The method of water purification employing biosorbent of natural water reservoir, immobilized onto the fibrous carriers was suggested. The perifiton carriers were used for purification of natural water in Chernobyl zone canal falling into r. Dnieper. The developed onto carriers perifiton sorbs and holds radionuclides, their activity onto the biosorbent to be 3-4 order higher than that into the water. Both total and separate
Sr β-activities, were determined to control radionuclide accumulation. At water/sorbent ratio of 1,2 m
/kg water activity was found to be 0,42.10
Sr respectivelly. In this case, the purification degree was 90,5 i 90,2%, respectively. The advantages of the method suggested are ass follows: simple realization, environmental friendly, avoidance of the valuable expenditure and complex expensive equipment to produce the biosorbet, possipility of succesfully purification of large volumes of the radioactive contaminated natural flowing water.