Spatial variations of 226Ra, 228Ra, 134Cs, and 137Cs concentrations in western and southern waters off the Korean Peninsula in July 2014

Publication date: February 2018
Source:Journal of Environmental Radioactivity, Volume 182
Author(s): M. Inoue, Y. Shirotani, S. Nagao, T. Aramaki, Y.I. Kim, K. Hayakawa
We examined the spatial distributions of ²²⁶Ra, ²²⁸Ra, ¹³⁴Cs, and ¹³⁷Cs concentrations (activities) in seawater off the western and southern Korean Peninsula in July 2014. Radium-228 (and ²²⁶Ra) concentrations in water samples varied widely from 5 to 14 mBq/L (2–4 mBq/L), showing a negative correlation with salinity, particularly at the surface off the western Korean Peninsula. This indicates that the seawaters in this area are fundamentally comprised of ²²⁸Ra-poor and high-saline Kuroshio Current water and ²²⁸Ra-rich and low-saline water (e.g., continental shelf water), with various mixing ratios. Although Fukushima Dai-ichi Nuclear Power Plant (FDNPP)-derived ¹³⁴Cs was below the detection limit (<0.08 mBq/L) in waters off the western Korean Peninsula, low level ¹³⁴Cs (0.1–0.2 mBq/L) was detected in waters off the southern Korean Peninsula accompanied by higher ¹³⁷Cs concentrations (1.6–1.9 mBq/L) relative to that off the western Korean Peninsula. Combined with the lower radium concentrations, the detection of ¹³⁴Cs is explained by mixing of FDNPP-derived radiocesium-contaminated Kuroshio Current water.



http://ift.tt/2BpaT9Q