The Effect of Some Common Insecticides upon C-14 Uptake in Phytoplankton

The acute effects of twlve common insecticides (DDT, DDE, methoxychlor, BHC, lindane, chlordane, dieldrin, Aldrin, endrin, txaphene, endosulfan, and mirex) upon insitu and in vitro phytoplankton were determeind utilizaing the c-14 technique of Steeman-Nielsen (1952).In situ tests were performed at Pawnee reservoir, Lancaster County, Nebraska.In Vitro experiments were performed with cultures of Anabaena flos-aquae, Selenastrum capricornutum, and Microcystis aeruginosa.Initial insecticide concentrations of 1.0 ppm, 0.1 ppm, 0.01ppm, and 1.0ppb were used for each series of tests. Results of the In Situ tests indicated that insecticides generally reduced productivity.Anabaena flos-aquae cultures exhibited the same general trend.Selenastrum capricornutum cultures were largely unaffected by the pesticides, while Microcystis aeruginosa cultures exhibited a great deal of photosynthetic stimulation with most of the insecticides used. Raw productivity values in mg carbon/m3/hr, percentages of control productivity, and relative pesticide ratings are given. A discussion of pesticide contamination of aquatic systems is included with the introductory material. Advisor: Gary L. Hergenrade