On May 23, 2018, the U.S. Environmental Protection Agency (EPA) held an “Environmental Modeling Public Meeting” (EMPM). As stated in the April 12, 2018, Federal Register notice announcing the meeting, the “EMPM provides a public forum for EPA and its stakeholders to discuss current issues related to modeling pesticide fate, transport, and exposure for pesticide risk assessments in a regulatory context.” The overall theme of the EMPM was the quantitative use of surface water monitoring data.

The morning session featured a series of presentations by representatives from EPA, the U.S. Geological Survey (USGS) and the Washington State Department of Agriculture concerning the development of a framework to use surface water monitoring data quantitatively in pesticide risk assessments. A major focus of the presentations was the exploration and evaluation of the capabilities of the USGS recently-developed model SEAWAVE-QEX to improve the robustness of surface water monitoring datasets so that they might be used in pesticide risk assessments. Further public presentations on the evaluation and development of the framework are scheduled at the American Chemical Society meeting to be held on August 19-23, 2018, in Boston, Massachusetts. There are plans to hold a Scientific Advisory Panel meeting on the framework in 2019, but no exact date has been set.

The afternoon session consisted of presentations by representatives of the registrant community. Topics addressed included developments in the use of surface water monitoring data in quantitative risk assessment, a statistical analysis of non-targeted monitoring data at the watershed scale, the creation of a curated database of water and sediment monitoring data for synthetic pyrethroids, the use of high-resolution spatial and temporal monitoring data to parameterize watershed scale drift exposure predictions, and an evaluation of model predictability using monitoring data and refined pesticide use at the watershed level.

Presentations from the May 23, 2018, EMPM will soon be posted to Docket No. EPA-HQ-OPP-2009-0879, accessible at www.regulations.gov.

Registrants should monitor these activities, as this effort at EPA represents a potential shift away from the current reliance exclusively on estimated water concentrations in quantitative human health and ecological risk assessments.