Priority control factors screening for soil pollution with heavy metal in southwestern China from the view of source-specific environmental risk

Quantitative source apportionment of ecological and health risks is essential to identify the priority control factors for risk control of soil heavy metals (HMs). A total of 144 topsoil samples were collected from Southeastern Yunnan Province to explore sources using positive matrix factorization (PMF), and source-specific risks were then evaluated by combining PMF and probabilistic risk assessment. The results indicated agricultural activities (16.1%), industrial activities (37.3%), vehicle emissions (19.6%), and natural sources (27.1%) were potential sources for soil HMs. Probabilistic ecological risk assessment revealed that As (70.62%) and Cr (61.52%) had higher ecological risk compared with other soil HMs. Probabilistic health risk assessment indicated that noncarcinogenic risk descended in the order of children (91.73%) > teenagers (70.66%) > adults (13.29%) > older adults (14.64%). Children had the highest carcinogenic risk (90.21%), while the lowest carcinogenic risk (5.58%) was found for teenagers. Source-specific risk assessment showed that industrial activities contributed the most to the ecological and carcinogenic risks, followed by natural sources, agricultural activities, and vehicle emissions. Moreover, the contributors to noncarcinogenic risks were ranked in the decreasing order of industrial activities, agricultural activities, natural sources, and vehicle emissions. Thus, industrial activities, As and Cr were determined the priority control factor in this study. The results provided scientific information to propose the strategies for pollution prevention and risk control of soil HMs.