UDC

Authors

Abstract

Tracers are the powerful tool to clarify the conceptual models of groundwater and the management strategy, including the conservation practices. They can provide substantial support for the identification and modeling of a pollutant flux as well as its transit time distribution and transfer into the aquifers. We studied groundwater samples in wells and springs of the sandy and carbonate deposits of the Northern Dvina depression at the junction zone of the Mezen syneclise and the Fennoscandian Shield. In assessing of old groundwater of the age of more than two thousand years and δ13С > –13 ‰ (δ13С is an indicator characterizing the ratio of carbon isotopes 13C and 12C in a sample compared to the standard) on a first approximation we can use a relatively simple Ingerson and Pearson model. The Mook model is most suitable when δ13С < –13 ‰. However, if the calculated value of the original radiocarbon activity in the collecting area exceeds 102.5 pmc we also use the Ingerson and Pearson model. The results of radiocarbon dating allowed us to identify the most vulnerable developing areas of fresh groundwater from the surface contamination in the quaternary deposits and coal formations, as well as the areas of the least mineralized groundwater in the Vendian Padun Formations. The radiocarbon age of these waters is defined as “modern”; for a more precise dating the short-lived isotopes should be used. Mineral waters are of the Late Pleistocene age; they can be contaminated from the surface only through the boreholes in case of technical defects in the construction and operation. Therefore, to determine the causes of long-term changes in the chemical and isotopic composition of these waters we should analyze the hydrodynamic and hydrochemical conditions in the aquifer system.

Keywords

References

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