Using POCIS and SPMD passive samplers to monitor pesticide concentrations in California surface waters

Poster Presentation

Prepared by R. Budd1, A. DaSilva2, A. Poulsen3
1 - Califonia EPA, Department of Pesticide Regulation, 1001 I St, Sacramento, CA, 95814, United States
2 - Department of Pesticide Regulation, 1001 I St , Sacramento, CA, 95814, United States
3 - University of California at Davis, One Shields Ave, Davis, CA, 95816, United States

Contact Information:; 916-445-2505


Traditional water monitoring techniques such as grab sample collection has limitations in determining average pesticide concentrations in systems with high input variability. Passive samplers are relatively new tools that allow for the determination of time-weighted average pesticide concentrations over longer time periods. The California Department of Pesticide Regulation (DPR) is investigating the ability of these techniques to measure environmentally relevant pesticide concentrations under field conditions. These techniques have the advantage over grab samples in measuring the dissolved pesticide concentration, which is typically cited as the bioavailable fraction. Semi-permeable membrane devices (SPMDs) are designed to measure contaminants with higher Kow values, while polar organic chemical integrative samplers (POCIS) are employed for more hydrophilic chemicals. In this investigation SPMD and POCIS membranes were deployed for 28 days within two surface water streams; one receiving agricultural runoff and the other receiving urban inputs. Samplers were deployed during three time periods to account for seasonal variability in pesticide concentrations and water temperatures. Concurrent time-weighted composite water samples were also collected during the period of the study. Membranes were analyzed for 41 currently registered active ingredients, spanning a large range of physiochemical properties. Results of these efforts will be summarized.