Glyphosate Human - Health Risk Assessment D3 81826

Page 1 of 3 UNITED STATES ENVIRONMENTA L PROTECTION A GENCY

WASHINGTON, D.C. 20460 OFFICE OF CHEMICAL SAFETY AND POLLUTION PREVENTION MEMORANDUM Date: 24 - March - 20 1 1 Subject: Glyphosate . Section 3 Registration for Application of the Potassium Salt of Gly phosate to Roundup Ready® Field Corn. Human - Health Risk Assessment . PC Codes: 103613 and 417300 DP Barcode: D38 1826 Decision No.: 437140 Registration No s . : 524 - 537; 524 - 549 Petition No.: 0F7741 Regulatory Action: Section 3 Risk Assessment Type: aggregate Case No.: 178 T XR No.: not applicable CAS No.: 70901 - 20 - 1 MRID No.: not applicable 40 CFR: 180.364 From: Tom Bloem, Chemist

Risk Assessment Branch 1; Health Effects Division (RAB1/HED; 7509P) \ Through: Dana M. Vogel, Branch Chief

George F. Kramer, Ph.D., Senior Chemist RABI/HED (7509P) To: James Tompkins/Hope Johnson RM 25

Registration Division (RD; 7505P) Gly phosate ( N - (phosphonomethyl) gl ycine) is a nonselective Group 9 herbicide that is currentl y registered for pre - and post - emergence application to a variety of fruit, vegetable, and field crops. Tolerances are currentl y established for residues of gl yphosate in/on various plant commodities at 0.2 - 400 ppm (40 CFR §180.364(a)) and for the combined residues of gl yphosate and N - acetyl - gl yphosate (expressed as gl yphosate) in/on field corn, so y bean, aspirated grain fractions , and livestock commodities at 0.1 - 310 ppm. The Gly phosate Reregistration Eligibility Decision document was issued September 1993. Monsanto indicated that they have developed a new variety of geneticall y- altered field corn ( MON 87 427 and MON87441) which enables properl y timed gl yphosate appl ications to provide tassel control . Monsanto indicated that tassel control is desired as this will allow the generation of specific cross pollinations without the use of traditional methods to control self pollination. T his new variety of field corn is to be used only in seed corn production (Monsanto termed the process Round Hy bridization SystemTM (RHS TM )) and involves sl ightl y later gl yphosate application than th at currentl y registered for fiel d corn ( same seasonal application rate ; see Attachment 1 for proposed application scenario).Glyphosate Human - Health Risk Assessment D3 81826

Page 2 of 3 The petitioner has submitted adequate magnitude of the residue data which indicates that the currentl y established field corn forage and grain tolerance s , as we ll as the currentl y established livestock tolerances, are adequate to cover th e proposed new use . H owever, the field corn forage tolerance , for the combined residues of gl yphosate and N - acetyl - gl yphosate (expressed as gl yphosate) , shoul d be increased to 13 ppm ( D383931, T. Bloem, 16 - Mar - 2011 ) . HED recentl y completed a human - health risk assessment associated with the application of gl yphosate to g ly

phosate - tolerant sweet corn (D372052, T. Bloem et al. , 31 - Aug - 2010). This assessment yielded an aggregate exposure to gl yp hosate which did not exceed HED's level of concern. HED concludes that a revised human - health risk assessment is unnecessary to support the current - proposed uses for the following reasons: ● No new toxicological data were submitted since the previous risk assessment (see D372052 (T. Bloem et al. , 31 - Aug - 2010) for a summary of the toxicological data) . ●The previous dietary

expo sure anal ys is assumed tolerance - level residues and 100% crop treated and the current action result in an increase in onl y the field corn forage tolerance (livestock feed item). ●Since no new toxicological data were submitted and a revised dietary exposure anal ys is is unnecessary , the previous conclusion s concerning the Food Quality Protection Act (FQPA) Safety Factor remain valid. ● The proposed new field corn application scenario does not necessitate a revised occupational exposure assessment (assessment conducted as part of the currently registered fie ld corn application scenario remains valid) . Recommendation: Provided the petitioner submits revised Sections B and F (see below) , HED concludes that the toxicological, residue chemistry , and occupational/residential exposure databases support a condit ional registration for the proposed application of gl yphosate to field corn. An unconditional registration may be established upon submission of data which adequatel y addresses the toxicological deficiencies specified below. Summary of Deficiencies:

 Acute and subchronic neurotoxicity studies.  Immunotoxicity

study . ●Section B: HED requests that the supplemental labels be altered to indicate the following: (1) the minimum spray

volume for ground and aerial application is >2 gallons per acre ( GPA ) ; (2 ) postemergent directions should indicate that they apply to field corn up to the V8 crop stage and that a maximum of 2.3 lb ae/acre/season may be applied; and (3) preharvest interval ( PHI ) of 30 day s for forage and 7 day s for grain and stover. ●Section F: HED requests that a revised Section F be submitted proposing a 13 - ppm field corn forage tolerance for the combined residues of gl yp hosate and N - acetyl - gl yp hosate (expressed as gl yphosate). Attachment 1: Proposed Application Scenarios and Requested Changes to the Proposed Labels T. Bloem:S10945:Potomac Yard 1:703 - 605 - 0217:7509P:RAB1Glyphosate Human - Health Risk Assessment D3 81826

Page 3 of 3 Attachment 1: Proposed Application Scenarios and Requested Changes to the Proposed Labels. The petitioner submitted proposed supplemental labels for Roundu p WeatherMAX ® (EPA Reg. No. 524 - 537) and Roundup Power MAX ® (Reg. No. 524 - 549); both of these products are soluble concentrate (SC) formulations consisting of gl yphosate as the potassium salt at 4.51 lb ae/gallon. The submitted supplemental labels indicat e that the application scenarios are for use in research field trials and for seed production of corn h ybrids using the RHS TM sy stem. Table 1 is a summary of the proposed application scenarios. The proposed use directions are similar to that currentl y reg istered with the exception of the tassel control instructions (V8 - V13); maximum seasonal application rate is the same. HED requests that the supplemental labels be altered to indicate the following (a revised Section B is requested): (1) the minimum spray volume for ground and aerial application is >2 GPA; (2) postemergent directions should indicate that they apply to field corn up to the V8 crop stage and that a maximum of 2.3 lb ae/acre/season may be applied; and (3) PHIof 30 day s for forage and 7 day s for grain and stover. Table 1 : Summary of Proposed Roundup Ready ® Field Corn Application Scenario . Formulation (EPA Reg. No.) App. Timing App. Rate (lb ae/acre) Max. App. Rate

(lb ae/acre) Use Directions and Limitations Roundup WeatherMAX ® (EPA Reg. No. 524 - 537 ; SC; 4.51 lb ae/gal ) Roundup Power MAX ® ( EPA Reg. No. 524 - 549 ; SC; 4.51 lb ae/gal ) preplant, at planting, preemergence not specified 3.72

- For use in research field trails and for seed production of corn hybrids using RHS TM

.

- Allow a minimum of 10 days between postemergent applications. postemergence 0.56 - 0.78 not specified tassel control (V8 - V13 or 100 growing degree units; before flowering) 0.39 - 1.13 2.26 preharvest 0.78 not specified postharvest not specified not specified maximum seasonal application rate -- 5.98