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

MEMORANDUM Date: l l-J UN-2015 OFF I CE OF C H EM I CA L SAFETY AN D POLL UTION PREVENT I ON



### SUBJECT: S ulfentrazon e: Res ponse to Comments o n the Pre limin ary Human H ealth Risk Assess m ent. P C Code: 129081 D ecis ion No.: 495324 Petiti o n No .: NIA Ri s k A ssess m e nt Type: NIA TXR No.: NIA MRID No.: NIA DP Barcod e: 0422814 Regi s tration No.: NIA Regu l atory Action: Registra tion Review Case No.: 723 1 CAS No.: 122 836-35-5 40 CFR: § 180.498 

### FROM: Kelly M. Lowe, Environmen tal Scienti s t

## .-::,**~ ~**  A n war Y. Dunb ar, Ph .D. ,

# Pha~macolog**i. st** **P':; =!!:**  George F

. Kramer , Ph.D

. , Sem or

## Chem**~ _Jii~iiiit-§riC,.._**  ------- - -- Ri sk Assessment Branch 1 ( RAB l ) Hea lth Effects Divis ion ( HED , 7509P) 

### THROUGH: Th ur sto n G. Morton , Ac tin g Branch C hi ef RAB l/H E D (7509 P) 

### TO: C hristina Sche lte ma , C hemical Re view Ma nager P es ticide R e-Eva lu ation Di vis ion (PRD) (7508P)

The S ulfentrazo n e Ri sk Assessment team ha s received comments on the Sulf e ntrazo ne Preliminary Human Hea lth Ri s k Asses s me nt (PRA; E P A Docke t JD : EPA-HQ-OPP-2009-0624- 00 16) and a ttac hed i s the respo n se to comments. Comments re lev ant to th e hum an hea lth PRA were prov ided by FMC Corp o ration.

Page I of4Sulfentrazone Response to Comments 0422814 

### Commen t #1 : (Page 20 , Section 4.4.4) " The residential assessment includes an FQPA SF of 1



### OX for inhalation exposures to account for the unce rtainty associated with the lack of an appropriate inhalation toxicity study." FMC Comment: FMC notes that section 4.4.4 s till accounts for a FQPA SF of 

### IOX due to a lack of an appropriate inhalation toxicity study. A 28 -day inhalation toxicity study ha s been sub mitted and ha s been determined acceptable by th e Agency (MR1D 49253902). Sectio n 4.1 of the s ul fent razone preliminary human healt h risk assessment states that the toxicological database for sulfentrazo ne is complete for risk assessment purposes and that the subchronic inhalation study ha s been submitted and reviewed by the Agency. The results hav e been incorporated in the risk assessme nt. 

### In addition , Section 4.4 o n page 20 "The RAB l risk assessment team recommends that the FQPA SF be reduced to 

### IX for all exposure scena rio s. The toxicity database is comp lete and dietary and residentia l exposure analyses are unlikely to underestimate exposure. " FMC requests that this error in Section 4.4.4 be corTected from a l OX SF to a IX SF as supported by th e study s ubmitted and corresponding Agency rev iew. EPA Re sponse: The Agency agrees with FMC Corporation that there is an erro r in Secti on 4.4.4, and will correct that section to reflect a 1 X SF. 

### Com ment #2 : ( Page 22 , Sectio n 4.5. l ) " Thi s inhal at ion study is protective for th e systemic effects ( including developmental effects seen in the ora l studies) for the following reasons: 1) th e dose spread in the inhalation study between th e NOAEL and LOAEL is l arge (40 to 600 m g/kg/ day)

.. . " FMC Comment: FMC no tes · that th ere i s an e rror in th e statement. The dose spread shou ld be corrected from 40 to 600 mg/kg/day to 60 to 400 mg/kg/ day. EPA Response: EPA co nfirms that the dose spread is 20, 60 , and 400 mg/kg/day. 

### Commen t #3: ( Page 28 , Sec ti on 5.3)

- Drinking Water Res idue Profile FMC Comme nt: The use of PR1SM-GW to provide estimates fo r groundwater provides overly conservative va lue s. PRISM- OW does not cons ider the best ava il ab le dat a. Four prospective groundwater studies have been submitted that s ho w significantly lower concentrations th a n esti'mated values from PR1SM-GW, eve n thou g h th e s ites where th ese studies were conducted are with i n the upper mo st percentile of grou nd water vulnerabi li ty. E PA R esponse: The Agency believes that the s tand a rd scenarios for the PRZM- GW mod el provide groundwater concentration es tim ates that are representati ve of the cond iti ons modeled using the avai lable in format ion on the pesti cide environmental fate and u se patterns. Indeed, the 6 scenarios currently used do represent evaluation of aquifers that are relatively vu lnerable to impacts from app lied pesticides. Should the Agency rece ive additional verifiable data regardin g the environmental fate and transport of s ulfentrazone residues that a llow for refinement of mode l inputs it will be utilize d in exposure modeling to support future risk asses sments. EFED beli eves th at the four PGW studies for s ulfentrazo ne provide useful insights into sulfentrazone imp acts on groundwater from normal use , but does not believe that it is scie ntifi ca ll y vali d to assume that the results of these studies directly provide upper-bound concentrations for sulfe nt razone res idu es in grou ndwate r. The se studies provide a useful but sma ll sam plin g of the range of conditions that may be assoc iated with the application of sulfentrazone and do not d irectly Page 2 of4Sulfentrazone Response to Comments 0422814 address the impacts of uses at the same s ite over multiple decades, which is assumed for screening for groundwater exposure with PRZM-GW. FMC Comment: The use of the tota l toxic residues (TTR) approach i s overl y s implified and does not consider all avai labl e data. When possible , environmental fate profi les and data of each residue of concern s hould be tre ated separately to appropriate ly represent chemica l transport. In this case , env ironmental fate data are available for the m etabo lite SCA , so the u se of the TTR approach s hou ld be refi ned to the sum of residues approach. E PA Re spo nse: The Agency has concluded th at parent and 3-carboxy li c acid s ul fentrazone a re the residues of concern for the drinking water assessment. The TTR values provided are th e sum of parent and 3

