In conditions of increasing anthropogenic pressure on the objects of the natural environment, an objective assessment of the hydrochemical state of water bodies is necessary, taking into account background values of heavy metals, the presence of which is associated only with natural factors. Therefore, the aim of our studies was to determine the concentration of heavy metals in groundwater lying in different geological and geomorphological conditions in a territory remote from the large industrial centers – Dnipro and Pavlograd. As a result of the carried out researches it was possible to establish the qualitative and quantitative composition of microelements that are contained in the ground waters of Prisamarya Dniprovske. The most common microelements from those that were determined were zinc, strontium, iron and manganese. In the groundwater of the floodplain of the Samara River the most common are zinc, strontium, iron and manganese. A distinctive feature of the groundwater of the first above-terrace is the presence of a large amount of iron – an average of 2 mg/l3, while this is not observed in the groundwater of the floodplain and steppe areas. This can be attributed to the chemical characteristics of forest litter from needles which has an acidic pH reaction. In turn, with acid reaction, iron passes from the bound state to the free state and, together with the descending streams of water, migrates from the soil to the groundwater. Among the microelements of the second above-the-top terrace, zinc, copper, iron and manganese predominate. Other trace elements from those that were determined are absent, or their number is below the sensitivity limit of the device. With a deep bedding of groundwater (22 m) and their slow water exchange with surface waters among the microelements, zinc, cadmium, copper, nickel, cobalt, iron and manganese predominate. The direction of the migration of microelements in the system soil ↔ groundwater can be determined by calculating the concentration of chemical elements in the soil and groundwater contained. The concentrations obtained for lead, copper, nickel and manganese in the majority of the investigated objects turned out to be less than one, which indicates the predominance of processes of removal of microelements from soil to groundwater. At the same time for groundwaters of the first above-the-top terrace there is accumulation of such microelements as copper and manganese. Here the maximum value of the clark concentration for copper is 18.14, for manganese 14.66. Considering the absence of close proximity to the territory of the research of large industrial facilities and highways with intensive traffic, the indicators obtained by us can be used as background values in complex biogeocenological studies. In addition, the values obtained can be useful for assessing the hydrochemical and toxicological state of natural waters, as well as for the integrated ecohydrological assessment of water bodies in this region.
Seasonal dynamics of cadmium and plumbum in the Turia and Pripyat rivers
