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[논문]제주지역 총부유 분진 중 자연방사성 핵종의 농도 특성 분석

한충훈, 임희정

김덕우

The atmospheric total suspended particulates (TSP) aerosols were collected at Gosan site of Jeju Island, which is one of the background sites of Korea, during January to April 2013. This study analyzed using Inductively Coupled Plasma - Dynamic Reaction Cell - Mass Spectrometer (ICP-DRC-MS) the concentrations of potassium, uranium and thorium. As a result, it was observed during this study that the radioactive concentrations of 40K, 232Th and 238U were within the scope of 14.188 ± 11.451 μBq/m3, 0.263 ± 0.226 μBq/m3 and 0.226 ± 0.282 μBq/m3, respectively. During Asian dust periods, the concentrations of 40K (33.221 ± 12.333 μBq/m3), 238U (0.788 ± 0.260 μBq/m3), and 232Th (0.865 ± 0.252 μ Bq/m3) were highly as 3.59, 5.51 and 7.86 times, respectively, compared to the non-event periods. For the haze event days, 40K (34.729 ± 10.792 μBq/m3), 238U (0.730 ± 0.261 μBq/m3), and 232Th (0.608 ± 0.475 μBq/m3) were highly as 3.75, 5.10 and 5.53 times, respectively, compared to the non-event days. For the fog-mist event days, 40K (19.970 ± 15.824 μBq/m3), 238U (0.371 ± 0.374 μBq/m3), and 232Th (0.329 ± 0.451 μBq/m3) were highly as 2.16, 2.59 and 2.99 times, respectively, compared to the non-event days. The correlations between the studied natural isotopes is a good positive correlation between 232Th and 238U (R2 = 0.9012), supporting the conclusion that they originated from the same source, mostly the crust. The average calculated 232Th/238U ratio was 1.01, which is close to the world average of unity. On the other hand, weak positive correlations between 232Th and 40K and between 238U and 40K were found, supporting the conclusion that 40K originated from other sources besides the crust.

2019-12-30