K. Suzuki, S. Watanabe, Y. Onozeki-Yuasa, H. Arai, H. Tanaka, T. Kuge, K. Tsunoda, M. Mori, S. Nohara, Y. Okada, and Y. Minai
The accident of the Fukushima Dai-ichi Nuclear Power Plant in March, 2011, released large amounts of radiocesium into the atmosphere, and contaminated the environment of Gunma Prefecture in eastern Japan. In particular, 640 Bq kg?1-wet of radiocesium concentration was found in wakasagi (Hypomesus nipponensis) in Lake Onuma on Mt. Akagi in August, 2011. Thus, to elucidate the body-size effect in weight-dependent and dynamics of radiocesium in the ecosystem of Lake Onuma, we determined the age of wakasagi, the body-weight class of the radiocesium concentration in wakasagi and the effective ecological half-life (Teff) of radiocesium in wakasagi 0+ from 2012 to 2016. The body-size effect was found for the 137Cs concentration of wakasagi fished from 2012 to 2015, i.e., the concentration of 137Cs increased with the increase in its body weight. On the other hand, no body size effect was found in 2016.
Research papers (academic journals)
