[Pollution Characteristics and Health Risk Assessment of Polychlorinated Biphenyls in E-waste Disposal...

To study the characteristics of polychlorinated biphenyls (PCBs) in waste residue-soil-vegetable in an e-waste dismantling area and the potential health risks to humans, three samples of e-waste residue were collected, and 10 and 18 samples were taken from farmland soil and vegetables (six lettuce, six green bean, and six cabbage samples), respectively, next to the waste residue. High-resolution gas chromatography-mass spectrometry was used to detect the content of PCBs in waste residue, soil, and vegetables. The results showed that the total PCBs levels were as follows:waste residue (11938 ng·g^-1, dw) > soil (45.54 ng·g^-1, dw) > vegetables (11.51 ng·g^-1, dw). The bio-sediment/soil enrichment factor values were as follows:lettuce samples (0.18) > green bean samples (0.05) > cabbage samples (0.01). There were 37 PCB identical homologues detected in the waste residue and soil, and 33 types were detected in vegetables, all of which were within the homologues detected in the waste residue and soil. Some homologues in the soil were correlated with cabbages (P<0.05). The column chart of PCB chlorination number in waste residues, soil, and vegetables showed that low-chlorinated biphenyls from trichlorobiphenyl to pentachlorobiphenyl mass fraction accounted for the largest proportion, accounting for 77.92%, 59.73%, and 73.96%, respectively. The proportion in the soil was relatively low, with the overall proportion showing a downward trend with increasing rate of chlorine generation. The results of the health risk assessment showed that the total HQ of PCBs in the soil and vegetables exposed to adults (male/female) and children was less than 1, which was at an acceptable level. The total CR of PCBs in the soil and vegetables exposed to adults (male/female) and children all exceeded 1×10^-6, which is at an unacceptable level, and the values for adults (male/female) were higher than those for children.