ASSESSMENT OF THE TOLERANCES FOR SECTION 3 REGISTRATION OF SHADEOUTJ (Rimsulfuron) ON TOMATOES

A Section 3 registration is being requested for ShadeoutJ which contains the herbicide, rimsulfuron. This registration is for a new use of rimsulfuron to control weeds in tomato fields. The proposed tolerance for rimsulfuron on tomatoes is 0.1 ppm. The critical acute No-Observed-Effect Level (NOEL) was 500 mg/kg/day based on a ruffled fur and transient weight losses in rats after a single exposure and death in pregnant rabbits after 9 days of exposure. The critical NOEL for evaluating chronic exposure was 1.6 mg/kg/day based on increased liver enzymes and testicular degeneration in dogs exposed to rimsulfuron in the diet for 1 year. There does not appear to be any increased pre-or postnatal sensitivity to rimsulfuron based on two developmental toxicity study and one reproductive toxicity study. Therefore, no additional uncertainty factor, as required under the FQPA, is recommended. There was no evidence of oncogenicity in long-term studies with either rats or mice exposed to rimsulfuron in their diet. No information was available for review regarding potential endocrine effects of rimsulfuron. The dietary exposure analysis utilized U.S. EPA established tolerances for all currently registered and proposed uses on commodities. The 95th percentile and the average exposure for each population subgroup were used in acute and chronic (annual) analysis, respectively. Based on the rapid degradation of rimsulfuron and its metabolites in water and soil, it is unlikely they would leach to groundwater. Therefore, no residues of rimsulfuron are anticipated in drinking water. Currently, there are no registered residential uses of rimsulfuron. No occupational exposure from aerial application of ShadeoutJ is expected since the label states not to apply by air. Workers applying rimsulfuron to tomatoes were considered to be potentially exposed during ground mixing/loading and application activities. A Margin of Exposure (MOE) of 100 is generally used as the benchmark for providing adequate protection of public health. This MOE takes into account the possibility that humans could be up to 10-fold more sensitive than the most sensitive test species on a dose per body weight basis and that the most sensitive human could be up to 10-fold more sensitive than an average person. The MOEs for potential acute and chronic dietary exposure were greater than 300,000 and 3,000, respectively. The highest potential chronic dietary exposure was approximately 3% of the U.S. EPA Reference Dose (RfD) for children 1-6 years old. The MOEs for potential acute and chronic occupational exposure were greater than …