Characteristics of Historical Underground Storage Sites of Capacitors Containing Polychlorinated Biphenyls
2022
Cui, Yong | Ning, Yuhang | Chen, Guo | Zhang, Lei | Wang, Xin | Cheng, Weiguo | Hou, Haimeng | Zhang, Chong | Wang, Jian
Historical underground storage sites for decommissioned capacitors containing polychlorinated biphenyls (PCBs) were import sources of high-concentration PCB contaminants. However, few studies have delved into the characteristics of these sites. We investigated the wastes and cleaned-up soil, soil PCB contamination, and potential risks of 16 underground PCB-capacitor storage sites in China. Among these sites, PCB leakage occurred at all the sites with direct burial (six sites) and brick structures (three sites) and at three out of the seven sites with cement structures. From each site, an average of 60.7 t of wastes and contaminated soil were cleaned up, and the contaminated soil accounted for an average of 65.5% of the total wastes. The maximum contents of total PCBs, 12 dioxin-like PCBs (DL-PCBs), and 7 indicator PCBs (ID-PCBs) in the soil samples of each site were 51–30,700 mg/kg, 1.1–379.7 mg/kg, and 2.3–10,340 mg/kg, respectively. The total PCB and PCB congener contents in soil showed clear short-range heterogeneity as differences of up to orders of magnitude were found within a short distance (e.g., 2 m). Based on the human health risk assessment model, the maximum risks of all the sites were above the acceptable risk level (10⁻⁶). More than a half of the samples within different sites showed higher risks as per calculations with total PCB contents than for calculations with DL-PCB contents, indicating that only focusing on DL-PCBs may underestimate the potential risks for PCB-capacitor storage sites.
显示更多 [+] 显示较少 [-]