Document ID: EPA-HQ-OPP-2012-0549-0014
Agency: epa
Document Type: Supporting & Related Material
Title: 
Posted Date: 2013-08-28T04:00Z

PC Code: 099100
                                                 DP Barcodes:  D403871, D405066
              OFFICE OF CHEMICAL SAFETY
AND POLLUTION PREVENTION
                 UNITED STATES ENVIRONMENTAL PROTECTION AGENCY
                            WASHINGTON, D.C.  20460
 --------------------------------------------------------------------------------

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

--------------------------------------------------------------------------------
MEMORANDUM

DATE:	April 04, 2013

SUBJECT:	Addendum of Drinking Water Exposure Assessment for the Section 3 New Use of Pyraclostrobin on Various Agricultural Crops and Residential Ornamentals

TO:		Andrew Ertman, Risk Manager Reviewer
		Barbara Madden, Product Manager
      Registration Division (7505P)

FROM:	Faruque Khan, Ph.D. Senior Fate Scientist
		Environmental Risk Branch I
		Environmental Fate and Effects Division (7507P)
		
APPROVED
BY:		Edward Odenkirchen, Ph.D, Acting Branch Chief
		Sujatha Sankula, Ph.D. Lead Biologist
		Environmental Risk Branch I
		Environmental Fate and Effects Division (7507P)

Executive Summary

This is an addendum to the earlier memorandum related to drinking water exposure assessment issued on February 13, 2013. This revised memorandum reflects recently withdrawn cranberry use by the registrant. In addition, exposure of pyraclostrobin in ground water was evaluated with the PRZM-GW model as well as recent published pyraclostrobin monitoring data were summarized in this memorandum. The estimated drinking water concentrations (EDWCs) of pyraclostrobin ( carbamic acid, [2-[[[1-(4-chlorophenyl)-1H-pyrazol-3-yl[oxy]methyl]phenyl methoxy-,methyl ester]) in surface water and ground water in support of the proposed Section 3 new use of pyraclostrobin for control of a variety of fungi on several use sites were summarized below. 

 The Interregional Research Project Number 4 is seeking registration of several new uses (described in Table 1)  of pyraclostrobin on one supplemental label for Cabrio[(R)] Fungicide and one supplemental label Headline[(R)] Fungicide as well as four supplemental labels for Pristine[(R)] Fungicide. Summary of directions for the proposed uses of pyraclostrobin were provided in Table 1.   

Some of the proposed end use products contain two active ingredients pyraclostrobin and boscalid. However, this assessment focuses only on the active ingredient pyraclostrobin. No degradates of pyraclostrobin were included in the drinking water assessment based on the recommendation from the Metabolism Assessment Review Committee (MARC) of Health Effects Division (USEPA 2001, D278044). The EDWCs for both surface and ground water recommended for use in HED's human health dietary risk assessment are summarized in Table 2. Estimated pyraclostrobin concentrations in surface water and ground water used for drinking water are summarized in Table 6. 
For the proposed use of pyraclostrobin in fruiting vegetables resulted in the highest surface water concentrations of at 16.6 ug/L for 1-10 year peak value from ground application and 1-10 annual year average of 1.1 ug/L from aerial application. The acute and chronic EDWCs resulting from the proposed application uses are lower than the EDWCs for surface water in the previously recommended drinking water assessments for pyraclostrobin for turf uses (USEPA 2007 D389729+). Since the EDWCs for surface water for proposed uses are lower than the previously recommended EDWCs for this chemical, the EDWCs for surface water will not supersede the EDWCs previously recommended for turf use. The Percent Cropped Area of 1.0 was assumed as pyraclostrobin has uses on ornamentals, turf, and a variety of agricultural crops. Revised EDWCs in groundwater superseded the EDWCs previously recommended for turf use. Recent monitoring data show pyraclostrobin detection of a maximum of 23.9 ng/L in surface water and a maximum of 4.8ng/L groundwater samples (Reilly et al., 2012). 

Table 1. Proposed New Uses and Conversion of Old Crop Groups to New Crop Groups for Pyraclostrobin 
                                   Use Site
                               Single App. Rate
                                (lbs. ai/A)[a]
                                   # of App
                              Seasonal App. Rate
                                 (lbs. ai/A) 
                          Retreatment Interval (days)
                                      PHI
                                 App. Type[b]
                            Geographic Restrictions
                                  EPA Reg # 
                                    Comments
                            Proposed New Uses  -  
                               Artichoke (Globe)
                                 0.15 -  0.18
                                       3
                                     0.55
                                     7-14
                                       0
                                     A,G,S
                                     None
                                   7969-199
Begin app. At the initiation of the protection phase when approximately 25% of the plants have bolted.
                                       
                                       
                                Belgium Endive
                     0.8 to 1.6 oz. per 1000 lbs roots[c]
                                   7969-199
Application made to roots when brought into cold storage and at the beginning of forcing.
                                   Persimmon
                                 0.15  -  0.18
                                       3
                                     0.55
                                     7-14
                                       0
                                     A,G,S
                                     None
                     Prior to onset of disease development
                                   Sugarcane
                                   0.15-0.2
                                       4
                                     0.78
                                     14-28
                                      14
                                     A,G,S
                                     None
                                   7969-289
                            Residential Ornamentals
                                     0.156
                                       6
                                     0.93
                                      14
                                       0
                                     NS[d]
                                     None
                                   7969-GLG
                Conversion of old crop group to new crop group 
                         Bulb vegetables (Group 3-07)
                                   0.1-0.15
                                       6
                                      0.9
                                      14
                                       7
                                     A,G,S
                                     None
                                   7969-199
                    Prior to onset of disease and continue
                       Bushberry and Caneberry subgroup 
                                   (13-07B)
                                 0.15 -  0.18 
                                       4
                                     0.73 
                                     7-14
                                       0
                                     A,G,S
                               Not for use in CA
                                   7969-199
                    Prior to onset of disease and continue
                          Citrus Fruit Group (10-10)
                                 0.15  -  0.24
                                       4
                                     0.88
                                     10-21
                                       0
                                     A,G,S
                                     None
                                   7969-289
                    Prior to onset of disease and continue
                       Fruiting Vegetables Group (8-10)
                                  0.10-0.20 
                                       6
                                      1.2
                                     5-14
                                       0
                                     A,G,S
                               Not for use in CA
                                   7969-187
                    Prior to onset of disease and continue
                Low growing berry subgroup (includes cranberry)
                                  (13-07G[)]
                                 0.15  -  0.18
                                       
