SEASONAL DYNAMICS OF HEAVY METALS CONTENT IN THE WELL WATER OF PRECARPATHIAN REGION

Abstract

The purpose of our study was to analyze the annual dynamics of heavy metals content in drinking water of Precarpathian region and to compare it with the standards of heavy metals content in water. The object of our study was well water in the region, where four areas depending on the specifics of the anthropogenic loading: industrial, recreational, agricultural and urban were defined for convenience. Each area differs by its level and type of pollution. To estimate the gross content of Zn, Mn, Fe, Cu, Pb, Co, Ni and Cd, the water samples were taken from 1-2 m depth, 10-fold concentrated using evaporation, and the content of heavy metals was determined with the method of atomic absorption spectrometry on the spectrometer С-115 at the wavelength corresponding the maximum absorption for each analyzed metal. The conducted researches showed that it is typical for the content of biogenic metals in the well water of recreational areas to increase in early spring, in the end of summer and in early autumn. The content of non-biogenic metals in the well water has peaks in early spring, in the midsummer and in the early autumn. On the industrial area, the concentration of biogenic metals in the well water increases from July till the end of studied period. The concentration of biogenic elements increases mostly in July but has the small peaks in October and in the end of winter period. The industrial activity do not result in exceeding the MPC of heavy metals. The well water of industrial area contains more iron and nickel comparing recreational area. On the other hand, the water of industrial area contains less zinc. The concentration of metals in well water of urban area, especially iron and nickel, is high in spring and in the autumn, but their concentrations does not exceed MPC level. The concentration of heavy metals in the well water of agricultural area is the same as for the industrial and urban areas with the increasing of metals content in autumn and winter and with the small peak in July. Iron, nickel and cobalt are mainly found in the water. Lead and cadmium, which are extremely toxic, were found in trace quantity. The conducted study permitted to find that the concentration of heavy metals in well water is determined by both the groundwater intake and by long-term accumulation in the biotic and abiotic components of water ecosystems. The general tendency is the decreasing the heavy metals concentration in abiotic components of water ecosystems during vegetation period of algae and hydrophytes and the rising of the concentration of metals in the end of the vegetation period. The exceeding of the background content for copper, iron, cobalt and nickel ions in the well water is the negative phenomenon.

Keywords: heavy metals, water, MPC, background quantity, Precarpathian region.