Artificial radionuclides in sediments of the Don River Estuary and Azov Sea

The Don River Estuary-Azov Sea system is an extension of the shallow continental shelf area of the Black Sea. A large data set of artificial radionuclides in bottom sediments of the Azov Sea has been compiled in order to examine the storage and migration of radionuclides within this highly restricted inland sea and to estimate the annual dose received by individuals in the local population who regularly consume fish. In recent years (1997-1999), the radionuclide content of surface sediments has been: 137Cs < or = 0.5-100 Bq/kg d.w. (mean = 33.8 +/- 25.9 Bq/kg d.w., n = 57), 90Sr = 0.2-5.7 Bq/kg d.w. (mean = 2.1 +/- 1.4 Bq/kg d.w., n = 34) and 239,240Pu = 0.31-0.51 Bq/kg d.w. (n = 2). In general, 137Cs activities increase with distance from the mouth of the Don River and correlate negatively with sediment grain size (r2 = 0.77, n = 21). The annual 137Cs-derived dose received by an individual through the trophic chain water-fish-humans (approximately 10(-6) Sv/yr) is well below regulatory recommended limits, indicating that current levels of radioactivity in the environment pose no threat to commercial fisheries operations for the bordering nations of Russia and Ukraine.     

渔业对俄罗斯巴伦支海和亚速海商业鱼类动态的影响:历史观察

本文提供了联合国环境规划署"全球国际水域评估"项目(UNEP-GIWA)评估俄罗斯各海域所使用的背景材料和分析结果.它概述了过去100年中巴伦支海和亚速海两海域的渔业发展状况.讨论了巴伦支海和亚速海渔业发展的主要阶段和渔业产量降低的主要原因.这两个在物理和地质特征方面明显不同的海域却在渔获量动态方面表现出相似的趋势.海洋生态系统的自然波动和对自然生态系统功能的人为干扰已导致了对生态系统健康的重大负面影响并造成渔获物构成和数量的消极变化.俄罗斯各海域渔获量的下降已成为俄罗斯联邦的关注焦点,有关俄罗斯渔业管理的各项修改政策也已实行.政策文件"2020年之前俄罗斯联邦有关渔业发展概念"也在此加以讨论.