An Assessment of the Impact of the Mining Industry on Soil and Plant Contamination by Potentially Toxic Elements in Boreal Forests

Abstract

This study was conducted in the territory of the industrial site of the Udachny Mining and Processing Division (Yakutia, northeast Russia). The objects of study were permafrost soils and two species of shrubs (Betula middendorffii T. and Duschekia fruticose R.). Soil and plant samples were analyzed using atomic absorption spectrometry for the presence of PTEs (Pb, Ni, Mn, Cd, Co, Cr, Zn, Cu, and As). The bioaccumulation factor (BAF), frequency of occurrence (Hi), pollution index (PI), and pollution load index (PLI) were calculated. The PI and PLI are calculated for both soil and two plant species for the first time in this study. The results showed that the soils have a high Ni, Cr, Co, As, and Mn content. It has been established that high soil pollution naturally leads to an increase in the concentration of elements in the leaves of shrubs. The soils and vegetation are dominated by elements associated with trap magmatism—Cr, Co, Cu, and dolerite dikes—Mn and Zn. For Betula middendorffii, the PLI was classified as unpolluted to moderately polluted, and Duschekia fruticosa. was classified as unpolluted. The high level of contamination is typical for areas located near industrial sites, such as waste dumps, kimberlite pipes, tailings ponds, and roads. The BAF results confirmed that the leaves of Betula middendorffii are able to accumulate more PTEs and have the highest level of resistance to PTE contamination in mining environments. This analysis showed that the consistent application of the PI, PLI, and BAF indices is very efficient in the ecological and biogeochemical assessment of the situation in industrial development areas.