During a recent climate webinar offered as part of the NOAA Science Day seminar series, NCCOS's Marie DeLorenzo explained how changing climate variables may influence pesticide toxicity in the coastal zone. Pesticides enter estuarine waters via runoff and drift from agricultural, turf grass, home and garden, and mosquito control applications.

DeLorenzo tested adult and larval grass shrimp, phytoplankton, and larval clams with pesticides commonly used to control insect, weed, and fungal pests. Then, she compared the toxicity of the chemicals using standard test conditions to toxicity under climate stress conditions (higher temperature, higher salinity, lower oxygen [hypoxia], and lower pH). In general, pesticides were more toxic under more extreme conditions than under conventional testing conditions. DeLorenzo's results suggest that future risk assessments should take climate variables into account in determining the safety of pesticide use within the coastal zone.

For more information, contact Marie.DeLorenzo@noaa.gov.