Evaluation and Spatial Diffusion of Health Risk of Persistent Organic Pollutants (POPs) in Soils Surrounding Chemical Industrial Parks in China

ABSTRACT

A case study of the cancer risk to humans posed by persistent organic pollutants (POPs) in an industrial area of China, which has a long history of contamination from many sources, is presented. Relatively great concentrations of POPs around the chemical industrial parks have the potential to be chronically carcinogenic to local people. Sixteen individual PAHs listed for priory control by the U.S. Environmental Protection Agency (USEPA), metabolites of DDTs, and isomers of HCHs were measured in soils and a human health risk assessment was conducted by use of USEPA exposure models for children and adults, respectively. Geostatistical methods were used to simulate the spatial diffusion of potential carcinogenic risk, and non-parametric Mann-Whitney U and Kruskal-Wallis tests were employed to analyze the impact of point sources on the surrounding area. The mean value of the sum of Excess Lifetime Cancer Risk (∑ELCR) exceeded the generally acceptable risk level of 1.0E-06 recommended by the USEPA for carcinogenic chemicals. The maximum ∑ELCR was 2.9E-04 for children, which was observed inside the chemical industrial parks. Contamination at the chemical industrial parks caused significant spatial diffusion of ELCR values caused by PAHs, DDT, and HCH.

Key Words:

• persistent toxic substances
• carcinogenic risk
• soil exposure
• spatial distribution

ACKNOWLEDGMENT

This study was supported by the National Basic Research Program of China (“973” Research Program) with Grant No.2007CB407307 and the Knowledge Innovation Program of the Chinese Academy of Sciences, with Grant No. KZCX2-YW-420-5. Prof. John Giesy's participation in the program was supported by the Einstein Professorship program of the Chinese Academy of Science.

Notes

^aCarcinogenic compounds.

^aSF available from Integrated Risk Information System (IRIS 2008).

^bWeight-of-Evidence classified as B₂ class; probable human carcinogen.

^cWeight-of-Evidence classified as C class; possible human carcinogen.