UN ITED S TATE S ENV I RO NM E NT AL PROTE C TION A GENCY WASHING TO N , D.C. 20460



### MEMORANDUM Date: March 27 , 20 14 OF FICE OF CH EM ICAL SA FETY & POLLU TI ON PREVE NTI ON



### SUBJECT: Thiram Tolerances. Conver sion to Carbon Disulfide Equivalent s to Harmoni ze with CODEX Expression of MRLs. 

### PC Code: 07980 1 

### Decision No.: 3435 02 

### Petition No.: N/ A 

### Risk Assessment Ty pe: NA 

### T XRNo .: NA 

### MRID No.: N/ A DP Barcode: D418504 

### Registration No.: N/ A Regulatory Action: Tolerance Change 

### Case No.: 0122 

### CAS No: 1 3 7-26-3 40 

### CFR: § 180.132 From: Susan V. Hummel , Senior C hemist

### ~ --------/ <ZA...-- Risk Assessment Branch IV '-

### ~ _.,.,- 

# b
Through:

To : Health Effec t s Di v is i on (75 09P)

### ~ Thurston G. Morton, Senior Ch e mist 

# ;J._j/1 Risk Assessment Branch IV Health E ffects Divis ion (7509P) Wilhelmina Li vingston, CRM, and Joseph Nevola Pesticide Reevaluation Divi s ion (7508P)
Tol erances for the dimethyl dithiocarbamates (thiram, ziram and ferbam) and the e thylenebi s dithiocarbamates (EBDCs) are being converted to being expressed as carbon disulfide equivalents, since it i s difficult to distingui s h among the various pe s ticides by analytical methods a lone. The to lerance expression shou ld read: To l erances are es tablished for residue s of the fungicide thiram (tetramethyl thiuram disulfide) , inclu di ng its metabo li tes and de gradate s , in or on the commodities in t he table below

. Compliance with the toleranc e lev els specified below i s to be det ermined by measuring only those thiram re s idues convertible to carbon disulfide , expressed as carbon disulfide, in or on the commodity.

Page 1 of3International Harmonization. The Codex Alimentariu s has established maximum residue limits (MRL), for "tota l dithiocarbamates, determi ned and expressed as mg carbon disu l fide per kg" in strawberry of 5 mglkg. HED h as recommended that all tolerances for dithiocarbamates , including thiram be converted to be expressed as ca rbon disu l fide, so that the tolerance expression will be compatible with CODEX, however the tolerance level will not be compatib l e for strawberry, si nce there are differences in Good Agricultural Practices (GAP). A copy of the International Residu e Limit Status (IRLS) sheet is attached to this memorandum.

Table 7. Tole r ance Summary for Thi r am. Current Tolerance Recommended Comments; Commodity (ppm Thiram) Tolerance ( ppm {Correct Commodity Definition] CSz) App le 7.0 5 The conversion factor is 0.63x Banana ' 0.80 2.0 Recommend ed tolerance is being rai sed from 0.50 ppm to 2.0 ppm CS 2 to harmonize with CODEX. Peach 7.0 Rec ommended tolerance is being raised 7.0 from 5.0 ppm to 7.0 ppm CS 2 to harmonize with CODEX. Strawberry 20 13 The conversion factor is 0.63x No U.S. reg 1 strat10ns as of March 13, 201 4

.
Enforcement Analytical Method. An Enforcement Anal ytical Method i s available to enforce the proposed to lerances. The Pesticide Analytical Manual (PAM) Vol. II lists Method I , II , III , IV, and A for the determination of di t hiocarbamate residues inion plant commodities. These methods are based on the decomposition of dit h i ocarbamates with release of CS 2. Using these methods , the CS 2 is swept through a trap to remove any H2 S and into a reaction tube containing a solution of copper acetate and an amine. A co l ored copper dithiocarbamate comp l ex is formed and its absorbance read as a measure of the original d i thiocarbamate. The stated limit of detection (LOD) for Method I is 0.5-4.0 ppm. More recent submissions have included alternate detection methods, headspace GC with Mass Spectrometry detection. Thiram may be detectab le using PAM I multiresidue methods without Florisil cleanup , but is not detected when Florisil cleanup is used

.

Page 2 of3Appendix I. Int ernational Residue Status 

### Thiram (P C Code 079801 ; Date ofRequest 3/ 12/ 14) Sum m ary of US and fntematio n a l To l e rances a nd Maximum R es idu e Limits Residue Definition: 

## us Canada Mexico 2 Co d ex 3 40 CFR 180 .1 32 bi s(d im et h y lthi o P lant: total carbamoyl)disu l dit hi o carb amates , Plant s : thiram ( tetram et h y l thiuram p h i de detennin e d as CS2 , disulfide) evo lved during acid digestion a nd expressed a s m g CS2 /kg. Commod ity 1 Tolerance (ppm) / Maximum Residue Limit (mg /kg) 

# us Canada M ex i c o:z Co d ex 3 Apple 7.0 5 5 Banana 0.80 

# -- 2 Peach 7.0 5 7 Stra wberry 20 7 

### 5 4

Completed: S .Hummel ; 03 / 13/ 14 I T here are no U
. S

. regtstrattOns as of 3/ 13 11 4 2 Mexico adopt s U S tolerances and/or Codex MRLs for it s e x port purposes. 3 

### * = ab s ent at the limit of quantitation ; Po = postharvest treatment , suc h as treatment of s tore d grains. PoP = proce ssed posth arvest treated commodi ty, s uch as processing of treated stored wheat. (fat) = to be measured on the fat porti o n of the s ample. MRLs indica te d as p ro p osed have not been finali zed by th e CC PR and th e CAC

. 4 MRL e s timate base d on th e use of thiram

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