Ecological Monitoring of the Unal Depression, Northern Ossetiya–Alania, Using Techniques of Biogeochemical Indication

Abstract

The paper presents analysis of the accumulation of toxic and vital chemical elements in discrete links of the food chain under conditions of a biogeochemical province in relation to the accumulation of phytochelatins and metallothioneins in the leaves of white birch (Betula pubescens). Gradients of metal concentrations are determined in the soils with increasing distance from the Unal tailing dump and the effects of these gradients on the concentrations of the elements in birch leaves. Correlations are determined between the concentrations of toxic elements in the pulp and leaves separately for the native sample and water washout. A strong correlation was found between the total dissolved concentration of all metals and the total metallothionein and glutathione concentrations. It is hypothesized that the biochemical system of glutathione is more closely related to the accumulation of metals by plants than the system of metallothioneins. Estimates are made whether it is possible to apply the method of bioindication of the ecological state of a territory by determining the fluctuating asymmetry of birch leaves. This bioindication parameter was evaluated separately for each of the cardinal points. It is demonstrated that a high total concentrations of the metals in soils and birch leaves is correlated with an increase in the fluctuating asymmetry of the leaves and the concentration level of sulfur-bearing biological active compounds. The bioindication technique is however still far from perfect and is difficult to apply and, hence, requires further studies.