The American Soybean Association (ASA) joined several agriculture groups this week in submitting comments to the Environmental Protection Agency (EPA) regarding spray drift in pesticide risk assessment.

EPA’s proposed guidance would direct agency activities and implement policies that would use the AgDRIFT model for ecological and drinking water risk assessments and residential exposure assessments from spray drift and would predict whether and to what extent no- spray buffer zones and other label requirements would be needed to mitigate expected spray drift exposures.

“We are concerned that the proposed guidance describes model conditions that routinely over- predict the exposures likely from typical spray applications when compared to actual drift deposition measured in published monitoring studies. EPA’s use of atypical assumptions and default input parameters overlooks many of the drift-reduction technologies (DRTs) and standard operating procedures (SOPs) that are now typical for aerial and ground applications,” the groups said in a letter. “EPA’s default parameters are rarely encountered in normal commercial pesticide applications.  The resulting modeling flaws assign unwarranted exposure risks to routine pest control situations, and require extremely large no-spray buffers to mitigate phantom risks.  Evaluation of drift-incident monitoring data and Reregistration Eligibility Decision (RED) records fails to provide support for AgDRIFT predictions, based on these default parameters, of drift or the buffers prescribed for risk mitigation.”

The groups urged EPA to embrace the use of DRTs and SOPs already in use and quickly implement its long- awaited DRT Program for verification and use of drift reduction technologies.

“We also urge EPA to provide in label language the flexibility for applicators to adopt the specific DRTs and SOPs warranted by the conditions experienced on a particular day at a particular site.  Such a regulatory platform is fully functional in Canada,” the letter stated.