
                                       
                    UNITED STATES ENVIRONMENTAL PROTECTION AGENCY
                               WASHINGTON, D.C.  20460
                                       
	OFFICE OF PREVENTION, PESTICIDE
	AND TOXIC SUBSTANCES
                                                                               

MEMORANDUM

Date:  July 30, 2014  - Draft Internal Deliberative

SUBJECT:	Thiabendazole.  PP# 3F8166.  New Seed Treatment Uses on Assorted Vegetables and Small Grains (vegetable, root (except sugar beet); subgroup1B, onion, bulb, subgroup 3-07A; Brassica, head and stem, subgroup 5A; vegetable, cucurbit group 9; alfalfa; spinach (including baby); and small grains (wheat, barley, oats, rye, and triticale).    Amendment to Increase Rate on Soybean.  Addendum.

PC Code:  060101
DP Barcode:  D410807 addendum
Decision No.:  476711, 476712
Registration No.:  100-889, 100-963
Petition No.:  3F8166
Regulatory Action:  Section 3 Registration
Risk Assessment Type:  Res Chem
Case No.:  2760
TXR No.:  NA
CAS No.:  148-79-8
MRID No.:  See MRID Summary Table
40 CFR:  180.242
	Ver.Apr.08

FROM:	Susan V. Hummel, Senior Chemist
		Risk Assessment Branch 4
		Health Effects Division (7509P)

THROUGH:	Thurston G. Morton, Senior Chemist
		Risk Assessment Branch 4
		Health Effects Division (7509P)		

TO:		Rosemary Kearns/Tony Kish, PM 22
		Registration Division (7505P)


This memo serves to update the tolerance expression for thiabendazole and the tolerance recommendations.

860.1550 Proposed Tolerances

The current tolerance expression for thiabendazole is:

"(1) Tolerances are established for the combined residues of the fungicide thiabendazole (2-(4-thiazolyl)benzimidazole) and its metabolite benzimidazole (free and conjugated) in or on the following food commodities:"  for plant commodities.

And 

"(2) Tolerances are established for the combined residues of thiabendazole (2-(4-thiazolyl)benzimidazole) and its metabolites 5-hydroxythiabendazole (free and conjugated) and benzimidazole in or on the following food commodities:" for livestock commodities.

The tolerance expressions need to be updated as follows to reflect our current guidance.   

(1) Tolerances are established for residues of thiabendazole, including its metabolites and degradates, in or on the commodities in the table below.  Compliance with the tolerance levels specified below is to be determined by measuring only the sum of thiabendazole (2-(4-thiazolyl)benzimidazole) and its metabolite benzimidazole (free and conjugated), calculated as the stoichiometric equivalent of thiabendazole, in or on the commodity.

(2) Tolerances are established for residues of thiabendazole, including its metabolites and degradates, in or on the commodities in the table below.  Compliance with the tolerance levels specified below is to be determined by measuring only the sum of thiabendazole (2-(4-thiazolyl)benzimidazole) and its metabolites 5-hydroxythiabendazole (free and conjugated) and benzimidazole (free and conjugated), calculated as the stoichiometric equivalent of thiabendazole, in or on the commodity.

International Harmonization.   There is no issue with International Harmonization for the current petition.  CODEX has not established any established maximum residue limits (MRLs) for thiabendazole on the requested commodities.  Canada has not established maximum residue limits (MRLs) for thiabendazole on the requested commodities.  We note that the U.S. tolerance expression is not harmonized with Canada, or CODEX.  This will be examined further during registration review.



Table 8. 	Tolerance Summary for Thiabendazole.  § 180.242
Commodity
Current/Proposed Tolerance (ppm)
Recommended Tolerance (ppm)
Comments; Correct Commodity Definition
alfalfa, forage
                                     0.02
                                     0.02
Alfalfa, forage
alfalfa, hay
                                     0.02
                                     0.02
Alfalfa, hay
alfalfa, seed
                                     0.02
                                       -
Tolerances are not normally set for alfalfa seed
barley, grain
                                     0.05
                                     0.05
Barley, grain
barley, hay
                                     0.15
                                      0.3
Barley, hay 
Revised level based on OECD tolerance calculation procedures, and to be consistent across all hays and straws.
barley, straw
                                     0.15
                                      0.3
 Barley, straw
Revised level based on OECD tolerance calculation procedures, and to be consistent across all hays and straws.
Brassica, Head and Stem, subgroup 5-A
                                     0.02
                                     0.02
 
oats, forage
                                      0.2
                                      0.3
Oats, forage
Revised level based on OECD tolerance calculation procedures, and to be consistent across all cereal grain forages.
oats, grain
                                     0.05
                                     0.05
Oats, grain
oats, hay
                                     0.09
                                      0.3
Oats, hay
Revised level based on OECD tolerance calculation procedures, and to be consistent across all hays and straws.
oats, straw
                                     0.09
                                      0.3
Oats, straw
Revised level based on OECD tolerance calculation procedures, and to be consistent across all hays and straws.
Onion, bulb, Subgroup 3-07A
                                     0.02
                                     0.02
 
radish, tops
                                     0.02
                                     0.02
Radish, tops
rye, forage
                                      0.2
                                      0.3
Rye, forage
rye, grain
                                     0.05
                                     0.05
Rye, grain
rye, straw
                                     0.15
                                      0.3
Rye, straw
Revised level based on OECD tolerance calculation procedures, and to be consistent across all hays and straws.
spinach
                                     0.02
                                     0.02
Spinach
triticale, forage
                                      0.2
                                      0.3
Triticale, forage
Revised level based on OECD tolerance calculation procedures, and to be consistent across all cereal grain forages.
triticale, grain
                                     0.05
                                     0.05
Triticale, grain
triticale, hay
                                     0.09
                                      0.3
Triticale, hay
Revised level based on OECD tolerance calculation procedures, and to be consistent across all hays and straws.
triticale, straw
                                     0.09
                                      0.3
Triticale, straw
Revised level based on OECD tolerance calculation procedures, and to be consistent across all hays and straws.
Vegetable, Cucurbit group 9
                                     0.02
                                     0.02
Vegetable, Cucurbit, group 9
Vegetable, root (except sugar beet), subgroup 1B
                                     0.02
                                     0.02
Revised level based on OECD tolerance calculation procedures. 
Wheat, grain
                                      1.0
                                     0.05
Current tolerance for wheat grain is 1.0 ppm, tolerance recommended in RED was 0.2 ppm.  Current recommendation is based on full new data set showing all non-quantifiable residues.
wheat, forage
                                      0.2
                                      0.3
Wheat, forage
Revised level based on OECD tolerance calculation procedures, and to be consistent across all cereal grain forages.
wheat, hay
                                     0.09
                                      0.3
Wheat, hay
Revised level based on OECD tolerance calculation procedures, and to be consistent across all hays and straws.
Wheat, straw
                                      1.0
                                      0.3
RED recommended lowering tolerance.  Current recommendation is to be consistent across all hays and straws.

	

