Impact of long-term operation of nuclear power plants on the marine ecosystem of Daya Bay.

Based on the monitoring data of Daya Bay in 2011-2017, the impact of long-term operation of nuclear power plants (NPPs) on the marine ecosystem was accessed. Cs and Sr in seawater and sediment of Daya Bay decreased with time. The environmental half-lives of Cs and Sr in seawater, Cs in sediment were 7.1 a, 11.7 a and 13.9 a, respectively. The total dose rates of the marine organisms ranged from 230.5 to 853.9 nGy/h, lower than the ERICA screening benchmark (10 μGy/h). Po, Ra and Th were the main dose contributors. Cs and Sr contributed to 0.01 %-0.06 % of the total radiation. Cs contributed to <0.6 ‰ of the committed effective dose for humans. There were almost no radiation effects on the marine ecosystem of Daya Bay from NPPs before 2017. In the future, there will be no radiation risk for the long-term discharge of low-level radioactive waste to Daya Bay.