                                       5
                                     0.92
                                     7-14
                                       0
                                     A,G,S
                                     None
                                   7969-187
     No later than 10% bloom or prior to disease development and continue
                            Oilseed crops Group 20
                                   0.10-0.20
                                       
                                       2
                                     0.39
                                     7-14
                                      21
                                     A,G,S
                                     None
                                   7969-289
Prior to disease development and continue...if conditions are conducive for disease development
                           Pome Fruit Groups (11-10)
                                 0.11  -  0.15
                                       4
                                     0.6 
                                     7-14
                                       0
                                     A,G,S
                                     None
                                   7969-187
         Begin applications prior to disease development and continue.
                   Root vegetables, 1B (except sugar beets)
                                  0.06 - 0.17
                                       
                                       6
                                     0.52
                                     7-14
                                       0
                                      AGS
                                     None
                                   7969-199
         Begin applications prior to disease development and continue.
                  Small fruit, vine climbing subgroup 13-07F
                           (except fuzzy kiwifruit)
0.10  -  0.15
                                       6
                                      0.9
                                     10-21
                                      14
                                     A,G,S
                                     None
                                   7969-187
Prior to onset of disease when conditions favor disease during early bloom, bunch pre-closure and veraison.
                  Tomato transplants for homeonwers market[4]
                                  0.1 -  0.2
                                       
                                       2
                                      1.1
                                     5-14
                                       0
                                     A,G,S
                                     None
                   Prior to disease development and continue
                                 Turnip greens
0.15  -  0.20 
                                       2
                                      0.4
                                     7-14
                                      14
                                     A,G,S
                                     None
                  Prior to disease development and continue.
a Adopted from "Summary of Directions for the Proposed Uses of Pyraclostrobin " provide by Registration Division (Appendix X)
b Application methods: Aerial (A), Ground (G) and Sprinkler (S)
[c] Indoor use, exposure to surface water and groundwater would be low. No exposure assessment was performed
[d] Not Specified, assumed hand spray 
[4]  Since tomato is in the fruiting vegetable cropgroup, no separate exposure assessment was performed for drinking water. 

Table 2.  Recommended EDWCs for Drinking Water risk assessment for  pyraclostrobin Use
Source of Drinking Water
            Pyraclostrobin concentration in drinking water (ug/L)

                                   Acute[1]
                             Non-Cancer Chronic[1]
                               Cancer Chronic[1]
Surface Water
                                     35.6
                                      2.3
                                      1.5
Groundwater[2]
                                     0.06
                                     0.02
                                     0.02
1 These are the highest EDWCs for previously evaluated use scenarios and the estimated acute and annual average surface water concentrations were 35.6 and 2.3 ug/L respectively.  Previously estimated groundwater concentrations for acute was  0.02 ug/L 2007, D389729+. 
2 EDWCs based on PRZM-GW model

Proposed Uses

The Interregional Research Project Number 4 is seeking registration of several new uses (described in Table 1) of pyraclostrobin on one supplemental label for Cabrio[(R)] Fungicide and one supplemental label Headline[(R)] Fungicide as well as four supplemental labels for Pristine[(R)] Fungicide.  

This assessment examines potential exposure to pyraclostrobin only.  Aerial, chemigation, and ground applications are proposed for the agricultural crops.   Five of the proposed uses were considered as not being previously assessed in drinking water assessments. These include use on globe artichoke, persimmon, low growing berries, sugarcane, and ornamentals (homeowner). Since aerial application provides higher exposure, major crops scenarios were simulated with aerial application. A ground application scenario was used to compare with the highest exposure scenario of aerial application (PA tomato STD). Resulted EDWCs for both aerial and ground are very comparable. Sprinkler irrigation assumed to be similar to ground application. An additional new use for Belgium endive was not considered in this assessment due to indoor use of pyraclostrobin.  

Residues of Concern

The Metabolism Assessment Review Committee (MARC) reported that the residue of concern for pyraclostrobin in drinking water is the parent only (USEPA 2001, D278044).  

Modeling Approach and Input Parameters

Models

	Surface Water 
The EDWCs were generated using EFED's standard suite of models. Pesticide Root Zone Model (PRZM v3.12.2, May 12, 2005) and Exposure Analysis Modeling System (EXAMS v2.98.04.06, Apr. 25, 2005) are simulation models coupled with the input shell PRZM/EXAMS (PE v5.0, Nov. 15, 2006) to generate EDWCs of pyraclostrobin residues that may occur in surface water for drinking water.  The PRZM model simulates pesticide movement and transformation from crop application through soil residue processes.  The EXAMS model simulates pesticide loading via runoff, erosion, and spray drift assuming a standard watershed of 172.8 ha that drains into an adjacent standard drinking water index reservoir of 5.26 ha, an average depth of 2.74 m.  A more detailed description of the index reservoir watershed can be found in Jones et al., 1998.  Standard percent cropped areas (PCA) were used for proposed uses as estimates of the extent of watershed on which crops are grown. The default PCA of 1.0 was used for the proposed uses because pyraclostrobin can be used in both agricultural and non-agricultural settings (USEPA 2012). 

