1Korea Research Institute of Standards and Science, Daejeon, Republic of Korea 2University of Science & Technology(UST) Radiation Measurement and Radiation Safety, Daejeon, Republic of Korea 3Hanyang University Department of Marine Sciences and Convergence Technology, Ansan, Republic of Korea 4National Institute of Environmental Research, Sejong, Republic of Korea
Received: October 7, 2015; Revised: December 3, 2015 Accepted: December 4, 2015.
ABSTRACT
The objective of this study is to identify the radionuclide distribution in public water by carrying out the analysis of artificial radionuclides(134Cs, 137Cs, 239+240Pu), natural radionuclide(210Pb) and TOC in the lake Euiam sediment in Chuncheon, South Korea. The 134Cs concentration in all lake sediments showed below MDA values, and the 137Cs concentration in lake sediment were ranged from MDA to 8.79 Bq·kg-1-dry. The 137Cs concentrations in surface sediment were reported to be 2.4 to 4.2 Bq·kg-1-dry. The lowest concentration of 137Cs was reported at St. 4 and the highest concentration was reported at St. 3, respectively. The 239+240Pu concentration in lake sediment were ranged from 0.049 to 0.47 Bq·kg-1-dry. The lowest concentration was reported at St. 2 and the highest concentration was reported at St. 3. The correlation(r) between the 239+240Pu concentration and /137Cs concentration in lake sediment presented higher values (0.54 to 0.97) and this suggests the behavior and origin of 137Cs is identical to the 239+240Pu in the sediment. The 134Cs concentration below MDA value and the 239+240Pu/137Cs ratio(mean value of 0.041) indicated that the artificial radionuclides in the sediment were originated from global fallout by the atmospheric testing of nuclear weapons conducted by former USSR and U.S.A, but not from the Fukushima Daiichi NPP accident. The sedimentation rate derived from 210Pb age-dating method at St. 2 is calculated to be 0.31±0.06 cm·y-1. This value is similar to the value (0.41±0.05 cm·y-1) estimated from the 137Cs maximum peak produced from early 1960’s. The content of TOC in lake Euiam sediments varied from 0.20 to 13.01%. While the highest correlation between TOC and 137Cs concentration in the sediment were found at St. 1, the others presented the low correlation.