Document ID: EPA-HQ-OPP-2008-0458-0009
Agency: epa
Document Type: Supporting & Related Material
Title: 
Posted Date: 2009-07-15T04:00Z

UNITED STATES ENVIRONMENTAL PROTECTION AGENCY

WASHINGTON, D.C.  20460

OFFICE OF              

PREVENTION, PESTICIDES

AND TOXIC SUBSTANCES 

MEMORANDUM

DATE:  	June 16, 2009 

SUBJECT:	Fenamidone – Response to Registrant Comment and Addendum to
12/18/08 Residue Chemistry Chapter to Support New Uses and Tolerances on
the Root Vegetable Subgroup 1B (except radish), Okra, Turnip Greens,
Cilantro Leaves and Grapes Grown East of the Rocky Mountains and 2/24/09
Residue Chemistry Chapter to Support New Rotational Crop Uses and
Tolerances on Field Corn, Sweet Corn and Soybean.

PC Code:  046679	DP Barcode:   D366172

Decision No.:  392843	Registration No.:  264-695

Petition No.:  7E7350, 8F7410	Regulatory Action: Section 3 Registration

Risk Assessment Type: N/A	Case No.:  N/A

TXR No.:  N/A	CAS No.:  161326-34-7

MRID No.: N/A	40 CFR:  180.579

REVIEWER:	Donna S. Davis, Chemist

		Alexandra LaMay, Biologist

Risk Assessment Branch VII

Health Effects Division (7509P)

THROUGH:	Michael S. Metzger, Chief

Risk Assessment Branch VII

Health Effects Division (7509P)

To:		Susan Stanton

		Barbara Madden, Minor Use Team Leader

		Daniel Rosenblatt, Chief

		Integration Minor Use and Emergency Response Branch

		Registration Division (7505P) 

Background

Previously, IR-4 submitted a petition (7E7350) to establish tolerances
for residues of the fungicide, fenamidone on the crop subgroup 1B (root
vegetable, except sugar beet), except radish.  This crop subgroup
includes turnip roots.  IR-4 also petitioned for tolerances for the
individual commodities, okra, turnip greens, cilantro leaves and grapes
grown east of the Rocky Mountains.  HED reviewed this submission
(12/18/08, D. Davis, D352806) and concluded there was insufficient
information on the potential transfer of residues to milk and meat
resulting from feeding fenamidone treated turnip greens to ruminants;
therefore HED could not recommend in favor of establishing a tolerance
for residues of fenamidone on turnip greens.  As a result, the
petitioner was requested to amend the proposed label to limit use on
turnip cultivars for root production only.

In a separate submission, Bayer CropScience petitioned (8F7410) the
Agency to establish rotational crop tolerances to support the planting
of field corn, sweet corn and soybeans at a 30 day plant back interval
(PBI) to fields that have been previously treated with fenamidone.  The
Agency reviewed this submission (2/24/09, A. LaMay, D357372) and
concluded that revised tolerances were required to support the
rotational crop uses.  

Subsequently Bayer CropScience submitted a response to these reviews,
addressing, among other issues the proposed turnip label restriction and
the proposed rotational crop tolerances (letter dated April 25, 2009
from Robyn Kneen, Registration Manager, Bayer CropScience to Rosemary
Kearns, EPA).  This memorandum addresses the residue chemistry issues
raised by Bayer CropScience.  Conclusions with respect to label
amendments and tolerance levels supersede those determinations made in
our 12/18/08 and 2/24/09 memoranda.  

Response to Comment

Turnip Green Label Restriction

EPA 12/18/08 Conclusion (PP 7E7350)

The Agency has concluded that the use of fenamidone on turnip
tops/greens, would result in an increase in the dietary burden for dairy
cattle to a level which would significantly exceeds the highest dose
testing in the available cattle feeding study.  As a result, it was not
possible to determine if revised milk and meat tolerances might be
required to support the use on turnip greens.  Therefore, the Agency did
not consider the turnip green use adequately supported by residue data
and required that the proposed label be amended to include a restriction
limiting the use only to turnip cultivars grown for root production.  

Bayer CropScience 4/25/09 Response

The petitioner proposed that instead of a restriction on use for turnip
cultivars for root production only, the label restrict against feeding
turnip tops.  BCS indicates that fodder turnips are fed to cattle and
are not the same as turnips grown to produce greens intended for human
consumption.