      Ground Water 

Screening Concentration in Ground Water (SCI-GROW v2.3, Jul. 29, 2003) is a regression model used as a screening tool to estimate pesticide concentrations found in ground water used as drinking water.  The SCI-GROW model and user's manual may also be downloaded from the EPA Water Models web-page (http://www.epa.gov/oppefed1/models/water/#scigrow).  PCAs are not used with the SCI-GROW model.

In addition, Tier 1 groundwater EDWCs for pyraclostrobin, resulting from its use on various crops were also derived using the PRZM-GW model (Pesticide Root Zone Model for Groundwater, version 1.0, August 31, 2012), with the GW-GUI (Graphical User Interface, version 1.0, August 31, 2012).  PRZM-GW is a one-dimensional, finite-difference model that estimates the concentrations of pesticides in groundwater.  It accounts for pesticide fate in the crop root zone by simulating pesticide transport and degradation through the soil profile after a pesticide is applied to an agricultural field.  PRZM-GW permits the assessment of multiple years of pesticide application (up to 100 years) on a single site.  Six standard scenarios, each representing a different region known to be vulnerable to groundwater contaminations, are available for use with PRZM-GW for risk assessment purposes. In PRZM-GW simulations, each of these standard scenarios was used.  PRZM-GW output values represent pesticide concentrations in a vulnerable groundwater supply that is located directly beneath a rural agricultural field following many years of pesticide application.

Input Parameters

A summary of the model input parameter values used in PRZM/EXAMS, SCI-GROW, and the PRZM_GW Models are in Table 3, Table 4, and Table 5 presented in respectively.   Input parameters were selected in accordance with EFED's "Guidance for Selecting Input Parameters in Modeling the Environmental Fate and Transport of Pesticides," Version 2.1 (USEPA, 2009). Sample model output files are located in Appendix B. 		

Table 3. PRZM/EXAMS Input Parameters for Pyraclostrobin Proposed Uses  
Parameter
Input Value 
Source
Comment

                                   Use Site
Scenario and Application Date

 Artichoke (Globe)
    CA Row Crop RLF 
Multiple application dates1
Label directions
See Section titled "Proposed Use" for full explanation

A combination of label directions and information related to crop profile in current scenarios for PRZM/EXAMS

 Bulb vegetable Group (3-07)
    CA Onion STD
  Multiple application dates
Label directions

 Bushberry and caneberry subgroup (13-07 A)
    OR Berries STD
Multiple application dates
Label directions

 Low growingberry (13-07G)
    CA Strawberry STD
    FL Strawberry STD
    Multiple application dates
Label directions

 Citrus Fruit Group (10-10)
     CA Citrus STD 
     FL Citrus STD 
Multiple application dates
Label directions

 Fruiting Vegetable Group (8-10)
    FL Tomato STD
    PA Tomato STD
    FL Pepper STD
Multiple application dates
Label directions
Not for use in CA

 Oilseed Group (20)
     MS Cotton STD
     NC Cotton STD
     ND Canola STD
Label directions

 Pome Fruit Group (11-10) 
    NC Apple STD
    OR Apple STD
    PA Apple STD
Multiple application dates
Label directions

Root vegetables 1B 
    FL Carrot
    ID Potato
    ME Potato
Multiple application dates
Label directions
(Except sugarbeet)

Small Fruit, vine climbing subgroup 
    CA Grape STD
    NY Grape STD
Multiple application dates
Label directions
(Except fuzzy kiwifruit)

Sugercane 
    FL Sugarcane STD
    LA Sugercane
Multiple application dates
Label directions

Turnip Greens
Label directions
Since the scenarios for turnip same as root vegetables and application rate for turnip is lower than the root vegetables group, no PRZM/EXAMS modeling was performed. Assumed EDWCs for turnip would be lower than the EDWCs for root vegetables 

Ornamentals (Residential)
CA Residiential RLF
CA Impervious RLF

March 1

Label provides partial information related to application. Registration Division (personal communication) provided application rate and frequency of application. 
Used similar approach described for Endengered Species Assessment
Residential scenario with 100% application rate 
Impervious scenario with 1.68% of application rate
Post process for exposure[2]
Applications per year
See Table 2
Label directions
See Section titled "Proposed Use" for full explanation
Application method
Foliar-Aerial, ground and sprinkler irrigation 

Label directions
Apply to all proposed uses
CAM
2

Default for foliar application
Hydrolysis (t1/2)
0
MRID 46902201
Stable 
Spray drift fraction 
Aerial: 0.16
Ground: 0.64
Sprinkler Irrigation: 

PRZM/EXAMS input guidance document 
Default for foliar application for drinking water assessment
Aerobic soil metabolism (t1/2)
 247.2 days 
45118631
MRID 45118632
MRID 45367504
Upper 90[th] %-ile confidence bound on the mean of  six half-lives[3] 
Aerobic aquatic metabolism (t1/2)
45.1 days
MRID 45118637
90[th]%ile reported half-lives for [14]C labeled chlorophenyl (8.4 days) and tolyl ( 26.4 days) rings.
Anaerobic aquatic metabolism (t1/2)
12.1 days
MRID 45118634
90[th]%ile reported half-lives for 14C labeled chlorophenyl (191 days) and tolyl ( 6.91 days)rings. 
Aquatic photolysis (t1/2)
0.11 days
MRID 45118629
90[th]%ile reported half-lives for 14C labeled chlorophenyl (0.05 days) and tolyl ( 0.08)  days)rings.

