A sequential extraction procedure has been applied to study the speciation of Chernobyl-derived radionuclides (137Cs and 90Sr) in soils from Norway, and from Byelorussia and the Chernobyl region in the USSR. Most 137Cs (greater than 80%) was strongly associated with soil components, whereas 90Sr was more mobile, up to 70% being found in the easily extractable fractions. The 90Sr: 137Cs ratio decreased with the distance from the reactor, reflecting the higher proportion of hot particles deposited in the regions close to the reactor, and the easily extractable fraction of 90Sr was significantly lower in the soils collected from the Chernobyl area. The distribution of stable Cs and stable Sr in the extraction fractions was similar for the various sites. Therefore, the location-specific differences in the distribution of 90Sr and, to a lesser extent, 137Cs arise because of fallout speciation rather than because of local environmental factors.

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Metal and tributyltin (TBT) contaminated sediments are problematic for sediment managers and the environment. This study is the first to compare Fenton’s reagent and electrochemical treatment as remediation methods for the removal of TBT and metals using laboratory-scale experiments on contaminated dredged sediment. The costs and the applicability of the developed methods were also compared and discussed. Both methods removed > 98% TBT from TBT-spiked sediment samples, while Fenton’s reagent removed 64% of the TBT and electrolysis 58% of the TBT from non-spiked samples. TBT in water phase was effectively degraded in both experiments on spiked water and in leachates during the treatment of the sediment. Positive correlations were observed between TBT removal and the added amount of hydrogen peroxide and current density. Both methods removed metals from the sediment, but Fenton’s reagent was identified as the most potent option for effective removal of both metals and TBT, especially from highly metal-contaminated sediment. However, due to risks associated with the required chemicals and low pH level in the sediment residue following the Fenton treatment, electrochemical treatment could be a more sustainable option for treating larger quantities of contaminated sediment.

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