RESUMO
Concentration profiles of polychlorinated biphenyls (PCBs) and toxicity risks of dioxin-like PCBs were investigated in soils collected from a capacitor-burial site. Based on the USEPA model of human health risk assessment, cancer and non-cancer risks for these soils were also estimated when used for residential and industrial purposes. It was observed that the average concentrations of total PCBs (sigma PCBs, 22 congeners) in the soils were 6.23, 19.3, and 1 540 mg x kg(-1) at different depths of 0-30 cm, 30-100 cm, and 200-250 cm, respectively. Tri-CBs and Tetra-CBs were the largest contributors to the total concentrations in the soils, making up 75.7%-94.0%. The toxic equivalent concentration (TEQs) of total PCBs was up to 457 microg x kg(-1), and PCB 126 had the highest contribution. Health risk assessment showed that under residential land uses, children was the most sensitive receptor although cumulative non-carcinogenic risks for both children and adults (0.927-1 760) nearly exceeded the acceptable level, while under industrial land uses except for the topsoil, the total non-carcinogenic risks for workers exceeded the acceptable level. Under residential and industrial land uses, PCBs in the soils had high carcinogenic risks that were more than the acceptable level of carcinogenic risks (10(-6)-10(-5)). Inhalation exposure was the major way subjected to the carcinogenic risk as well as to the non-carcinogenic risk, regardless of children, adults, and workers involved.
