RADIOACTIVE CONTAMINATION OF THE TECHA RIVER, THE URALS

The Techa River in the Urals was contaminated with high-level radioactive waste from the MAJAK nuclear installation around 1950. The total discharge to the river amounted to 100 PBq with Sr-90 and Cs-137 contributing approximately 10 PBq each. This study has shown that the river presently contains approximately 0.3 TBq Sr-90, >6 TBq Cs-137, and approximately 8 GBq Pu-239, Pu-240. The estimates were made for the part of the river starting 50 km from the point of discharge and ending 240 km downstream at the confluence with the Iset River. Radioactivity was measured only in the upper 0.10-m sediments layer. The external dose rates from the contamination range from 0.1-30 muGy h-1. The activity concentrations decrease exponentially or by power functions with distance.