Spatial distribution of polychlorinated biphenyls in soil around a municipal solid waste incinerator

The impact of a typical municipal solid waste incinerator (MSWI) on polychlorinated biphenyl (PCB) concentrations in the surrounding soil was studied. Six stack gas samples were taken from the MSWI and 21 soil samples were collected from sampling sites between 300 and 1700 m from the MSWI stack. The total (sigmaPCB) concentrations of dioxin-like (dl) PCBs and indicator PCBs in the stack gas samples were between 3.41 and 34.3 ng/m3, and the corresponding toxic equivalents (TEQs) ranged from 4.45 to 66.9 pg WHO-TEQ/m3, with a mean of 28.6 pg WHO-TEQ/m3. A total of 2.43 g WHO-TEQ of PCBs per year was calculated to be released into the environment from MSWIs in China. The sigmaPCB concentrations in the soil samples ranged from 28.0 to 264.4 pg/g, with mean and median values of 127.6 and 127.7 pg/g, respectively, while the TEQ values were between 0.020 and 0.18 pg WHO-TEQ/g, with mean and median values of 0.074 and 0.062 pg WHO-TEQ/g, respectively. Comparing this study with other studies performed around the world suggest that PCB emission from incinerators has a critical influence on PCB concentrations in the surrounding soil. An exponential function equation is proposed, which indicates a clear decline in sigmaPCB concentrations with increasing distance from the stack. A contour map created using an ordinary kriging interpolation technique showed that a limited area (< or = 1250 m radius) from the stack was clearly influenced by PCB emission from the MSWI.