Transformation of Fresh Groundwater Composition over Time in the Republic of Tatarstan

Abstract

The spatio-temporal variability of fresh groundwater composition was analyzed in four regions with different natural and technogenic conditions. The results obtained show no significant changes in the groundwater composition of the agricultural areas over the last 60 years. As for the industrial oil refinery zone, intense groundwater pollution was observed only in the nearby areas of sludge reservoirs and waste landfills. However, it did not extend further than 1.0–1.5 km in the direction of the filtration flows. This is partly due to the high buffer capacity of the geological environment. In the areas with intensive oil production, the composition of fresh groundwater changed most negatively over long distances. Depending on the temporal concentration gradients, the following four degrees of change in the groundwater composition were distinguished: extremely weak, weak, medium, and high. The latter two were typical of the central parts of the oil-bearing areas, with the groundwater mineralization in the upper part of the section reaching 10 g/L and the hardness of 70 mmol/L.

Keywords

• groundwater composition variability
• groundwater pollution
• agricultural areas
• industrial oil refinery zone
• oil-bearing areas
• concentration gradients
• buffer properties of geological environment
• industrial waste landfills