This study presents distribution of naturally occurring radioactive materials in groundwater in Jeju island. Radon (222Rn) and potassium (40K) concentrations were performed by using Liquid Scintillation Counter and Ion Chromatograph respectively. In addition, the activities of uranium and thorium nuclides were analyzed by Inductively Coupled Plasma Mass Spectroscopy. Groundwater samples were collected from 9 sites of water intake facilities for wide area supply in Jeju island from September 2022 to September 2023. The 40K concentrations of groundwater ranged between 0.050 and 0.400 Bq·L-1. The radon concentrations in groundwater were in the range of 0 to 60 Bq L-1, and there was no groundwater exceeding the range of 148 Bq L-1 proposed by the US EPA. The distribution of uranium and thorium in groundwater varied from 0 to 500 ng L-1 and 0 to 2.4 ng L-1, respectively. The concentrations of uranium did not exceed 30 μg L-1, thresholds indicated by the US EPA. By analyzing the concentrations of 40K, 222Rn, 238U and 232Th, the annual effective dose of residents can be assessed. The evaluated residents’ effective dose from natural radionuclides due to intake of drinking water is less than the recommended value of 100 μSv y-1. Consequently, this study indicates that the cancer risks of the residents in Jeju island from naturally occurring radioactive materials ingested with water is insignificant.

This study presents distribution of naturally occurring radioactive materials in groundwater in Jeju island. Radon (222Rn) and potassium (40K) concentrations were performed by using RAD H2O of RAD7 and 940 Professional IC Vario, respectively. In addition, the activities of uranium and thorium nuclides were analyzed by ICP-MS. All of the groundwater samples were collected from 29 sites from August to October 2022. The radon concentrations in groundwater were in the range of 0 to 60 Bq L-1, and there was no groundwater exceeding the range of 148 Bq L-1 proposed by the US EPA. The distribution of uranium in groundwater varied from 0 to 0.6 μg L-1 and did not exceed 30 μg L-1, thresholds indicated by the US EPA.

The purpose of this study was to introduce strategies and projects through which local government can play a role in mitigating damage to health when addressing the health challenge posed by radon (222Rn). We first compared and analyzed naturally occurring radioactive material (NORM) in the soil of relatively high (Geumsan) and low (Boryeong) concentration areas of indoor radon (222Rn) to understand the factors influencing concentrations. Mortality rates linked to lung cancer in the areas were also compared and analyzed in the study (T-test). We selected two key priority research studies and four key strategies based on status analysis and a review of domestic and international policy trends in relation to radon (222Rn). As a result of comparing the radium and thorium in the soil with indoor radon concentrations, Geumsan had a higher mean concentration of indoor radon (222Rn = 182.8 Bq/m3) and recorded a higher concentration of radium (226Ra = 48.4 Bq/kg) than Boryeong (226Ra = 43.9 Bq/kg). These findings show that Geumsan, which had a high concentration of radium (226Ra), revealed a high concentration of radon (222Rn), a radioactive decay material of radium (226Ra), demonstrating that the concentration of indoor radon (222Rn) can vary according to geological and soil characteristics. The age standardized mortality from lung cancer per 100,000 people was 31.6 in Geumsan and 27.3 in Boryeong (p < 0.05). These findings show that there is likely an association between the concentration of indoor radon (222Rn) and mortality from lung cancer. Two key priority research studies include a survey on factors influencing exposure to radon (222Rn) in local environments and preparation of a potential map of radon (222Rn). Four key strategies include “management of exposure factors regarding radon (222Rn),” “environmental health services provided to protect radon (222Rn) exposure,” “management of technical support measures for radon (222Rn),” and “disclosure regarding the risk of radon (222Rn) exposure (risk communication).”

