UNITED STATES ENVIRONMENTAL PROTECTION AGENCY WASHINGTON, D.C. 20460

MEMORANDUM Date: 08-AUG-2013 OFFICE O F C HEM ICAL SAFETY AN D POLLUT ION PRE V ENTION

SUBJECT: Prometryn: Response to Comments on the Human Health Assessment Scoping Document.
PC Code: 080805 Decisio n No.: 479824 Peti t ion No.: N / A Ri s k Assessment Type: N/ A TXR No.: N / A MRID No.: N /A DP Barcode: 0412527 Registrat io n No.: N / A Regu l atory Action: Registration Rev i ew Case No.: 467 CAS No.: 7287-19-6 40 CFR: § 180.222 FROM: Kelly M. Lowe, Environmental**Scie~ist** :- Sarah J

. Levy,

### Chemist~ 

## C) Risk Assessmen t Branch 1 (RAB 

# 0 H ealth Effects Division (HED , 7509P) THROUGH: Dana Vogel, Acting Branch Chief

# ~5=**~** George F. Kramer, Ph .D ., Senior Chemist**~** RAB 1/HED (7509P) TO: Christina Scheltema, Chemical Revi ew Manager Pesticide Re-Evaluation Division (PRO) (7508P)

The HED Prometryn R is k Assessment team has received comments on the Prometryn Registration Review Scoping Document (EPA Docket ID : EPA-HQ-OPP-2013-0 032-0011) and attached is HED's response to comments. Comments relevant to HED ' s scoping document were provided by Syngenta. The Agency has considered these comments and will utilize them, along with any newly available data, during the registration review of prometryn.

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# -Prometryn Response to Comments DP# 412527 Comment #1: EPA S tate ment: (Page 3) "After preliminary review ofthe metabolism 

### in rice study, it appears that the metabolism in rice presents a d ifferent metabolic profile than the celery and cotton profiles; th erefore, HED is still requesting a root crop metabolism study

. " Syngenta Comment : A roo t crop (carrot) metabolism study is being conducted per EPA's request. However, we respectfully reques t clarification regarding the conclusion that prometryn's metabo lic profile in rice is diffe rent than that in cotton and celery. In HED's response to the prometryn metabo li sm in rice study, HED concluded that prometryn's metabol i c profile in ri ce was quali tati vely different than that i n celery and cotton and that in celery and cotton parent was the major residue, whi le in rice metabolite GS-17794 was the majo r residue. We believe that the rice metabolism study shows a qualitatively s i milar metabolic profile to that of cotton & celery. Furthermore, we believe that the quantitative d iffe rences HED noted can be attribut ed to normal variance that is commonly seen in metabolism profiles of different crops. Should the car rot metabolism study reveal a s im ilar metabo lic profile to that of rice, cotton and celery, prometryn will have four metabo lism studies showing a simil ar metabolic profile in four dissimilar crops. We would like confirmati on that if the abo v e determinati on is made by HED, further crop meta b olism s tudi es with prometryn will not be required at that time

. HED's Response: HED agrees with Syngen ta that prometryn's metabolic profile appears simila r in cotton, celery, and rice

. However, HED misstated that the profile was qualitati ve ly different. Th e statement should have read tha t the metabolic profile in rice was quantitatively different in rice than that 

### in celery and cotton

- not qualitatively different. HED agrees that if the root metabolism study shows that th e metabolic profile is qualitatively similar to the other metabolism studi es submi tted, ad d itional me tabolism studies invo lving root crops will li kely not be requested. Comment #2: EPA Statement : (Page 7) "HED is also requesting a rum i nant feeding study at this time since the livestock dietary burden could change significantly pending the results of the root crop metabolism stu dy." Syngenta Comment : Based on the qu alitatively simil ar metabolic profiles demonstrated in cotton, celery and rice, there is no reason to believe that the carrot metabolism s t udy wi ll indicate the need for a ruminant feeding study

. Should the carrot study re veal a meta b ol ic profile with qualitatively significant diffe rences, we would like to discuss the appropriateness of a ruminant feeding study with HED at that time. HED's Response: HED agrees with Syngenta that the need for a rumi nant feeding study should be evalua ted after the carrot (o r ot h er root crop) metabolism study is submitted and evaluated by HED. Comment #3: EPA Statement: (Page 19, Attachment 4) "Celeriac; Postemergence. Up to the 6- to 8- leaf stage ; Max App Rate: 4 lb ai /A

. " Syngenta Comment: Syngenta's prometryn product labels specify a maximum single application rate to celeriac of 2 lb ai/A. We are not aware of any prometryn product labe l s that allow a single application rate of 4 lb ai/A to celeri ac . Page 2 of4Prometryn Response to Comments DP# 4 1 2527 HED's Response: There is a registered product (Promet ryn 4L; EPA Reg. #66222- 1 5; label date 2-JUL-2012) th at allows for one postemergence application to celeriac at a 

