Document ID: EPA-HQ-OPP-2016-0013-0012
Agency: epa
Document Type: Supporting & Related Material
Title: 
Posted Date: 2017-05-11T04:00Z

UNITED STATES ENVIRONMENTAL PROTECTION AGENCY
WASHINGTON D.C., 20460
                                   OFFICE OF
                              CHEMICAL SAFETY AND
                             POLLUTION PREVENTION
                                   OFFICE OF
                              CHEMICAL SAFETY AND
                             POLLUTION PREVENTION

June 28, 2016	
                                                             	 
MEMORANDUM

SUBJECT: 	Drinking Water Assessment of Flonicamid Use on Legume Vegetables, Citrus and Greenhouse Peppers. PC Code: 128016; DP Barcode: 431454. 433010

TO:		Barbara Madden, Team Leader 05 
      Sidney Jackson, Risk Manager Reviewer 
		Risk Integration Minor Use, and Emergency Response Branch 
      Registration Division 

	Richard Gebken, Product Manager 10
	Carmen Rodia, Reviewer
	Invertebrate-Vertebrate Branch 2
	Registration Division

	Christine Olinger, Chief
	Risk Assessment Branch 3
	Health Effects Division 

FROM:	Colleen M. Rossmeisl, DVM, Biologist
	James A. Hetrick, Ph.D., Senior Science Advisor
	Environmental Risk Branch 3
	Environmental Fate and Effects Division (7507P)
            
THROUGH:	Dana Spatz, Branch Chief
      Environmental Risk Branch 3
            Environmental Fate and Effects Division (7507P)	

REVIEWED	Rosanna Louie-Juzwiak, RAPL
BY:		Environmental Risk Branch 3
            Environmental Fate and Effects Division (7507P)	

IR-4 is seeking the addition of new uses of flonicamid [Beleaf(TM)-50SG Insecticide ( EPA Reg. No. 71512-10) and Flonicamid 50WG (EPA Reg. No. 71512-9)] on legumes, citrus and greenhouse peppers for the control of aphids, leafhoppers, whitefly, and plant bugs. The proposed new use requests ground, aerial, or chemigation spray applications of flonicamid at a maximum seasonal application rate of  0.267 lb a.i./A and a maximum single application rate of 0.181 lb a.i./A. This represents an increase in the current maximum single application rate but does not increase the maximum seasonal rate.  

Estimated drinking water concentrations (EDWC) were determined for legumes and citrus with appropriate rates and buffers as specified on the current label. The addition of greenhouse pepper use was not modeled as this represents an indoor use only and calculated EDWCs for legumes and citrus would be more conservative than those predicted for greenhouse peppers. A total toxic residue (TTR) approach, which considers the parent compound and its major degradates of concern previously identified by HED, were considered in this analysis. Tables 1  -  3 provide information on input parameters, application rates modeled and spray drift fractions. EDWCs were derived using the Pesticide in Water Calculator (PWC version 1.52). Based on this analysis, predicted EDWCs do not exceed EDWCs for existing uses of flonicamid in surface water or groundwater, as outlined in the most recent drinking water assessment, dated June 24, 2013, Drinking Water Assessment to Assess Flonicamid Use on Alfalfa and Clover Grown for Seed, Fruiting Vegetables, Mint, Tree Nuts, and the Expansion to the Full Crop Group for Pome Fruit and Stone Fruit. Based on the June 2013 drinking water assessment, the concentration of total toxic residues of flonicamid (flonicamid TTR) in ground water is predicted to not exceed 15.9 ug/L for the daily peak and 9.92 ug/L for the 30 year annual average, which was associated with a single application rate of 0.133 lb a.i./A (2 applications per year) on fruiting vegetables. As these EDWCs are greater than the maximum predicted surface water or groundwater concentrations associated with the proposed new uses, as reported in Tables 4 and 5 below, EFED recommends that HED continue to use the EDWCs provided in the June 2013 drinking water assessment. 

Table 1. Proposed New Uses for Flonicamid   
                                       
                                   Crop/Site
                                       
                           Application Type/ Method
                                       
                        Single Application Rate Range 
                                  (lb a.i./A)
                                       
                      Maximum Application Rate Per Season
                                  (lb a.i./A)
                          Maximum Application Number
                                       
                      Minimum Retreatment Interval (days)
Legume Vegetables Subgroup
Ground/Aerial/Chemigation[A]
                                     0.133
                                     0.267
                                       2
                                       7
Citrus

                                0.089  -  0.181
                                     0.267
                                       3
                                       7
A Chemigation not modeled

