Measurement of 137Cs in the soil in Korea by low-level background gamma-ray spectrometer

137Cs was measured in soil samples collected in Korea from 2006 to 2008 using a low-level background gamma-ray spectrometer that was designed and developed by KRISS (Korea Research Institute of Standards and Science). The objectives of this study are to evaluate the newly developed low-level background gamma-ray spectrometer and, consequently, to provide information on the horizontal and vertical distribution of 137Cs in Korean soil. 137Cs concentrations in surface soil varied from 12.8 ± 0.9 to 108 ± 4 Bq kg−1, and the vertical profiles of 137Cs from the Nari basin in Ulleung Island in the East Sea/Sea of Japan and Seongsan Ilchulbong Peak, Jeju Island, showed a higher concentration in the surface layer that gradually decreased with depth. On the other hand, the 137Cs concentration in soil samples collected from Bukhan Mountain National Park in Seoul showed a subsurface maximum and decreased with depth. The 137Cs inventories in the soil column were calculated to be 1,830–4,360 Bq m−2 with a mean of 2,770 Bq m−2, which was the same order of magnitude as the global fallout inventories in the mid-latitude region of the Northern Hemisphere.