UNITED STATES ENVIRONMENTAL PROTECTION AGENCY 

WASHINGTON D.C., 20460 

OFFICE OF 

CHEMICAL SAFETY AND 

POLLUTION PREVENTION 

MEMORANDUM 

Subject: 

From: 

Through: 

To: 

PC Code: 111401 

DP Barcode: 428847 

August 27, 2015 

Reclassification ofProfenofos Terrestrial Plant and Chronic Avian Reproduction 

Ecotoxicology Studies 

Michael Wagman, Biologist ~~~'­ Environmental Risk Branch 6 

Environmental Fate and Effects Division (7507P) 

Mark Corbin, Branch Chief ~ r n ((:,-L_f-l jEnvironmental Risk Branch 6 \.i)( 

Environmental Fate and Effects Division (75 P) 

Christina Scheltema, Chemical Review Manager 

Kelly Sherman, Branch Chief 

Risk Management and Implementation Branch 3 

Pesticide Re-evaluation Division (7508P) 

In preparation for the Registration Review draft risk assessment for profenofos (PC Code 

I 11401, 0414148), due later this year, a review of the available ecotoxicological data was 

conducted. While the classification for many of the previously submitted studies did not change 

after review (still deemed "Acceptable"), the classification for the available terrestrial plant 

(MRIDs 41627305 & 4 1627307) and one avian chronic reproduction (MRlD 00086661) studies 

did change. The reasons for the change in the study classifications was due to the use of 

technical grade active ingredient (TGAI) as the test substance in place of a typical end-use 

product (TEP) in the terrestrial plant studies and due to the lack of an acceptable NOAEC in the 

avian reproduction study. These study limitations introduce uncertainty in the risk assessment's 

ability to accurately assess risk to terrestrial plants and chronic risk to birds. EFED has 

reclassified the studies from "Acceptable" to "Supplemental" (either quantitative or qualitative 

as described below). The list of the studies and rationale for reclassification of each study is 

provided below. 

For terrestrial plants, additional data is not needed at this time. However, for chronic risk to 

birds, the lack of an acceptable NOAEC results in the inability to determine a level of 

environmental residues on dietary items below which risk could be precluded. Therefore, the 

lack of an acceptable chronic avian reproduction study with bobwhite quail is considered a major 
data gap and new data would be needed in order to define an exposure level below which birds 

would not be considered to be at chronic risk. 

Table 1: Ecotoxicological data for Profenofos 

MRID GDLN & Study Title Study Remarks 

' Classification 1 

Study was previously identified as 

850.4100 Supplemental acceptable. Study may be used 

41627307 Seedling emergence quantitatively in risk assessment. See 

below for rationale for downgrade. 

Study was previously identified as 

41627305 850.4150 Supplemental acceptable. This study may not be used 

Vegetative vigor quantitatively in risk assessment. See 

below for rationale for downgrades. 

Sn1dy was previously identified as 

00086661 2 850.2300 Supplemental acceptable. This study may not be used 

A vi an reproduction quantitatively in risk assessment. See 

below for rationale for downgrades. 

1 O PPIN Classifications: 

Acceptable; Acceptable/Guideline; Acceptable/Non-Guideline; Cited; Confirmatory; Decision Deferred; 

Extraneous submission ; G uideline; In Review; minimum; No Decision; Partially Acceptable; Satisfactory; 

Screened-acceptable for review; Screened-not acceptable; Supplementa l; SupplementaVNon-Guideline; 

Unacceptable; Unacceptable/Guideline; Unacceptable/Non-Guideline; Upgradeable. 

2 EPA Accession Number; No MRlD number was assigned for this study. 

EFED has reviewed and reclassified the following studies submitted for profenofos (PC Code 

111401): 

• Chetram. R. 1990. Profenofos Tier 2 Vegetative Vigor Nontarget Phytotoxicity Study 

using Profenofos Technical (Curacron): Lab Project Number: LR90-408. Unpublished 

Study prepared by Pan-Agricultural Laboratories. Inc. 133 p. MRID 416273-05. 

This Tier 2 vegetative vigor study, conducted with TGAI (90.4% purity) was initially determined 

to be acceptable with no effects observed at the highest dose tested ( 1.0 lbs a.i./A). However, 

EPA requires that terrestrial plant ecotoxicity studies be conducted with TEP formulations 

because the use of TGAI as the test substance may underestimate toxicity to plants. Typical end 

use products may include adjuvants or surfac~ants that increase the toxicity of the parent 

compound to terrestrial plants. Since this is a vegetative vigor test, designed to evaluate the 

effects to terrestrial plants from the spray drift of profenofos formulations where terrestrial plants 

are likely to be exposed to the entire formulated product (i.e. profenofos plus any surfactants or 

adjuvants), it is possible that terrestrial plants may be more sensitive than this study indicates. 

Therefore, this study has been downgraded to supplemental and may only be used qualitatively 

in the risk assessment. However, a new study is not requested at this time since the available 

data indicate that profenofos is comparatively less toxic to terrestrial plants than other taxa and 

would need be considerably more toxic than the available data indicates in order to result in a 

risk concern for terrestrial plants from spray drift. 
• Chetram, R. 1990. Profenofos: Tier 2 Seedling Emergence Nontarget Phytotoxicity Study 

using Profenofos Technica (Curacron): Lab Project Number: LR90-41 0. Unpublished 

Study prepared by Pan-Agricultural Laboratories, Inc. 135 p. MRID 416273-07. 

This Tier 2 seedling emergence study, conducted with TGAI (90.4% purity) was initially 

determined to be acceptable. However, EPA requires that terrestrial plant ecotoxicity studies be 

conducted with TEP formulations because the use of TGAI data may underestimate toxicity to 

plants, as is explained above. TEPs may include adjuvants or surfactants that increase the 

toxicity of the parent compound to terrestrial plants. However, surfactants and other inert 

ingredients in TEP are likely to disassociate from the test substance before reaching the plant life 

stage tested in this study. Therefore, this study has been downgraded to supplemental but may 

still be used quantitatively for risk assessment purposes. 

• Fink, R. and J.B. Beavers. 1978. Final Report: One-generation Reproduction StudyBobwhite Quail: CGA-15324 Technical: Project No. 108-151. (Unpublished study 

received Nov. 6, 1981 under 100-598: prepared by Wildlife International. Ltd., submitted 

by Ciba-Geigy Corp., Greensboro, N.C.; COL: 246218-AB 

This chronic avian reproduction study was originally considered to be acceptable. However, 

EPA requires that chronic studies with avian species obtain a dose at which no significant 

adverse effects occur (the NOAEC). In this study, profenofos resulted in reproductive 

impairment (reduction in egg production and the viability of eggs) to bobwhite quail at all doses 

tested (lowest dose tested was 1 ppm). Therefore, this study has been downgraded to 

supplemental and may only be used qualitatively for risk assessment purposes. The lack of a 

valid NOAEC results in the inability to define a dose on dietary items below which no chronic 

effects would be expected. Therefore, this is considered a major data gap and a new avian 

reproduction study (OCSPP 850.2300 guideline) with bobwhite quail is needed. 

References: 

USEPA, 2015. Transmittal of the Draft Environmental Fate and Ecological Risk Assessment in 

Support ofthe Registration Review ofProfenofos (DP Barcode 414148). September, 2015. 

USEP A/OCSPP/OPP.