Uncertainty Analysis of Human Health Risk Assessment of Soils Contaminated with High Concentrations of Arsenic in a Coal Chemical Industry Area in Northwest China

In this study, high-concentration arsenic pollution was used as the research object. The As content of 12 soil samples collected in a large coal chemical area in northwest China was determined by inductively coupled plasma mass spectrometry (ICP-MS). Then, based on The technical guidance of risk assessment of contaminated sites (HJ15.3-2014), we analysed the carcinogenic risk of high-concentration As and, on this basis, carried out uncertainty analysis on the risk assessment of different exposure pathways. For 12 sampling points, the risk of oral intake of soil particles exceeded 10(-6), while skin contact with soil and inhaled soil particles also exceeded the recommended value of carcinogenic risk by 10(-6), and the total cancer risk was over 10(-5). Monte Carlo simulation was used to analyse the carcinogenic risk of the typical high-concentration arsenic-contaminated coal-to-olefin sampling area at the site. The results showed that the probability of an output level below 10(-6) decreased as the concentration of the contaminant increased, and the risk distribution range increased as the concentration of the pollutants increased. The results of 10,000 Monte Carlo simulations showed that the single-contaminant arsenic was more likely to cause cancer risk by oral intake of soil, and its lowest carcinogenic risk value reached 1.58 x 10(-5), which is much higher than the risk standard value of 10(-6). Therefore, the uncertainty of the proposed parameters had an impact on the assessment results, but after carefully determining the values of the sensitive soil parameters for the high-risk areas, the risk assessment results still exceeded the recommended values. Changes in a small number of conditions in high-concentration arsenic-contaminated areas cannot reduce the harm to human health and must be of great concern. In short, the site has high levels of human health risks due to soil arsenic pollution. The area should be marked as an arsenic risk control area to prevent possible risks to human health.

Automated summary

This study focused on high-concentration arsenic pollution and analyzed the carcinogenic risks associated with different exposure pathways in a coal chemical area in northwest China. The results showed that oral intake, skin contact, and inhalation of arsenic-contaminated soil particles all posed risks exceeding recommended values. Monte Carlo simulations indicated that the risk of arsenic-induced cancer was significant, emphasizing the need for risk control measures in the contaminated area.