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Abstract Groundwater at legacy nuclear facilities around the world is contaminated with radionuclides including strontium-90 and technetium-99, which are often present as co-contaminants. Here we investigated whether biostimulation of indigenous microbial communities by glycerol phosphate can co-treat 90Sr through incorporation into phosphate biominerals, and 99Tc through microbially-induced reduction of the sediment to form less mobile Tc(IV) phases via reaction with reduced species (e.g. Fe(II)). Results showed that 95% of Sr was removed from solution in sediment microcosms treated with glycerol phosphate, and sequential extraction showed that ~18% of the Sr in the resulting solid phase was associated with the pH 5 Na-acetate fraction and 75% was in the ion exchangeable fraction. This removal and partitioning to recalcitrant phases during glycerol phosphate treatment was greater than in the untreated controls, where only 60% of Sr was removed from solution, and of the solid-associated Sr, 95% was present in the exchangeable fraction. Fitting of Sr K -edge EXAFS spectra confirmed these findings, with shell by shell fitting suggesting ~30% of sediment-associated Sr was present in a coordination environment consistent with phosphate biominerals following glycerol phosphate treatment, whilst Sr was present only as outer-sphere complexes in the controls. In addition,16S rRNA sequencing of sediments stimulated with glycerol phosphate demonstrated the growth of potential phosphate-solubilising species such as Chryseobacterium and Serratia spp. Finally, glycerol phosphate treatment stimulated bioreduction via addition of electron donor in the form of glycerol to the system, in turn this stimulated the removal of 99Tc from solution concomitant with microbial Fe(III) reduction to form poorly soluble hydrous Tc(IV)O 2 like phases. In sediments amended with an electron donor, the microbial community also reflected the onset of bioreduction with an increased relative abundance of Fe(III) and sulfate-reducing bacteria such as Geothrix , Geobacter and Desulfobulbus spp. Overall these results suggest application of glycerol phosphate offers a promising bioremediation strategy to co-treat both 90Sr and 99Tc contaminated groundwaters, and promotes the formation of Sr-phosphate and Tc(IV) bearing biominerals when reducing conditions are maintained. Combined with past work which shows the scavenging of uranium from solution following addition of glycerol phosphate, this extends the scope for glycerol phosphate as a treatment for radioactive contamination in groundwaters. [ABSTRACT FROM AUTHOR]

Uniqueness of radioecological situation in Ukraine is due to the presence of large areas of peat soils spread, for which abnormally high rates of radioactive cesium in plants are observed. Even in 30 years after the Chernobyl accident, agricultural products exceeding the requirements of AS-06 on peat soils with levels of contamination by 137Cs of about 37 kBk/m2 is produced. Developed and tested traditional antiradiation measures did not receive, due to some circumstances, the state support for the contaminated area. Therefore, we proposed alternative approaches to improve the radioecological situation on the contaminated peat soils.

Averaged assessments of radiological effectiveness dynamics of mineral fertilizers of long-term application at the late phase of ChNPP accident have been carried out on the base of 3-5-years experiments. The influence of mineral fertilizers, used in different doses for agricultural plants, has been shown for intensity of 137Cs accumu-lation by plants on various soil-climatic conditions of radioactively contaminated territory of the Ukraine.

Uniqueness of radioecological situation in Ukraine is due to the presence of large areas of peat soils spread, which observed abnormally high rates of radioactive cesium plants. Even in 30 years after the Chernobyl accident on peat soils with levels of contamination by 137Сs about 37 kBk/m² agricultural products exceeding the requirements of AS-06. Developed and tested traditional antiradiation measures are not received due to circumstances, state support for the contaminated area. Therefore, we proposed different approaches to improve the radioecological situation on the contaminated peat soils. [ABSTRACT FROM AUTHOR]

Averaged assessments of radiological effectiveness dynamics of mineral fertilizers of long-term application at the late phase of ChNPP accident have been carried out on the base of 3-5-years experiments. The influence of mineral fertilizers, used in different doses for agricultural plants, has been shown for intensity of 137Cs accumulation by plants on various soil-climatic conditions of radioactively contaminated territory of the Ukraine. [ABSTRACT FROM AUTHOR]

The legislative framework allows HSE to regulate contaminated land on licensed sites. HSE considers land and materials contaminated with radioactivity to be radioactive waste and will regulate it accordingly. Licensees should address contaminated land in their strategies formanaging radioactive wastes. Safety cases to justify those strategies should show what options have been considered and that risks imposed on present and future generations will be as low as reasonably practicable. [ABSTRACT FROM AUTHOR]