Distribution of Polychlorinated Biphenyls (PCBs) and Toxic Equivalency of Dioxin-Like PCB Congeners in Rural Soils of Beijing, China

The soil quality in rural area may associate with the health of local residents and food safety. This study aimed to investigate the spatial and vertical distribution of PCBs in rural soils of Beijing, and the source identification of PCBs and toxic equivalency calculation of dioxin-like PCB congeners were conducted. The mean of total PCB concentrations in Beijing rural soils was 11.01 ng g-1. The congener profiles were predominated by lowly chlorinated congeners such as Di-CBs, Tri-CBs and Tetra-CBs. No significant difference of PCBs concentrations was observed between plain and mountain areas, and PCBs were slightly accumulated in the surface soils of Beijing rural area. Long-range transport of volatile PCB congeners was also an important source in addition to local sources of PCBs from electronic products. Toxic equivalency concentrations of dioxin-like PCB congeners met Canadian soil quality guidelines for agricultural soils, indicating a lower risk of PCBs to human health.