Analytical Determination of Pesticide Metabolites and Carrier Chemicals in Wisconsin Wells

Measurements were made of atrazine, alachlor, cyanazine and metribuzin. Early in the study, upon the request of the Wisconsin Department of Natural Resources personnel, it was decided to focus much of the analytical work on metribuzin. Metribuzin is a widely used pesticide, particularly in sandy areas of the state where contamination of groundwater from surface application of pesticides is a problem. A method to measure metribuzin and its likely metabolites was developed and it proved to be better than any reported in the literature when metribuzin and all metabolites were considered. The method employed solid phase extraction and high performance liquid chromatography. The method was used to test groundwater samples, collected by the Wisconsin Department of Agriculture, Trade and Consumer Protection, for metribuzin and metabolites. Analysis of these samples showed that all of the key metabolites of metribuzin can exist in groundwater, sometimes at concentrations in excess of the parent compound. Besides metribuzin, the method was used for measuring atrazine and metabolites, alachlor and metabolites and cyanazine and metabolites. Thus, it showed promise as a multiresidue technique. The work culminated in a technical paper submitted for publication to the journal Water Research (copy attached).