Residues of endocrine-disrupting PCBs in drinking water-influence of water and wastewater treatment in Szczecin (Poland)

Drinking water is subjected to several stages of treatment, but it can still retain residues of endocrine-disrupting compounds. These include polychlorinated biphenyls (PCBs). The aim of this study was to assess the efficiency of water and wastewater treatment processes on reducing residues of endocrine-disrupting PCB congeners in drinking water and treated wastewater. The analyses were performed with liquid-liquid extraction and gas chromatography coupled with mass spectrometry. PCB congener residues were found in 18% of the drinking water samples. The water treatment process reduced the content of these compounds within a wide range of 4% to 100%. Estimates of consumer exposure to these compounds from drinking water consumption accounted for as much as 30% of the tolerable weekly intake (TWI). The wastewater treatment process reduced the concentration of PCB congeners by 38-98%, with trace contents in the treated wastewater (from 0.02 center dot 10-6 to 6.21 center dot 10-6 mg/l).