The primary project goals are to develop, test, and validate methods for analysis of six or more pyrethroid insecticides in water, colloids, sediments, and biota. As part of the method development, each step of sample collection, processing, and analysis will be carefully tested, and modified if needed, to insure quantitative recovery and sufficient sensitivity to measure environmentally-relevant concentrations. The analysis of pyrethroid insecticides in water will be a joint venture between three laboratories: U.S. Geological Survey's Organic Chemistry Laboratory in Sacramento (USGS), California Department of Fish and Game's Water Pollution Control Laboratory in Rancho Cordova (CDF-WPCL), and the California Department of Food and Agriculture's laboratory in Sacramento (CDFA). This approach gives us maximum expertise and access to a wide variety of instrumentation. The method will be validated by analysis of a limited number of environmental water samples by all three laboratories. The final result will be a routine method for water analysis that is operational in the three different laboratories. The CDFG laboratory will also develop methods for bed sediments and biota while the USGS laboratory will focus on methods for colloids and suspended sediments. Both laboratories will be able to build upon knowledge gained during the development of the method for water and their own experience with these matrices.