Vapor pressure
6.88x10[--7] (mmHg) 
--
MRID 470780-01to 470780-08
Solubility in water 
(pH 7, 20 °C)
2.7mg/L
--

Molecular weight
388 g/mole
--

Henry's Law constant (20 °C)
1.3x10-7 atm.m3 /mol
--
Estimated1
Partition coefficient Koc
9304 mL/g 
MRID 46808411
Average Koc  (7889, 16000, 7889, 6000, 9000, 9436, and 9304)  
[1] = Since pyraclostrobin can be applied based on pest pressure, multiple application dates were used to simulates pyraclostrobin exposure in drinking water. Application dates and exposure were provided in appendix X
[2][(Residential EEC) x (0.5 amount pervious surface) x (% treated, 0.15 for woody ornamental)] + [Impervious Surface EEC x 0.5 amount impervious surface]
[3]= http://www.epa.gov/oppefed1/models/water/input_parameter_guidance.htm

Table 4. SCI-GROW (v2.3) Input Parameter Values for Pyraclostrobin
                                   Parameter
                                     Value
                                    Source
                                   Comments
Application Rate (lbs a.i./acre)
                                     0.184
                              EPA Reg # 7969-199
                                Proposed label
Number of applications
                                       5
                              EPA Reg # 7969-199
                                       
Koc (mL/g)
                                     9000
                                 MRID 46808411
Median of seven KOC values.  There is not a three fold difference in observed values. 
Aerobic soil metabolism t (1/2) (days)
                                      161
                                 MRID 45118631
                                 MRID 45118632
                                 MRID 45367504
    Median of four values.  There was not a five-fold difference in values.

Table 1. Input values for the PRZM-GW model for ptraclostrobin.
                                       
                                 Variable Name
                                       
                                  Data Value
                                  Data Source
                                    MRID(s)
                                    Comment
Application Method
Aerial (fruiting vegetable), 

Proposed labels
                               EPA Reg# 7969-187
                                       
Application Rate 
(lbs. a.i./acre) [kg/ha]
0.20 [0.22] (fruiting vegetable), 
Proposed labels
                               EPA Reg# 7969-187
                                       
Application Frequency
6 times per year 
Proposed labels
                               EPA Reg# 7969-187
                                       
Application Interval (days)
5 days  
Proposed labels
                               EPA Reg# 7969-187
                                       
Hydrolysis
t1/2 = stable
48409101
                               EPA Reg# 7969-187
                                       
Aerobic Soil Metabolism
t1/2 = 247.2days
45118631
MRID 45118632
MRID 45367504
     Upper 90[th] %-ile confidence bound on the mean of  six half-lives[1]
Koc
9304 mL/goc
MRID 46808411
Average Koc  (7889, 16000, 7889, 6000, 9000, 9436, and 9304)  [1]
[1] EFED input parameter guidance: http://www.epa.gov/oppefed1/models/water/przm_gw/wqtt_przm_gw_input_guidance.htm

Table 5. Modified Tier I Rice Model (for Estimating Exposure from Use on Cranberries) Input Parameters for Pyraclostrobin
Input Parameter
Value
Comments
Source
Application rate
(lbs a.i./A)
0.88
Maximum proposed annual application rate
Proposed label
Organic carbon partition coefficient (Koc) (L/kgOC)
9304
Represents the mean Koc value for parent (n=7)
MRID 46808411

Modeling Results

      Estimated pyraclotrobin concentrations in surface water and ground water used for drinking water are summarized in Table 6. Estimated concentrations in surface water for use on fruiting vegetable resulted in the highest EDWC at 16.6 ug/L for acute from ground application and annual average of EDWCs from aerial application.  Acute estimated pyraclotrobin concentrations in surface water used for drinking water for other uses ranged from 1.4 to 16.6 ug/L.  Estimated annual average concentrations ranged from 0.1to 0.9 ug/L.  SCIGROW model simulated concentrations in ground water was 6.2E-03 ug/L for the highest application rate. The SCIGROW and PRZM-GW concentrations represent groundwater concentration that might be expected in shallow unconfined aquifers under sandy soils. All  PRZM-GW scenarios , 3 required the use of an extended weather file, which allows the user to run the simulation for up to 100 years in order to observe breakthrough. PRZM_GW simulated groundwater concentrations are lower than SCIGROW model and  listed in Table 7 for six vulnerable sites.

Table 6.  EDWCs for Pyraclostrobin Applications to Various Crops and Home Owner Garden
Drinking Water Source
Crop
Crop Scenario
1-in-10-year Peak Exposure 
1-in-10-year Annual Mean Exposure 
                            30-year Mean Exposure 

                             Concentration (ug/L)
Surface water[1]
Artichoke
CA Rowcrop_RLF
                                       
                                    2.2-3.1
                                       
                                      0.2
                                       
                                      0.1

Berry-bush/cane
OR Berry STD
                                       
                                    2.5-4.1
                                       
                                    0.3-0.4
                                       
                                      0.3

Berry-low growing
FL Strawberry STD

                                       
                                    4.8-5.1
                                       
                                       
                                    0.4-0.5
                                       
                                       
                                    0.3-0.4
                                       

Bulb vegetable
CA Onion STD
                                       
                                      1.6
                                       
                                      0.1
                                       
                                      0.1

Citrus
CA Citrus STD
FL Citrus STD
                                       
                                    1.9-2.0
                                    4.7-8.6
                                       
                                    0.1-0.2
                                      0.5
                                       
                                      0.1
                                    0.3-0.4

Fruiting vegetable
CA Tomato STD
FL Pepper STD
 FL Tomato STD
PA Tomato STD 
PA Tomato STD (G)[2]
                                       
                                    2.0-2.7
                                    8.7-9.1
                                   8.8-10.9
                                   11.3-16.2
                                   11.2-16.6
                                       
                                    0.3-0.4
                                      0.8
                                    0.8-0.9
                                    0.8-1.1
                                    0.8-1.0
                                       
                                    0.2-0.3
                                      0.6
                                    0.7-0.6
                                    0.7-0.9
                                    0.6-0.8

Oilseed
MS Cotton STD
NC Cotton STD
ND Canola STD
                                       
                                    5.8-7.6
                                    .8-7.5
                                    1.9-2.8
                                       
                                    0.4-05
                                    0.3-04
                                      0.1
                                       
                                      0.3
                                      0.3
                                      0.1

Pome Fruits
NC Apple STD
OR Apple STD
PA Apple STD
                                       
                                    4.6-8.6
                                    3.9-6.1
                                       
                                    0.4-0.5
                                    0.2-0.3
                                    0.3-0.4
                                       
