	UNITED STATES ENVIRONMENTAL PROTECTION AGENCY

	WASHINGTON D.C., 20460

	OFFICE  OF 

	PREVENTION, PESTICIDES AND 

	TOXIC SUBSTANCES

MEMORANDUM	PC Code No. 129106

	DP Barcode: D331978

									Date:   September 21, 2006

Subject: IR-4 Tolerance Petition for Cymoxanil (Tanos®) Use on
Caneberries: DW Assessment

To: 	Shaja Brothers, Risk Manager Reviewer

	Daniel Rosenblat, Risk Manager

	Registration Division (7505P)

From:	Dirk Young, Ph.D., Environmental Engineer

	Thomas Steeger, Ph.D., Senior Scientist

	Environmental Fate and Effects Division (7507P)

Thru:  Elizabeth Behl, Chief

	Environmental Risk Branch IV/EFED (7507

The Environmental Fate and Effects Division (EFED) has reviewed the
Inter-Region 4 (IR-4)  tolerance petition (DP Barcode D331978) for use
of cymoxanil (Tanos®) on caneberries to control Spur blight (Dydimella
appinata), anthracnose (Elsinoe veneta), Botrytis cane blight and fruit
rot (Botrytis cinerea) and Cladosporium fruit rot. Tanos® is a
formulated endproduct containing 25% famoxadone (PC Code 113202) and 25%
cymoxanil.  Only cymoxanil is considered in this assessment.  Based on
cymoxanil alone, the maximum proposed application rate for caneberries
is 0.19 lbs a.i./acre with a maximum of 6 applications.   The
reapplication interval is 7 days.  The maximum annual rate of cymoxanil
alone is 1.1 lbs a.i./acre.

  

	The newly proposed application rate is less than the rates evaluated in
the previous new use of cymoxanil grapes and hops (DP D323681).  
Therefore no new drinking water concentrations are needed for the
proposed use.  Tier 1 drinking water concentrations based on the
previously assessed use on grapes appear in Table 1.  Environmental fate
data used for model input has been taken from the cymoxanil Section 3
assessment (DP Barcode D233366) for potatoes.  

Table   SEQ Table \* ARABIC  1 .  Estimated drinking water
concentrations for Cymoxanil11

	Acute  (µg/L)	Chronic  (µg/L)

Groundwater1	0.003	0.003

Surface Water2	19	0.10

1. Concentrations determined from the grape application (0.25 lbs per
acre, 10 times), which was the highest application rate reported for the
new proposed uses.



Environmental Fate Summary.  

Cymoxanil hydrolyzes rapidly under both alkaline and neutral media (34
hours at pH 7, 31 minutes at pH 9) but degrades slowly under acidic
conditions (148 days at pH 5).  Cymoxanil photodegrades quickly (1.8
days) in near-surface aqueous media, and dissipates readily in aerobic
and anaerobic soils with half lives on the order of hours to days. 
Major degradates formed from these processes generally degraded quickly
with half-lives on the order of days.  Field dissipation studies of
cymoxanil showed dissipation half lives of from 1 day (in Maryland) to
8.7 days in California) and also showed no detections of cymoxanil 15 cm
for the duration of the test.   Cymoxanil is moderately mobile with a
mean Koc of about 120 ml/g.  

Drinking Water Assessment

A Tier 1 drinking water assessment was performed using FIRST (version
1.0) for surface water and SciGRow (version 2.3) for groundwater. Input
parameters were chosen per current EFED guidance and appear in Tables 2
and 3.  Output for the two models appears in Table 1. 

Table   SEQ Table \* ARABIC  2 . FIRST (ver 1.0) model inputs for
cymoxanil drinking water estimate

Input Name	Value	Reference

Application	0.25 lb/acre, 10 times, 7 days apart	Label for grapes

PCA	0.87	Default  (EFED Input Parameter Guidance 2000)

Kd	0.29	Lowest non-sand value, (EFED Input Parameter Guidance 2000

Aerobic soil metabolism half life	3.6 days	Calculated from the single
available value for US soil by multiplying by 3.  See section 3. 

Application Method	aerial	Label

Wetted in?	no	Label 

Water solubility	78	See section 3.

Hydrolysis (pH =7)	1.4 days	MRID 44180738

Aerobic aquatic metabolism half life	7.2 days	In the absence of data,
the aerobic soil metabolism input was multiplied by 2  (EFED Input
Parameter Guidance 2000

Aqueous photolysis 

half life	1.8 days	MRID 44180739, 44180740



Table 3. SCIGROW (ver 2.3) model inputs for cymoxanil groundwater
concentration estimate

Input Name	Value	Reference

Application	2.5 lb total	Label for grapes

Koc	39 ml/g	Lowest Koc 1

Aerobic soil metabolism 

Half-life	1.2 days	Single measured value reported in 7/11/02 review
(D275802) of MRID 44180743.

1. Koc values of 39, 110, 240, 106 derived from Freundlich coefficients
of 0.29, 2.86, 1.38, 1 and 0.70 and organic matter contents of 1.3, 4.5,
1, and 1.3 percent, respectively.

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