Levels, congener profile and inventory of polychlorinated biphenyls in sediment from the Songhua River in the vicinity of cement plant, China: a case study.

This study investigated the contamination levels, homologue, and congener profiles and evaluated the residue inventory of polychlorinated biphenyls (PCBs) in sediment of the Songhua River in the vicinity of cement plant. The total concentration of detected 35 PCB congeners ranged from 1.12 to 2.19 ng/g dry weight (dw) in sediment, with a mean value of 1.56 ng/g dw, and the concentration of PCBs decreased in the following order: the downstream > cement plant > upstream. The results of total organic carbon (TOC)-normalized PCB concentrations indicate that the sediments have low potential ecological risk in this area. The study results on homologue and congener of PCBs show that the emissions from cement production could be the major sources of PCBs in sediment, and the low-chlorinated PCBs will be exchanged among air, water, and sediment with increasing temperature during summer and flow to downstream with water during the wet season. The spatial density and total burden of PCBs in the surface sediments were 17.2 ng/cm(2) and 1.2 kg, respectively. To our knowledge, this study is the first to explore the pollution characteristics of unintentionally produced PCB emissions from cement industry by means of monitoring sediment samples.