Characterization and Risk Assessment of PolychlorinatedBiphenyls in City Park Soils of Xi’An, China

Polychlorinated biphenyl (PCB) concentrations in surface soil samples (0–10 cm) from 23 city parks (8 urban and 15 suburban) from Xi’An, China were presented. The average concentration of R7 PCBs among all the sites was 1.68 ng g-1 dry weight. High detection frequency (100 %) of PCB 28 and PCB 52 suggested wide occurrence of PCB contaminations in Xi’An. Among these PCBs, PCB 28, 52 and 153 were the most dominant compounds (14.9 %, 39.3 % and 9.5 % of the R7 PCBs on average, respectively). ‘‘Urban fractionation effect’’ was found in Xi’An. In other words, PCB concentrations were higher in the urban city park soils than those in suburban park soils. The PCB contamination in Xi’An city park soils were at a low level based on the Dutch guideline. However, dioxinlike PCB congeners were detected from 12 parks, which indicated further investigation was urgently required in future. Furthermore, total PCB concentrations were used to evaluate the cancer risk via ingestion, dermal and inhalation and the results showed that the total cancer risk was at the very low level in this area.