Application of potassium chloride to a Chernobyl-contaminated lake: modelling the dynamics of radiocaesium in an aquatic ecosystem and decontamination of fish

Abstract

This study tests a whole-lake experiment to reduce the bioaccumulation of radiocaesium (137Cs) in fish in lakes contaminated by the Chernobyl accident. In many lakes in the Chernobyl contaminated areas, radiocaesium activity concentrations in fish are still significantly higher (up to 100 times in some species) than acceptable limits for human consumption. Estimates of the long-term rate of decline of 137Cs in fish in these regions, in the absence of countermeasures, show that radioactivity in fish in some lakes may remain above acceptable consumption limits for a further 50-100 years from the present date. In February 1998 we applied 15 t of potassium chloride to Lake Svyatoe, Kostiukovichy. The addition of potassium chloride fertilizer to the lake resulted in a decrease in activity concentration of 137Cs to approximately 40% of pre-countermeasure values in a number of different fish species. In contrast to Lake Svyatoe, 137Cs activity concentrations in fish from four control lakes showed no systematic decrease over the study period. Simplified models for transfers of 137Cs in lakes successfully 'blind' predicted the changes in 137Cs in water and fish resulting from this major alteration of the potassium concentration of the lake. The experiment represents the first test of a predictive model for the dynamics of radiocaesium in response to a major perturbation in potassium (its major competitor ion) in a whole lake ecosystem.

Observed half-lives of 3H, 90Sr and 137Cs in hydrosphere in the Vltava River basin (Bohemia)

“…This CF range also corresponds with the data published by other authors, e.g. Smith et al (2002Smith et al ( , 2003, found the CF values in the range between 0.1 and 10 m 3 /kg. The data set of 90 Sr was insufficient for assessing the trends in the 90 Sr concentration.…”

The influence of a whole-lake addition of stable cesium on the remobilization of aged 137Cs in a contaminated reservoir

“…The ratio of 137 Cs atoms displaced to the number of 133 Cs atoms added in Pond 4 was greater than the ratios of 137 Cs atoms displaced to K atoms added in Lake Kostiukovichy (Smith et al, 2003) where the addition of 1.0!10 29 K atoms resulted in the displacement of approximately 5.2!10 18 137 Cs atoms in the first year following the addition. An approximate ratio of one 137 Cs atom displaced per 1.9!10 10 K atoms.…”

“…The addition of K to Lake Kostiukovichy (Smith et al, 2003) was performed to test the effectiveness of K additions as a remediation technique to reduce 137 Cs concentrations in biota. The K addition resulted in a 10-fold increase in K concentrations and a 50% reduction in 137 Cs concentrations in fish despite a 3-fold increase in 137 Cs concentrations in the water.…”

“…The K addition resulted in a 10-fold increase in K concentrations and a 50% reduction in 137 Cs concentrations in fish despite a 3-fold increase in 137 Cs concentrations in the water. The greater availability of K in the water column reduced the 137 Cs uptake in biota despite an increased 137 Cs concentration in the water (Smith et al, 2003).…”

“…Numerous such manipulations have occurred (Hakanson and Andersson, 1992;Smith et al, 2001), but 137 Cs concentrations in the water were apparently only measured for the K addition experiment in Lake Kostiukovichy (Smith et al, 2003). This K addition resulted in increased 137 Cs concentrations in the water.…”