UNITED STATES ENVIRONMENTAL PROTECTION AGENCY 

WASHINGTON, D.C. 20460 

OFFICE OF CHEMICAL SAFETY 

AND POLLUTION PREVENTION 

MEMORANDUM 

DATE: 

SUBJECT: 

TO: 

FROM: 

November 25, 2013 

Response to Public Comments on the Preliminary Environmental Fate and 

Ecological Risk Assessment for the Registration Review of Fluazinam 

(PC Code No. 129098; DP Barcode 0416328) 

Steven Snyderman, Risk Manager Reviewer 

Avivah Jakob, Team Leader 

Patricia Parrott, Chief 

Risk Management and Implementation Branch III 

Pesticide Re-evaluation Division (7508W) 

Jo

Justin 

se L. 

Hous

Melendez, 

enger, Biologist 

Chemist (" &iP:"~-

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Environmental Risk Branch V /IC}-"- II/ Z 6 ( 13 

Environmental Fate and Effects Division (7507C) 

THROUGH: Mah T. Shamim, Ph.D., Chief 

Environmental Risk Branch V 

Environmental Fate and Effects Division (7507C) 

In response to the "Preliminary Environmental Fate and Ecological Risk Assessment for the 

Registration Review of Fluazinam" (Document ID EPA-HQ-OPP-2009-0039-0019 in 

www.regulations.gov ) (DP Barcode: 0411177, dated June 4, 20 13), ISK Biosciences Corporation 

(ISKBC) provided comments during the public comment period. ISKBC is the sole U.S. 

registrant of record for tluazinam. The purpose of this memorandum is to address those 

comments. The Environmental Fate and Effects Division (EFED) used an outline-type of format 

to address the comments. The comments were often written verbatim while other times they 

were summarized, as required. EFED's purpose of the document is to respond to 

technical/scie:nce-related questions and comments. 

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1. ISKBC Comment: EFED used the default 35 day foliar dissipation half-life in determining 

exposure and risk estimates in the T -REX model rather than values from submitted studies that 

were used by EFED in previous reviews. ISKBC has submitted two foliar dissipation studies, 

one on peanutts (MRID 46991302) and another on potatoes (MRID 46991303). The input value 

that was previously used by EFED for terrestrial exposure in risk assessment was 7.33 days 

which repres{:nts the 90th percentile of the upper confidence bound on the mean of six half-life 

values for total residues. Since it is the Agency's intent to use the best data available, ISKBC 

suggests that half-live values from these two foliar dissipation studies (MRID 46991302 and 

46991303) be used for the foliar dissipation half life in estimating exposure and ecological risk 

in the T-REX model as was done in the Problem Formulation. 

EFED Response: EFED acknowledges the receipt of the above mentioned studies and that 

relevant foliar dissipation half lives show a 90th percentile upper confidence bound value of 

7.33 days for peanuts and potatoes. While the submitted foliar dissipation half lives do 

indicate that for potatoes and peanuts, fluazinam does dissipate faster than the default value 

of 35 days within T-REX, EFED included in its preliminary risk assessment an analysis of 

the results of the overall risk conclusions if the 7.33 day half life was used instead of the 

default 35-days. This analysis is provided below. 

There is uncertainty in the RQs generated by T-REX for all registered uses of jluazinam 

relating to the foliar dissipation half life. T-REX uses a default foliar dissipation half life of 

35 days in the absence of 3 or more values that are derived from studies demonstrating that 

the foliar dissipation half life is less than 35 days. For jluazinam, there are two foliar 

dissipation studies available (peanut and potato, MRID 46991302, and 46991303, 

respectively) that estimated a foliar dissipation half life of7.33 days. Using the cucurbit use 

as an example, T-REXwas run with the study derivedfoliar dissipation half life of7.33 days 

instead of the default 35 days. The results indicate that acute and chronic RQs are roughly 

one half for dose and dietary-based RQs to birds and mammals. If approximately the same 

results are shown to be true for all uses of jluazinam, while acute and chronic RQs would be 

reduced. it would not entirely eliminate acute risk to birds or chronic risk to birds and 

mammals. Under the 35 day assumption of foliar dissipation half life in T-REXthere were 

three registered uses ofjluazinam (apples, cucurbits, and fruiting vegetables) that exceeded 

all acute LOCs for birds and all registered uses exceeding at least the acute endangered 

species LOC. Using a 7.33 day dissipation half life would result in no uses exceeding the 

acute high risk LOC but 12 of 14 (86%) registered uses would still exceed the acute 

endangered species LOC for at least one food item for birds. For chronic risk to birds, 

using a lower half life would result in 9 of 14 uses (64%) that exceed the chronic LOC for at 

least one food item compared to 13 of 14 (93%) of uses that exceed the chronic LOC with 

default half life. 

