Radionuclides in surface waters around the damaged Fukushima Daiichi NPP one month after the accident: Evidence of significant tritium release into the environment

摘要

Following the Fukushima nuclear accident (2011), radionuclides mostly of volatile elements (e.g., I-131, Cs-134,Cs-137, Te-132) have been investigated frequently for their presence in the atmosphere, pedosphere, biosphere, and the Pacific Ocean. Smaller releases of radionuclides with intermediate volatility, (e.g., Sr-90), have been reported for soil. However, few reports have been published which targeted the contamination of surface (fresh) waters in Japan soon after the accident. In the present study, 10 surface water samples (collected on April 10, 2011) have been screened for their radionuclide content (H-3, Sr-90, I-129, Cs-134, and Cs-137), revealing partly unusually high contamination levels. Especially high tritium levels (184 +/- 2 Bq.L-1; the highest levels ever reported in scientific literature after Fukushima) were found in a puddle water sample from close to the Fukushima Daiichi nuclear power plant. The ratios between paddy/puddle water from one location only a few meters apart vary around 1% for Cs-134, 12% for I-129 (I-131), and around 40% for both H-3 and Sr-90. This illustrates the adsorption of radiocesium on natural minerals and radioiodine on organic substances (in the rice paddy), whereas the concentration differences of H-3 and Sr-90 between the two waters are mainly dilution driven. (C) 2019 Elsevier B.V. All rights reserved.