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


	PC Code:  044309
	DP Barcode:  D395349

MEMORANDUM	October 22, 2012


SUBJECT:	Drinking Water Exposure Assessment in Support of the Proposed IR-4 New Uses of Clothianidin on Strawberry, Citrus Fruit Group, and Pistachio

TO:	Sydney Jackson, Risk Manager Reviewer
	Barbara Madden, Risk Manager (RM05)
	Registration Division (7505P)
          AND
               Marianne Lewis, Risk Manager Reviewer
	Venus Eagle, Risk Manager (RM01)
	Registration Division (7505P)


FROM:	Reuben Baris, Environmental Scientist
	Environmental Risk Branch 6
	Environmental Fate and Effects Division (7507P)

	Mark Corbin, Chief
	Environmental Risk Branch 6
	Environmental Fate and Effects Division (7507P)


This memorandum summarizes the Environmental Fate and Effects Division's (EFED) assessment of drinking water exposure resulting from the proposed new uses on strawberry, citrus, and pistachio supported by the Interregional Research Project No. 4 (IR-4).

The previously registered use of clothianidin as a seed treatment for rice resulted in an estimated drinking water exposure concentration of 72 ppb. The assessed application rate was equivalent to 0.084 lb a.i./A (USEPA, 2012; DP 393235, 393972). This value is greater than the estimated drinking water concentrations (EDWCs) resulting from the proposed uses on strawberries, citrus, and pistachios (the current action). Therefore EFED recommends the use of the Tier I rice value of 72 ppb in the Health Effects Division (HED) dietary risk assessment. Table I compares the Tier I rice EDWCs to EDWCs resulting from the proposed uses.

Table 1.  Tier I EDWCs for drinking water exposure assessment based on the proposed clothianidin uses on strawberries, citrus, and pistachios compared to the previously registered rice EDWC.
Use
Model 
                         Application rate, lbs a.i./A
                              (# of applications)
                                      PCA
                                     Acute
                                    Chronic
Surface water drinking water sources, downstream of rice paddy (0.084 lb a.i./A)
Tier I Rice Model (v1.0)
                                     0.084
                                      (1)
                                      --
                                    72 ppb
                                  <72 ppb
Maximum aerial application rate for proposed new uses (strawberry, citrus, pistachio)
FIRST
                                      0.1
                                      (1)
                                     0.87
                                      8.1
                                      2.6
Maximum soil application rate for proposed new uses (strawberry, citrus, pistachio)
FIRST
                                      0.2
                                      (1)
                                       
                                     16.1
                                      5.2



References:

USEPA. 2012. Tier I Drinking Water Exposure Assessment for the Section 3 New Uses of Clothianidin on Rice and Leafy Vegetables. Memorandum from Reuben Baris to Michael Doherty, dated Spetember 15, 2011. DP barcodes: 393235, 393972. United States Environmental Protection Agency, Office of Chemical Safety and Pollution Prevention, Washington, DC.

