ORGANOCHLORINE CONTAMINANTS IN DOUBLE-CRESTED CORMORANTS FROM GREEN-BAY, WI .1. LARGE-SCALE EXTRACTION AND ISOLATION FROM EGGS USING SEMI-PERMEABLE MEMBRANE DIALYSIS

A 41.3-kg sample of double-crested cormorant (Phalacrocorax auritus) e gg contents was extracted, yielding over 2 L of egg lipid. The double- crested cormorant (DCC) egg extract, after clean-up and concentration, was intended for use in egg injection studies to determine the embryo toxicity of the organic contaminants found within the eggs. Large-scal e dialysis was used as a preliminary treatment to separate the extract ed contaminants from the co-extracted sample lipids. The lipid was dia lyzed in 80 x 5 cm semi-permeable membrane devices (SPMDs) in 50-ml al iquants. After the removal of 87 g of cholesterol by freeze-fractionat ion, the remaining lipid carryover (56 g) was removed by 100 routine g el permeation chromatography (GPC) operations. A 41,293-g sample was t hus extracted and purified to the extent that it could easily be place d at a volume of 5 mi, the volume calculated to be necessary for the e gg injection study. Analyses were performed comparing contaminant conc entrations in the final purified extract to those present in the origi nal egg material, in the extract after dialysis and cholesterol remova l, and in the excluded materials. Recoveries of organochlorine pestici des through dialysis and cholesterol ranged from 96% to 135%. Total po lychlorinated biphenyls in the final extract were 96% of those measure d in the original egg material. Analysis of excluded lipid and cholest erol indicated that 92% of the polychlorinated dibenzo-dioxins and -fu rans were separated into the final extract.