- carboxylic acid su lfentrazone, consistent with the definition of the residues of co ncern. FMC Comment: FM C s upport s the Crop Life America position that the SCI-GROW model would provide an adequate representation of conservative groundwater exposure. The dietary ri sk assessment using the drinking water exposure estimates from SCI-GROW would better r e present potential, worst-case dietary expos ure. EPA Re s ponse: The Agency has decide d to support the primar y use of PRZM

- G W for screening for groundwater exposure. PRZM-GW modeling can be refined to represent more closely actua l use conditions and pesticide behavior by si te if there are available data. 

### If the r eg istrant believes that the exposure estimates with PRZM-GW are unnecessarily co n servative, then a s ubmi ssio n outlining their position with specific verifiable data s hou ld be submitted, and would be reviewed by the Age ncy. 

### Co mment # 4: (Page 31) Table 6.1.1 Re s id ential Handler Non-cancer Exposure and Risk Assessments for Su lfentrazone FMC Comment: Tab le 6.1. l ha s inhalation LOC 

## = 100. The discrepancy li es wi thin Section 6.1 o n page 30 that states that inhalation exposure risk es timates for residential handlers are not of concern ( i. e. MOEs**~** 30 for inJ1alation). FMC requests that the error in Table 6.1. I be changed to match Sect ion 6.1 and Section 4.5. l to a SF of 30X to account for 3X interspecies and I OX intraspecie s uncertaint y factor s. E PA Response: H ED agrees that th ere is an error in Tabl e 6. 1

. 1 and will correct th e table to indicate th e LOC for inhalation is 30. 

### Co mment #5: (Page 37-40) Table 9 .1. I Occupational Handler Non-cancer Exposure and Risk Assessme nt s for Sulfentrazone FMC Comment: Table 9.1.1 ha s inhalation LOC = 100. The discrepancy lie s within Section 9.1 on page 36 that states that occupational handler exposure and ri sk estimates indi cate that s hortand interme diate-term dermal and inhalation MOEs are not of concern to HED (i.e. MO**Es ~**  I 00 fo r dermal an d MOE s**30** for inhalation). FMC req uests that the error in Table 9.1. 1 be changed to match Sec tion 9.1 and Section 4.5. l to a SF of 30X to account for 3X interspecies and 1 OX in traspecies uncertainty factors. EPA Re spo n se : HED agrees that there is an error in Table 9. I. I and will correct the table to indicate the LOC for inhalation is 30. Page 3 of4Su I fentrazone Response to Comments 0422814 

### Comment #6: (Page 43) Table A.2. Acute Toxicity Profile

- Sulfentrazone FMC Comment: Row 4 , column 3 : The correct MRID number fo r "Acute dennal" study is 41911607. EPA Response: There are two acute dermal studies for sulfentrazone, one in mice and the other in rats (M RlD s 419 11 606 and 41911607, respec tiv e ly). HED acknowledges that th e rat study shou ld a l so be listed on the acute toxicity profile table. 

### Comment #7: (Page 44) Table A.3. Toxicity Profile

- Su lfentrazone FMC Comment: Row 3 , Column 2: The cotTect MRID number for "90-Day ora l toxicity (mice) " study is 43004602. EPA Response: H ED acknowledges that the correct MRlD number is 43004602. 

### Comment #8: (Page 54) Table B. l. 

### Physiochemical Properties of Technical Grade Sulfentrazone FMC Comme nt: FMC notes that there is an error in Table 

### B. l , which states that UV/visible absorption spectrum data is not available. FMC requests that the error be corrected to include data from the study " UV /visib le absorption spectrum data is available for sulfentrazone technical with the title "Su lf entrazone (TGAI and PAI): Detennination of UV/Visible Absorption and Molar Absorptivity " (MRlD 4852160 1) which has previously been subm itted to address this data requirement. EPA Response: BED acknowledges that a stud y was submitted to address the UV/ visible absorption s tudy. The table in the PRA will be re v ised.

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