Types and Source Apportionment of Polycyclic Aromatic Hydrocarbons (PAHs) in Soil-Groundwater of a Closed Coking Plant in Shanxi Province, China

To clarify the impact of coking industry activities on the soil-groundwater Polycyclic aromatic hydrocarbon (PAH) occurrence, a typical coking site in Shanxi Province was taken as the study area, and soil and groundwater samples were collected to analyze the pollution level, composition, and distribution of PAHs in soil-groundwater. The sources of PAHs in the study area were identified based on the positive matrix decomposition model (PMF); the health risks of PAHs were calculated based on the carcinogenic and non-carcinogenic health risk model from the Technical Guidelines for Risk Assessment of Soil Pollution for Construction Land (HJ 25.3-2019) and toxicity equivalent quantity (TEQ). The results showed that Sigma PAHs of soil ranged from 0 to 6077.7 mg/kg, with an average value of 198.02 mg/kg; Sigma PAHs of groundwater ranged from 0 to 18.30 mg/L, with an average value of 9.39 mg/L. In horizontal distribution, Sigma PAH content and types in the tar processing area were much higher than those in the surrounding area, and PAHs might migrate to the southwest through infiltration; in vertical distribution, Sigma PAH content reached a peak at 5 m underground. According to the PMF model results, four primary sources of Sigma PAHs were identified, which were the coking production source (55.0%), coal and petroleum combustion source (22.6%), atmospheric deposition source (13.1%) and residents living source (9.3%). The total average aPAH carcinogenic and non-carcinogenic health risks of soil in the study area were 7.05 x 10(-6) and 0.695; the average TEQ(BaP-Sigma PAHs) was 1.650 mg center dot TEQ/g; as for groundwater, they were 3.08 x 10(-6) and 32.04; the average TEQ(BaP-Sigma PAHs) was 9.390 mu g center dot TEQ/L, indicating that PAHs both in soil and groundwater had potential health risks. This study provides a basis for the same coking site type for pollution control, secondary utilization, and data support for future site restoration.

Automated summary

This study investigated the impact of coking industry activities on the occurrence of Polycyclic aromatic hydrocarbons (PAHs) in soil and groundwater. A typical coking site in Shanxi Province was studied, and soil and groundwater samples were collected for analysis. The results showed high levels of PAHs in the tar processing area, with potential migration to the southwest. Four primary sources of PAHs were identified, including coking production, coal and petroleum combustion, atmospheric deposition, and residents' activities. The study also calculated the health risks of PAHs and found potential risks in both soil and groundwater. This research provides valuable information for pollution control and site restoration of similar coking sites.