Polychlorinated biphenyls in two typical landforms of Southern Anhui province, China: Sources, air-soil exchange, and risk assessment

Polychlorinated biphenyls (PCBs) were detected in the atmosphere and soil of Southern Anhui, China. The average concentration of ∑26PCBs in the atmosphere along the Yangtze River (YR) was 32 pg m−3, and was higher than that in the HuangShan Mountain (HM) which was 17 pg m−3. The average soil concentrations of ∑26PCBs along the YR and in the HM were 1.6 and 1.3 ng g−1, respectively. The mean percentages of tri-CBs were less than 40% in both air and soil samples. The percentages of penta- and hexa-CBs in air and soil samples were relatively higher than those in Chinese commercial PCBs and unintentionally produced PCBs. These homologue patterns indicated that PCBs in the environmental matrices of Southern Anhui might originate from other distant sources. In southern Anhui, most highly chlorinated congeners presented net gaseous deposition from air to soil, while lower chlorinated congeners preferred net volatilization from soil to air. PCBs in the environmental matrices of the HM were diluted with increasing altitude, suggesting that PCBs in this region might origin from some external sources, and be transported to the HM by atmosphere. Half of the sampling sites along the YR and one site in the HM had the cancer risks for ∑26PCBs through the inhalation exposure higher than acceptable risk level of 10−6. Only one sampling site had the cancer risk for ∑26PCBs through the accidental soil ingestion >10−6.