Document ID: EPA-HQ-OPP-2017-0224-0008
Agency: epa
Document Type: Supporting & Related Material
Title: 
Posted Date: 2018-07-23T04:00Z

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

                                                                               

October 24, 2017
													
MEMORANDUM

SUBJECT:	Drinking Water and Ecological Risk Assessment for Flonicamid New Use on Clover and Crop Additions to Groups 5-16, 4-16B, 20C, 22B and 4-16A. PC Code: 128016; DP Barcode: DP439904, DP441256, DP441257, DP441258, DP441253, DP441254, DP441255

TO:			Sidney Jackson, Risk Manager Reviewer 
			Minor Use and Emergency Response Branch 	
            Registration Division 

            Richard Gebken, Product Manager 10 
                  Carmen Rodia, Environmental Protection Specialist, Risk Manager Reviewer 
			Insecticide-Vertebrate Branch 2
            Registration Division (7505P)
            
                  Thomas Moriarty, Branch Chief
      	Risk Assessment Branch 3
      	Health Effects Division 

FROM:		Colleen M. Rossmeisl, DVM, Biologist
			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)

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 clover and additions to crop groups 5-16, 4-16B, 20C, 22B and 4-16A. The registrant proposed several crop group conversions without changes in application rates or methods. Brassica (cole) leafy vegetable subgroup is converted to brassica head and stem vegetable subgroup 5-16 and Brassica leafy greens subgroup 4-16b. Several new uses on subgroup 20C, 22B and 4-16A are requested, as outlined in the proposed labels. 

The proposed new use requests ground, aerial, or chemigation spray applications of flonicamid at a maximum seasonal application rate of 0.18 lb a.i./A and a maximum single application rate of 0.089 lb a.i./A for clover and a maximum seasonal application rate of 0.267 lb a.i./A and a maximum single application rate of 0.089 lb a.i./A for additional uses added to crop groups. These application rates are the same as many existing and previously assessed uses of flonicamid. Therefore, as application rates are similar, toxicity and fate data are unchanged, and models and guidance are unchanged, risk conclusions from previous assessments are applicable to assessment of this new use, with the exception of watercress, which was added as a new use to the brassica leafy vegetables crop group (4-16B). Aquatic exposure estimates for watercress use are based on a different set of assumptions than dry-field crops given that watercress is grown on fields that are flooded with water. Aquatic estimated environmental concentrations (EECs) for watercress are not modeled with the Pesticide in Water Calculator (PWC) as previously used for flonicamid, but are modeled using the Pesticide in Flooded Applications Model (PFAM). Therefore, watercress was the only new use for which a new analysis was conducted; details of this analysis are provided below.

The watercress analysis resulted in EECs that are lower than maximum EECs and estimated drinking water concentrations (EDWCs) for previously assessed uses of flonicamid. Therefore, risk conclusions for this assessment rely on previous risk assessment results, as outlined below.

Drinking Water Assessment Conclusions and Recommended EECs

In the most recent drinking water assessment (USEPA, 2016A), EFED determined that the EDWCs did not exceed previously calculated EDWCs for existing uses of flonicamid in surface water or groundwater, as provided in the 2013 drinking water assessment (USEPA, 2013). The 2013 assessment predicted the concentration of total toxic residues of flonicamid (flonicamid TTR) in ground water do not exceed 15.9 ug/L for the daily peak and 9.92 ug/L for the 30-year annual average.  Therefore, for the proposed new uses herein, EFED recommends that HED continue to use these EDWCs provided in the June 2013 drinking water assessment.

Ecological Risk Assessment Conclusions

In the October 2016 ecological risk assessment for flonicamid use on citrus and legumes (USEPA, 2016B), no acute or chronic risk quotients (RQs) for listed or non-listed birds, mammals, freshwater fish, or freshwater invertebrate species exceeded the Level of Concern (LOC).  RQs also did not exceed the acute LOC for listed or non-listed estuarine/marine fish.  Additionally, no RQs for listed and non-listed plants exceeded the LOC. Based on the lack of chronic bee toxicity data, uncertainty remained regarding risks to terrestrial invertebrates. Additional summary details from the 2016 assessment are provided below. 

 No acute or chronic risk quotients RQs for listed or non-listed birds, mammals, freshwater fish, or freshwater invertebrate species exceeded the LOC and no acute RQs exceeded the acute LOC for listed or non-listed estuarine/marine fish.  Additionally, no RQs for listed and non-listed plants exceeded the LOC.  