EPA Response

The Agency has considers the BCS response and has consulted with Agency
experts on both cattle feeding practices and turnip cultivars.  While
the Agency maintains that it is not appropriate to place a feeding
restriction on the label, we do concur with the registrant that turnip
cultivars which are grown as animal feed items are separate and distinct
from turnip cultivars which produce turnip greens for human consumption.
 Therefore, provided the registrant is willing to amend the proposed
label to specify that the use of fenamidone on turnips is “not for use
on forage turnips grown for livestock feed”, HED concludes that there
are no animal feed items associated with the newly proposed uses and the
previous impediment to establishing a turnip green tolerance is now
removed.  HED has no objection to the establishment of a tolerance for
residues of fenamidone on “turnip, greens” at 55 ppm under 40 CFR
180.579.

Rotational Crop Tolerance Levels

EPA 2/24/09 Conclusion (PP 8F7410)

The Agency reviewed the original submission and concluded that the data
collection method used to generate field trial data had not been proven
to recover all regulated metabolites of fenamidone.  Therefore, in
determining tolerance levels, the Agency applied correction factors to
the field trial data which had been submitted.  Further for commodities
for which there were no detectable residues, the Agency summed the
combined limits of quantitation (LOQs) for each constituent in the
tolerance expression to determine the appropriate tolerance level for
that commodity.  The Agency recommended the following rotational crop
tolerances be established under 40 CFR 180.579(d):

Corn, field,
grain…………………………………………………………
…..0.04 ppm

Corn, sweet, kernel plus cob with husks
removed.…………………….……..0.04 ppm

Corn, sweet,
forage…………………………………………………………
...0.20 ppm

Corn, field,
forage…………………………………………………………
…0.30 ppm

Corn, sweet,
stover…………………………………………………………
…0.45 ppm

Corn, field,
stover…………………………………………………………
….0.30 ppm

Soybean,
seed…………………………………………………………
……...0.04 ppm

Soybean,
forage…………………………………………………………
…....0.15 ppm

Soybean,
hay……………………………………………………………
……0.25 ppm

Bayer CropScience 4/25/09 Response

The BCS response to the Agency’s proposed revised tolerances focused
on three primary areas:

The analytical method was sufficient to detect all regulated metabolites
of fenamidone.

The addition of LOQ is not appropriate for commodities without
detectable residues and this addition, causes a trade irritant issue.   

The Agency erred in its use of the MRL (maximum residue limit)
calculator by incorrectly incorporating MLE (maximum likely estimate)
values into the analysis.

In addition to raising these issues, BCS proposed the following
tolerances:

Corn, field,
grain…………………………………………………………
…..0.02 ppm

Corn, sweet, kernel plus cob with husks
removed.…………………….……..0.02 ppm

Corn, sweet,
forage…………………………………………………………
...0.15 ppm

Corn, field,
forage…………………………………………………………
…0.30 ppm

Corn, sweet,
stover…………………………………………………………
…0.20 ppm

Corn, field,
stover…………………………………………………………
….0.40 ppm

Soybean,
seed…………………………………………………………
……...0.02 ppm

Soybean,
forage…………………………………………………………
…....0.15 ppm

Soybean,
hay……………………………………………………………
……0.25 ppm

EPA Response

Subsequent to the 4/25/09 BCS response, the registrant has withdrawn
their comments about the adequacy of the analytical methodology and no
longer objects to the use of correction factors.  The Agency has
considered the registrants concern about the addition of LOQs and agrees
that where there are no detectable residues found in the field trials,
the use of the method LOQ is adequate to cover all regulable fenamidone
residues likely to result in field corn grain, soybean seed, and sweet
corn kernel plus cob with husk removed.  Further, the Agency has
reviewed our use of the calculator and concurs that an error occurred in
using the MRL calculator.  That error has been corrected and the revised
results of the MRL calculator are included in the attachment to this
memorandum.  

The Agency’s final recommendations with respect to tolerance levels to
support these rotational crops are as follows:

Corn, field,
grain…………………………………………………………
…..0.02 ppm

Corn, sweet, kernel plus cob with husks
removed.…………………….……..0.02 ppm

Corn, sweet,
forage…………………………………………………………
...0.15 ppm

Corn, field,
forage…………………………………………………………
…0.25 ppm

Corn, sweet,
stover…………………………………………………………
…0.20 ppm

Corn, field,
stover…………………………………………………………
….0.40 ppm

Soybean,
seed…………………………………………………………
……...0.02 ppm

Soybean,
forage…………………………………………………………
…....0.15 ppm

Soybean,
hay……………………………………………………………
……0.25 ppm

The Agency notes that these recommendations are consistent with the BCS
most recent proposal with the exception of the field corn forage
tolerance, which the Agency is now recommending be lower than the BCS
proposal.  

Attachment 1.  MRL Calculator Results

Soybean Forage

 

 

Soybean Hay

 

 

Field Corn Forage

 

 

Field Corn Stover

 

 

Sweet Corn Forage

 

 

Sweet Corn Stover

 

 

Fenamidone Addendum to 12/18/08 and 2/24/09 Residue Chemistry Chapters

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