This study was carried out considering that activated carbon physically adsorbs radon. Among the air cleaners equipped with activated carbon filter, eight air cleaners sold in Korea were selected and the radon reduction rate experiment was conducted. The instrument used an ionization chamber type instrument with a sensitivity of 3 CPM. The experiment was carried out by excluding the natural rate of reduction of radon in order to accurately grasp the radon reduction rate of activated carbon filter. Of the eight air purifiers, only three showed a reduction rate of more than 30%, while the remaining five air purifiers showed a reduction rate of less than 20%. This does not seem to be much different from the natural reduction rate. In addition, since it is not adsorbed by radon alone due to the nature of activated carbon, it is expected that the reduction rate will be lower in a real life environment.

오늘날 경제의 발전과 함께 여러 가지 환경 문제가 발생했다. 자연스레 사람들은 환경에 대한 관심이 높아졌으며 특히 식수에 대한 안전성과 오염도 조사에 대한 중요성이 부각되고 있다. 우리나라 국민들이 식수로 이용하는 지하수에서 우라늄 및 222Rn 이 다수 지역에서 검출되고 있다. 따라서 이 연구는 지하수 내 포함된 222Rn 농도를 측정하는데 보다 정확한 측정을 위한 방법을 알아보고자 한다. 실험은 알파, 베타 펄스의 분석이 용이한 펄스파형분석 기능을 가진 저 준위 액체섬광계수기를 이용하여 실험하였다. 지하수 시료와 혼합하는 섬광체의 조제, 유효기간은 시간이 지날수록 검출값은 낮아지고, 에너지 스펙트럼도 낮은 쪽으로 channel 이동이 있었다. 섬광체의 구입시기가 오래 될수록, 개봉한 후 방치시간이 지날수록 검출값이 낮아짐을 확인했다. 사용목적이 다른 섬광체를 사용했을 경우 channel 이동으로 에너지를 확인할 수 있다.

라돈은 우라늄-238과 토륨-232가 방사성붕괴 과정을 거친 후 생성되며, 무색, 무취의 불활성 기체로서 지하 또는 밀폐된 공간에 축적된다. 우라늄-238과 토륨-232는 지각의 암석이나 토양 등에 포함 돼 있다. 건축자재는 암석이나 토양을 재료로하여 만들어 진다. 가스 형태의 라돈은 호흡기를 통해 폐로 유입되고 라돈의 딸핵종이 폐나 기관지에 침적 되어 폐암을 일으키는 원인이 된다. 본 연구는 광주광역시 광산구에 위치한 신축 아파트를 대상으로 창문을 닫고 열은 상태에서 라돈 측정기를 이용하여 측정하였다. 측정 결과로 보아 신축 아파트 실내 평균 라돈농도는 미국 일반인 공기 중 라돈가스 최대허용농도 기준치 4 pCi보다 이하의 값이 나타난다는 것을 볼 수 있다. 측정 결과로 볼 때 신축 아파트의 라돈농도로 인한 피폭은 크지 않을 것으로 예상한다. 그러나 라돈가스가 신체 내에 축적이 되면 폐와 같은 경우는 폐암과 같은 피폭에 의한 피해를 얻을 수 있으므로 방사선 방어적 측면에서 측정 결과와 같이 라돈 농도를 낮추기 위해 창문을 자주 열어 환기를 시켜 피폭을 줄이는 것이 필요하다고 생각 된다.

The aim of this study is to determine harmful radioactive gas(Rn^222)-concentrations in soils and to suggest the anormalous regions of Rn^222 -concentration in Taejeon area. The range of Rn^222 -concentration in the soils (45 samples) of the survey area is 100 to 2,475 (pCi/L) and mean±δ of those values is 489±05 (pCi/L). The 2% (4 samples) of soil-gas samples (45 ones) collected in the survey area is corresponded to high risk level, 53% (24 samples) to medium one and 43% (19 samples) to low one. Especially, The Rn^222-concentration is relatively higher in schistose granite region than in other rock units (two-mica granite and biotite granite) in the survey area. The Rn^222-concentration is propotional to the uranium contents in the soils. The soil hardness among the various factors is correlative with Rn^222-concentrations. To prevent the damage from Rn^222 -concentrations, it is necessary to close the cracks of underground structure and to consider methods reducing Rn222-concentration for the anormalous regions.