St. Petersburg Division, Sergeev Institute of Environmental Geology, Russian Academy of Sciences, Srednii Prosp. 41, St. Petersburg, 199004, Russia; Institute of Earth Sciences, St. Petersburg State University, Universitetskaya nab., 7-9, St. Petersburg, 199034, Russia.
St. Petersburg Division, Sergeev Institute of Environmental Geology, Russian Academy of Sciences, Srednii Prosp. 41, St. Petersburg, 199004, Russia; Institute of Earth Sciences, St. Petersburg State University, Universitetskaya nab., 7-9, St. Petersburg, 199034, Russia.
J Environ Radioact. 2023 Aug;264:107189. doi: 10.1016/j.jenvrad.2023.107189. Epub 2023 May 9.
The study is focused on the hydrogeological conditions and the chemistry of groundwater of the Vendian aquifer in the western part of the Leningrad oblast (Karelian Isthmus and the area near Sosnovy Bor town) and St. Petersburg City, where groundwater features higher radioactivity, but nevertheless it is used for drinking water supply. Data on the radiological characteristics, which have been determined in the estimation of the quality of groundwater used for drinking are generalized and analyzed. These characteristics include the gross alpha and gross beta activity and the specific activity of natural radionuclides Rn, Ra, Ra, Pb, Po, U, and U. The data were subjected to statistical and correlation analysis to determine the hygienic criteria for the use of groundwater of this aquifer for drinking water supply and to study the sources and the processes of formation of the natural radiological background. Groundwater quality standards were shown to be exceeded in the majority of the analyzed wells. The brackish water in the southern, deeper, part of the aquifer system was shown to have higher radioactivity and relatively high concentrations of Ra, Ra, Pb, and Po, compared with fresh water in the northern part of the territory, of which higher, though nonuniform, Rn activity is typical. Relationships between the radiation characteristics of groundwater are considered along with the causes of formation of groundwater radionuclide composition as a result of the higher radioactivity of the host deposits and the chemistry of groundwater; changes in the radiological and hydrochemical background groundwater characteristics from the north to the south are characterized in accordance with the subsidence of the aquifer system and an increase in the stagnation of the hydrochemical regime. The analysis of the well-known relationship between the concentrations of radium isotopes in groundwater, uranium and thorium isotopes in the host rocks, and groundwater residence time in the aquifer, along with the comparison of the available field data with calculation results, suggested the conclusion that the concentration of uranium in the water-bearing rocks in the major portion of the area under consideration is higher than its regional mean values.
本研究聚焦于列宁格勒州西部（卡累利阿地峡和索斯诺夫博尔镇附近地区）和圣彼得堡市维典含水层的水文地质条件和地下水化学特性。尽管这些地区的地下水放射性较高，但仍被用于饮用水供应。本文综合分析了用于饮用水的地下水质量评估中所确定的放射性特征数据。这些特征包括总α和总β活度以及天然放射性核素 Rn、Ra、Ra、Pb、Po、U 和 U 的比活度。对数据进行了统计和相关性分析，以确定该含水层地下水用于饮用水的卫生标准，并研究天然放射性本底的形成来源和过程。研究结果表明，在分析的大多数井中，地下水质量标准均超标。与北部地区的淡水相比，南部较深含水层系统的半咸水放射性更高，Ra、Ra、Pb 和 Po 浓度相对较高，而北部地区的Rn 活度较高，尽管非均匀分布。考虑到放射性特征之间的关系以及形成地下水放射性核素组成的原因，包括母岩的较高放射性和地下水化学性质的变化，从北到南的地下水放射性和水化学背景特征的变化特点为含水层系统沉降和水化学状态停滞加剧。分析了地下水、母岩中铀和钍同位素以及地下水在含水层中滞留时间之间的镭同位素浓度的已知关系，并将可用的现场数据与计算结果进行比较，结果表明，考虑区域内大部分地区的含水岩石中铀的浓度高于其区域平均值。
