.0%	Upper 95.0%

Intercept	4.59590763	0.013164533	349.1128622	5.07445E-18	4.565550164
4.626265	4.56555	4.626265

X Variable 1	-0.000817701	7.95769E-05	-10.27560564	6.92635E-06
-0.001001206	-0.00063	-0.001	-0.00063

Appendix A. (Continued)

SUMMARY OUTPUT North Dakota Loam

Regression Statistics

	Multiple R	0.936554482

	R Square	0.877134298

	Adjusted R Square	0.861776085

	Standard Error	0.013476664

	Observations	10

	ANOVA

 	df	SS	MS	F	Significance F

	Regression	1	0.010372661	0.010372661	57.11174276	6.56337E-05

	Residual	8	0.001452964	0.00018162

	Total	9	0.011825625	 	 	 

	 	Coefficients	Standard Error	t Stat	P-value	Lower 95%	Upper 95%	Lower
95.0%	Upper 95.0%

Intercept	4.590231719	0.00595015	771.4480106	8.92778E-21	4.576510647
4.603953	4.576511	4.603953

X Variable 1	-0.000271457	3.59202E-05	-7.557231157	6.56337E-05
-0.00035429	-0.00019	-0.00035	-0.00019

Appendix B. SCIGROW Output Files

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:Boscalid on Turf (Parent + Unextracted)

 time is  9/10/2009  10:26:38

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

  Application      Number of       Total Use    Koc      Soil Aerobic

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

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

      0.350           6.0           2.100      8.21E+02     1503.0

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

 groundwater screening cond (ppb) =   1.51E+00 

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

SciGrow version 2.3

 chemical:Boscalid on Turf (Parent Only)

 time is  9/10/2009  11:22: 1

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

  Application      Number of       Total Use    Koc      Soil Aerobic

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

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

      0.350           6.0           2.100      8.21E+02      364.0

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

 groundwater screening cond (ppb) =   5.88E-01 

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

 SciGrow version 2.3

 chemical:Boscalid on Alfalfa (Pristine)

 time is  9/10/2009  10:24:21

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

  Application      Number of       Total Use    Koc      Soil Aerobic

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

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

      0.280           3.0           0.840      8.21E+02     1503.0

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

 groundwater screening cond (ppb) =   6.05E-01 

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

Appendix B. SCIGROW Output File (continued)

SciGrow version 2.3

 chemical:Boscalid on Alfalfa (Endura)

 time is  9/10/2009  10:25:26

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

  Application      Number of       Total Use    Koc      Soil Aerobic

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

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

      0.480           3.0           1.440      8.21E+02     1503.0

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

 groundwater screening cond (ppb) =   1.04E+00 

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

SciGrow version 2.3

 chemical:Boscalid on Citrus (Group 10)

 time is  9/10/2009  10:26: 3

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

  Application      Number of       Total Use    Koc      Soil Aerobic

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

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

      0.290           4.0           1.160      8.21E+02     1503.0

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

 groundwater screening cond (ppb) =   8.35E-01 

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

Appendix C. FIRST Output Files

RUN No.   4 FOR Boscalid         ON   Turf          * INPUT VALUES * 

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

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

     ONE(MULT)    INTERVAL    Koc   (PPM )   (%DRIFT)     AREA    (IN)

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

   .350(  2.076)   6  14     655.0    6.0   GROUND( 6.4) 100.0    .0

   FIELD AND RESERVOIR HALFLIFE VALUES (DAYS) 

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

   METABOLIC  DAYS UNTIL  HYDROLYSIS   PHOTOLYSIS   METABOLIC  COMBINED

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

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

   2073.00        2          N/A       .00-     .00   ******   4146.00

   UNTREATED WATER CONC (MICROGRAMS/LITER (PPB)) Ver 1.1.0  JAN 1, 2007

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

        PEAK DAY  (ACUTE)      ANNUAL AVERAGE (CHRONIC)      

          CONCENTRATION             CONCENTRATION            

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

            105.338                     30.175

Appendix C. FIRST Output Files (continued)

   RUN No.   5 FOR Boscalid         ON   Turf          * INPUT VALUES * 

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

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

     ONE(MULT)    INTERVAL    Koc   (PPM )   (%DRIFT)     AREA    (IN)

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

   .350(  2.000)   6  14     655.0    6.0   GROUND( 6.4) 100.0    .0

   FIELD AND RESERVOIR HALFLIFE VALUES (DAYS) 

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

   METABOLIC  DAYS UNTIL  HYDROLYSIS   PHOTOLYSIS   METABOLIC  COMBINED

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

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

    490.00        2          N/A       .00-     .00   980.00    980.00

   UNTREATED WATER CONC (MICROGRAMS/LITER (PPB)) Ver 1.1.0  JAN 1, 2007

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

        PEAK DAY  (ACUTE)      ANNUAL AVERAGE (CHRONIC)      

          CONCENTRATION             CONCENTRATION            

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

            101.358                     26.754

Appendix C. FIRST Output Files (continued)

RUN No.   1 FOR Boscalid         ON   Alfalfa       * INPUT VALUES * 

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

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

     ONE(MULT)    INTERVAL    Koc   (PPM )   (%DRIFT)     AREA    (IN)

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

   .280(   .836)   3  14     655.0    6.0   AERIAL(16.0)  87.0    .0

   FIELD AND RESERVOIR HALFLIFE VALUES (DAYS) 

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

   METABOLIC  DAYS UNTIL  HYDROLYSIS   PHOTOLYSIS   METABOLIC  COMBINED

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

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

   2073.00        2          N/A       .00-     .00   ******   4146.00

   UNTREATED WATER CONC (MICROGRAMS/LITER (PPB)) Ver 1.1.0  JAN 1, 2007

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

        PEAK DAY  (ACUTE)      ANNUAL AVERAGE (CHRONIC)      

          CONCENTRATION             CONCENTRATION            

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

             38.089                     11.254

Appendix C. FIRST Output Files (continued)

RUN No.   2 FOR Boscalid         ON   Alfalfa       * INPUT VALUES * 

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

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

     ONE(MULT)    INTERVAL    Koc   (PPM )   (%DRIFT)     AREA    (IN)

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

   .480(  1.433)   3  14     655.0    6.0   AERIAL(16.0)  87.0    .0

   FIELD AND RESERVOIR HALFLIFE VALUES (DAYS) 

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

   METABOLIC  DAYS UNTIL  HYDROLYSIS   PHOTOLYSIS   METABOLIC  COMBINED

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

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

   2073.00        2          N/A       .00-     .00   ******   4146.00

   UNTREATED WATER CONC (MICROGRAMS/LITER (PPB)) Ver 1.1.0  JAN 1, 2007

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

        PEAK DAY  (ACUTE)      ANNUAL AVERAGE (CHRONIC)      

          CONCENTRATION             CONCENTRATION            

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

             65.296                     19.292

Appendix C. FIRST Output Files (continued)

   RUN No.   3 FOR Boscalid         ON   Citrus        * INPUT VALUES * 

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

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

     ONE(MULT)    INTERVAL    Koc   (PPM )   (%DRIFT)     AREA    (IN)

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

   .290(  1.154)   4  10     655.0    6.0   AERIAL(16.0)  87.0    .0

   FIELD AND RESERVOIR HALFLIFE VALUES (DAYS) 

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

   METABOLIC  DAYS UNTIL  HYDROLYSIS   PHOTOLYSIS   METABOLIC  COMBINED

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

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

   2073.00        2          N/A       .00-     .00  
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          CONCENTRATION             CONCENTRATION            

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

             52.583                     15.536

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