PCBs in sludge: development of a practical extraction procedure and its application in an urban water resource...

Sludges originating from water resource recovery facilities act as a sink for various contaminants including polychlorinated biphenyls (PCBs). Investigation of such pollutants provides detailed information about the pollutant burden of the region from which incoming wastewater is derived. However, the current extraction methods for PCBs in wastewater and sludge are both time- and solvent-consuming. Therefore, the purposes of this study were to develop a practical PCB extraction procedure and to monitor PCB levels in sludge originating from an urban water resource recovery facility (WRRF). Procedure applicability was shown by comparing the extraction results of certified reference materials with that of Soxhlet and by checking surrogate recovery. Diethyl ether, hexane, and hexane:acetone mixture were evaluated as the PCB extraction solvent; hexane was the most efficient solvent with the recovery results (89 to 102%) in an acceptable range of 70 to 130%. The PCB concentrations of the WRRF sludges were in the range of 3.6 ± 0.3 to 64.4 ± 9.3 μg/kg dry matter.