Persistent organic pollutants (POPs) in the topsoil of typical urban renewal area in Beijing, China: Status, sources and potential risk

Abstract

In order to assess the health risk of persistent organic pollutants (POPs) in the topsoil of a typical urban renewal area, a comprehensive study was conducted to determine their spatial distribution, possible sources and potential carcinogenic risk. Topsoil samples were collected from former chemical industrial areas in south-east Beijing and tested for concentrations of POPs, including polycyclic aromatic hydrocarbons (PAHs), organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs). The concentration of PAHs ranged from 126.68 to 365926.17ng/g, OCPs ranged from 2.38 to 933.12ng/g, and PCBs ranged from 47.04 to 3883.77ng/g. The spatial distribution of POPs was mapped using a geographic information system (GIS) to identify hotspots. Although PAHs, OCPs and PCBs varied in terms of their concentration and spatial distribution, the sources of each type of POPs were identified using multivariate statistical analysis and the diagnostic ratios method. Total lifetime carcinogenic risk (TLCR) for PAHs, OCPs and PCBs exposure was evaluated quantitatively for each sampling site using the Risk Assessment Guidance for Superfund (RAGS) methodology, and a risk distribution map was created. The TLCR values of 76% sites for the PAHs were higher than the target level for individual excess lifetime cancer risk (10−6) and with 12% sites were higher than the acceptable levels (10−4) for residential cancer risk. There are 28% sites that have TLCR above 10−6 for recreational exposure to PAHs.