Conceptual model and results of long-term radioecological monitoring of the effect zone of liquid discharges from the Beloyarsk nuclear power plant

Relevance. The long-term use of the Olkhovsk bog as a natural filter on the way of the liquid discharges of the Beloyarsk Nuclear Power Plant (BNPP) led to radionuclide contamination of the Olkhovsk bog-river system that became a source of secondary pollution.

Intention. To assess the radioecological state of the BNPP liquid waste zone based on a special system for monitoring environmental pollution by long-lived radionuclides.

Methodology. Samples of water, bottom sediments, and soils were studied at the reference points of the bog-river system.

Results and Discussion. Over the 35 years of the BNPP operation, pollution of the upper layers of bottom sediments has decreased due to redistribution of radionuclides with surface runoff, depth migration and radioactive decay. After the reconstruction of discharges, the removal of radionuclides into open hydrographic network decreased by 2–3 times and amounted to 48.2 ∙ 10⁶ Bq ∙ year^–1 for ⁹⁰Sr and 94.8 ∙ 10⁶ Bq ∙ year–1 for 137Cs. The migration of radionuclides to adjacent Olkhovsk bog-river system territories is still limited by the coastal strip of flooded soils.

Conclusion. Radioecological situation in the Olkhovsk bog-river system is potentially dangerous. Migration processes (movement of the pollution front along the drain vector) can result in increased transfer of radionuclides into an open hydrographic network and require constant monitoring. For a balanced assessment of the radiation hazard of Olkhovsk bogriver system, it is necessary to assess current stocks of radionuclides.

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