                                      0.3
                                      0.2
                                      0.2

Persimmon
NC Apple STD
                                       
                                    9.1-5.3
                                       
                                      0.4
                                       
                                      0.3

Root Vegetable
FL Carrot STD
ID Potato STD
ME Potato STD
                                       
                                    3.9-6.0
                                    1.7-1.8
                                    4.4-5.8
                                       
                                      0.4
                                      0.1
                                    0.4-0.5
                                       
                                      0.3
                                      0.1
                                    0.30.4

Small Fruit (Vine)
CA Grape STD
NY Grape STD
                                       
                                    1.4-1.7
                                   10.7-13.9
                                       
                                      0.2
                                    1.2-1.3
                                       
                                      0.2
                                      0.9

Sugarcane
FL Sugarcane STD
LA Sugarcane STD
                                       
                                    6.7-9.9
                                   9.6-13.8
                                       
                                  0.8-0.7-08
                                    0.9-1.0
                                       
                                   0.05-0.08
                                      0.7

Home Owner Garden-Woody Ornamental
CA Residential STD
                                       
                                       
                                      3.6
                                       
                                       
                                      0.2
                                       
                                       
                                       -
Groundwater
Generic  Scenario
                                   6.08E-03
                                   6.08E-03
                                   6.08E-03
1 = Surface water EDWCs are estimated for aerial application
[3] = The reported EDWCs are based on ground application to compare with the highest EDWCs for the PA Tomato scenario for aerial application.  

Table 7. PRZM-GW results based on pyraclotrobin use.
                                       
                                     Crop
                                   Scenario
                                    Highest
                                     Daily
                                 Value (ug/L)
                       Post Breakthrough Average (ug/L)
                  Average Simulation Breakthrough Time (days)
Tomato
(0.20  lbs a.i./A x 6 applications)
FL citrus
                                   6.15E-02
                                   1.59E-02
                                  Incomplete

FL potato
                                   7.45E-11
                                   1.68E-11
                                  Incomplete

GA peanut
                                    1.59E10
                                   9.94E-12
                                  Incomplete

NC cotton
                                   4.88E-04
                                   1.24E-04
                                  Incomplete

DELMARVA sweet corn
                                   5.54E-05
                                   7.04E-06
                                  Incomplete

WI corn
                                    3.5E-09
                                   2.23E-10
                                  Incomplete

Monitoring Data

Data on pyraclostrobin were available in the United States Geological Survey (USGS) National Water-Quality Assessment (NAWQA) Program Data Warehouse (http://infotrek.er.usgs.gov/nawqa_queries/jsp/swmaster.jsp) searched on February 11, 2013.  Pyraclostrobin was not detected in the surface water samples collected in Georgia (limit of quantitation (LOQ) = 2.8 ng/L). Ten bottom material samples were also collected in Georgia and pyraclostrobin was not detected  (LOQ =1.6 ug/kg-sediment) in all ten samples. However, recently Reilly et al. (2012) reported pyraclostrobin residues in surface water and groundwater samples.  For surface water, a total of 60 water samples were analyzed for pyraclostrobin.  Pyraclostrobin was detected in 42% of surface water samples.  The maximum concentration of pyraclostrobin in surface water was 23.9 ng/L.  For groundwater, a total of 12 water samples were analyzed for pyraclostrobin.  Pyraclostrobin was detected in 40% of ground water samples.  The maximum concentrations of pyraclostrobin ranged from non-detect to 4.8 ng/L.
   
Drinking Water Treatment

There is no available information on the effects of drinking water treatment on pyraclostrobin.  The EDWCs in this assessment are representative of concentrations in drinking water source water (pre-treatment).  For surface water, the conceptual model assumes that a pesticide reaches surface water via spray drift or surface runoff and it is instantaneously mixed and concentrations are observed in the water body.  Pyraclostrobin is stable to hydrolysis.  Therefore, pyraclostrobin will not degrade by hydrolysis during the time that elapses from drinking water intake through distribution to the first tap.  Pyraclostrobin is also stable to aqueous photolysis.  Therefore, if ultraviolet light were used as a means of disinfection, degradation of pyraclostrobin would not be expected to be significant.  Pyraclostrobin has long degradation rate in aerobic aquatic metabolism and aerobic metabolism is therefore, not expected to be a significant loss mechanism in water treatment.  The most successful drinking water treatment process for removal of pesticides from drinking water is thought to be treatment with granular activated carbon (GAC) which is only used in larger drinking water treatment facilities.  The ability of GAC to remove pesticides will vary with the properties of the chemical, the viability of the biofilm on the GAC, and whether the sorption sites on GAC have reached capacity (Badriyha et al., 2003; Zhao et al., 1999).  Data on the sorption of pyraclostrobin to GAC are not available; however, high Koc (9304 mL/g) value of pyraclostrobin suggests that there is a potential for removal of pyraclostrobin through GAC treatment due to its high adsorption coefficient. 

Uncertainties

The highest estimated concentrations provided in this assessment were generated from Tier 1 models and are conservative estimates of pyraclostrobin concentrations in untreated drinking water.  There were a number of uncertainties associated with this drinking water exposure assessment.  The major uncertainty is from the use of the Tier I Rice Model with a modified depth for cranberries.  This model only estimates a peak concentration inside the bog.  Therefore, it likely overestimates chronic concentrations and is expected to be conservative for acute/peak EDWC as water will have a residence time between leaving a cranberry bog and reaching a drinking water intake.  Additionally, the model was originally developed for rice and management of cranberries is different than rice and the model was not validated using monitoring data for cranberries.  Therefore, there is some uncertainty in using the model for cranberries.  Additionally, the Tier I Rice Model does not account for degradation and the annual average EDWC is likely overestimated; however, due to pyraclostrobin's stability in water, the overestimation may not be that high.

