### UNITED STATES ENVIRONMENTAL PROTECTION AGENCY WASHINGTON, D . C . 20460 OFFICE OF CHEMICAL SAFETY AND POLLUTION PREVENTION MEMORANDUM DATE : June 3 , 2016 SUBJECT: Response to Comments on the Health Effects Divis ions Sulfonylurea Risk Assessments

PC Code: 085601 , 108209 , 118601 , 118602, 119009,119011, 122001,122009,122010,122020, 122021, 128721,128820, 128845 , 128887, 128901, 128969 , 128973 , 129002, 129008 , 129009 , 129031 , 129091 Deci sion No .: 514016 Pet ition No .: NA Ris k Assessmen t Type : Single Chemical/Aggregate TXR No. : NA

MRID No .: NA FROM : Monique M . Perron , Sc.D ., Toxicologist Risk Assessment Branch 1 (RAB6) Hea lth Effects Di vision (HED; 7509P) DP No .: D431776

Regi stration No .: NA Regulatory Action : Registration Review Case No.: NA CAS No .: 141776 -32 - 1 , 213464 - 77 - 8, 64902 - 72 -3, 122548 -33 - 8, 290332 - 10 -4 , 104040- 78 - 0 , 74222 - 97 - 2, 208465 - 21 - 8, 74223 - 64 - 6, 173159- 57 -4, 144550-36 -7, 100784-20 - 1, 83055-99 - 6 , 79227 - 27 - 3, 79277 -27 -3 , 101200 -48 - 0 , 90982- 32 -4, 82097 -50 -5, 86209 -51 - 0, 126535-15 -7, 111991 - 09 -4, 122931 -48 -0 , 94125 - 34 - 5 , 97780 - 06 -8 40 CFR : NA

THROUGH: Char les 

# w. Smith Ill, Acting Associate Division Director Q

### ~ HED (7509P)

### ~ TO: Margaret Hathaway/Kevi n Costello Risk Management and Im plementat ion Branch II 

### & IV Pesticide Re - evaluation Division (PRO ; 7508P)

Page 1 of 4Introduction: The pu r pose of this document is to provide the Health Effects Division's (HED) response to the publi c comments received on the individual HED sulfo ny lurea (SU) draft risk assessments (DRAs) . These risk assessments are available on htt p: //www.regulation s.g ov in the following dockets : • Bensulfuron-methyl (EPA- HQ-OPP -2011 - 0663) • Chlorimuron - ethyl (EPA- HQ-OPP - 2010 - 04 78) • Chlorsulfuron (EPA- HQ-OPP - 2012 - 0878) • Flazasulfuron (EPA- HQ-OPP- 2011 - 0994) • Foramsulfuron (EPA- HQ-OPP -2012 - 0387) • Halosulfuron - methyl (EPA-HQ-OPP-2011 -0745) • lmazos ulfuron (EPA- HQ-OPP -2015-0625) • lodosulfuron - methyl-sodium (EPA- HQ-OPP - 2012-0717) • Mesosulfuron - methyl (EPA-HQ- OPP-2012 - 0833) • Metsulfuron - methyl (EPA- HQ-OPP -2011 - 0375) • Nicosulfuron (EPA- HQ - OPP-2012 - 03 72) • Orthosulfamuron (EPA- HQ-OPP - 2011-0438) • Primisulfuron - methyl (EPA-HQ-OPP -2011 - 0844) • Prosulfuron (EPA-HQ-OPP-2011 - 1010) • Rimsulfuron (EPA-HQ- OPP-2012 -0178) • Sulfometuron - methyl (EPA-HQ -OPP-2012 -0433) • Sulfosulfuron (EPA-HQ- OPP-2011 - 0434) • Thifensulfuron - methyl (EPA-HQ-OPP -2011 - 0171) • Triasulfuron (EPA- HQ-OPP -20 1 2-0115) • Tribenuron-methy l (EPA- HQ-OPP - 2010 - 0626) • Trifloxysulfuron-Sodium (EPA- HQ-OPP -2013 -0409) • Triflusulfuron - methyl (EPA-HQ- OPP-2012 - 0605) HED appreciates the public's comments on the SU PRAs, has considered all of them, and has addressed them as ap propriate below . Each o f the commen t s id ent ified below in this memo is individually addressed and is referenced by its specific comment number . Chlorimuron - methyl, EPA-HQ-OPP-2010-0478-0036 (R . Ambrose , DuPont Crop Protection) : Comment Summary: During the review of this draft risk assessment, and that from September 14, 2009, an error was discovered in the d escription of effects observed in the 90 -day dog study (MRID#: 132745 ). This study is utilized to set chronic dietary and short -term inhalation point- of- departures for chlorimuron. In summary Tables 4.3.1 entitled "Toxicological Doses and Endpoints for Chlorimuron ethyl for Use in D ietary and Non - Occupational Hum an Healt h Risk Assessments" and 4 . 3.2 ent itl ed "Summary of Toxicological Doses and Endpoin t s for Chlorimuron ethyl for Use in Occupational Human Hea lth Risk Assessments " ; EPA indicates the Lowest Observed Adverse Effect Leve l (LOAEL) of 42.7 mg/kg/day is based on " h emato log i cal changes", which is correct. However, it states these changes are "increased" hematocrit, hemoglobin and erythrocyt e counts ... Our report sta te s that these parameters are actually "decreased" . Decreases in these parameters are also consistent with histopathological data demonstrating recovery from the observed mild hemolytic anemia (hematopoiesis in various tissues and tendency toward increased reticulocytes, etc . ) .Page 

