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Pesticide News Story: Triazine Cumulative Risk Assessment Decisions Comments Requested on Cumulative Decision, Simazine RED, and Propazine TRED

For Release: June 23, 2006

EPA has completed its cumulative risk assessment for the chlorinated triazine class of pesticides and concluded that, with mitigation measures for atrazine and simazine outlined in those individual decisions, the cumulative risks associated with the triazines are below the Food Quality Protection Act regulatory level of concern level of concern. Triazine tolerances - residue limits in food and feed - have been reassessed and found to meet safety standards established by the Food Quality Protection Act. The chlorinated triazine pesticides include atrazine, simazine, propazine, and their three chlorinated degradates. The Agency has finalized its Interim Reregistration Eligibility Decision for atrazine, completed in 2003, through this cumulative assessment. EPA requests public comment by August 21, 2006, on the triazine cumulative risk assessment, the Reregistration Eligibility Decision for simazine, and the tolerance reassessment decision for propazine. EPA notes that products containing the triazine pesticides still must complete product reregistration, through which product labeling changes and associated risk mitigation measures will be implemented.

Atrazine and simazine are used on a variety of food and feed crops including grains, fruits, and nuts, as well as on turf grasses grown in the Southeastern United States. Propazine is registered for indoor greenhouse use only and has existing tolerances established for residues on sorghum. While EPA's triazine cumulative assessment includes atrazine, simazine, and their three chlorinated degradates, it excludes propazine because no dietary, drinking water, or residential human exposure to propazine is anticipated from any of the currently registered uses.Examining three regions of the United States where triazine residues are likely to co-occur (the Midwest, California, and Florida) and four exposure scenarios (drinking water in each region, plus combined drinking water and home lawn or golf course exposure in Florida), EPA concluded that cumulative exposures to triazine residues are not of concern in any of the four exposure scenarios.

The triazine pesticides share a common neuroendocrine mechanism of toxicity that results in both developmental and reproductive effects. The Food Quality Protection Act of 1996 directs EPA to consider available information concerning the cumulative effects on human health that may result from dietary, residential, or other non-occupational exposure to multiple chemicals that, like the triazines, share common mechanisms of toxicity. Through Federal Register notices published on June 21, 2006, the Agency opened public comment periods closing on August 21, 2006, on the triazine cumulative risk assessment, simazine RED, and propazine TRED decisions. For additional information, see EPA's fact sheet, Triazine Cumulative Risk Assessment and Atrazine, Simazine, and Propazine Decisions at http://www.epa.gov/oppsrrd1/cumulative/triazine_fs.htm. The Federal Register  notices are available at http://www.epa.gov/fedrgstr/EPAFR-CONTENTS/2006/June/Day-21/contents.htm

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