Jialin Ni

Oceans are repositories of radionuclides. Radionuclides are transferred through the food chain and cause ionizing radiation hazards for marine organisms. In this study, the transfer characteristics of ²²⁶Ra, ⁴⁰K, ¹⁴C, ³H, ¹³⁷Cs and ⁹⁰Sr in organisms at different trophic levels in the eastern coast of Yantai city were investigated. The risk of ionizing radiation to organisms was assessed using the ERICA Tool 2.0. The results show no significant changes in the concentration of any of the nuclides in the coastal area compared to the preoperation period of the nuclear power plant. The transfer factor of ¹³⁷Cs, ⁴⁰K, ²²⁶Ra, ¹⁴C, ⁹⁰Sr and ³H at the different trophic levels of marine organisms were 2.09, 1.29, 1.17, 1.15, 1.06 and 0.74, respectively. The dose rates of ionizing radiation to organisms from six radionuclides ranged from 32.02 nGy·h^-1 to 195.49 nGy·h^-1 and had a mean value of 102.86 ± 57.30 nGy·h^-1. The main artificial radionuclides (¹⁴C, ³H, ⁹⁰Sr, ¹³⁷Cs) released by nuclear power plants in the study area produced negligible radiation doses to marine organisms. However, other artificial radionuclides present in the effluents of nuclear power plants (⁹⁹Tc, ^110mAg and ¹³¹I) as well as other natural radionuclides (includes ²¹⁰Po, ²¹⁰Pb, etc) were not included, and further evaluation of these is recommended.

Using the constituent elements of vulnerability, an evaluation index system for the ecological vulnerability of coastal areas under oil spill stress is established based on “Sensitivity–Adaptive Capacity-Exposure”. After selecting a gulf in China as the main case study in this work, the cluster analysis and reference method were applied in grading and value assigning for all indexes. In addition, the analytic hierarchy process and expert evaluation method were used to determine the index weighting. Finally, a comprehensive evaluation method was adopted in the evaluation studies on the ecological vulnerability of the gulf coastal zone under oil spill stress. Results show the differences between the gulf area and areas that belong to different ecologically-vulnerable areas under oil spill stress.