1

OFFICE OF

PREVENTION, PESTICIDES AND

TOXIC SUBSTANCES

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 
2

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 (SCIGROW2)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. 
3

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 
4

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)

<1x10-8torr (<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 Halflife for Parent only

(days)

182, 

578, 

408,

289

MRIDs

45405208(Supplemental)

45405209(Supplemental)

45643802(Acceptable)

-

Aerobic Soil 

Metabolism Halflife 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 Halflife

no signficant 

degradation

MRID 45405214 Study was 

classified as 

supplemental

Anaerobic Aquatic 

Metabolism Halflife

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.
5

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 
6

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®)

Proposed Label -
7

10 (Citrus, Pristine®)

14 (Turf, DP D343753)

Percent Cropped Area 

(decimal)

0.87 (Alfalfa & Citrus)

1.0 (Turf)

EFED PCA Guidance No PCA 

Factors for 

Nonagricultural 

use sites (Turf)

Organic Carbon 

Partition Coefficient 

(Koc; L/kg-oc)

655 MRID 45405216 Represents the 

lowest nonsand 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 
8

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 
9

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. 
10

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

1

0 Mean 364.25 Mean 1502.5 =AVERAGE(G3:G6)

1

1 STDEV

169.784

9 STDEV

773.685

8 =STDEV(G3:G6)

1

2 n^0.5 2 n^0.5 2 =4^0.5

1

3 t90 1.476 t90 1.476

from input parameter 

guidance

1

4

1

5 tinput

489.551

3 tinput 2073.48 =G10+((G13*G11)/G12)
11
12

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
13

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
14

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
15

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
16

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 

************************************************************************
17

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 

************************************************************************
18

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
19

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)
20

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 * 
21

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

 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)
22

 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 ****** 4146.00

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

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

 PEAK DAY (ACUTE) ANNUAL AVERAGE (CHRONIC) 

 CONCENTRATION CONCENTRATION 

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

 52.583 15.536