Environmental Solutions, Geological Survey of Finland, Vuorimiehentie 5, 02151 Espoo, Finland.
Department of Geosciences and Geography, University of Helsinki, Finland.
Mar Pollut Bull. 2021 Nov;172:112924. doi: 10.1016/j.marpolbul.2021.112924. Epub 2021 Sep 9.
Anthropogenic radionuclides are among those human impacts, which can be seen widely in the marine and terrestrial ecosystems. Fallout from the 1986 Chernobyl nuclear power plant accident has rendered the Baltic Sea as the most polluted marine body in the world with respect to Cs. This research investigated sediment cores from 56 sites around the Gulf of Bothnia, Baltic Sea. Radioactivity from Cs in sediments has generally declined due to natural/radioactive decay of Cs over the last decades. However, Cs contents in subsurface sediments remain at elevated levels compared to pre-Chernobyl levels. The highest Cs activity contents in subsurface sediments (>4000 Bg kg) occur in coastal areas including estuaries. These areas often experience severe anthropogenic pressure. The southern Bothnian Sea, Kvarken archipelago, and southern Bothnian Bay all show elevated Cs values in subsurface sediments. Sedimentary Cs can also help constrain recent rates of sedimentation. Post-Chernobyl sedimentation rates in the Gulf of Bothnia varied from 0.1 to 4.8 cm/year with an average sedimentation rate of 0.54 cm/year.
人为放射性核素是人类活动对海洋和陆地生态系统产生广泛影响的因素之一。1986 年切尔诺贝利核电站事故的沉降物使波罗的海成为世界上受 Cs 污染最严重的海洋水体。本研究调查了波罗的海波的尼亚湾 56 个地点的沉积物岩芯。由于 Cs 的自然/放射性衰变，过去几十年中，沉积物中 Cs 的放射性已普遍下降。然而，与切尔诺贝利之前的水平相比，底层沉积物中的 Cs 含量仍然较高。表层沉积物中 Cs 的最高放射性活度（>4000 Bg kg）出现在包括河口在内的沿海地区。这些地区经常受到严重的人为压力。南部波的尼亚海、 Kvarken 群岛和南部波的尼亚湾的底层沉积物都显示出 Cs 值升高。沉积 Cs 还可以帮助约束最近的沉积速率。波的尼亚湾的切尔诺贝利后沉积速率变化范围为 0.1 至 4.8 cm/年，平均沉积速率为 0.54 cm/年。
