                     U. S. ENVIRONMENTAL PROTECTION AGENCY
                            Washington, D.C. 20460	
                                                                               
									                          



OFFICE OF PREVENTION, PESTICIDES AND TOXIC SUBSTANCES	
                                                                               
                                                                PC Code: 123802
                                                               DP Codes: 403954
                                                               October 22, 2012


MEMORANDUM

SUBJECT:     Fomesafen Drinking Water Assessment for a new IR-4 Use on Cantaloupe, Cucumber, Pea, Succulent pea, Pumpkin, Summer squash, Watermelon, Winter squash, and Succulent soybean (Edamame)

TO:	Barbara Madden, Risk Manager
            Laura Nollen, Risk Manager Reviewer 
            Registration Division (7505P)           
                       
FROM:	He Zhong, Ph.D., Biologist
	Environmental Risk Branch I
		Environmental Fate and Effects Division (7507P)
                        
APPROVED  Ed Odenkirchen, Ph.D., Acting Branch Chief
BY:	Sujatha Sankula, Ph.D., Lead Biologist 
            Environmental Risk Branch I
	Environmental Fate and Effects Division (7507P)

Summary
This assessment provides estimated drinking water concentrations (EDWC) for fomefaen (trade name: Reflex[(R)] Herbicide) in both surface water and ground water in support of human health risk assessments for a new IR-4 use on cantaloupe, cucumber, pea, succulent pea, pumpkin, summer squash, watermelon, winter squash, and succulent soybean (Edamame).  Based on the proposed supplemental label (EPA Reg. No. 100-993), a maximum of 1.5 pts/acre of the formulated product (0.375 lbs a.i./acre or 0.42 kg a.i./ha) may be applied annually preemergence and postemergence as broadcast application by aerial and ground spray in the EPA regions 1, 2, 3, 4 and 5.  According to the preliminary data from Tier-II PRZM/EXAM modeling and EDWCs for the same application rate from the previous DW assessments for fomesafen on pepper, cotton, soybeans, dry beans, snap beans, potato and tomato (USEPA 2010, DP 373599, 373601 and USEPA 2009, DP365204) at the PCA 0.87, the proposed EDWCs are not expected to supersede the previous upper bound EDWC values (USEPA 2005, DP 322213).  Therefore, EFED continues to recommend the previous upper bound EDWC values for  surface source drinking water concentrations of 34.8 μg/L for peak (acute), 13.1 μg/L for annual average (non-cancer chronic), and 30-year annual average concentration of 6.5 μg/L (cancer chronic).  EFED also recommends using the ground water monitoring concentration of 1 μg/L as the benchmark concentration for fomesafen in ground water source drinking water because it represents actual use conditions of fomesafen on soybeans on a vulnerable soil.  

References

USEPA.  2005.  Revised Tier II Drinking Water Assessment for Fomesafen use on cotton, Soybeans, Dry Bean, and Snap Beans.  DP Barcodes: 322213.  pp. 20.

USEPA.  2009.  Drinking Water Assessment for Fomesafen use on cotton, soybeans, dry beans, snap beans, potato and tomato, DP Barcode: 365204.  pp 41.   

USEPA.  2010.  Drinking Water Assessment for Fomesafen Use on Pepper.  DP Barcode: 373599, 373601.  pp11



