(full paper is archived in the Miller Library)
Title: Uptake of C14-DDT by mixed phytoplankton
Student Author(s): Stearns, Richard M.
Location: Final Papers Biology 175H
Date: June 1969
Abstract: C14-DDT uptake by populations of mixed phytoplankton are investigated by centrifugation and liquid scintillation techniques. Plankton in culture densities of 0.03 mg/ml to 0.41 mg/ml in C14-DDT solutions of 0.3 to 100 ppb showed DDT concentrations (gm DDT/ gm dry weight plankton) of 210 ppb to 170 ppm. Concentration factors comparing final DDT concentrations in cells with initial solution concentrations are found between 700 and 13000. Phytoplankton take up between 40% and 70% of the DDT in solution in less than four hours and generally less than 15 minutes. Formalin killed cells take up the same amount of DDT as live cells. Lugol preservative killed cells take up less DDT than live cells. Cells incubated in dark B.O.D. bottles take up the same amount of DDT as cells incubated in the light. Less dense cultures concentrate DDT more than dense cultures. Plankton appear to concentrate DDT more in dilute DDT solutions than in concentrated solutions. Phytoplankton containing DDT removed to dilute DDT solution retained 70% to 90% of their DDT after two hours.