SPATIAL DISTRIBUTION OF THE CONTENT OF HEAVY METALS IN THE BELAYA RIVER ECOSYSTEM

Abstract

This paper presents the results of the research on the content and spatial distribution of heavy metals in the system of “water – bottom sediments” of the Belaya River. Quantitative data were obtained and the authors performed comparative analysis of the pollution of various abiotic environments of the river ecosystem. The pattern of vertical distribution of heavy metals in bottom sediments is shown to be linked to the level of pollution and conditions of the river flowage. Concentration of dissolved and suspended forms of the studied elements (the content of Fe, Mn, Cu, Pb, Zn, the oxidation-reduction potential, рН, turbidity and water temperature) in water samples from different gauge stations of the Belaya River is characterized by heterogeneity. There is a clear tendency for the increase of the content of Fe, Mn, Zn, and Cu down the river flow with the maximum concentrations in the foothill zone of the Republic. The studied heavy metals have prevalence of the suspended form of migration. Concentration of heavy metals in bottom sediments is considerably uneven in their distribution in different sites of the Belaya River. Bottom sediments are noticeably polluted with Zn and Pb at the village of Ministochnik, the aul of Bzhedugkhabl, and at the river mouth. In the lower watercourse of the Belaya River, contamination of bottom sediments with Cu prevails. In the gauge stations with low content of heavy metals, their vertical distribution is quite homogenous. In less polluted parts of the river, flowage plays an important role in vertical distribution of heavy metals. For example, with weak flowage (the part of the river from the village of Ministochnik to the aul of Bzhedugkhabl), the highest concentrations are in the surface layers of 0-10 cm in comparison to the layer of 10‒30 cm. With strong flowage (Dakhovskaya stanitsa), the lowest content of heavy metals is in the upper layer of 0‒10 cm, and the highest is in the layer of 10‒30 cm.