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

Yiyao Cao,Hong Ren,Zhiqiang Xuan,Yaoxian Zhao,Meibian Zhang,Dongxia Zhang,Xiangjing Gao,Zhongjun Lai,Zhixin Zhao,Shunfei Yu,Peng Wang,Xiaoming Lou

doi:10.1038/s41598-021-00114-y

Abstract

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 137Cs and 90Sr in environmental and food samples around Qinshan nuclear power plant in 2012–2019. The distribution levels, temporal variations and source terms of 137Cs and 90Sr 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 90Sr and 137Cs concentrations and 137Cs/90Sr 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 90Sr and 137Cs, especially the 137Cs/90Sr activity ratio, are sensitive indicators for detecting potential radioactive releases. Nevertheless, overall 90Sr and 137Cs 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.

Highlights

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
We report for the first time a long-term observation of 137Cs and 90Sr in environmental and food samples collected around Qinshan nuclear power plant (QNPP) during 2012–2019
The late occurrence of 137Cs peak compared to 90Sr peak in 2016 could be due to the association of 137Cs to fine particles suspended in the atmosphere which prolonged the residence time of 137Cs in the atmosphere; and the plum rain in the second quarter of 2016 flushed the fine particles and thereby prompted the deposition of 137Cs onto the ground. Both 90Sr and 137Cs activity concentrations in the atmosphere around QNPP were generally low in the past decade, and can be considered as baseline concentrations

Summary

Introduction

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. We report for the first time the long-term monitoring data of 137Cs and 90Sr in environmental and food samples around Qinshan nuclear power plant in 2012–2019. Peak values of 90Sr and 137Cs concentrations and 137Cs/90Sr 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. In contrast to 137Cs, long-term monitoring data for 90Sr activity in environmental and food samples worldwide are sparse This fact is mainly attributed to the long and tedious sample preparation and measurement procedures for 90Sr. The Qinshan nuclear power plant (QNPP) is the first nuclear power plant in China and officially commenced commercial operation in December 1991. The annual effective dose was estimated for the local public based on our measurement data

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Results

Conclusion