ASSAY OF POLYCHLORINATED BIPHENYL BIOACCUMULATION FROM SEDIMENTS BY MARINE BENTHIC COPEPODS USING A NOVEL MICROEXTRACTION TECHNIQUE

A study was undertaken to measure Aroclor 1254 body burdens in two ben thic marine copepods, Amphiascus tenuiremis and Microarthridion littor ale. A microextraction technique was developed which utilizes 100 mu L of total extraction volume and as few as 20 copepods (approximately 2 5 mu g of dry tissue mass). Copepods were homogenized and extracted in a 100-mu L closed vial with alkaline media (4 M NaOH, 50 mu L) and is ooctane (50 mu L) spiked with an internal standard (hexachlorobenzene) , creating a colloidal suspension. After centrifugation, Aroclor 1254 quantification by GC-ECD was directly determined from the organic solv ent phase. Spiked samples of Aroclor 1254 yielded recoveries of 95% +/ - 12% (n = 11). Body burdens of sediment exposed (88.3 +/- 6.6 ng/mg o f dry weight sediment) copepods were measured over a 12-day period, an d predicted body burdens with 95% confidence intervals were calculated . Maximum levels found in A. tenuiremis (0.39 ng/mu g of dry tissue we ight) and M littorale (0.23 ng/mu g of dry tissue weight) were reached after 8 days of exposure and agree with other uptake values reported in the literature. This technique allows for the quantification of tot al PCBs in very small sample masses (approximately 25 mu g of dry tiss ue weight). Additional benefits include bioaccumulation studies in oth er benthic species as well as trophic transfer estimates between meibe nthos and higher trophic levels.