Environmental and human health risks associated with soil potentially toxic element exposure around the largest coal fired power plant in Southern Russia

The combustion of solid fuel at power plants pollutes adjacent areas with potentially toxic elements (PTEs), which increases risks to public health in the vicinity of these facilities. With an installed electric capacity of 2258 MW, the Novocherkassk Power Plant (NPP) is the top electric energy producer in Southern Russia. This facility is located in the vicinity of one of the largest cities in the Rostov Region, Novocherkassk, with a population of 168,035 people. Among the major cities in the region, Novocherkassk is characterized by the maximum level of atmospheric pollution. The study was conducted at 12 monitoring sites laid along the radii emanating from the NPP chimneys. The sites were located in the near-source influence zone (up to 3 km) in various directions and at greater distances (from 3 to 20 km) downwind. In this study, various indicators of environmental quality (geoaccumulation index (Igeo), pollution index (PI), and Nemerow pollution index (NPI)) as well as human health risk model (US EPA 1989) were applied to identify spatial distribution and to evaluate risks of seven PTEs (Cr, Mn, Ni, Cu, Zn, Cd, and Pb) in soils. The results demonstrate the relationship between the features of atmospheric circulation and PTE content in soils within the NPP impact zone. The main pattern in spatial distribution of soil pollution is a decrease in the concentrations of PTEs with distance from the source. The influence of NPP can be traced out to approximately 7 km downwind. The total content of PTEs in the soils slightly exceed the Clarke values for the upper continental crust, as well as the world average concentrations of these elements in soils (up to two times). Moderate to high pollution by Cd and Pb, according to the Igeo, is characteristic of the soils at a distance of up to 3 km to the NPP. The PI also demonstrates higher pollution estimates relative to distance from the source; soils in impact zone of NPP are characterized by low or no pollution by Cr, Mn, Ni, Cu, and Zn, and moderate pollution by Cd and Pb. Soils located in the leeward zone are moderately polluted with Ni and Zn and very strongly to strongly polluted with Cd and Pb. According to the NPI values, pollution decreases from heavy in the area immediately downwind of the source to slight for most of the territory under consideration. The risks of noncarcinogenic effects on children are assessed as low, their occurrence is attributed to the intake of Mn, Ni, and Pb, while for adults there was no significant general toxic risk associated with the intake. The total carcinogenic risk to human health slightly exceeds the permissible standard for soils in close vicinity of the enterprise due to the potential intake of Ni, Cd, and Pb.

The reported study was funded by RFBR, project number 19-05-50097 and Grant of President of Russian Federation, no. МК-6137.2021.1.5.