Investigation of environmental radioactivity levels and human health risk around San'ao Nuclear Power Plant (China) before operation

Baseline study on environmental radioactivity levels and public health conditions are crucial before the operation of nuclear facilities. Our goal is to establish a baseline database before the operation of San'ao Nuclear Power Plant (SNPP). To achieve this, water and food samples collection was carried out around the SNPP from 2021 to 2022 for laboratory analysis to determine the radioactivity levels. Thereafter, annual effective dose (AED) to local residents were evaluated by the analysis results and cancer incidence rates were analyzed by health data of local residents. Our results showed that the gross alpha and beta activity concentrations in water varied within < 0.016-0.023 Bq/L and 0.031-0.080 Bq/L, respectively. The Sr-90 and Cs-137 activity concentrations range from 3.1 to 9.7 mBq/L and 0.11-0.42 mBqg/L in water, and range from 0.037 to 0.95 Bq/kg and 0.015-0.38 Bq/kg in food. All obtained results of gross alpha and beta, Sr-90 and Cs-137 were below the thresholds of World Health Organization (WHO) and Chinese national standard. The AED induced by ingestion of food or drinking water were below the thresholds of WHO or Chinese national standard, indicating that radiation exposure was at a safe level. The incidence rate of all cancer sites combined among the residents around the SNPP was slightly higher than other regions, but still remained at the same scale. However, the incidence rate of thyroid cancer stood out to be significantly higher than the national average value in China, presumably due to excessive iodine intake in the study region.