(full paper is archived in the Miller Library)
Title: DDT uptake in Emerita analoga and levels of DDT residues of populations from Asilomar Beach and near the mough of the Salinas River
Student Author(s): King, Richard E.
Location: Final Papers Biology 175H
Date: June 1969
Abstract: The filter feeding san dcrab, Emerita analoga, is abundant in sandy beaches on California shores. It is an important food source for the Barred Surfperch and several shore birds including the Snowy Plover, Sanderling, and Sandpiper. Several California birds and fishes contain high levels of DDT and its derivatives. Emerita is in a position ot concentrate DDT residues from water, plankton, and detritus, and pass them on to fishes and fords through the food chain. To measure the rate of uptake of DDT from seas water, sand crabs were exposed to solution of C14-DDT at concentrations of 0.1, 0.2, 0.4, 0.6, 0.8, and 1.0 ppb for 12 hours. Sand crabs burrowed in sand took up a constant amount of DDT in concentrations of 0.4 ppb 1.0 ppb (increases from 10x to 25x). Sand crabs free in sea water took up amounts of DDT proportional to the DDT concentration in the sea water (an increase of 55x). Natural levels of DDT residues were determined by gas liquid chromatography in populations of sand crabs from the mouth of the Salinas Rive, which drains and agricultural valley where DDT use is widespread, and from Asilomar Beach, an exposed ocean beach several miles away. Approximately 80ppb of DDE were found in both populations. Only trace amounts of DDT were present in sand crabs from Asilomar Beach, while approximately 140 ppb were found iont sand crabs from the mouth of the Salinas River.