RADIOACTIVE CONTAMINATION OF THE TECHA RIVER IN THE URALS

In the 1950's, the Techa River was contaminated with highly radioactiv e waste from the ''Mayak'' nuclear enterprise. The total discharge of radionuclides into the river is estimated as 10(17) Bq, including as m uch as 10(16) Bq each of Sr-90 and Cs-137. At present, the river's wat er and soils contain about 0.3 . 10(12) Bq of Sr-90, more than 6 . 10( 12) of Cs-137, and about 8.10(8) Bq of Pu-239, Pu-240. The estimate wa s made for the part of the river beginning 50 km from the site of the discharge and ending 240 m downstream, before the Techa River empties into the Iset River. The greater part of the discharged radionuclides has been deposited in a series of reservoirs in the upper reaches of t he Techa. The concentration of radionuclides in the water and soils of the Techa River decreases exponentially or according to an exponentia l function with distance.