PCDD/PCDF pollution in soils and sediments from the Pearl River Delta of China

This study reported detection of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) for 62 soil samples and 3 sediment samples collected from the Pearl River Delta, a rapidly industrialized and highly populated area of South China. The results show that the PCDD/F concentrations ranged from 97.6 to 9,600 ng kg−1 and that the average total concentrations of PCDD/Fs are 1311, 2504, 1320 and 2335 ng kg−1 (dw), and 1.24, 3.99, 4.80 and 2.63 ng WHO1998–TEQ kg−1 for the samples collected from remote mountains, suburban areas, industrial areas, and residential/commercial areas, respectively. The WHO1998–TEQ values calculated for 17 soil samples are higher than 4 ng kg−1 but lower than 20 ng kg−1, whereas the WHO1998–TEQ values calculated for the remaining 45 samples are lower than 4 ng kg−1. According to the Canada soil quality guideline, the PCDD/F concentrations in 27.4% of the tested soil samples in this study are greater than the Canadian background concentrations, and the PCDD/F concentrations for the remaining soil samples (73.6%) are lower than the Canadian background concentration.