Influence of environmental factors on pesticide levels in sport fish.

The extent of pesticide contamination of sport fish from lakes and reservoirs in Indiana is described. Environmental and water quality factors significantly influenced the concentration of pesticides in fish. The influence of these factors was different between natural lakes and humanmade reservoirs. Largmouth bass (Micropterus salmoides), sunfish (Lepomis sp), and bullheads (Ictalurus sp.) were collected and analyzed for dieldrin, aldrin, DDT, DDE, heptachlor, and heptachlor epoxide. The collections and concurrent lake surveys were made during 1972-73. Soil and decaying plant particles appeared to influence the levels of dieldrin and sigma DDT taken up by largemouth bass. Strong correlations were observed between lake turbidity and true color and residue levels in the fish. Residue concentrations were also observed to vary between fish species, the seasons of the year, and watershed land uses.