Potential implications of future climate and land-cover changes for the fate and distribution of persistent organic pollutants in Europe

Paul, Alexander G. and Hammen, Volker C. and Hickler, Thomas and Karlson, Ulrich G. and Jones, Kevin C. and Sweetman, Andrew J. (2012) Potential implications of future climate and land-cover changes for the fate and distribution of persistent organic pollutants in Europe. Global Ecology and Biogeography, 21 (1). pp. 64-74. ISSN 1466-822X

Abstract

Aim  Climate change is having far-reaching effects on the global environment. Here, the ALARM (Assessing Large-scale Risks for Biodiversity with Tested Methods, European Union 6th Framework Programme) climate change scenarios were used to assess changes to the fate of selected persistent organic pollutants (POPs). Scenarios detailing climate and land-cover changes, such as precipitation, temperature and vegetation cover, were used as input in a European multi-media chemical fate model to help understand their impact on the environmental fate and behaviour of POPs over the period 1990–2100 in Europe.Location  Europe.Methods  Chemicals chosen for study included four classical POPs (two polychlorinated biphenyl congeners and two polybrominated diphenyl ether congeners). Using 30-year time steps, the model was run in steady-state mode four times for each chemical and each ALARM scenario.Results  PCB153 displayed the greatest changes, with a reduction in burden of up to 40% in some Mediterranean compartments (e.g. soil and fresh water) under the worst case climate change scenario. The overall continental persistence of PCB153 was reduced by 1.5 years (12%) due to increased volatilization and degradation in air from a drier and warmer south-western Europe. This predicted loss resulted in a transfer and redeposition to the cooler and wetter north-eastern Europe, and increased the burden of PCB153 to Arctic compartments by up to 22%. The remaining chemicals displayed less pronounced changes, particularly under more the sustainable scenarios.Main conclusions  Overall, the model simulations suggest that the dominant driver behind differences seen between the present and climate-changed future scenarios is temperature, resulting in a slight shift in chemical distribution from surface compartments to the air. This subsequently leads to a reduced continental persistence for PCBs and a north-easterly migration due to prevailing meteorological conditions. As a result of these calculations, it is reasonable to conclude that chemicals with properties similar to PCBs may experience enhanced mobility due to climate change. However, the climate-induced temperature changes were not large enough to significantly alter the distribution of brominated diphenyl ethers (BDEs), which are less volatile and have greater enthalpies of phase change.