这项研究的重点是列宁格勒州西部(卡累利阿地峡和索斯诺维·博尔镇附近地区)和圣彼得堡市的Vendian含水层的水文地质条件和地下水化学,地下水具有较高的放射性,但它是用于饮用水供应。有关放射特性的数据,对用于饮用的地下水质量估算中确定的数据进行了概括和分析。这些特征包括总α和总β活性以及天然放射性核素222Rn的比活,226Ra,228Ra,210Pb,210Po,238U,和234U。对数据进行了统计和相关性分析,以确定使用该含水层的地下水供应饮用水的卫生标准,并研究自然放射性背景的来源和形成过程。在大多数分析的井中,地下水质量标准均被超过。南部的咸水,更深,含水层系统的一部分被证明具有较高的放射性和相对较高的226Ra浓度,228Ra,210Pb,和210Po,与香港北部的淡水相比,其中较高的,虽然不统一,222Rn是典型的活性。由于宿主沉积物的较高放射性和地下水的化学性质,考虑了地下水的辐射特征与地下水放射性核素组成形成的原因之间的关系;根据含水层系统的沉降和水化学状态停滞的增加,从北到南的放射性和水化学背景地下水特征的变化进行了表征。对地下水中镭同位素浓度之间众所周知的关系进行了分析,宿主岩石中的铀和钍同位素,和地下水在含水层中的停留时间,连同可用现场数据与计算结果的比较,得出的结论是,所考虑区域主要部分的含水岩石中的铀浓度高于其区域平均值。
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 222Rn, 226Ra, 228Ra, 210Pb, 210Po, 238U, and 234U. 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 226Ra, 228Ra, 210Pb, and 210Po, compared with fresh water in the northern part of the territory, of which higher, though nonuniform, 222Rn 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.