Reconstruction of the Long-Term Dynamics of Particulate Concentrations and Solid–Liquid Distribution of Radiocesium in Three Severely Contaminated Water Bodies of the Chernobyl Exclusion Zone Based on Current Depth Distribution in Bottom Sediments

A Konoplev ,Dmitry Samoilov,Gennady Laptev,Kyrylo Korychenskyi,Hrigoryi Derkach,Hlib Lisovyi,Serhii Kirieiev,Kenji Nanba,Yasunori Igarashi ,Valentin Protsak

doi:10.3390/land11010029

A Konoplev , Dmitry Samoilov + Show 8 more

Open Access

https://doi.org/10.3390/land11010029

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Abstract

Given the importance of understanding long-term dynamics of radionuclides in the environment in general, and major gaps in the knowledge of 137Cs particulate forms in Chernobyl exclusion zone water bodies, three heavily contaminated water bodies (Lakes Glubokoe, Azbuchin, and Chernobyl NPP Cooling Pond) were studied to reconstruct time changes in particulate concentrations of 137Cs and its apparent distribution coefficient Kd, based on 137Cs depth distributions in bottom sediments. Bottom sediment cores collected from deep-water sites of the above water bodies were sliced into 2 cm layers to obtain 137Cs vertical profile. Assuming negligible sediment mixing and allowing for 137Cs strong binding to sediment, each layer of the core was attributed to a specific year of profile formation. Using this method, temporal trends for particulate 137Cs concentrations in the studied water bodies were derived for the first time and they were generally consistent with the semiempirical diffusional model. Based on the back-calculated particulate 137Cs concentrations, and the available long-term monitoring data for dissolved 137Cs, the dynamics of 137Cs solid–liquid distribution were reconstructed. Importantly, just a single sediment core collected from a lake or pond many years after a nuclear accident seems to be sufficient to retrieve long-term dynamics of contamination.

Highlights

Thirty-five years after the Chernobyl nuclear power plant (ChNPP) accident, studies of radioactive contamination of water bodies continue to be of importance and relevance due to the need to understand long-term processes and dynamics
Closed and semi-closed lakes and ponds were found to be most sensitive to radioactive contamination, as evidenced by numerous studies conducted in the Chernobyl contaminated areas [1,2,3,4,5] and the Fukushima Dai-ichi nuclear power plant zone [6,7,8,9,10], as well as in the PA Mayak area [11,12,13] and in the USA including Savannah River site [14,15,16]
Despite a vast number of studies of radionuclide behavior in such water bodies, most of them lacked broad temporal coverage and did not deal with long-term changes in radionuclide concentrations. This is especially true for particulate concentrations in the Chernobyl zone water bodies, with the monitoring system primarily focused on dissolved concentrations as being the most important in terms of radionuclide mobility and bioavailability [17,18]

Summary

Introduction

Thirty-five years after the Chernobyl nuclear power plant (ChNPP) accident, studies of radioactive contamination of water bodies continue to be of importance and relevance due to the need to understand long-term processes and dynamics. Despite a vast number of studies of radionuclide behavior in such water bodies, most of them lacked broad temporal coverage and did not deal with long-term changes in radionuclide concentrations. This is especially true for particulate concentrations in the Chernobyl zone water bodies, with the monitoring system primarily focused on dissolved concentrations as being the most important in terms of radionuclide mobility and bioavailability [17,18]. This study, to our knowledge, is the first attempt to apply the approach for lakes and artificial pond

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