Many agricultural pesticides are present at very low concentrations.
Samples were taken one to five times a month from March 1993 through May 1994. Detections of pesticides usually, but not always, were related to pesticides used on crops in the drainage basins. Five pesticides were at concentrations that could adversely affect aquatic life. Displays the table in-line in your browser as text. The table has 13 columns and 45 rows, plus notes.