^ eo ° A *¦ £ ¦& USB,' *1 PRO^ UNITED STATES ENVIRONMENTAL PROTECTION AGENCY WASHINGTON. D.C. 20460 JUN I 81990 OFFICE OF PESTICIDES ANO TOXIC SUBSTANCES MEMORANDUM SUBJECT: Dietary Exposure Analysis for the Proposed Use of Nicosulfuron (Accent) on Corn, PP#9F3763. FROM: James P. Kariya Dietary Risk Eva^C HED/SACB (H7509C) System (DRES) Staff TO: Robert Taylor, PM-25 Fungicide-Herbicide Branch Registration Division (H7505C) Action Requested Estimate the risk of adverse health effects from dietary exposure to Accent through the proposed use on corn. Discussion 1. Toxicology Endpoint: The routine chronic DRES analysis used a reference dose (RfD) of 1.25 mg/kg body weight/day, based upon a NOEL of 125 mg/kg body weight/day and an uncertainty factor of 100 from a 1-year feeding study in dogs. Effects of concern include decreased gain in body weight, and increased relative liver and kidney weights. The RfD was approved by the HED reference dose committee on 6-14-90, but has not been reviewed by the EPA RfD Committee. 2. Residue Information: There are no published tolerances for Accent. The current analysis includes only the proposed tolerance on corn grain (0.1 ppm). Since there is no human consumption of corn forage, corn fodder, or corn silage, the proposed tolerances on these commodities have not been used. The Dietary Exposure Branch concluded that tolerances for milk, meat, fat, or meat by-products are not needed (memo, J.B. Stokes to R. Taylor, 6-13-90, page 2) , so these commodities are not included in the DRES run. A summary of the residue information used in the analysis is attached as Table 1. 3. Exposure Analysis: The DRES chronic exposure analysis uses tolerance level residues and 100 per cent crop treated to estimate ------- Dietary Exposure Analysis, page 2 the Theoretical Maximum Residue Contribution (TMRC) for the overall U.S. population and 22 population subgroups. Results of the DRES analysis are given in Table 2. 4. Comments: Given the assumptions listed in section 2 above, the proposed tolerance on corn grain is likely to lead to exposures that are well below l/100th of 1 percent of the RfD (the level below which no effects are likely to occur if exposure occurs continuously for a lifetime). Risk is likely to be even less if, as noted in the DEB memo (J.B. Stokes to R. Taylor, 6-13-90, page 10) the levels in corn are below 0.05 ppm rather than the 0.1 ppm level assumed for this DRES run. Finally, please note that this DRES analysis assumed a concentration factor of 1.5 for corn sugar, which may also lead to an overestimate of the risk. Although the risk of effects from chronic exposure appears to be negligible, and although there is no reason to believe that Accent causes effects through acute exposures, it should be noted that this substance has not been rated for its carcinogenic potential. Therefore, no conclusion can be made at this time concerning the presence, absence, or degree of risk of carcinogenicity. Attachments cc: DRES (Kariya), DEB (Loranger), Caswell #359J, G. Ghali ------- Table 1. TOLERANCE ASSESSMENT SYSTEM ROUTINE CHRONIC ANALYSIS DATE: 06/14/90 PAGE: 1 CHEMICAL INFORMATION STUDY TYPE EFFECTS REFERENCE DOSES DATA GAPS/COMMENTS STATUS Accent (IN V9360-7) 1yr feeding- dog Decreased body wt gain; ADI UF -->100 No data gaps. RfD/PR complete 06/14/90. Caswell #359J NOEL= 125.0000 mg/kg increased relative liver OPP RfD= 1.250000 CAS No. 111991-09-4 5000.00 ppm & kidney weights. EPA RfD= 0.000000 Does not require Develop- A.I. CODE: 129008 LEL= 500.0000 mg/kg Onco classification pend- mental Peer Review. CFR No. 180. 