Document ID: EPA-HQ-OPP-2014-0225-0009
Agency: epa
Document Type: Supporting & Related Material
Title: 
Posted Date: 2014-08-06T04:00Z

\* MERGEFORMAT
                 UNITED STATES ENVIRONMENTAL PROTECTION AGENCY
                            WASHINGTON, D.C.  20460
                                                     OFFICE OF CHEMICAL SAFETY 
                                                       AND POLLUTION PREVENTION
MEMORANDUM

Date:	April 22, 2014 

SUBJECT:	Fluopicolide.  Section 3 Registration of an Increased Tolerance on Tuberous and Corm Subgroup 1C Vegetables and Potato Processed Waste for Fluopicolide.  Summary of Analytical Chemistry and Residue Data.       
            
PC Code:  027412 (fluopicolide) & 027402 (BAM)
DP Barcode:  D417354
Decision No.:  481092
Registration No.:  59639-139
Petition No.: 3F8191
Regulatory Action: Section 3 
Risk Assessment Type: Not Applicable
Case No.: Not Applicable
TXR No.: Not Applicable
CAS No.: 2008-54-4
MRID No.: 49177301
40 CFR: §180.627 

FROM:	Peter Savoia, Chemist
		Risk Assessment Branch V/VII
		Health Effects Division (7509P)
				
THRU:	Michael S. Metzger, Branch Chief
		Danette Drew, Chemist
		Risk Assessment Branch V/VII
		Health Effects Division (7509P)
		
TO:	Tony Kish, Risk Manager
		Dominic Schuler, Risk Manager Reviewer 
		Fungicide Branch
		Registration Division (7505P)

I.  Action Requested

The Valent U.S.A. Corporation has submitted PP# 3F8191 which requests to amend the tolerances on tuberous and corm subgroup 1C vegetables and potato processed waste established for the fungicide fluopicolide.  This action is being sought to prevent the possible seizure of commodities for over tolerance residues which were legally treated with an early season soil application that has since been restricted.  Fluopicolide is a fungicide active ingredient used for the control of plant diseases caused by Oomycetes.  Permanent tolerances are established under 40 CFR §180.627 for residues of fluopicolide (parent only) which include levels previously determined on potatoes for post-emergence foliar applications.  To support this request, Valent has provided modeling calculations which estimate the concentrations of residues that can occur in potato tubers from this use while field trials are being completed (MRID No. 49177301).  Valent is currently conducting soil application residue field trials and will submit these data as soon as they become available to validate the amended potato tolerances requested with this petition.  Upon submission of the completed field trial studies, the Agency will evaluate these data to determine if it is necessary to either increase or decrease the amended tolerances and remove the label restriction prohibiting this use.  
II. Recommendations

In consideration of these data, there are no residue chemistry issues that would preclude amending the established tolerances for residues of fluopicolide in tuberous and corm subgroup 1C vegetables and potato processed waste.  Based on the maximum residue levels estimated in the modeling calculations provided by the registrant, an amended tolerance of 0.3 ppm is appropriate for tuberous and corm subgroup 1C vegetables (current tolerance is 0.02 ppm).  In regard to potato processed waste, processing data previously provided for potato indicate that residues of fluopicolide do in fact concentrate in wet peels; therefore, an amended tolerance of 1.0 ppm is recommended for potato processed waste (current tolerance is 0.05 ppm).  A revised human health risk assessment evaluating the implications on dietary exposure from increased fluopicolide residues on tuberous and corm subgroup 1C vegetables and potato processed waste is forthcoming.

III. Detailed Considerations

Modeling Calculations.  The modeling calculations provided by Valent are made using a "worst-case" scenario to estimate fluopicolide residue concentrations in potato tubers following directed soil application (Table 1).  This is represented by modeling the maximum labeled rate for application which depicts two directed soil treatments made at the maximum rate of 0.125 lb ai/A (140 g ai/ ha) and a 30-day re-treatment interval (RTI).  It estimates the soil residue to be concentrated around the tubers in a band occupying 50% of the field area grown in low organic carbon content soil which provides the greatest potential for uptake by the root system.

