Geochemical Cs 137-decontamination of fish populations in a closed lake reservoir

A full-scale, 11 years long (1997-2007) experiment on the artificial introduction of potassium (as KCl) in a non-drainage lake as a countermeasure to the Cs 137 accumulation in fish has been performed. The K+ content in water has been increased from 1 to 10 mg/dm3, and, as a consequence, a stable decrease of Cs 137 in fish by 47-82% (red-eye on the average by 63-69%, roach and perch - 47-82, pike - 53-81%) has been recorded. An increase of the Cs 137 concentration in water from 3.8 to 10-18 Bq/dm3 due to radioactive cesium desorption from bottom sediments caused by excess potassium, has been noted as a side effect. (authors)