20000.00 ppm ONCO: Pending. ing submission of histor- ical control information. LISTING OF EXPOSURE BY RAC FOR: U.S. POPULATION - 48 STATES |--EXISTING TOLERANCES--| FOOD | TOLERANCE (PPM) | TMRC CODE FOOD NAME NEW PENDING PUBLISHED (UG/KG/DAY) %RfD |-NEW & PENDING TOLERANCES-| TMRC (UG/KG/DAY) %RFD 24002EA CORN,GRAIN-ENDOSPERM 24002HA CORN,GRAIN-BRAN 24002SA CORN SUGAR 270020A CORN,GRAIN-OIL 0.10000 0.10000 0.10000 0.10000 0.016540 0.000000 0.014575 0.002280 0.0013 0.0000 0.0011 0.0001 CROP GROUP TOTALS FOR CEREAL GRAINS: GRAND TOTAL TMRC: 0.033395 GRAND TOTAL % OF THE RfD: 0.0027 0.033395 0.0027 POPULATION SUBGROUP TOTALS 0.000000 0.0000 0.033395 0.0026 POPULATION TOTAL TMRC 0.033395 POPULATION TOTAL % OF THE RfD 0.0026 ------- Table 2. TOLERANCE ASSESSMENT SYSTEM ROUTINE CHRONIC ANALYSIS DATE: 06/14/90 PAGE: 1 CHEMICAL INFORMATION STUDY TYPE EFFECTS REFERENCE DOSES DATA GAPS/COMMENTS STATUS Accent (IN V9360-7) lyr feeding- dog Decreased body wt gain; AD I UF -->100 No data gaps. RfD/PR complete 06/14/90. Caswell #359J NOEL® 125.0000 mg/kg increased relative liver OPP RfD» 1.250000 CAS No. 111991-09-4 5000.00 ppm & kidney weights. EPA RfD= 0.000000 Does not require Develop- A.I. CODE: 129008 LEL= 500.0000 mg/kg Onco classification pend- mental Peer Review. CFR No. 180. 20000.00 ppm ing submission of histor- ONCO: Pending. ical control information. TOTAL TMRC (MG/KG BODY WEIGHT/DAY) NEW TMRC DIFFERENCE EFFECT OF ANTICIPATED RESIDUES AS PERCENT AS PERCENT POPULATION SUBGROUP CURRENT TMRC* NEW TMRC** OF RFD OF RFD U.S. POPULATION - 48 STATES 0.000000 0.000033 0.002672 0.002672 U.S. POPULATION - SPRING SEASON 0.000000 0.000032 * 0.002598 0.002598 U.S. POPULATION - SUMMER SEASON 0.000000 0.000034 0.002729 0.002729 U.S. POPULATION - FALL SEASON 0.000000 0.000034 0.002727 0.002727 U.S. POPULATION - WINTER SEASON 0.000000 0.000033 0.002632 0.002632 NORTHEAST REGION 0.000000 0.000024 0.001898 0:001898 NORTH CENTRAL REGION 0.000000 0.000030 0.002415 0.002415 SOUTHERN REGION 0.000000 0.000041 0.003242 0.003242 WESTERN REGION 0.000000 0.000039 0.003103 0.003103 HI SPAN ICS 0.000000 0.000060 0.004760 0.004760 NON-HISPANIC WHITES 0.000000 0.000030 0.002363 0.002363 NON-HISPANIC BLACKS 0.000000 0.000046 0.003710 0.003710 NON-HISPANIC OTHERS 0.000000 0.000030 0.002391 0.002391 NURSING INFANTS (< 1 YEAR OLD) 0.000000 0.000032 0.002538 0.002538 NON-NURSING INFANTS (< 1 YEAR OLD) 0.000000 0.000098 0.007817 0.007817 FEMALES (13+ YEARS, PREGNANT) 0.000000 0.000023 0.001871 0.001871 FEMALES 13+ YEARS, NURSING 0.000000 0.000021 0.001678 0.001678 CHILDREN (1-6 YEARS OLD) 0.000000 0.000087 0.006927 0.006927 CHILDREN (7-12 YEARS OLD) 0.000000 0.000063 0.005008 0.005008 MALES (13-19 YEARS OLD) 0.000000 0.000038 0.003063 0.003063 FEMALES (13-19 YEARS OLD, NOT PREG. OR NURSING) 0.000000 0.000031 0.002494 0.002494 MALES (20 YEARS AND OLDER) 0.000000 0.000021 0.001674 0.001674 FEMALES (20 YEARS AND OLDER, NOT PREG. OR NURS) 0.000000 0.000018 0.001460 0.001460 ~Current TMRC does not include new or pending tolerances. **New TMRC includes new, pending, and published tolerances. ------- |