Polychlorinated biphenyls (PCBs) in UK and Norwegian soils: spatial and temporal trends.

Lead, Wendy A. and Steinnes, Eiliv and Bacon, Jeffrey R. and Jones, Kevin C. (1997) Polychlorinated biphenyls (PCBs) in UK and Norwegian soils: spatial and temporal trends. Science of the Total Environment, 193 (3). pp. 229-236. ISSN 0048-9697

Abstract

Contemporary soil samples from 46 sites across the UK and 12 sites in Norway have been analysed for a range of PCB congeners. Results show spatial differences, in terms of concentration and congener profile. The difference is partly caused by an increased proportion of the mid-molecular weight congeners in the samples from Norway. The soils from southern Norway and the UK contained similar amounts of PCBs per unit area: those from northern Norway contained lesser amounts. The possible influence of long-term air-soil exchange, latitudinal fractionation processes and differences in land management practices on the observed patterns is discussed. Archived soils (1951–1974) from the UK sites have also been analysed and the results show increasing concentrations of these compounds up to the late 1960s/early 1970s, after which there has been a substantial decline. This temporal trend is in accordance with that reported in previous studies. However, it is possible that some of the archived samples were contaminated in the process of air-drying. Due to this contamination artifact, it is not possible to ascertain whether the scale of the observed temporal differences truly reflect changes in the environment. The data are discussed in terms of possible spatial/temporal trends and the potential for air-soil exchange of these compounds.