Table 1.  Fluopicolide Directed Soil Application Parameters Modeled for Treating Potatoes. 
Parameter 
                                     Value
                                    Comment
Application Rate
2 Treatments @ 0.125 lb ai/A (140 g ai/ha) following a 30-day RTI.
Maximum single and seasonal application rate.  Follows one application at planting and the second at hilling. 
Depth of Residue Incorporation
20 cm
General rooting depth of potato plants.
Soil Bulk Density
1.1 g/cm[3]
Common value for cultivated loam soil.
Broadcast or Banded Application
Banded application across 50% of soil.
Simulates directed application at planting and hilling.
Fluopicolide Half-Life in Soil
181 days
Average dissipation Half-Life observed in field studies. 
    
For this determination, two approaches were used to model the residues taken up by the root system and translocated to the potato tubers or possibly found on its surface from contact with contaminated soil.  Prior studies have shown that foliar residues do not translocate through the phloem of the potato plant to the tubers.  However, with directed soil application at planting and hilling, there is potential for residues to occur through this longer duration of exposure which could be taken up by the root system.  In consideration of this effect, the first modeling approach works to evaluate the potential for translocation to the potato tubers based on the physical properties of the fluopicolide active ingredient.  The second model in turn works by utilizing data from the radiolabeled potato metabolism study to provide an empirical approach for estimation.  In these models developed by Valent, the residues of fluopicolide found in/on potato tubers following directed soil application are estimated to be in the range of 0.2 to 0.25 ppm.  Both approaches are found to derive similar estimations therefore showing the Valent models aptly depict the residues of fluopicolide that could occur in potatoes following treatment.  

Processed Food and Feed.  No new processing data were submitted in support of this petition.  
Adequate processing data were received and reviewed in connection with the prior petitions submitted by the registrant for establishing the post-emergence foliar use of fluopicolide on potatoes.
These data showed that fluopicolide residues concentrate in potato wet peels and the theoretical processing factor of 4.0x was used to set the current potato processed waste tolerance.  Based on the models provided by Valent, residues of fluopicolide found in/on potato tubers are estimated to be in the range of 0.2 to 0.25 ppm following directed soil application.  Using the highest estimated value of 0.25 ppm and the theoretical concentration factor of 4.0x, an amended tolerance of 1.0 ppm would be appropriate for potato processed waste.   

Tolerance Assessment and International Harmonization.  Permanent tolerances for residues of parent fluopicolide are established under §180.627.  A spreadsheet summarizing the international residue limits established on fluopicolide for tuberous and corm subgroup 1C vegetables is presented in Appendix A.  There are no MRLs established on the fluopicolide uses by Codex or Mexico.  However, the establishment of an increased U.S. tolerance will exceed the Canadian MRL of 0.02 ppm on various tuberous and corm vegetables.  Harmonization with the Canadian MRL is not possible since Canada has not yet established directed soil applications on potatoes for use.  In regard to potato processed waste, Canada does not establish tolerances on livestock feedstuffs. 

IV. Conclusions 

The residue chemistry database is complete for supporting the tolerances established on tuberous and corm subgroup 1C vegetables and potato processed waste for post-emergence foliar applications (D370762, D. S. Davis, 08/19/2010).  Adequate metabolism (crops, livestock, and rotational crops), storage stability, and processing data are available to support the registration of these uses.  Adequate methods are also available for enforcement of the tolerances established on these commodities.  To accommodate directed soil applications to potatoes, Valent is currently conducting field trials and will submit these data as soon as they become available.  In the interim, HED concludes that the modeling data provided are acceptable for estimating residue concentrations that may be found in potato tubers as a result of this use.

