Radioactive contamination of the Techa River in the Urals

In the 1950s, the Techa River was contaminated with highly radioactive waste from the open-quotes Mayakclose quotes nuclear enterprise. The total discharge of radionuclides into the river is estimated as 1017 Bq, including as much as 1016 Bq each of 90Sr and 137Cs. At present, the river's water and soils contain about 0.3·1012 Bq of 90Sr, more than 6·1012 of 137Cs, and about 8·108 Bq of 239,240Pu. The estimate was 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 the Techa. The concentration of radionuclides in the water and soils of the Techa River decreases exponentially or according to an exponential function with distance