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oa Analysis of Increasing 90Sr Migration with Groundwater from the Chornobyl NPP
- Publisher: European Association of Geoscientists & Engineers
- Source: Conference Proceedings, 18th International Conference Monitoring of Geological Processes and Ecological Condition of the Environment, Apr 2025, Volume 2025, p.1 - 5
Abstract
Paper shows the conditions for the formation of high 90Sr concentrations in the interval of neutral or close to neutral (pH = 6.5–7.5) groundwater of the industrial site of the Chernobyl nuclear power plant, based on samples from well 21-1A. It is shown that high volumetric activities of 90Sr in the range of 50–2550 Bq/L in groundwater are formed under the influence of ionic strength (IS). According to long-term monitoring observations at the ChNPP industrial site, the dynamics of 90Sr activity concentration increase in observation wells almost coincides with the dynamics of groundwater IS increase from “background” values of 2–5 mmol/L to maximum values of 18.2 mmol/L. High volumetric 90Sr activities of groundwater simultaneously or with some advance accompanied by high values of ionic strength, as well as concentrations of chlorine, nitrate, sulfate, bicarbonate, potassium and sodium ions. The concentrations of calcium ions also fluctuate in synchrony with the dynamics of 90Sr distribution. Such dynamics indicates that 90Sr and anions and cations move with groundwater at the same speed, i.e., practically without being sorbed, as is typical for chloride ion (CI), nitrate ion (NO3), sulfate ion (SO4 2−), bicarbonate ion (HCO3) and other anions. Reduction of sorption properties of soils occurs due to the influence of groundwater ionic strength, which exceeds the value of 10–12 mmol/L.