For mammals, there was no acute LOC exceedances using the default half life and so these 

RQs would be further reciuced. For chronic risk, every registered use of jluazinam exceeded 

the chronic LOC for mammals for all sizes classes and at least one food item. With the use 

of the lower 7.33 day half life, this risk finding would still remain true. While there is 

uncertainty in the fact that these RQs may be lower as a result of shorter half lives 

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demonstrated by available data, even the employment of this data would not change the 

overall nsk picture from how it currently stands in terms of determinations. 

It is stated by ISKBC that "given the short dissipation half life of 7.33 days, this 

demonstrates the rapid dissipation of Fluazinam, and thus acute risk should not be of 

concern. " As shown above, while the two submitted foliar dissipation indicate a shorter half 

life of fluazinarn than is assumed by the default value in T-REX, for birds, there would still 

be acute risk for listed species in 86% of registered uses and chronic risk in 64% of 

registered uses. For mammals, there was no acute risk indicated using the default half life 

value and even when the 7.33 value is used, chronic risk is indicated in all registered uses of 

fluazinam. Therefore, as stated previously, the overall risk picture of acute and chronic risk 

indicated to birds and chronic risk indicated to mammals would not be impacted. 

Finally, it is noted that ISKBC presented in its comments the results ofT-REX model runs 

for potatoes and peanuts using both the upper bound and mean Kenaga values. As part of its 

standard practice for screening level risk assessment, EFED uses the results of the upper 

bound Kenaga values to estimate terrestrial RQs. 

2. ISKBC Comment: EFED used the ECOSAR (vl.O) model within EPISUITE (v.4.0) in 

which acute and chronic toxicity was predicted for fluazinam' s eight degradation products of 

CAPA, DAPA, AMPA, DCPA, MAPA, HYPA, G-504, and SDS-67200 to freshwater fish, 

freshwater invertebrates, freshwater algae, and saltwater fish. ISKBC has provided a number of 

studies involving direct measurement of metabolite/degradate toxicity to various non target 

organisms; these were provided in the Supplemental Reduced Risk Rationale Fluazinarn Turf 

Uses (IB-2010-RRR-001). In all comparable cases, the actual toxicity is much lower (by up to 

several orders of magnitude) than that predicted by ECOSAR. Any refmed ecological risk 

assessment should take the reduced toxicity of metabolite versus parent into account. ISKBC 

conducted a Tier 2 modeling of fluazinam and it should be pointed out that "fluazinarn was not 

predicted to :adversely affect freshwater invertebrates, marine fish or estuarine/marine benthic 

organisms in an acute exposure. Further, it was not predicted to adversely affect any aquatic 

organisms from chronic exposure and that fluazinam risk quotients are well below the trigger 

value for non-endangered acute risk." (Supplemental Reduced Risk Rationale Fluazinam Turf 

Uses Respon~;e to EPA Letter of October 27,2011 (MRID 48650301) Discussing Issues 

Raised in the March 1, 2011 Meeting (IB-2010-RRR-001)). 

EFED Response: As part of its ECOSAR analysis in the preliminary risk assessment, 

EFED determined, based on the predicted toxicity of the degradates as compared to parent 

fluazinarn, which degradates would be excluded from the total toxic residue (TTR) 

approach. In this analysis, EFED determined that the degradates CAP A, HYP A, and DCP A 

would not be included in the TTR approach. Of the remaining 5 degradates no supplemental 

information beyond the ECOSAR estimates was provided for DAP A and MAP A. For SDS67200, the sediment toxicity studies to Chironomus tentans and Hyalella azteca (MRIDs 

48571413 and 48571414) were cited, but these studies were already incorporated into the 

preliminary risk assessment. The remaining 2 degradates, AMPA and G-504 have estimates 

provided that indicate less toxicity than ECOSAR estimates. It is not indicated in response 

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document from ISKBC whether the "NOEC," is derived from an acute or chronic study. 

