Targeting pesticide hotspots in estuarine watersheds.

A simple screening method is presented for identifying coastal counties or portions of coastal counties within estuarine watersheds that have a potential for being the source of agricultural runoff containing toxic levels of pesticide residues. The method uses pesticide use estimates from the National Oceanic and Atmospheric Administration's (NOAA's) National Coastal Pollutant Discharge Inventory. To demonstrate the method, an example is presented identifying potential areas of concern in the estuarine drainage areas (EDAs) of Delaware Bay and Pamlico Sound. To confirm the prediction of potential toxicity, the areas identified by this preliminary analysis would have to be evaluated in more detail by an instream pesticide monitoring program or by using a comprehensive agricultural runoff model. The purpose of the screening approach proposed is to target potential hotspots in estuarine watersheds more efficiently so that limited environmental management resources can be more effectively directed to assess the impact of agricultural pesticide residues on the health of the estuarine environment.