Review of historical monitoring data on Techa River contamination

The Mayak Production Association (MPA) was the first Russian site for the production and separation of plutonium. The extensive increase in plutonium production during 1948-1955, as well as the absence of reliable waste-management technology, resulted in significant releases of liquid radioactive waste into the rather small Techa River. It resulted in chronic external and internal exposure of about 30,000 residents of riverside communities. The paper presents main historical data on Techa River radioactive contamination: Mayak complex operating history, available information on source-term and environmental monitoring data. Analysis of the available historical monitoring data indicates that the following reliable data sets can be used for reconstruction of doses received during the early periods of operation of the MPA: temporal pattern of specific beta activity of river water for several sites in the upper Techa region since July 1951; average annual values of specific beta activity o f river water and bottom sediments as a function of downstream distance for the whole river since 1951; gamma-exposure rates near the shoreline as a function of downstream distance for the whole Techa River since 1952; gamma-exposure rate as a function of distance from the shoreline for several sites in the upper and middle Techa since 1951