Health Risk Assessment of Groundwater Contaminated by Oil Pollutants Based on Numerical Modeling

To provide theoretical support for the protection of dispersed drinking water sources of groundwater, we need to accurately evaluate the time and scope of groundwater pollution hazards to human health. This helps the decision-making process for remediation of polluted soil and groundwater in service stations. In this study, we conducted such an evaluation by coupling numerical modeling with a health risk assessment. During the research, soil and groundwater samples were collected and analyzed for 20 pollutants. Fifty-six percent of the heavy contaminants and 100% of the organic contaminants exhibited maximum values at the location of the oil depot. Gray correlation analysis showed that the correlation between background samples and soil underlying the depot was 0.375-0.567 (barely significant to insignificant). The correlation between the reference sequence of other points was 0.950-0.990 (excellent correlation). The correlation of environmental impact after oil depot leakage followed the order: organic pollutants > heavy metals > inorganic pollutants. The groundwater simulation status and predictions indicated that non-carcinogenic health risks covered 25,462 m² at the time of investigation, and were predicted to extend to 29,593 m² after five years and to 39,873 m² after 10 years. Carcinogenic health risks covered 21,390 m² at the time of investigation, and were predicted to extend to 40,093 m² after five years and to 53,488 m² after 10 years. This study provides theoretical support for the protection of a dispersed drinking water source such as groundwater, and also helps the decision-making process for groundwater and soil environment improvement.