Spatial variations of low levels of 134Cs and 137Cs in seawaters within the Sea of Japan after the Fukushima Dai-ichi Nuclear Power Plant accident

Abstract Our method based on low background γ-spectrometry enabled the measurement of low radiocesium concentrations in only 20 L of seawater. In May 2011 after deposition of radiocesium, 134 Cs concentration in surface water within the Sea of Japan was confirmed to be significantly small (