As noted in the prior residue chemistry memorandum for the foliar applications to tuberous and corm vegetables (D370762), there are livestock feed items associated with the use of fluopicolide on potatoes.  A subsequent assessment was recently made for rotational corn which found livestock Maximum Reasonable Dietary Burden (MRBD) was unaffected by this action; therefore, no recalculation was performed (D410652, A. Kamel, 04/17/2013).  A new theoretical livestock diet was developed accordingly using the processed potato waste alternate feedstuff to determine dietary burden based on its last recalculation (D370762, D. S. Davis, 08/19/2010).  Incorporating the amended potato processed waste tolerance which is recommended into these calculations results in a MRBD of 2.133 for dairy cattle and 0.896 for beef cattle.  Using the previously submitted fluopicolide ruminant feeding study, HED concludes that based on these increased MRBD levels there is still not likely to be a transfer of residues of fluopicolide to ruminant commodities.  Processed potato waste is not fed to poultry or swine; therefore residues in these livestock commodities will not occur as a result of this use.  
With regards to the dietary burden to livestock, fluopicolide also shares a common metabolite, BAM with another active ingredient dichlobenil.  BAM is considered a residue of concern for risk assessment purposes which may also be found in some livestock feedstuffs.  In accordance, a determination is needed to address if these potential residues of concern may be found in livestock feedstuffs that have been treated with fluopicolide or dichlobenil.  Dietary burden calculations made in the prior assessment used the LOQ (0.01ppm) as the concentration of BAM in processed potato waste since there were no detectable residues of BAM in the RAC or any of its processed commodities.  Based on the updated dietary burden calculations and the level of exaggeration in the submitted feeding study for BAM, HED concludes that residues of BAM are not likely to be found in ruminant commodities.  In all, the metabolites BAM and PC1are not part of the model which is depicted and is not considered for tolerance purposes but will be considered in the accompanying risk assessment.   

References

DP No.:	D370762
Subject:	Fluopicolide.  Petitions to Establish Tolerances on Potatoes, Sugar Beets, Carrots, Rotational Wheat, and Livestock Commodities.  Summary of Analytical Chemistry and Residue Data.  
From:	D. S. Davis
To:	J. Whitehurst/T. Kish
Dated:	08/19/2010
MRIDs:	47745901 and 47745902

DP No.:	D410652
Subject:	Fluopicolide. Petition for Section 3 Registration and Establishment of Tolerances on Rotational Corn.  Summary of Analytical Chemistry and Residue Data.
From:	A. Kamel
To:	T. Kish and D. Schuler
Dated:	04/17/2013
MRIDs:	48809201 and 48842201

Appendix A

International Residue Limits
 
                              (027412; 01/14/2014)
Summary of US and International Tolerances and Maximum Residue Limits 
Residue Definition:
US 
Canada
Mexico[2]
Codex
§ 180.627    (a) General. (1)  fluopicolide [2,6-dichloro-N-[[3-chloro-5-(trifluoromethyl)-2-pyridinyl]methyl]benzamide]
Plants: 2,6-dichloro-N-[[3-chloro-5-(trifluoromethyl)-2-pyridinyl]methyl]benzamide

Plant and livestock commodities: fluopicolide. 
The residue is fat-soluble.
Commodity[1]
                Tolerance (ppm) /Maximum Residue Limit (mg/kg)

US
Canada
Mexico[2]
Codex
Potato, processed waste
1.0

Vegetable, tuberous and corm subgroup 1C
0.3
0.02 arracacha, arrowroot, cassava roots,  chayote roots, Chinese artichokes, chufa, edible canna, ginger roots, Jerusalem artichokes, lerens, potatoes, sweet potato roots, tanier corms, taro corms, true yam tubers, turmeric roots,  yam bean root

Completed:  M. Negussie; 01/16/2014
[1] Includes only commodities of interest for this action.  Tolerance values should be the HED recommendations and not those proposed by the applicant.
2 Mexico adopts US tolerances and/or Codex MRLs for its export purposes.