An additional element of uncertainty derives from the conceptual model used in this assessment, whereby applications of pesticide are made to a single bog.  In reality, the water used to flood a cranberry bog may be "recycled" and used to flood multiple bogs, and/or stored and used to re-flood the same bog later during the year.  Thus, the same volume of water may receive greater pesticide loadings than label restrictions would seem to imply.   Additionally, applications may be made to dry cranberry bogs that are subsequently flooded.  

Literature Cited

Jones, R. D., S. Abel, W. R. Effland, R. Matzner, R. Parker.  1998.  An Index Reservoir for Use in Assessing Drinking Water Exposure.  Proposed Methods for Basin-scale Estimation of Pesticide Concentrations in Flowing Water and Reservoirs for Tolerance Reassessment.  Presentation to FIFRA Science Advisory Panel, June 29-30, 1998.  Online at: http://www.epa.gov/scipoly/sap/1998/index.htm

Reilly, T.J., Smalling, K.L., Orlando, J.L. and K.M. Kuivila. 2012.  Occurrence of boscalid and other selected fungicides in surface water and groundwater in three targeted use areas in the United States. Chemosphere 89:228-234.

USEPA, 2007.  Pyraclostrobin. Outcome the the HED Metabolism Assessment Review Committee  (MARC) Meeting Held on September 20, 2001. Health Effects Division.  Office of Pesticide Programs. United States Environmental Protection Agency (D 278044). 

USEPA, 2007.  Drinking water assessment for turf and golf courses. Environmental Fate and Effects Division.  Office of Pesticide Programs. United States Environmental Protection Agency (D D389729+. 

USEPA. 2009. Guidance for Selecting Input Parameters in Modeling the Environmental Fate and Transport of Pesticides, Version 2.1.  Environmental Fate and Effects Division.  Office of Pesticide Programs. United States Environmental Protection Agency. Available at http://www.epa.gov/oppefed1/models/water/input_parameter_guidance.htm (Accessed February 10, 2013).

USEPA. 2010. Guidance on Development and Use of Percent Cropped Area Adjustment Factors in Drinking Water Exposure Assessments.  Environmental Fate and Effects Division, Office of Pesticide Programs, United States Environmental Protection Agency. Available at http://www.epa.gov/oppefed1/models/water/pca_adjustment_dwa.pdf (Accessed November 29, 2010).

Zhao, X., Hickey, R. F., & Voice, T. C. 1999.  Long-term evaluation of adsorption capacity in a biological activated carbon fluidized bed reactor system. Water Research, 33(13).

                           Appendix A: Model Outputs
Model: PRZM/EXAMS

stored as PATomG_DW_15-07.out
                                                                               
                                                                               
                                                                               
                                                                               
Chemical: Pyraclostrobin
                                                                               
                                                                               
                                                                               
                                                                               
                                                                               
PRZM environment: PAtomatoSTD.txt, modified Tueday, 29 May 2007 at 14:01:58 
EXAMS environment: ir298.exv, modified Tueday, 26 August 2008 at 06:14:08
Metfile: w14751.dvf, modified Tueday, 26 August 2008 at 06:15:00
                      Water segment concentrations (ppb)
                                                                               
                                     Year
                                     Peak
                                     96 hr
                                    21 Day
                                    60 Day
                                    90 Day
                                    Yearly
                                       
                                     1961
                                      5.9
                                      5.1
                                      2.7
                                      1.5
                                      1.1
                                      0.4
                                       
                                     1962
                                      6.5
                                      5.3
                                      2.7
                                      1.9
                                      1.7
                                      0.8
                                       
                                     1963
                                      6.7
                                      5.5
                                      2.9
                                      2.3
                                      1.7
                                      0.7
                                       
                                     1964
                                      3.3
                                      2.8
                                      1.9
                                      1.4
                                      1.2
                                      0.7
                                       
                                     1965
                                      3.6
                                      3.1
                                      1.9
                                      1.1
                                      0.9
                                      0.5
                                       
                                     1966
                                     17.5
                                     14.1
                                      7.1
                                      3.3
                                      2.6
                                      1.0
                                       
                                     1967
                                      4.0
                                      3.3
                                      2.3
                                      1.5
                                      1.2
                                      0.7
                                       
                                     1968
                                     16.1
                                     12.8
                                      6.2
                                      2.9
                                      2.3
                                      0.8
                                       
                                     1969
                                      8.9
                                      7.1
                                      4.5
                                      2.1
                                      1.6
                                      0.6
                                       
                                     1970
                                      4.5
                                      3.6
                                      2.0
                                      1.4
                                      1.0
                                      0.7
                                       
                                     1971
                                      5.4
                                      4.5
                                      2.5
                                      1.8
                                      1.3
                                      0.7
                                       
                                     1972
                                      7.1
                                      5.9
                                      4.5
                                      2.7
                                      1.8
                                      1.0
                                       
                                     1973
                                     16.6
                                     13.3
                                      6.6
                                      3.2
                                      2.4
                                      1.0
                                       
                                     1974
                                      9.5
                                      7.8
                                      4.7
                                      2.4
                                      1.9
                                      0.9
                                       
                                     1975
                                     24.5
                                     19.7
                                     10.6
                                      5.1
                                      3.7
                                      1.2
                                       
                                     1976
                                     10.5
                                      8.6
                                      4.9
                                      3.0
                                      2.4
                                      1.0
                                       
                                     1977
                                      2.4
                                      2.1
                                      1.6
                                      1.3
                                      1.2
                                      0.6
                                       
                                     1978
                                      1.8
                                      1.5
                                      1.1
                                      0.9
                                      0.9
                                      0.5
                                       
                                     1979
                                      7.6
                                      6.2
                                      4.1
                                      2.5
                                      1.8
                                      1.0
                                       
                                     1980
                                      8.1
                                      6.6
                                      3.4
                                      2.6
                                      1.9
                                      0.6
                                       
