Spatial distributions and risk assessment of PCDD/Fs, PCBs, and PCNs in soil collected from South Korea

Polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), polychlorinated biphenyls (PCBs), and polychlorinated naphthalenes (PCNs) are three groups of structurally similar POPs. Among these POPs, 17 PCDD/Fs and 12 dioxin-like PCBs (dl-PCBs) have been investigated more widely due to their high toxicity to biota and humans. Several PCNs could have similar toxicity to PCDD/Fs and dl-PCBs. The Korean Ministry of Environment has conducted annually nationwide monitoring of them in soil since 2008. In this study, soil samples at 61 national POPs monitoring stations in suburban, urban, and industrial areas were collected. After Soxhlet extraction and cleanup using multi-layer silica gel column, the pollutants were analyzed using GC/HRMS. The mean TEQ concentrations of PCDD/Fs, PCBs, and PCNs (3.25??4.40, 0.42??0.83, and 0.08??0.13 TEQ pg/g, respectively) in the industrial area were higher than those in the other areas. The sum of TEQ concentrations (PCDD/Fs+PCBs+PCNs) in some industrial stations (Banwol, Incheon, and Ulsan, Yeochun, and Pohang) were higher than those of the soil quality guideline from Canada (4 pg TEQ/g). Health risk assessments through ingestion, dermal contact, and inhalation intake were also performed using Korean data. As a result, cancer risks via the ingestion intake were higher than those from the others. The total cancer risks in the industrial area (mean: 3.34??10-7 for children and 3.07??10-7 for adults) were higher than those in other areas. However, cancer risks from the soil samples of South Korea were not exceeded the carcinogenic bench mark level described by US-EPA (1??10-6), suggesting the safe level