### maximum rate of up to 8 pts ( 4 lb ai) 

### per acre up to the 6 to 8 leaf stage. This is not a Syngenta product. Comment #4: EPA Statement : (Page 19, Attachment 4) "Cotton; Groundboom; Preplant; Max App Rate: 1 lb ai/A." Sy n genta Comment: The Section 3 Caparol4L l abe l allows for groundboom or aerial preplant incorporated app li cation to cotton at up to a maximum si n gle applicat i on rate of 2.4 lb ai/A in AZ , CA, and NM only. HED's Response: HED agrees that the maximum rate identified in the scop ing document for preplant ground applications to cotton i s not in fact the highest rate allowed by p rometryn FIFRA Section 3 labels. The 1-lb ai/A rate was the hi ghest rate identified for SLN uses. HED will use the higher Section 3 registered rates in the registration review assessment. Comment #5 : EPA Statement: (Page 19, Attachment 4) "Cotton; Groundboom; Postemergence; Max App Rate 1.6 lb ai /A." Syngenta Comment : The Secti on 3 Caparol4L label allows for groundboom or aerial post-emergence applicati on to cotton at up to a maximum single applicati on rate of2.4lb 

### ailA in CA only for winter weed control. HED' s Response: The postemergence rate identified in Attachment 4 is meant to represent the maximum label r ate allowed for applications made after the crop has emerged

. T he Caparol4L label appears to allow a rate of2.4 lb ai/A after weeds have emerged, but before the crop has emerged. HED will confirm the promet ryn use pattern during registration rev iew to ensure the correct app li cation rate is used in the human health ris k assessment. Comment #6: EPA Statement: (Page 20, Attachment 4) "Leafy petioles crops (cardoon, celery, Chinese celery, celtuce, Florence fennel, rhubarb, Swiss cha rd)." Syngenta Comment : The crops cardoon, celtuce and Swiss chard were removed from all Syngenta prometryn product l abels

. Rhubarb is also not l abeled as part of this crop group, as different directions for use are given in a specific rhubarb section. HED's Response: It i s noted that th e Syngenta Caparol4L label (EPA Reg. #100

- 620; dated 27-SEP

- 201 1) does not include use on cardoon, celtuce, and Swiss chard. However, at the time of comp letion of the scop ing document (28-FEB-2013), another 

### product label for Prometryn 4L (EPA Reg.# 66222

- 15; dated 2-JUL-2012) did include this crop group in the use directions. Label amen dments for this product were approved by EPA in March 20 1 3

. The most recent prometryn labels will be reviewed for registration review and the human health assessment will reflec t the current prometryn Page 3 of4Prometryn Response to Comments DP# 412527 labels. 

### Comment #7: EPA Statement: (Page 20, Attachment 4) "Leafy pe tioles crops (cardoon, celery, Chinese celery, celtuce, Florence fennel, rhubarb, Swiss chard); Post

- transplant Max App Rate: 3.2lb ai/A." Syngenta Comment: Syngenta's prometryn product l abels spec ify a maximum single application rate to celery , Chinese celery and Swiss chard of 1.6 lb ai/A. Whi le some non -Sy ngenta prometryn labels all ow app li cat i on to celery at an app li cation r ate of up to 3.2 lb ai/A, we are not aware of any prometryn product labels that allow a single application rate of3.2 Jb ai/A to the leafy pet i oles crop subgroup. HED's Response: According to the label for Prometryn 4L (EPA Reg. # 66222-15), app li cat ions to transplanted leafy petio le crops can be made at up to 6.4 pt/A in HI (3.2 lb ai/A). 

### Comment #8: EPA Statement: (Page 20, Attachment 4) "Leafy petioles crops (cardoon, celery, Chinese celery, celtuce, Florence fennel, rhubarb , Swiss chard); Postemergence Max App R ate: 1 lb ai /A." Svngenta Comment: In t he post-emergence directi ons for use secti on for celery, Chinese celery and Fl orence fennel on the Caparol 4L label, the maximum single application rate is 1.6 lb ai/ A, instead of 1.0 lb ai/A. HED's Response: Based on the Caparol4L l abel (EPA Reg

. #100-620; dated 27-SEP20 11 ), the hi ghest application rate for postemergent broadcas t applications i s 2 pt/ A or 1 lb ai/ A. According to the product label , these appl i cations are allowed after the crop has 2

- 5 true leaves and can be made over the top of the crop. This same product label appears to allow a higher rate of 3

. 2 pt/A or 1.6 lb ai/A for pre-emergence applications. 

### Comment #9: EPA Statement: (Page 20 , Attachment 4) "Pigeo n peas; Application E quipment: Groundboom." Syngenta Comment: The C aparol 4L label al so allows aerial application to Pigeon Peas in Puerto Rico only

. HED 's Response: HED agrees that aerial application should be considered in the assessment as an additional application method for pigeon peas. T his will be reflected in the registration review assessment. 

### Comment# 10: Svngenta Comment: We have evaluated the MRLs es tab li shed in the US, Canada, EU , and Australia and have comp il ed this information in Appendix 1. HED's Response: HED will work to h armon i ze tolerances and minimize trade irritants duri ng registration review. Page 4 of4