National Water-Quality Assessment (NAWQA) Program
NAWQA chemical analyses encompassed the most complete range of pesticides ever measured in a single assessment, and included many of the pesticides that are, or have been, the most heavily used in the United States (Appendix 1). The NAWQA Program analyzed for water-soluble pesticides—most of which were in use during the 1992–2001 study period—in stream water and ground water. Organochlorine pesticides, most of which were heavily used in the past but had their uses in the United States discontinued decades ago, were assessed in bed sediment and fish tissue—environmental media in which they accumulate because of their persistence in the environment, low water solubility, and tendency to associate with particulates.
In general, USGS analytical methods were designed to measure concentrations as low as economically and technically feasible. Studies of contaminant occurrence and behavior benefit from the most information possible at all concentration levels, and such data help to identify emerging issues and to track changes in concentrations over time.
For each sampling medium, information is provided on the pesticide compounds analyzed and the analytical approach and methods used.
Pesticides in Stream Water and Ground Water
Appendix 1A. Pesticide compounds analyzed in NAWQA water samples
Appendix 8A. Analytical Approach and Methods for Pesticides in Stream Water
Appendix 8B. Analytical Approach and Methods for Pesticides in Ground Water
Organochlorine Pesticides in Bed Sediment and Whole Fish
Appendix 1B. Pesticide compounds analyzed in NAWQA bed-sediment or whole-fish samples
Appendix 8C. Analytical Approach and Methods for Organochlorine Pesticides in Stream Bed Sediment and Whole Fish