U NI TE D STATES ENV I RONMENTAL PROTEC T ION AGEN CY WASHINGTON D. C.
, 20460

PC C odes: 128922 and 12892 3 DP Barcode : D421435

Date: August 5
, 2013

MEMORANDUM

SUBJECT: R esponse t o Public Comment s on the Ima zethapyr and lm azetha pyr Ammonium

FROM: Sal t R eg i s tration Review Probl em Formula tion :.L" 

## (;.' /**~.#- ~**  Edward Odenkirchen, Ph.D.
, Senio r Scientist

## 2"'**~** / .- & 

## f

. 

# /L/ Stephen Wente, Ph.D., B iologist

### /~ -

### ~ P / 

### >"j /7 Environmenta l Risk Bran ch I Environmental Fate and Effects Div i sio n (7507P) Office of Pesticide Program s

# --**~ ko.~** **'5 (\l.~**  THROU GH: Sujatha Sank ula
, Ph.D

. , Branch C hief / 

## \ v \,..... )**~_..::;;::----** I Environm e ntal Risk Branch I Env ironm en tal Fate and Effec t s D ivi sion (7507P) Office of Pestic id e Program s

TO: Katherine St. C lair
, Chemical R e v i ew Manager Cathryn Britton
, Team L e ad e r Ke v in C ostello
, Branch Chief Ri sk Manageme nt and Impl ementat i on Branch II Pe s ticid e R e-Eval uation Division Office of P est i c id e Programs (7 5 08P )

In response to the " R e gistrat ion Revi ew Problem Formulation for I mazethapyr and lmazethap yr Ammonium Salt " (D 4 1 5245)
, BASF and the California Department of Pestic i de Regulation (DPR) su bmitt ed comments ( BA SF) and monitoring data (C alifornia DPR) durin g the public comment period

. Th e purpose of**~his** m emor andum i s to address t h ese comments and data

s ubmi ssio ns.
Monitoring Data

The Agency greatly appreciates receivin g relevant monitoring data from th e Ca lifornia D epartme nt of P esticide R egulatio n

. The data wi ll be considered and used (as approp riate ) in future ri sk assessmen t s.

### 2 Comments by BASF

Comment: Honey bee toxicity of residues on foli age study (OCSPP Guideline 850.3030) is a conditional study required only when the formulation contains one or more active ingredients having an acute LD50 of < 11 μ g per bee as determined in the honey bee acute contact study (40 CFR 158.630). The Environmental Fate and Eff ects Division (EFED) Preliminary Problem Formulation document states on page six (2002 ec ological risk assessment for imazethapyr use on rice and clover) that, “Imazetha pyr is practically non-toxic (LD 50 

### >100 μ g/bee) to honey bees; therefore low risk was assumed for beneficial te rrestrial invertebrates.” Thus, BASF respectfully requests that the requirement for honey b ee toxicity of residues study be waived.

EPA Response: The requested study can be waived.

Comment: Honey bee larval toxicity study (OECD 237) requested in the preliminary work plan is a new data requirement. BASF agrees to conduct this study, and woul d like to note that the TGAI is the test material most often used to support all outdoor end-use products. The TEP is used for testing only when there are speci fic concerns with the TEP formulation.
EPA Response: The study should be conducted with TGAI.

Comment: The Executive Summary on page four of the Environmental Fate and Effects Division (EFED) Preliminary Problem Formulati on document states that the Tier 2 seedling emergence study (OCSPP guideline 850.4100) is liste d as a data gap “place holder” pending completion of data evaluation for the submitted study (MRID 44996102). BASF requests the Data Evaluation Record (DER) for this study.

EPA Response: The study is still undergoing review. When the DER is completed, BASF will receive notification and a copy.

Comment: The Executive Summary on page four of the Environmental Fate and Effects Division (EFED) Preliminary Problem Formulati on document states that the Tier 2 vegetative vigor study (OCSPP guideline 850.4150) is listed as a data gap “p lace holder” pending completion of data evaluation for the submitted study (MRID 44996101). BASF requests the Data Evaluation Record (DER) for this study.

EPA Response: The study is still undergoing review. When the DER is completed, BASF will receive notification and a copy.

Comment: BASF had previously submitted an aquatic plant growth study for degradate CL 266858 with Lemna gibba (MRID 45161322). Page 28 of the E nvironmental Fate and Effects Division (EFED) Preliminary Problem Formul ation document states that this study was

### 3 classified as invalid. BASF will review this stud y for deficiencies, and is aware that “In the absence of acceptable data, the compound may be c onsidered of equal toxicity as the parent herbicide, or an extrapolation from available struct ural analogs’ toxicity re lative to parent will be used to establis h an endpoint.”

EPA Response: No response necessary.