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

NOTE TO ISOFETAMID FILE

DATE: May 29, 2015

SUBJECT: Isofetamid: Risk Management Decisi on Regarding Several Ecological Studies

TO: Cynthia Giles-Parker, Chief Fungicide Branch Registration Division

FROM: Heather Garvie Fungicide Herbicide Branch Registration Division

Isofetamid is being proposed for use on almond, lettuce, grapes (Subgroup 13-07F), low growing berries (Subgroup 13-07G), rapes eed (Subgroup 20A), and turf (com mercial and residential). One technical product (EPA File Symbol 71512- ER) and two end-use products [Isofetamid 400SC Fungicide (EPA File Symbol 71512-EE) a nd Isofetamid Turf Fungicide (EPA File Symbol 71512-EG)] are being proposed for regist ration in the United States. The maximum proposed single application rate is 0.572 lb a.i./acre (grapes) and the maximum annual application rate proposed is 3.65 lb a.i./acre (t urf). Application methods include ground spray, aerial spray, and chemigation.

As part of the evaluati on of this new active ingredient, th e EPA discussed uncertainties in the

risk conclusions attributed to the defici encies associated with certain data ( i.e. , the daphnid chronic toxicity study, as well as the cyanobacter ia study). Overall, based on the available data and predicted exposures in the environment, the EPA noted that repeating the following studies is not expected to alte r the risk conclusions for the proposed uses, in the contex t of the assessed application rates and uses. Therefore, based on the current risk conclusions ( i.e. , the level of concern was not exceeded for the respective taxa), the EPA has determined that although these two studies were deemed supplemental or par tially acceptable, they sa tisfy these two data requirements in support of the proposed isofetam id uses. Study-specific discussions are listed below regarding the rationale for not needing additio nal data at this time. The EPA concludes atthis time that there are no outstanding issues from the standpoint of EPA’s proposed regulatory position or proposed labels that are raised by these classifications.

‐ Daphnid Chronic Toxicity Test, OCSPP Guideline 850.1300

‐ Cyanobacteria ( Anabaena flos-aquae ), OCSPP Guideline 850.5400

Daphnid Chronic Toxicity Test . The only chronic toxicity data cu rrently available for isofetamid and an aquatic invertebrate are for the waterflea ( Daphnia magna ). In the waterflea study there was reduced length at all test concentrations resulting in a NOAEC of <0.39 mg a.i./L. The effects at the 0.39 mg/L concentration were slight (the average lengths for the waterfleas in the

control versus the waterfleas at the 0.39 mg/L concentr ation were 4.92 mm and 4.85 mm, respectively). As such, this study is classified as ‘supplemental.’ Because the 0.39 mg a.i./L is only 2 times the highest 21-day average EEC for the uses modeled (wet-harvested cranberry), there is uncertainty in this risk conclusion. Wh ile a definitive NOAEC wo uld help address this uncertainty, at 0.39 mg a.i./L, no chronic risk is expected ( i.e. , the risk quotient is below the level of concern of 1).

Cyanobacteria (Anabaena flos-aquae) . Acceptable data are currently only available for three, instead of four, species of non-vascular aquatic plan t. Due to the low toxicity of isofetamid seen in the three available algal studies, as well as the predicted envir onmental concentrations, additional plant data are not expected to change the current risk conclusions ( i.e. , no risk to nonlisted or listed plants).

Although the two aforementioned studies were deem ed supplemental or partially acceptable, they satisfy these two data requirements in support of the propos ed isofetamid uses.

Additionally, ISK Biosciences Corporation requested a wa iver for two ecological studies: fish early-life stage (freshwater), guideline 850.1400; and acute fish toxicity, guideline 850.1075. Based on the available data and predicted exposur es in the environment, the Agency believes

that the submission of these two studies would not alter the risk conclusions for the proposed uses (with the exception of the pr oposed wet-harvested cranberry use), and in the context of the assessed application rates and uses , waives these studies. A more detailed discussion of these

two studies can be found in the document titled Isofetamid: Status of Ec ological Effects Data in Support of the Proposed Section 3 Uses, dated 5/29/15, which can be found on the isofetamid regulatory docket (Docum ent ID: EPA-HQ-OPP-2013-0138).