The Distribution and Health Risk Assessment of Potential Toxic Elements in Atmospheric Deposition from Ion-Adsorption Rare Earth Mining Areas in the Ganzhou City of Southeast China

Abstract

Potential toxic elements (PTEs), including Pb, Cr, Cd, Ni, Cu, As, and Mo, are common pollutants in ion-adsorption rare earth mines (IAREEMs), and atmospheric deposition is an important method of PTE migration. However, the level of PTE atmospheric deposition in and around IAREEMs remains unknown. We established 25 stations at typical sites in the Ganzhou city of southeast China. An exposure assessment model was used to evaluate the health risks for adults and children. The results show that the concentration and fluxes of atmospheric deposition of PTEs follow the order of Pb > Cu > Cr > Ni > As > Mo > Cd, and most PTEs present no human health risk. However, due to the high toxicty of As, it poses both carcinogenic and non-carcinogenic risks to children as indicated by the analysis of an exposure assessment model of heavy rare earth minerals in Longnan county, Ganzhou city. The As concentration in atmospheric deposition ranged from 3.18 to 251.87 mg kg−1, and the As atmospheric fluxes in atmospheric deposition ranged from 0.11 to 39.4 mg m−2 y−1. This is because As-rich materials (e.g., arsenic-adsorbing clay zones and chernovite-(Y) (Y[AsO4])) are exposed in fully weathered layers, and the formed suspended particulate matter is transported into the atmosphere at Longnan county. Consequently, restoring vegetation to reduce particulate matter transport is an important method for controlling the spread of pollutants. These results provide significant insights into pollution characteristics and prevention in and around mining areas under the influence of atmospheric deposition.

Keywords

• atmospheric deposition
• potential toxic elements
• health risk assessment
• ion-adsorption rare earth mining
• Ganzhou city of southeast China