Assessment of the radiation quality of groundwater with an increased uranium isotope ratio 234U/238U (Pre-Volga region, European Russia)

The article is devoted to assessing the radiation quality formation of groundwater with anomalous excesses of 234 U on example the Pre-Volga region (European part of Russia). It was found that exceeding the reference values of groundwater radiological toxicity in a number of cases is associated with anomalously high activity of 234 U. Isotopic ( 2 H, 18 O) and chemical data indicate that the anomalous 234 U/ 238 U ratios are of cryogenic origin related to the effects of past climatic fluctuations on the aquifers. Such groundwater formed from thawed permafrost at extremely low uranium concentrations may have unsatisfactory radiological quality due to anomalous excesses of 234 U.