Ohta Tomoko, Fifield L Keith, Palcsu László, Tims Stephen G, Pavetich Stefan, Mahara Yasunori
Nagaoka University of Technology, Nagaoka, Japan.
The University of Tokyo, Kashiwa, Japan.
Sci Rep. 2023 Nov 11;13(1):19672. doi: 10.1038/s41598-023-46853-y.
The opportunity to measure the concentrations of H and Cl released by the Fukushima nuclear accident in 2011 directly in rain was lost in the early stage of the accident. We have, however, been able to reconstruct the deposition record of atmospheric H and Cl following the accident using a bore hole that was drilled in 2014 at Koriyama at a distance of 60 km from the accident. The contributions of H and Cl from the accident are 1.4 × 10 and 2.0 × 10 atoms m respectively at this site. Very high concentrations of both H (46 Bq L) and Cl (3.36 × 10 atoms L) were found in the unsaturated soil at depths between 300 and 350 cm. From these, conservative estimates for the H and Cl concentrations in the precipitation in the ~ 6 weeks following the accident were 607 Bq L and 4.74 × 10 atoms L, respectively. A second hole drilled in 2016 showed that H concentrations in the unsaturated soil and shallow groundwater had returned to close to natural levels, although the Cl concentrations were still significantly elevated above natural levels.
2011年福岛核事故发生初期，失去了直接测量雨水中释放的氢和氯浓度的机会。不过，我们利用2014年在距事故现场60公里的郡山市钻探的一个钻孔，重建了事故后大气中氢和氯的沉降记录。在该地点，事故中氢和氯的贡献分别为1.4×10和2.0×10个原子/平方米。在深度为300至350厘米的非饱和土壤中，发现氢（46贝可/升）和氯（3.36×10个原子/升）的浓度都非常高。据此，保守估计事故后约6周内降水中氢和氯的浓度分别为607贝可/升和4.74×10个原子/升。2016年钻探的第二个钻孔显示，非饱和土壤和浅层地下水中的氢浓度已恢复到接近自然水平，尽管氯浓度仍显著高于自然水平。
