Migration of radioactive contaminants discharged into the Yenisei river by the Krasnoyarsk mining and chemical complex

Abstract. Cooling waters from three reactors have been discharged into the Yenisei since 1958. Radioactive monitoring of water and bottom sediments was based on systematic observation at stationary monitoring sites and field studies. Regular observations were carried out in the near zone of the discharge and at measuring sections 250, 370 and 890 km far from the discharge point. The major contributors to water radioactive contamination were 2 4 Na, "P, 4 6 Sc, 5 4 Mn, s l C r and 6 5 Zn. At a distance of 15 km from the point of discharge of cooling waters, the concentrations of short-lived radionuclides were 10-100 times and those of long-lived radionuclides 100-1000 times lower the levels set by standards of radioactive safety. The studies of interface distribution in the river water suspended material system show that only 2 4 Na, 5 1 Cr and 3 2 P move in the liquid phase in the river water, whereas l j 7 Cs is evenly distributed between the suspended material and the liquid phase, most radionuclides moving primarily with the suspended material. Chemical forms of isotopes occurrence in water were determined. 1