Distribution of trace metals and an environmental risk assessment of the river sediments in the area of the Lomonosov diamond deposit (NW Russia)

This article is devoted to the study of trace metals in the bottom sediments of watercourses in the area of the developed Lomonosov diamond deposit, which is the largest industrial diamond deposit in Europe. Samples of river sediments were taken from the Zolotitsa River and all its tributaries in the area of the diamond deposit. In addition, samples of kimberlites and rocks were selected from the quarries. It was established that the average concentration of metals in all types of rocks extracted from the quarries was significantly higher than that in river sediments and naturally decreased in the following order: kimberlites (D-3-C-2), Vendian enclosing rocks (V-2) and overlying Quaternary and Carboniferous deposits (Q and C-2). The results suggest that the mining and beneficiation complex plays a significant role in increasing the metal content in the river sediments, which is reliably recorded by the change in the physicochemical parameters of river sediments due to the anthropogenic impacts. The heavy metal pollution in river sediments in the area of Lomonosov diamond deposits is due to three main factors: (1) the discharge of quarry water into the peatbog-filtration fields and then into the river, (2) erosion of the rock dumps and natural factors and (3) the process by which the products from the weathering of kimberlites are transferred to the riverbed, and this transfer process requires further clarification. The results of this research can provide management references for the pollution control of the diamond mining industrial zone and the prevention of basin environmental risks.