Concentrations of PCBs in agricultural soils of typical regions in Pearl River Delta
珠江三角洲典型地区表层农田土壤中多氯联苯残留状况

A total of 384 soil samples were collected from surface agricultural soils of typical regions of Pearl River Delta,China.Six common congeners of PCBs(PCB28,PCB52,PCB101,PCB138,PCB153 and PCB180) were analyzed.The results showed that the detection frequency of Σ6PCBs was 78.13% and the average concentration of Σ6PCBs was 0.42 μg/kg.Both the detection frequency and the average concentration of PCB138 were higher than those of the other PCBs.There were differences among the concentrations of six PCBs in soil.The detection frequency of PCB101 was lowest(10.16%),but its average concentration was up to 0.11 μg/kg owing to PCB101 of 32.44 μg/kg found in one soil sample,which suggested the heavy soil pollution around the site.There were the significant linear correlations of the concentration of PCB52 with soil organic matter and clay content.It could be also derived that there was the correlation between the concentration of low chlorinated PCBs and soil physicochemical properties.High chlorinated PCBs were easily concentrated in typical sites and their concentration might be much higher than that of low chlorinated PCBs.