### UNITED STATES ENVIRONMENTAL PROTECTION AGENCY WASHINGTON, D.C. 20460 OFFICE OF CHEMICAL SAFETY AND POLLUTION PREVENTION



### MEMORANDUM

Date : October 26, 2015 Subject: 

### Pron a mide (Pro pyzami de) . H armonizati on of the Recommended Permanent Tolerance for Leaf Lettuce.

From:

Through:

To: PC Code: 101701 Decision No.: 493477 Petition No.: 4 F8 30 I Risk Assessment Type: NA TXRNo
. : NA MRID No.: See Below Ideliz Negr6n-E ncarnaci6n, Ph.D. , Chemist Risk Assessment Branch V H ealth Effects Division (HED ; 7509P) Michael S
. Metzger , Branch Chief Risk Assessment Branch V (HED; 7509 and DP Barcode: D429782 Registration No.: 62719

- 394 Regulatory Action: Section 3 Registration Case No.: NA CAS No.: 23950-58-5 40 CFR: 180.3 17

David 

### J. Mi ll er , Ph.D. , Branch Chief Chemistry and Exposure Branch (HED ; 7509P) R ay Kent , Ph.D. , Toxicologist Immediate Office (HED; 7509P) and Reuben B aris , Ri sk Manager Registration D iv is i on (7505P)

Page 1 of 2Pronamide Hannonization of L e af Lem1ce Tole rance Barcode 04 2 9 7 8 2



### Background f n the residue chem i s try c hapter evaluating th e petition to establi s h a U.S. r eg i stration for u se of pronamide on leaf le ttu ce , HED previou s l y recommended in favor of a t o le ranc e at 2 ppm fo ll owing Organisation fo r Econ omic Co

- operati o n and D evelo pm e nt (OECD ) calc ulation procedures ( I. Neg ron-Encarnacion , 04 24598. 0 1 / 1 5/2 015). A lth oug h th e Canadian m ax imum residue limit (MRL) for lettuce is 1 ppm , at th a t tim e HED reco mm e nd ed in favor of harmonization if the u s e pattern was modifi ed by in creasi ng the pre-harvest interva l (PHI ) by I 0 days. Based on feedback receive d from the registrant through the Reg is tra ti o n Division (e lec tronic communication from Bari s Re ub e n o n I 0 / 08 / 2015), the r eg is tra nt mad e an argument that the tol e rance of I ppm can be supported fo r th e proposed use. In consideration of the reg is trant requ es t , f urth e r ana lys i s of th e available data and MRLs in other co untri es was mad e , in order to d ete rmin e i f a to le rance of 

### l. O ppm co uld be s upported in th e inte re st of harm o ni z ati on. 

### Revisions to Recommended To leranc e The recommended U.S
. tolerance of 2 ppm wa s estimated following OECD ca lc ulation proce dure s u s in g fi e ld trial data that supports th e inte nded use pattern. Th e data of th e 2009 dec lin e trial s was organ ize d in the follow ing fou r sets: 0.5 lb ai / A (25 da y- PHI ), 1.0 lb a i / A (35- day PHI) , 1.5 lb a i/ A (45 -d ay PHI) , and 2.0 lb a i / A (55 -d ay PHI ). A ll data se t s res ult in a rounded MRL of2 ppm w ith the exception of the 0.5 lb ai/A which results in a rounded MRL of 1.5 ppm. B ased on these calculations , the tolerance sugges ted by the OECD ca lc ulati on procedures i s 2 ppm. Fo ll owi ng Canada's MRL of l ppm for residues of p ronamide o n lettuce the registrant had proposed a tolerance of 1.0 ppm fo r leaf lettuce. A search in the Globa l MRL database for MRLs that cove r r es idues of pronamide in/o n head l e t

tuce and l eaf lettuce resulted in a li st of MRLs estab l is h ed or adopted in co untri es around the world with val ues rangin g fro m 0.2 ppm to 1 ppm ( d a ta from GlobalMRL.com obta in e d on 10 / 08 /20 1 5). The res idu e definition is ge nerally pare nt pro namid e wh il e in s om e countr ies it s metabol ites a r e in c lud e d as wel l. Th e hi g he st re s idu e ob ta in e d from th e crop field trial data with leaf l ettu ce was 1. 0 ppm which is at th e tolerance leve l. Because s ub s tanti al data i s ava il ab le for pronamide on leaf lettuce ( 1 8 c rop field trial s in the US ; 8 of those w ith 4 different use pattern s) , residues decline significantl y within da ys (e.g. m ean residues observed in the 2009 decline trial s decrease by a facto r of 0.6 in com p a ri son to those from sa mple s harvested 10 da y s before) , and MRL s estab li s he d by most co untrie s are at 1 ppm o r below , HED recommend s in favo r of a tolerance of I ppm for leaf le ttuc e . 

### Co nclu s ion In o rd e r to harmon iz e with the Canadi an MRL for le ttuc e , H E D recommends in favor of a U .S. tolerance fo r leaf lettuce at l ppm.

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