Table 2. Input Parameters Used in PWC Modeling to Estimate Flonicamid and Total Toxic Residues (Flonicamid ,TFNA, TFNG, TFNA-AM, TFNA-OH) Concentrations in Drinking Water 
Study Type
Flonicamid 
(PC Code:128016)
Total Toxic Residues
Data Source
Molecular Weight
229 g/mole
229 g/mole (parent )
Calculated
Water Solubility
5.3 g/L

5.3 g/L (parent )
Product Chemistry
Vapor Pressure
7.07 x 10[-9] torr 

7.07 x 10[-9] torr (mm Hg, parent molecule)
Product Chemistry
Hydrolysis
stable  
stable 
(parent molecule, no data available for degradation products)
MRID 45656801
Aqueous Photolysis
stable  
stable
(parent molecule, no data available for degradation products)
MRID 45656802
Aerobic Soil Metabolism
2.58 days 
(90[th] confidence bound on the mean half-life)
4.2 days
 (mean t1/2 + (t90 x s)/n[1/2])

MRID 45854818 
MRID 45656804
Aerobic Aquatic Metabolism
 5.16 days  
(2X from the aerobic soil metabolism half-life)
55.1 days 
(mean t1/2 + (t90 x s)/n[1/2])
 MRID 45854821

Anaerobic Aquatic Metabolism
 482.1 days
(3X anaerobic aquatic metabolism half-life) 
stable
MRID 45854821

Mobility
Avg Koc = 19.03 
0 mL/g Koc for degradation products because there was no measurable sorption observed in batch equilibrium studies.
MRID 45656805 (parent only)
MRID 45854901
MRID 45854904
MRID 45854902

Table 3. Factors Required for Spray Drift Adjustment
                        Spray Drift Adjustment Factors
                             Spray Drift Fraction

                                    Ground
                                    Aerial
Spray Buffer (ft)
                                      25
                                      150
Streams
                                   0.083[A]
                                    0.0606
Reservoir
                                   0.0227[B]
                                    0.0352
Area of Streams (ha)
                                      0.6
Area of Reservoir (ha)
                                     5.25
                             Adjusted Spray Drift
                                  Fraction[C]
                                    Ground
                                    Aerial
Spray Buffer (ft)
                                      25
                                      150
Index reservoir
                                    0.0321
                                    0.0421
                                       
                                       
                                       
[A] AgDrift spray drift fraction calculated for 25 feet buffer assuming a stream 
width of 4 meters (13 ft).
[B] AgDrift spray drift fraction calculated for 150 feet buffer assuming a reservoir 
width of 82 meters (269 ft).
[C] Adjusted spray drift fraction calculated as per Guidance on Modeling Offsite Deposition of Pesticides via Spray Drift for Ecological and Drinking Water Assessments December 20, 2013.
                    

Table 4. PCA1 corrected Estimated Drinking Concentrations for Flonicamid and Its Degradation Products (TFNA, TFNG, TFNA-AM, TFNA-OH)  in Surface Source Water Using PWC
                                HED Crop Group
                                     Model
                                   Scenario
                              Application Method
                                 1 in 10 year
                            30 year Annual Average
                                       
                                       
                                       
                                     Peak
                                Annual Average
                                       
                                       
                                       
                                       
                                     ug/L
                                    Citrus
                                   FL Citrus
                                 Ground Spray
                                     9.737
                                     1.001
                                    0.42133
                                       
                                       
                                 Aerial Spray
                                     9.373
                                    0.9646
                                    0.41587
                                       
                                   CA Citrus
                                 Ground Spray
                                    0.68341
                                    0.18837
                                    0.12558
                                       
                                       
                                 Aerial Spray
                                    0.70525
                                    0.20566
                                    0.14742
                                    Legumes
                                   MI beans
                                 Ground Spray
                                    12.285
                                    2.7755
                                     1.456

                                       
                                 Aerial Spray
                                    11.921
                                    2.6936
                                    1.4287

                             OR snbeans          
                                 Ground Spray
                                    3.0394
                                    0.51051
                                    0.17836

                                       
                                 Aerial Spray
                                    2.9848
                                    0.5096
                                    0.19019

                                   IL beans
                                 Ground Spray
                                    7.6895
                                    1.3104
                                    0.63973

                                 Aerial Spray
                                    7.4529
                                    1.2831
                                    0.63336
[1] PCA = 0.91

Table 5. Estimated Drinking Water Concentrations of Total Toxic Residues (Flonicamid, TFNA, TFNG, TFNA-AM, TFNA-OH) in Ground Water Using PWC
                                    Residue
                                   Scenario
                              Peak Concentration
                      Average Breakthrough Concentration
                               Breakthrough Time

                                     ug/L
                                     Days
TTR (Flonicamid + Degradation Products)
                                   FL Citrus
                                     11.37
                                     2.36
                                      713