 Maximum acute RQ for animals = 0.03
 Maximum chronic RQ for animals = 0.29
 Maximum RQ for plants = 0.73

 Effects on Honey Bees and Other Non-Target Terrestrial Invertebrates

    Concern remains with regard to the potential for delayed mortality and sublethal (behavioral) effects with exposure levels as low as 2.6 ug a.i./bee. Recently submitted acute studies have provided extended exposure durations, but several studies still demonstrated continued mortality at study termination, with increases in mortality rates occurring between the 72 and 96-hour final sampling points. It is anticipated that the chronic bee studies pending for registration review will provide additional information on risks to terrestrial invertebrates. 
  
 Chronic risk to estuarine/marine animals could not be quantified due to a lack of toxicity data, but risk from chronic exposure appears to be unlikely based on available freshwater animal chronic toxicity data, and the estimated exposure to these animals.

 In the terrestrial plant studies, no effects were observed at the highest treatment levels tested (0.134 lb a.i./A). However, labeled rates for citrus and ornamentals exceeds the maximum rate tested. As such, additional studies for terrestrial plants at higher single application rates (0.267 lb a.i./A) are pending for registration review.

Watercress Exposure Analysis

Aquatic Risk from Flonicamid Use on Watercress

The Pesticide in Flooded Applications Model (PFAM) was used to determine aquatic exposure concentrations of flonicamid due to use on watercress, which requires flowing water during the growing period. The PFAM model was parameterized to mimic a flowing water condition in the watercress bed. A weir height of 1.5 inches (0.0381 m) and a minimum depth of 0.5 inches (0.0127 m) were simulated based on the crop profile for watercress. A turnover rate of 7.4 was used. Per proposed flonicamid labels (EPA Reg. No. 71512-10; EPA Reg. No. 71512-09), flonicamid may not be applied when watercress is flooded. Water must be turned off 24 hours in advance of an application, and may be turned back on 24 hours after the application. Therefore, the simulation also included a dry period of 24 hours before and after each application. January application dates were selected based on the rainy season of the referenced crop profile scenario; other application dates were simulated and relatively minor changes in EECs occurred, with January representing the most conservative of the dates modeled. As such, the modeled scenario is expected to represent upper bound flonicamid concentrations that would reasonably occur in the water column onsite after application. While watercress production practices may vary across the United States, conditions are not expected to be too different as there are standard crop requirements in terms of water flow and depth. Often watercress supply water is recirculated reducing the likelihood of offsite exposure.   

Table 1 includes input parameters for the PFAM analysis and PFAM input and output screenshots are provided in Appendix A. Chemical specific parameters are consistent with those used in recent modeling for flonicamid; additional details can be found in recent assessments (USEPA, 2016). Results including estimated EECs in the watercress bed are shown in Table 2.

Table 1. Model input parameters for watercress analysis with PFAM

Parameter
Input Value and Unit
Data Source
Maximum single application rate x maximum # of application
0.089 lb ai/A (0.129 kg ai/HA) x 3
EPA Reg. No. 71512-10; EPA Reg. No. 71512-09
Method of application
Foliar Spray
Product Label as above
Application efficiency and drift
Not applicable (0)
PFAM Model Input Guidance, Version 2.1 (USEPA, 2016)
PFAM turn over/day
7.4 (watercress)
Calculated for watercressa

Relative date: Post emergence specific date (January 1) and 7-days reapplication intervals
Assumed 7-days for interval between 2nd and 3rd applications; 24 hour pre and post draw down of water
Application interval and rates and model simulations reflect pre- and post- application draw down per label specifications [a] 
Molecular Weight
229 g/mole (parent)
Calculated
Water Solubility

5.3 g/L (parent)
Product Chemistry
Vapor Pressure

7.07 x 10[-9] torr (mm Hg, parent molecule)
Product Chemistry
Hydrolysis
stable 
(parent molecule, no data available for degradation products)
MRID 45656801
Aqueous Photolysis
Stable
(parent molecule, no data available for degradation products)
MRID 45656802
Aerobic Soil Metabolism
4.2 days[b]
MRID 45854818 
MRID 45656804
Aerobic Aquatic Metabolism
55.1 days[b]
 MRID 45854821
Anaerobic Aquatic Metabolism
Stable
MRID 45854821

Mobility
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
Heat of Henry J/mol @25°C
54872 
Estimated (USEPA, 2016)
     [a] Per proposed labels (EPA Reg. No. 71512-10; EPA Reg. No. 71512-09) "Flonicamid may not be applied when watercress is flooded. Water must be turned off 24 hours in advance of an application, and may be turned back on 24 hours after the application."
     [b] 90% on the mean for TTR

Table 2. EECs in watercress bed.