                                     1981
                                      4.6
                                      3.7
                                      2.0
                                      1.2
                                      1.0
                                      0.6
                                       
                                     1982
                                      3.3
                                      2.7
                                      1.5
                                      0.9
                                      0.7
                                      0.5
                                       
                                     1983
                                      5.8
                                      5.0
                                      3.3
                                      2.2
                                      1.9
                                      0.8
                                       
                                     1984
                                      3.4
                                      2.8
                                      1.5
                                      1.1
                                      1.0
                                      0.6
                                       
                                     1985
                                      5.6
                                      4.5
                                      2.3
                                      1.5
                                      1.4
                                      0.6
                                       
                                     1986
                                      5.1
                                      4.1
                                      2.3
                                      1.3
                                      1.0
                                      0.7
                                       
                                     1987
                                      8.5
                                      7.0
                                      5.6
                                      2.8
                                      2.4
                                      0.9
                                       
                                     1988
                                      3.7
                                      3.0
                                      1.6
                                      1.0
                                      0.7
                                      0.5
                                       
                                     1989
                                      8.3
                                      6.7
                                      3.7
                                      1.9
                                      1.8
                                      0.8
                                       
                                     1990
                                      6.1
                                      5.0
                                      2.8
                                      1.8
                                      1.7
                                      0.8
                                       
                                                                               
                                                                               
                                                                               
                                                                               
                                                                               
                                                                               
                                                                               
                                                                               
Sorted results
                                                                               
                                                                               
                                                                               
                                                                               
                                                                               
                                                                               
                                     Prob.
                                     Peak
                                     96 hr
                                    21 Day
                                    60 Day
                                    90 Day
                                    Yearly
                                                                               
                                      0.0
                                     24.5
                                     19.7
                                     10.6
                                      5.1
                                      3.7
                                      1.2
                                                                               
                                      0.1
                                     17.5
                                     14.1
                                      7.1
                                      3.3
                                      2.6
                                      1.0
                                                                               
                                      0.1
                                     16.6
                                     13.3
                                      6.6
                                      3.2
                                      2.4
                                      1.0
                                                                               
                                      0.1
                                     16.1
                                     12.8
                                      6.2
                                      3.0
                                      2.4
                                      1.0
                                                                               
                                      0.2
                                     10.5
                                      8.6
                                      5.6
                                      2.9
                                      2.4
                                      1.0
                                                                               
                                      0.2
                                      9.5
                                      7.8
                                      4.9
                                      2.8
                                      2.3
                                      1.0
                                                                               
                                      0.2
                                      8.9
                                      7.1
                                      4.7
                                      2.7
                                      1.9
                                      0.9
                                                                               
                                      0.3
                                      8.5
                                      7.0
                                      4.5
                                      2.6
                                      1.9
                                      0.9
                                                                               
                                      0.3
                                      8.3
                                      6.7
                                      4.5
                                      2.5
                                      1.9
                                      0.8
                                                                               
                                      0.3
                                      8.1
                                      6.6
                                      4.1
                                      2.4
                                      1.8
                                      0.8
                                                                               
                                      0.4
                                      7.6
                                      6.2
                                      3.7
                                      2.3
                                      1.8
                                      0.8
                                                                               
                                      0.4
                                      7.1
                                      5.9
                                      3.4
                                      2.2
                                      1.8
                                      0.8
                                                                               
                                      0.4
                                      6.7
                                      5.5
                                      3.3
                                      2.1
                                      1.7
                                      0.8
                                                                               
                                      0.5
                                      6.5
                                      5.3
                                      2.9
                                      1.9
                                      1.7
                                      0.7
                                                                               
                                      0.5
                                      6.1
                                      5.1
                                      2.8
                                      1.9
                                      1.7
                                      0.7
                                                                               
                                      0.5
                                      5.9
                                      5.0
                                      2.7
                                      1.8
                                      1.6
                                      0.7
                                                                               
                                      0.5
                                      5.8
                                      5.0
                                      2.7
                                      1.8
                                      1.4
                                      0.7
                                                                               
                                      0.6
                                      5.6
                                      4.5
                                      2.5
                                      1.5
                                      1.3
                                      0.7
                                                                               
                                      0.6
                                      5.4
                                      4.5
                                      2.3
                                      1.5
                                      1.2
                                      0.7
                                                                               
                                      0.6
                                      5.1
                                      4.1
                                      2.3
                                      1.5
                                      1.2
                                      0.6
                                                                               
                                      0.7
                                      4.6
                                      3.7
                                      2.3
                                      1.4
                                      1.2
                                      0.6
                                                                               
                                      0.7
                                      4.5
                                      3.6
                                      2.0
                                      1.4
                                      1.1
                                      0.6
                                                                               
                                      0.7
                                      4.0
                                      3.3
                                      2.0
                                      1.3
                                      1.0
                                      0.6
                                                                               
                                      0.8
                                      3.7
                                      3.1
                                      1.9
                                      1.3
                                      1.0
                                      0.6
                                                                               
                                      0.8
                                      3.6
                                      3.0
                                      1.9
                                      1.2
                                      1.0
                                      0.6
                                                                               
                                      0.8
                                      3.4
                                      2.8
                                      1.6
                                      1.1
                                      1.0
                                      0.5
                                                                               
                                      0.9
                                      3.3
                                      2.8
                                      1.6
                                      1.1
                                      0.9
                                      0.5
                                                                               
                                      0.9
                                      3.3
                                      2.7
                                      1.5
                                      1.0
                                      0.9
                                      0.5
                                                                               
                                      0.9
                                      2.4
                                      2.1
                                      1.5
                                      0.9
                                      0.7
                                      0.5
                                                                               
                                      1.0
                                      1.8
                                      1.5
                                      1.1
                                      0.9
                                      0.7
                                      0.4
                                                                               
                                       
                                       
                                       
                                       
                                       
                                       
                                       
                                                                               
