RADIOACTIVE CONTAMINATION OF GROUNDWATER IN THE CHORNOBYL EXCLUSION ZONE: CURRENT STATUS, LONG-TERM TRENDS, AND CHALLENGES IN MONITORING SYSTEM MODERNIZATION

• Дата: 2026
• Автор: Бугай, Д.О.
• Формат: Стаття
• Мова: Англійська
• Опубліковано: Institute of Geological Sciences, NAS of Ukraine 2026
• Теми: Chornobyl Exclusion Zone; groundwater contamination; strontium-90; radionuclide migration; monitored natural attenuation; groundwater monitoring; radioactive waste disposal sites
• Онлайн доступ: http://geojournal.igs-nas.org.ua/article/view/355864
• Назва журналу: Geological journal

Groundwater contamination by radionuclides in the Chornobyl Exclusion Zone (CEZ) has been recognized since the early post-accident period (i.e., May – June 1986), when large-scale protective measures were implemented, as a potential pathway for the transport of radioactivity to the river network of the Pripyat–Dnipro basin. This study reviews long-term monitoring data and research results on radioactive contamination of groundwater in the CEZ, with particular attention to spatial patterns, temporal trends, and implications for monitoring and management strategies. Analysis of monitoring datasets for the period 1989–2024 shows that 90Sr remains the primary contaminant of concern in groundwater, with concentrations locally reaching 105–106 Bq m⁻³ in areas influenced by radioactive waste burial sites and contaminated water bodies. In contrast, 137Cs concentrations in groundwater are generally low, typically below 100 Bq m⁻³ and well below the drinking water standard. Long-term trends indicate an overall stabilization and gradual decline of 90Sr concentrations in the majority of monitoring wells over the last decade, reflecting depletion of the source term and natural attenuation processes in the vadose zone and aquifer. These observations, together with the results of modelling analyses reviewed in this paper, support the strategy of monitored natural attenuation (MNA) as an appropriate approach for managing contaminated groundwater in the CEZ, provided that reliable monitoring demonstrates plume stability and acceptable risk levels for potential receptors, including the Pripyat River. At the same time, the existing groundwater monitoring system has several limitations related to monitoring well design, spatial coverage, and sampling methodologies. Results from detailed polygon field studies show that higher radionuclide concentrations may occur in specific hydrogeological zones that are not adequately captured by the current monitoring network. The paper discusses priorities for modernization of the groundwater monitoring system in the CEZ, including optimization of monitoring objectives, improvement of monitoring well design and sampling methods, integration of geochemical and radiological observations, and development of updated methodological guidance. Modernization of the monitoring system will enable more reliable assessment of contaminant migration and provide a stronger scientific basis for longterm management of radioactive groundwater contamination in the CEZ.