Peak Daily Average (ug/L)
21-day average (ug/L)
60-day average (ug/L)
365-day (annual) average (ug/L)
4.22
3.32
2.04
0.466

Comparison of peak EECs from the 2016 ecological risk assessment (9.2 ug/L for peak, 21- and 60-day values) indicates maximum predicted EECs for watercress use are less than EECs for other flonicamid uses. Therefore, ecological risk determinations from the previous assessments for flonicamid are protective for uses on watercress.

Considering drinking water exposure, if the watercress bed concentration is used as a conservative estimate of EDWCs, the predicted concentration in the bed is less than those predicted in the most recent drinking water assessment (15.9 ug/L for the daily peak and 9.92 ug/L for the 30-year annual average).  Additionally, the impact on drinking water sources due to the use of flonicamid on watercress is expected to be low. According to the U.S. Department of Agriculture National Statistics (NASS) there were less than 1,000 acres of watercress harvested in 2012 (USDA, 2014). Overlap analysis of proprietary data (locations east of the Mississippi) with community drinking water intake watersheds suggest minimal overlap with watercress use sites, supporting that flonicamid use on watercress is an insignificant source of drinking water exposure compared to other currently registered uses. The Biological Economic Analysis Division (BEAD) stated that watercress production is less than 1,000 acres spread over multiple states with a low percent crop treated acres in the largest watercress production area (95th percentile crop treated acreage is 4 acres in CA). These data indicate a low potential for contamination of surface source drinking water from flonicamid applications to watercress. Therefore, EDWCs for flonicamid use on other agricultural uses are expected to be protective of flonicamid use on watercress. 

Terrestrial Risk from Flonicamid Use on Watercress

Based on data extrapolated from mustard seed and cabbage, watercress may be attractive to bees; however, watercress is harvested prior to bloom when not grown for seed production. (USDA, 2015). The proposed uses for flonicamid do not include seed production for watercress. Risks to terrestrial birds and mammals is not anticipated as application rates are the same as those previously assessed for flonicamid.  Flonicamid is not anticipated to be a risk concern to piscivorous birds and mammals from bioaccumulation in aquatic organisms in the watercress bed based on a low octanol-water partition coefficient (Kow = 1.9).

REFERENCES

Hutchinson, L. 2005. Ecological Aquaculture: A Sustainable Solution. Permanent Publications, Hyden House Ltd, East Meon, Hampshire, England

USDA, 2014. U.S. Department of Agriculture National Statistics (NASS). Agricultural
Statistics 2014. 

USDA, 2015. Attractiveness of Agricultural Crops to Pollinating Bees for the Collection of Nectar and/or Pollen.

USEPA, 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. Memorandum from the Environmental Fate and Effects Division to the Registration Division, Office of Pesticide Programs, Office of Chemical Safety and Pollution Prevention.  June 24, 2013. DP 408552, 408555, 412695.

USEPA, 2016A.  Drinking Water Assessment of Flonicamid Use on Legume Vegetables, Citrus and Greenhouse Peppers. Memorandum from the Environmental Fate and Effects Division to the Registration Division, Office of Pesticide Programs, Office of Chemical Safety and Pollution Prevention.  June 28, 2016.  DP 431454, 433010.

USEPA, 2016B.  Ecological Risk Assessment for Flonicamid Use on Legume Vegetables, Citrus and Greenhouse Peppers. Memorandum from the Environmental Fate and Effects Division to the Registration Division, Office of Pesticide Programs, Office of Chemical Safety and Pollution Prevention.  October 20, 2016.  DP 432940, 432954, 432958, 432959, 432960, 432965, 432966, 432974, 431392.

Appendix A.  PFAM Inputs, Scenario Parameters and Output

Chemical input parameters:

Watercress scenario parameters:

PFAM Outputs: