• Environmental Analysis Health and Toxicology
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• 제30권
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• pp.5.1-5.8
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• 2015

Objectives We aimed to assess the radiation exposure for epidemiologic investigation in residents exposed to radiation from roads that were accidentally found to be contaminated with radioactive cesium-137 ($^{137}Cs$) in Seoul. Methods Using information regarding the frequency and duration of passing via the $^{137}Cs$ contaminated roads or residing/working near the roads from the questionnaires that were obtained from 8875 residents and the measured radiation doses reported by the Nuclear Safety and Security Commission, we calculated the total cumulative dose of radiation exposure for each person. Results Sixty-three percent of the residents who responded to the questionnaire were considered as ever-exposed and 1% of them had a total cumulative dose of more than 10 mSv. The mean (minimum, maximum) duration of radiation exposure was 4.75 years (0.08, 11.98) and the geometric mean (minimum, maximum) of the total cumulative dose was 0.049 mSv (<0.001, 35.35) in the exposed. Conclusions An individual exposure assessment was performed for an epidemiological study to estimate the health risk among residents living in the vicinity of $^{137}Cs$ contaminated roads. The average exposure dose in the exposed people was less than 5% of the current guideline.

• 자원환경지질
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• 제51권2호
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• pp.113-120
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• 2018

체르노빌과 후쿠시마와 같은 원자력 사고를 통해 환경으로 방출되는 방사성 세슘($^{137}Cs$)은 화학적 독성과 ${\gamma}$ 선 방출, 그리고 긴 반감기($t_{1/2}=30.2$ 년) 때문에 주된 감시대상 방사성 핵종 가운데 하나이다. 1족 알칼리 금속인 세슘은 점토광물에 잘 흡착되며, 특히 운모류 광물인 일라이트와 특이적 흡착을 하는 것으로 알려져 있다. 이는 일라이트의 frayed edge sites 에 세슘이 선택적 흡착을 일으키기 때문이며, 이러한 흡착 지점은 일라이트의 풍화 정도 및 결정도에 따라 달라질 수 있다. 따라서 본 연구는 인공 풍화 실험(pH=2.0 at $50^{\circ}C$)을 통해 일라이트 표면을 개질함으로써 세슘의 흡착 성능을 증가시키기 위해 수행되었다. 일라이트의 층간 양이온들(K, Ca)은 반응 1일 이내에 다량 용출되는 반면, 결정 구조를 구성하는 Si와 Al은 점진적으로 용출되었다. 또한 일라이트 시료의 결정도가 감소하여 인위적인 화학적 풍화가 발생하였음을 지시하였다. 저농도의 세슘과 흡착 실험을 진행한 결과, 흡착분배계수가 기존에 비해 약 2배 증가하였다. 이러한 결과는 비교적 저온에서 손쉽게 일라이트의 흡착 성능을 개선할 수 있음을 암시한다.

• Nuclear Engineering and Technology
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• 제36권4호
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• pp.304-315
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• 2004

The ageing effects of radionuclides in radioactive soil on remediation using the electrokinetic method were analyzed. Comparative experiments were conducted for the reactive soil around a TRIGA research? reactor contaminated with $^{137}Cs\;and\;^{60}Co$ for 15 years and the non-reactive soil that was intentionally contaminated with $Cs^+\;and\;Co^{2+}$ for 3 days. It was observed that because of an aging effect on $^{137}Cs$, the efficiency of removing it decreased. $H_{2}SO_4$ used as an additive to increase the removal efficiency showed a higher removal capability than other chemicals for both $^{137}Cs\;and\;^{60}Co$. The efficiency of removing radionuclides from the radioactive soil in the column was proportional to the capability of the added chemical to extract radionuclides. It took 10 days to achieve a $54\%$ removal of $^{137}Cs$ and a $97\%$ removal of $^{60}Co$ from the soil. The volume of the soil wastewater discharged from the soil column by the electrokinetic method was $20\%$ below that for soil washing.

• 방사선산업학회지
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• 제6권1호
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• pp.1-9
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• 2012

In spite of colossal efforts taken for safe handling and storage of radioactive waste, the uncontrolled release of radiocesium ($^{137}Cs$ and $^{134}Cs$ isotopes) into the natural environment is inevitable. $^{137}Cs$ is of particular concern because of its long half-life, ability to transfer into biota through food chains, as well as its great mobility, bioavailability, and chemical and ecophysiological similarity with potassium. Radiocesium is released anthropogenically into the environment. Mushrooms are known for their ability to accumulate radionuclides, particularly radiocesium, which is heterogeneously distributed in the individual parts of mushrooms, and it is found that mushrooms are a hyper-accumulator of radiocesium from their environment than other vegetation. Mushrooms play a major role in the mobilization, accumulation, and translocation of cesium, i.e., decontamination of soils (mycoextraction) polluted with cesium radioisotopes, and this capacity appears to be a relevant bioindicator of cesium contamination in the environment. Moreover, the extension of mycelium into the soil makes the use of mushrooms as bioindicators of radiocesium possible. This paper reviews the potential of mushrooms in the accumulation of radiocesium from the environment, and dissertates the salient features to support the employment of mushrooms in environmental biomonitoring as a sensitive bioindicator of radiocesium contamination.

• Journal of Radiation Protection and Research
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• 제45권4호
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• pp.154-162
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• 2020

Background: Several studies have reported that wild mushrooms contain high amounts of radioactive cesium (137Cs). After the Fukushima Daiichi Nuclear Power Plant Accident, a significantly high concentration of 137Cs has been detected in wild mushrooms, and their consumption may be the cause of the chronic internal exposure of local consumers to radioactivity. Therefore, an accurate evaluation of the internal radioactivity resulting from mushroom ingestion is needed. Materials and Methods: The 137Cs elution rate through the cooking and digestion stages was evaluated using in vitro experiments. The edible mushroom Pleurotus djamor was taken as a sample for the experiments. The mushrooms were cultivated onto solid media containing 137Cs. We evaluated the internal dose based on the actual conditions using the elution rate data. For various cooking methods, the results were compared with those of other wild edible mushrooms. Results and Discussion: From the elution experiment through cooking, we proved that 25%-55% of the 137Cs in the mushrooms was released during soaking, boiling, or frying. The results of a simulated digestion experiment after cooking revealed that almost all the 137Cs in the ingested mushrooms eluted in the digestive juice, regardless of the cooking method. The committed effective dose was reduced by 20%-75% when considering the dissolution through the cooking process. Conclusion: We found that cooking lowers 137Cs concentration in mushrooms, therefore reducing the amount of radioactivity intake. Besides, since there were differences between mushroom types, we demonstrated that the internal exposure dose should be evaluated in detail considering the release of 137Cs during the cooking stages.

• 한국방사성폐기물학회:학술대회논문집
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• 한국방사성폐기물학회 2017년도 춘계학술논문요약집
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• pp.340-341
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• 2017

• 방사성폐기물학회지
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• 제19권1호
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• pp.39-49
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• 2021

The behaviors of various desorption agents were investigated during the desorption of cesium (Cs) from samples of clay minerals and actual soil. Results showed that polymeric cation exchange agents (polyethyleneimine (PEI)) efficiently desorbed Cs from expandable montmorillonite, whereas acidic desorption solutions containing HCl or PEI removed considerable Cs from hydrobiotite. However, most desorption agents could desorb only 54% of Cs from illite because of Cs's specific adsorption to selective adsorption sites. Cs desorption from an actual soil sample containing Cs-selective clay mineral illite (< 200 ㎛) and extracted from near South Korea's Kori Nuclear Power Plant was also investigated. Considerable adsorbed 137Cs was expected to be located at Cs-selective sites when the 137Cs loading was much lower than the sample's cation exchange capacity. At this low 137Cs loading, the total Cs amount desorbed by repeated washing varied by desorption agent in the order HCl > PEI > NH4+, and the highest Cs desorption amount achieved using HCl was 83%. Unlike other desorption agents with only cation exchange capabilities, HCl can attack minerals and induce dissolution of metallic elements. HCl's ability to both alter minerals and induce H+/Cs+ ion exchange is expected to promote Cs desorption from actual soil samples.

• 한국광물학회지
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• 제26권3호
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• pp.209-218
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• 2013

원자력 발전소 중대사고에 의해 방사성 세슘($^{137}Cs$)이 지하수계로 유출될 경우를 가정하여, 연구 지역의 깊이에 따른 암석매질의 특성을 규명하고 세슘의 흡착계수를 정량적으로 평가하였다. 대상지역인 신고리 원전 3, 4호기의 지하 암석매질은 주로 석영 및 장석류로 이루어진 화강암 계열이며, 운모류를 10~20% 함유하고 있다. 비교적 얕은 심도(6.3~7.4 m)의 파쇄대에서 2차 광물인 녹니석이 일부 포함되어 있었지만, 기반암에서는 거의 발견되지 않았다. $^{137}Cs$의 흡착분배계수($K_d$)는 파쇄대 지역에서 약 880~960 mL/g로 기반암 지역에서의 820~840 mL/g보다 비교적 높게 나타났으며, 이는 파쇄대에 포함되어 있는 풍화생성물인 2차 광물들에 의한 영향으로 판단된다. 따라서 $^{137}Cs$이 지하 매질로 유출될 경우 대부분은 천부 지역에 흡착되어 세슘에 의한 오염 확산 속도가 지연될 것이라고 예상되며, 이러한 결과는 원자력 발전소 안정성 평가인자 자료로 활용될 것으로 기대된다.

• 자원리싸이클링
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• 제31권5호
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• pp.20-25
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• 2022

본 연구에서는 방사성 폐액내 포함된 방사성 핵종인 세슘-137(Cs-137) 및 스트론튬-90(Sr-90)의 친환경적인 제염을 위해 미세조류의 적용 가능성을 평가하였다. Cs-137 및 Sr-90이 각각 함유된 일원계 표준 방사성 용액과 3차 증류수를 희석하여 1.5 Bq/mL Cs-137, 1.0 Bq/mL Sr-90 농도로 제조한 뒤 실험에 사용하였다. 미세조류는 2종을 사용했으며, Sr-90 제염에는 Chlorella Vulgaris를 사용하였고, Cs-137 제염에는 Hematococcus pluvialis를 사용하여 실험을 수행하였다. 실험 방법은 2주 간 배양된 미세조류를 반투과막이 부착된 병에 투입한 뒤, 미세조류가 투입된 병을 제조된 방사성 용액에 투입하여, 반투과막을 통해 미세조류와 방사성 용액이 48 시간 동안 반응하도록 하였다. 각 시료에 대한 방사능 농도 분석은 γ선 동위원소인 Cs-137은 감마선 핵종 분석기를 사용하였고, β선 동위원소인 Sr-90은 액체섬광계수기(LSC: Liquid Scintillation Count)를 사용하였다. 실험 결과, Cs-137은 약 88.0 %, Sr-90은 약 89.7 % 제염이 가능함을 확인하였으며, Sr-90은 2단 제염 방법에 의해 최종적으로 약 98.6 % 제염이 가능하였다.

• 한국환경농학회지
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• 제4권1호
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• pp.18-24
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• 1985

원자력시설(原子力施設)로부터 방출(放出)될 수 있는 방사성물질(放射性物質)의 하나인 $Cs^{137}$을 토양(土壤)에 처리하여 수도(水稻)에 의한 흡수(吸收)와 그 분포(分布)에 미치는 가리비료(加里肥料)와 Cs담체의 영향을 조사하여 다음과 같은 결과(結果)를 얻었다. 1) 시험토양(試驗土壤) 10㎏에 20 ${\mu}$Ci수준(水準)까지의 $Cs^{137}$처리에서도 수도생육(水稻生育)에 어떤 영향을 볼 수 없었다. 2) 가리(加里)첨가에 따라서 수도(水稻)의 수양(水稻)과 수도체내(水稻體內) K함양(含量)이 증가(增加)하였으나 Ca, Mg의 함양(含量)은 감소(減少)되었으며 수도(水稻)의 $Cs^{137}$흡수(吸收)도 크게 억제(抑制)되었으나 Cs담체첨가는 $Cs^{137}$흡수(吸收)를 증가(增加)시켰다. 3) 수도체내(水稻體內) K와 $Cs^{137}$의 부위별(部位別) 분포(分布)는 동일한 경향으로서 일반적으로 이들 두 원소의 함량은 줄기에서 가장 높았고 다음이 잎, 왕겨, 종실, 현미의 순서였다. 그러나 $Cs^{137}$/K의 함양비(含量比)는 수도체(水稻體) 각 부위(部位)에서 일정치 않았으며 현미와 왕겨등의 종실에서 높았고, 잎과 줄기에서 더 낮았다. 4) 수도(水稻)의 $Cs^{137}$흡수률(吸收率)은 K첨가 증가에 따라서 크게 감소(減少)되었는데 K무첨가구에서는 $0.02{\sim}0.47%$ 범위있고 최고첨가구 (16 ㎏/10a)에서는 $0.01{\sim}0.04%$ 범위였다. 또한 담체첨가구에서의 흡수률(吸收率)은 $0.03{\sim}0.23%$였고 담체무첨가구에서는 $0.01{\sim}0.10%$범위였다. 5) 재배토양(栽培土壤)의 pH와 치환성(置換性) K가 낮은 토양(土壤)에서 수도(水稻)의 $Cs^{137}$흡수(吸收)가 높았으며, 토양(土壤) pH와 치환성(置換性) K가 증가(增加)됨에 따라 흡수(吸收)는 감소(減少)되었고 토양(土壤)의 양(陽)이온 치환능(置換能)과 점토함량이 높으면 수도(水稻)의 $Cs^{137}$흡수(吸收)도 증가되었다.