Long-term variation of Sr-90 and Cs-137 in environmental and food samples around Qinshan nuclear power plant, China

Environmental radioactivity monitoring in the surroundings of nuclear facilities is important to provide baseline data for effective detection in case of any radioactive release in the region. In this work, we report for the first time the long-term monitoring data of Cs-137 and Sr-90 in environmental and food samples around Qinshan nuclear power plant in 2012-2019. The distribution levels, temporal variations and source terms of Cs-137 and Sr-90 in the investigated samples were discussed. The annual effective dose (AED) for the local population from the ingestion of foods was also evaluated. Peak values of Sr-90 and Cs-137 concentrations and Cs-137/Sr-90 activity ratio were observed in total atmospheric deposition in 2016 and some water and food samples in the following years. This seems to be associated to an additional radioactive input, mostly likely from the operational release of a local facility. This demonstrates that Sr-90 and Cs-137, especially the Cs-137/Sr-90 activity ratio, are sensitive indicators for detecting potential radioactive releases. Nevertheless, overall Sr-90 and Cs-137 activity concentrations measured during 2012-2019 in this work were at the background levels with average AED far below the internationally permissible limit and recommendation.