A Large-sample Extractor for Determining Organic Contaminants in the Great Lakes

"The construction and operation of two large-sample extractors onboard the CSS Limnos are described. They were used to extract water samples of approximately 50-L volume with dichloromethane during the monitoring cruises on lakes Erie, Huron, Ontario and Superior in early 1986. Both whole water and clarified water were extracted. The dichloromethane extracts were later analyzed for organochlorines, chlorobenzenes, polychlorinated biphenyls, and polynuclear aromatics by the National Water Quality Laboratory in Burlington, Ontario. A solution containing surrogate standards was continuously added at a fixed rate to the water being extracted. The recoveries of these surrogates provide a continuous measure of the extraction efficiency and reproducibility of the analytical process, and confirm that the processes used are valid"--Abstract, p. v.