The distribution of Polychlorinated Biphenyls (PCBs) in the River Thames Catchment under the scenarios of climate change

• Published in: The Science of the total environment Vol. 533; pp. 187 - 195
• Main Authors: Lu, Qiong, Johnson, Andrew C., Jürgens, Monika D., Sweetman, Andy, Jin, Li, Whitehead, Paul
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 15.11.2015
• Subjects: Catchments; Climate Change; England; Environmental Monitoring; Fish; Fugacity; Geologic Sediments - chemistry; Mathematical models; PCBs; Polychlorinated biphenyls; Polychlorinated Biphenyls - analysis; River Thames; Rivers; Rivers - chemistry; Soil (material); Water Pollutants, Chemical - analysis; England; British Isles; British Isles, England, Thames R; Fugacity; PCBs; Climate change; Fish; River Thames
• ISSN: 0048-9697; 1879-1026
• DOI: 10.1016/j.scitotenv.2015.06.084

Measurements have shown low levels of PCBs in water but relatively high concentrations in the resident fish of the River Thames (UK). To better understand the distribution and behaviour of PCBs in the Thames river basin and their potential risks, a level III fugacity model was applied to selected PCB congeners (PCB 52, PCB 118 and PCB 153). The modelling results indicated that fish and sediments represent environmental compartments with the highest PCB concentrations; but the greatest mass of PCBs (over 70%) is likely to remain in the soil. As emissions decline, soil could then act as a significant secondary source of PCBs with the river bed-sediment functioning as a long-term reservoir of PCBs. The predicted changes in temperature and rainfall forecast in the UK Climate Projections 2009 (UKCP09) over the next 80years had only a modest influence on PCB fate in the model. The most significant result was a tendency for climate change to enhance the evaporation of PCBs from soil to air in the Thames catchment. [Display omitted] •The fate of PCBs in the Thames catchment was evaluated with a fugacity model.•We predict most PCB mass in soil, but highest concentrations in fish and sediment.•As primary emissions decline, soil could act as a major secondary source of PCBs.•The PCB levels in fish are expected to drop below the US EPA's threshold by the 2020s.•Climate change over a 80yr period had only a modest effect on fate.