                                      0.1
                                     16.6
                                     13.3
                                      6.6
                                      3.2
                                      2.4
                                      1.0
                                                                               
                                       
                                       
                                       
                                       
                                       
                          Average of yearly averages:
                                      0.7
                                                                               
                                                                               
                                                                               
                                                                               
                                                                               
                                                                               
                                                                               
                                                                               
                                                                               
Inputs generated by pe5.pl - Novemeber 2006
                                                                               
                                                                               
                                                                               
                                                                               
                                                                               
                                                                               
                                                                               
                                                                               
                                                                               
                                                                               
                                                                               
Data used for this run:
                                                                               
                                                                               
                                                                               
                                                                               
                                                                               
Output File: PATomG_DW_15-07
                                                                               
                                                                               
                                                                               
                                                                               
Metfile:
w14751.dvf
                                                                               
                                                                               
                                                                               
                                                                               
                                                                               
PRZM scenario:
PAtomatoSTD.txt
                                                                               
                                                                               
                                                                               
                                                                               
                                                                               
EXAMS environment file:
ir298.exv
                                                                               
                                                                               
                                                                               
                                                                               
                                                                               
                                                                               
Chemical Name:
Pyraclostrobin
                                                                               
                                                                               
                                                                               
                                                                               
                                                                               
Description
Variable Name
Value
Units
Comments
                                                                               
                                                                               
Molecular weight
mwt
                                                                            388
g/mol
                                                                               
                                                                               
                                                                               
                                                                               
Henry's Law Const.
henry
                                                                       1.30E-07
atm-m^3/mol
                                                                               
                                                                               
                                                                               
Vapor Pressure
vapr
                                                                       6.88E-07
torr
                                                                               
                                                                               
                                                                               
                                                                               
Solubility
sol
                                                                            2.7
mg/L
                                                                               
                                                                               
                                                                               
                                                                               
Kd
Kd
                                                                               
mg/L
                                                                               
                                                                               
                                                                               
                                                                               
Koc
Koc
                                                                           9304
mg/L
                                                                               
                                                                               
                                                                               
                                                                               
Photolysis half-life
kdp
                                                                           0.11
days
Half-life
                                                                               
                                                                               
                                                                               
Aerobic Aquatic Metabolism
kbacw
                                                                           45.1
days
Halfife
                                                                               
                                                                               
                                                                               
Anaerobic Aquatic Metabolism
kbacs
                                                                           12.1
days
Halfife
                                                                               
                                                                               
                                                                               
Aerobic Soil Metabolism
asm
                                                                          247.2
days
Halfife
                                                                               
                                                                               
                                                                               
Hydrolysis:
pH 7
                                                                              0
days
Half-life
                                                                               
                                                                               
                                                                               
Method:
CAM
                                                                              2
integer
See PRZM manual
                                                                               
                                                                               
Incorporation Depth:
DEPI
                                                                              0
cm
                                                                               
                                                                               
                                                                               
                                                                               
Application Rate:
TAPP
                                                                           0.22
kg/ha
                                                                               
                                                                               
                                                                               
                                                                               
Application Efficiency:
APPEFF
                                                                           0.99
fraction
                                                                               
                                                                               
                                                                               
                                                                               
Spray Drift
DRFT
                                                                          0.064
fraction of application rate applied to pond
Application Date
Date
15-07
dd/mm or dd/mmm or dd-mm or dd-mmm
Interval 1
interval
                                                                              7
days
Set to 0 or delete line for single app.
app. rate 1
apprate
                                                                            0.2
kg/ha
                                                                               
                                                                               
                                                                               
                                                                               
Interval 2
interval
                                                                             14
days
Set to 0 or delete line for single app.
app. rate 2
apprate
                                                                            0.2
kg/ha
                                                                               
                                                                               
                                                                               
                                                                               
Interval 3
interval
                                                                              7
days
Set to 0 or delete line for single app.
app. rate 3
apprate
                                                                            0.2
kg/ha
                                                                               
                                                                               
                                                                               
                                                                               
Interval 4
interval
                                                                             14
days
Set to 0 or delete line for single app.
app. rate 4
apprate
                                                                            0.2
kg/ha
                                                                               
                                                                               
                                                                               
                                                                               
Interval 5
interval
                                                                              7
days
Set to 0 or delete line for single app.
app. rate 5
apprate
                                                                            0.2
kg/ha
                                                                               
                                                                               
                                                                               
                                                                               
Record 17:
FILTRA
                                                                               
                                                                               
                                                                               
                                                                               
                                                                               
                                                                               
                                                                               
IPSCND
                                                                              1
                                                                               
                                                                               
                                                                               
                                                                               
                                                                               
                                                                               
UPTKF
                                                                               
                                                                               
                                                                               
                                                                               
                                                                               
                                                                               
Record 18:
PLVKRT
                                                                               
                                                                               
                                                                               
                                                                               
                                                                               
                                                                               
                                                                               
PLDKRT
                                                                               
                                                                               
                                                                               
                                                                               
                                                                               
                                                                               
                                                                               
FEXTRC
                                                                            0.5
                                                                               
                                                                               
                                                                               
                                                                               
                                                                               
Flag for Index Res. Run
IR
Reservoir
                                                                               
                                                                               
                                                                               
                                                                               
                                                                               
Flag for runoff calc.
RUNOFF
total
none, monthly or total(average of entire run)

Model SCIGROW

                                    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:Pyraclostrobin
                         time is  2/10/2013   7:50:44
   ------------------------------------------------------------------------
      Application      Number of       Total Use    Koc      Soil Aerobic
    rate (lb/acre)  applications   (lb/acre/yr)  (ml/g)   metabolism (days)
   ------------------------------------------------------------------------
         0.156           6.0           0.936      9.00E+03      161.0
   ------------------------------------------------------------------------
                 groundwater screening cond (ppb) =   6.18E-03
   ************************************************************************

Model PRZM_GW