FEATURES OF THE FORMATION OF HIGH STRONTIUM CONCENTRATIONS IN DRINKING GROUNDWATER NEAR THE SEA COAST

Estimates of strontium concentration factors in groundwater have been carried out in various regions of the world, however, as a rule, analyzes and interpretations were carried out for the entire set of hydrochemical data, without separating water samples with high and low strontium content. Therefore, correlations were often approximate. This study summarizes a new approach to the use of non-traditional tracers, including carbon and uranium isotopes, to study areas that are promising for drinking water supply. Water samples were divided into two clusters according to the content of strontium: 1) more than 7 mg/l, 2) less than 7 mg/l, and the goal was to understand the features of the formation of Sr concentrations for each cluster separately. It was found that in the samples of the first cluster there is a high correlation of Sr and total mineralization, along with a correlation of Sr with SO\(_{4}^{{2 - }}\), which may be due to high concentrations of Sr in carbonates with a high content of gypsum and celestite. The dedolomitization processes and the presence of reducing conditions in aquifers also have an effect. An increase in Sr concentrations due to upwelling of brackish water is not confirmed. In samples from the second cluster, low concentrations of Sr are associated with oxidative conditions in aquifers. No correlation was found between Sr and total mineralization due to low and discrete concentrations of gypsum and celestite in carbonates. There was no effect of dedolomitization. The upwelling of brackish water, on the contrary, can have a significant effect on the increase in Sr concentrations.