Human health risk assessment and risk source analysis of arsenic in soil from a coal chemical plant in Northwest China

Abstract

Arsenic (As) is a potentially toxic element and poses risks to human health during coal chemical technology application. Human health risk of As in coal chemical industry was seldom reported. The results of As human health risk distribution for the entire coal chemical plant in our study may provide theoretical and practical support to reduce human health risk of As in coal chemical industry. We collected 153 soil samples with a chessboard sampling method in a coal chemical plant in northwestern China. Arsenic concentrations in the soil were measured with inductively coupled plasma mass spectrometry (ICP-MS) after the soil samples were digested. Human health risk of As was assessed through three exposure pathways including inhalation, skin contact, and oral intake. A human health risk distribution map of As for the entire plant was obtained by kriging method. The integrated carcinogenic risk of As in the soil was 8.59–13.31 times of the acceptable standard (1.00E-06), which was established by the Ministry of Environmental Protection of China, while the hazard quotient was within the acceptable range (< 1.00). Oral intake, through which 76.61% of the total carcinogenic risk was contributed, was the main pathway of As to human body and gave the smallest control threshold (1.59 mg kg−1) among the three exposure pathways. The smallest control threshold was recommended as the safety control threshold of As in this plant. Moreover, the highest carcinogenic risk and the largest hazard quotient were found in the Power Unit and its downwind direction (in the southeast of plant) because of As disposal and the local prevailing wind. In the present study, As spatial distribution in the soil was obtained. A map of As human health risk distribution for the entire coal chemical plant was obtained with kriging method based on limited sampling points, which was more robust compared with traditional methods. Arsenic human health risk sources were also analyzed. The results may be applied in the process of reducing human health risk of As in coal chemical industry.