2023 年8 月24 日,日本政府启动福岛核污染水排海,这将进一步增加对海洋生态环境的辐射风险。分析了福岛核污染水中主要人工放射性核素的浓度,估算了其在福岛核污染水中的储量。根据东京电力公司公布的数据发现,截至2023 年3 月,福岛核污染水储罐中3H的浓度为(1.9~25.0)×105 Bq/L,明显超出日本法律允许的3H 的最大排放浓度(6×104 Bq/L);部分核污染水储罐中90Sr 和129I 的浓度也高于日本法律允许的90Sr 和129I 的最大排放浓度(30 Bq/L和9 Bq/L)。经估算,在排海前福岛核污染水中3H和129I 的储量分别为0.9 PBq(1 PBq=1×1015 Bq)和6.2×109 Bq,这与核事故阶段3H和129I 泄漏到海洋中的量(0.1~1.0 PBq 和6.9×109 Bq)相当。此外,进一步对福岛核污染水中典型放射性核素(如3H、14C、60Co、90Sr、129I、134,137Cs 和239,240Pu 等)在海洋环境中的迁移转化行为进行了论述,重点介绍了福岛放射性核素在太平洋海域的迁移路径,及其在海洋沉积物上的吸附和海洋生物中的富集行为。期望为我国应对福岛核污染水排海提供一定的科学依据和见解。
Abstract:On
24 August 2023, the Japanese government started the discharge of the Fukushima
nuclear contaminated water (FNCW) into
the North Pacific, which will increase some radiation risks to the marine ecological
environments. Here we analyzed the concentrations of the major artificial
radionuclides in the FNCW and estimated their inventories. Based on the data
provided by Tokyo Electric Power Company, we found that the concentrations of 3H
in FNCW tanks as March 2023 ranged from 1.9×105 Bq/L to 25.0×105 Bq/L, significantly exceeding the maximum release concentration for 3H
(6×104 Bq/L) allowed by Japanese law. Besides, the concentrations of 90Sr and 129I in some FNCW tanks were also higher than
the corresponding maximum release concentrations (30 Bq/L for 90Sr
and 9 Bq/L for 129I) allowed by Japanese law. The inventories of 3H
and 129I in the FNCW before the discharge were estimated to be 0.9 PBq and
6.2×109 Bq, respectively, which were comparable to the leakage
amounts of 3H (0.1~1.0 PBq) and 129I (6.9×109 Bq) to the ocean
during the nuclear accident stage. We further discussed the migration and
behavior of typical Fukushima radionuclides (e.g., 3H, 14C, 60Co, 90Sr, 129I, 134,137Cs and 239,240Pu)
in the marine environments from three aspects: ①the
transport of Fukushima radionuclides by ocean currents in the Pacific; ②sediment
adsorption to radionuclides and ③marine
biota uptake of radionuclides. This study is expected to provide some
scientific foundations and insights for the radiation monitoring and risk assessment
that may be required to respond to the discharge of FNCW.