Polychlorinated biphenyls (PCBs) in soils of the Moscow region: Concentrations and small-scale distribution along an urban–rural transect

In soils of the Moscow region, we examined PCB concentrations in bulk samples and aggregate fractions. Topsoils under grassland and forest at five locations along a southeast-bound transect from Moscow and at a northeastern background location (grassland only) were analysed. We collected aggregates1 cm and fractionated them into interior and exterior portions and also analysed the remaining soil without the aggregates1 cm. The concentrations of the sum of 17 PCBs (sigma17PCBs) in 35 bulk soil samples ranged from 3.1 to 42 microg kg(-1). This was 48-61% of the sigma33PCBs determined in 23 selected samples. The congeners 138(+158), 101 and 52 were most abundant. All PCB concentrations and the…