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### EPA Response: The endpoint for the 90 day dog study will be revised in any future chlor i muron - methyl risk assessments to state that hematocrit, hemoglobin and erythrocytes were decreased at the mid and hi g h dose in the st udy . Chlorsulfuron, EPA- HQ-OPP -2012 -0878-0035 (E . Bockrath, DuPont Crop Protection) Comment Summary: DuPont requests that EPA refer to its DER of MRID 41983101 and a recent supplemen tal rabbit study i n MR ID 48735102. DuPont is requesting that EPA update the review of this study . EPA Re sponse : HED thanks DuPont for the comment. The review for this study and any potential impacts on endpoints for chlorsu lfuron will be updated in any future chlorsulfuron risk assessments. Foram sulfuron, EPA- HQ-OPP -2012-0387 -0026 (T. Moore, Bayer CropScien ce ): Comment Summary : Foramsulfuron is currently only registered for use in ground application in turf grass and vegetative management (non-crop) . Th e use patterns for foramsulfuron i n corn are no l onger registered. Bayer voluntarily canceled Option ® Corn Herbicide (Reg. No . 264 -685). This information was released via the Agency in a public notice on June 16th, 2015 in the notice of receipt 80 FR 34408 . EPA Response : Any future risk assessments for foramsul f uron will specify that corn i s no l onger a registered use . Primi sulfuron - methyl, EPA-HQ-OPP -2011 -0844 -0029 (S. Pvl es, Syngenta Crop Protection, LLC}: Comment Summary: Gu id eline study numb ers 870.11 and 870. 1 2 are included in th e acute tox icity table (Table B. 2.1) twice, it is not clear why these endpoints are repeated (the MRID numbers are the same for both acute oral, and both acute dermal studies listed) . Please clarify the duplication . EPA Re sponse : HED acknowledges the d upli cat ion error in the table. Since the revision does not impact the risk calculations or conclusions, no revision was u ndertaken at this time. However, HED will remove the duplicated lines for any future risk assessments for primisulfuron-methyl. Nicosulfuron, EPA- HQ- OPP-2012 -0372-0051 (R . Ashley, DuPont Crop Protection) Comment Summary: DuPont noted that in the HED RA, it states that the coarse screen water number was used for nicosulfuron. However, in the " Drinking Water Exposure Assessment for the 22 SUs " , nicosulfuron is listed as one of the 8 compounds for which refined screen data was generated. EPA Re sponse: HED thanks DuPont for the commen t . Given the risk picture for nicosulfuron there was no need to utilize the refined drinking water number in the nicosulfuron d i etary assessment. Tribenuron-methyl , EPA-HQ-OPP -2010-0626 -0037 (R . Ambrose, DuPont Crop Protection): Comment Summary : The point of departure for the acute dietary assessment is correctly identified as 300 mg/kg/day , which is the No Observed Adverse Effect Level (NOAH) from the acute neurotoxicity study (MRID# 48732501, DuPont Study Report Number: DuPont-31859 Revision 1). The lowest Page 3 of 4

### Observed Adverse E ffect level (lOAEL) of 1 000 gm/kg/day is correctly identified based on the body weight and body weight gain reductions observed . However, the transient effects on moto r activity and rearing are co nsidered to be secondary to these effect s o n body weight and are NOT cons idered to be a spec ifi c neurotoxic e ffect as cha r acterized in th e health assessmen ts. Th erefore we would suggest an amendmen t of the basis for the Point of Departure (POD) which excl ud es neurotoxicity as an end point ; since there is no indication tha t tribenuron methyl has the potential to cause a specific neurotoxic effect. EPA Re sponse : The endpoin t for the acu t e neurotoxicity study will be updated in any future tribenuron methyl risk assessments to clarify that th e clinical signs observed are attributed to the systemic effects seen in the study . Triflusulfuron-methyl, EPA- HQ-OPP-2012-0605-0027 (8 . Bieber, DuPont Crop Protection): Comment Summary: On Page 28 of 32, Table E. 2 Phys i cochemical Properties of the report for triflusulfuron methyl, the unit of solvent solubility should be mg/ml or g/L. EPA Re sponse: HED thanks DuPont for the comment. HED will correct the unit of solvent solubility to reflect g/L in any future triflusulfuron - methyl risk assessments.

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