Between Underground and the Deep Blue Sea: Contamination of Mine Water Effluents by Polychlorinated Biphenyls (PCBs)

Abstract

Polychlorinated biphenyls (PCBs) were used as industrial chemicals due to their beneficial physicochemical properties in many applications until the recognition of their adverse effects. Although being banned for decades, PCBs are still ubiquitous in the environment due to their congener-specific high persistence and their ongoing remobilization from contaminated sites. While mining influenced water (MIW) was generally known to be a potential source of PCB contamination, hardly anything was known about concentrations, congener patterns, or PCB loads. For further elucidation of environmental risks, 14 MIW samples from five mine water effluents were analyzed for a set of 58 PCB congeners and biphenyl by a specifically optimized SPME-GC-MS method (LOD 0.004-0.58 ng L-1). As a result, 53 mono- to heptachlorinated congeners could be detected in concentrations of 0.01-25.9 ng L-1 per congener, of which mainly tri- but also di- and tetrachlorinated PCBs were identified in higher concentrations. Total PCB concentrations (0.02-0.12 mg m-3) and annual loads (0.1-0.7 kg PCBs a-1 per mine) show the relevance of MIW as an additional point source for PCB release to the environment. Implementation of water treatment is recommended to achieve a decrease in these contaminant loads in agreement with worldwide efforts to eliminate PCBs.