Uptake from Sea Water and Clearance of 14C-p,p′-DDT by the Marine Copepod Calanus finmarchicus

Abstract

It is impossible to measure the uptake rate of p,p′-DDT by copepods from sea water directly since uptake and depuration occur simultaneously. Copepods were found to lose p,p′-DDT exponentially in flowing sea water with a rate constant of kj = 0.048/day; [Formula: see text]. Five experiments were performed to obtain uptake rates with DDT concentrations ranging from 32.5 to 1337 pptr in sea water. Copepod uptake of p,p′-DDT from sea water is amply described by a single-compartment model, [Formula: see text], which accounts for influx and efflux of DDT. Calculated influx rate constants, ki, varied between 1.5 and 2.7 × 103/day. These results enable prediction of DDT levels in nonfeeding copepods if the concentration of DDT in sea water is known.