These studies are currently in review where it will be determined if there is sufficient 

evidence that the measured toxicity of these degradates is less than that of the estimates 

provided by ECOSAR. 

3. ISKBC Comment: Several studies that were submitted by ISKBC in response to Agency 

requests for data were not included in the study list in Appendix F of the Preliminary Risk 

Assessment (PRA). These include two soil dissipation studies for Nova Scotia (MRID 

45584207) and Ontario (MRID 45584208), a second vascular aquatic plant study (Lemna, MRID 

48571402), several diatom studies (MRID 48571403 to 06), a freshwater microcosm study 

(MRID 4857ll411), and numerous studies conducted using metabolites I degradation products of 

fluazinam, some of which are discussed in the text, but not listed in the reference table. The 

registrant rec·eived the DERs for the two soil dissipation studies and a separate response was 

submitted for these studies to address questions raised in those DERs. In addition, several 

analytical method studies for soil, water, and sediment were submitted to the Agency that have 

apparently be:en reviewed based on comments in Appendix F. Since they had not seen these 

reviews they requested these DERs and will respond to any comments in separate 

correspondence. All of the above mentioned studies should be considered in the further 

environmental review of fluazinam. 

EFED Responses: Regarding the terrestrial field dissipation studies (MRID 45584207 and 

45584208), the submitted responses (MRID 49203501) were evaluated and the studies were 

upgraded from unacceptable to supplemental. The DER amendments will be issued 

separately; however, these submissions do not alter the overall conclusions of the PRA. 

Regarding the analytical method studies for soil, water, and sediment, these DERs were 

previously issued to PRD and sent to the ISKBC. EFED looks forward to any comments 

that could address issues found in such DERs. 

EFED confirms receipt and of the aquatic vascular plant study (MRID 48571402) as well as 

the aquatic nonvascular plant studies (MRIDs 48571403, 48571404, 48571405, and 

48571406). The aquatic vascular plant study with Lemna was not incorporated into the 

preliminary risk assessment because it was determined to be invalid based on solvent 

interference. Similarly, an aquatic nonvascular plant toxicity study with a freshwater diatom 

(MRID 4-8571406) was reviewed and determined to be invalid for solvent interference. The 

other referenced aquatic nonvascular plant studies (MRIDs 48571403, 48571404, and 

48571405) were upgraded from invalid classification to acceptable, supplemental, and 

supplemental, respectively in a 2012 memo (D394293, D394295, 394251 , 394253, 394235, 

and D394254). Despite these studies being inadvertently not included in the preliminary 

risk assessment, these studies yielded endpoints that were higher than the most sensitive 

aquatic nonvascular plant toxicity study available (MRID 48612301), and therefore the risk 

conclusions for aquatic nonvascular plants would not be impacted. 

4. ISKBC Comment: ISKBC recently submitted a study related to the evaluation of fluazinam 

uses and their relationship to federally listed species entitled "Endangered Species and Their 

Proximity to Fluazinam Use Sites in the United States", MRID #48879701. This study was 

conducted through use of the FIFRA Endangered Species Task Force (FESTF) Information 

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Management System (IMS) and contains best available data on the proximity of federally listed 

species to potential fluazinam use sites and other best available information, such as species 

attribute data.. ISKBC understands that the EFED document is a preliminary risk assessment and 

is not intended to make findings related to endangered species jeopardy. However, as the 

Preliminary Risk Assessment is intended to reflect the best information available to the Agency 

for purposes of conducting a thorough risk assessment, ISKBC feels that the information in the 

submitted report will ultimately be very helpful to the Agency in fulfilling its requirement to 

assess risk to endangered species. ISKBC is encouraged that the risk assessment document 

mentions the need for an analysis of the type in the submitted report and specifically mentions 

the FIFRA EJO.dangered Species Task Force (p. 60). Should EPA's use of the data be facilitated 

by delivery of the data in an alternate format, this can be readily compiled from the currently 

submitted data. 

EFED Response: EFED acknowledges receipt of the above referenced document. 

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