• Journal of Environmental Science International
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• v.7 no.2
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• pp.149-156
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• 1998

Enoronmental problems caused by certain geologic conditions Include pollution of soil by heavy metal, acidization of souls , acid mine drainage, Pound-water pollution, and natural radioactivity, as well as zoo-logical hazards such as landslide and subsidence. The acrid mine drainage contains large amount of heavy metals nO, therefore. cause serious pollution onto the nearby drainage systems and soils. In spite of this prospective environmental danger, few studies have been done on the acid mine drainage derived from non-metallic ore deposits such as pyrophyllitefNapseok) deposits. The sudo-bearing pyrophyllite ores, alteration zones, and mine talllngs of pyrophylllte deposits produce acrid mine drainage by the okidation of weathering. Compared to the fresh host rocks, the ores and altered rocks of pyrophyllite deposits produce acidic solution which contain higher amount of heavy metals because of OeP lower buffering capacity to acrid solution. The pus of urine water and nearby stream water of pyrophyllite deposits are 2.1~3.7, which are strong- ly acidic and much lower than that (6.2~7.2) of upstream water and than that (6.8~7.6) of the stream water derived from the non-mineralized area. This study reveals that this acrid mine drainage can affect the downstream area which is 8km far from the pyrophyllite deposits, even though the drain Is diluted with abundant non-contaminated river water This suggmists that not only acid mine drainage but also the sulfide-bearing sediments originated from the pyrophyllite deposits move downstream and form acidic water through continuous oxidation reaction. The heavy metals such as Pb, Zn, Cu, Cd, Nl, Mn and Fe are enriched In the mine water of low pH, and their contents decrease as the pH of mine water Increases because of the Influx of fresh stream wainer. SoUs of the Pyrophyulte deposits are characterized by high contents of heavy metals. The stream sediments containing the yellowish brown precipitates formed by neutralization of acid mine drainage occur in all parts of the stream derived from the pyrophyllite deposits, and the sediments also contain high amounts of heavy metals. In summary, the acid mine drainage of the pyrophyllite deposits is located in the upstream part of Hoidong water reservoir in Pusan contains large amounts of heavy metals and flows into the Holdong water reservoir without any purification process. To protect the water of Holdong reservoir, the acid mine drainage should be treated with a proper purification process.

• Analytical Science and Technology
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• v.28 no.6
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• pp.377-384
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• 2015

A survey of the artificial radionuclides in rivers and lakes was conducted to investigate their levels in surface water. Water samples were collected at 60 points and analyzed by gamma-ray spectrometry with a measurement time of 10,000 seconds for ¹³⁴Cs, ¹³⁷Cs, and ¹³¹I. The obained values were lower than MDA for all points, except one point for ¹³¹I that was 0.533±0.058 Bq/L. ¹³¹I is known as a radioactive material that occurs frequently in sewage treatment plants. Because it is often used for medical treatments and subject to spreading into the environment due to the excretion from the patients. For the point where ¹³¹I was detected, we conducted additional investigation on the upstream river point and the effluent points of nearby sewage treatment plant to find the source of ¹³¹I. ¹³¹I was not detected at the upstream points of one of the upstream sewage treatment plants but found at the downstream points with the level being 0.257±0.034 to 0.799±0.051 Bq/L, proving the sewage treatment plant was the ¹³¹Isource.

• Journal of Radiation Protection and Research
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• v.41 no.3
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• pp.268-273
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• 2016

Background: This study was a long-term evaluation of $^{137}Cs$ and $^{90}Sr$ activity concentrations in seawater samples from the East Sea, Korea, in order to establish current activity levels. Results and long-term monitoring trends will be useful in the future monitoring of environmental radioactivity. Materials and Methods: Surface seawater samples were collected quarterly from Guryongpo and Jangho in the East Coast between 1998 and 2010 and the quarterly deep seawater samples were collected from three sites in the sea adjacent to Ulleung-do between 2012 and 2015. The activity concentrations of $^{137}Cs$ were measured using a gamma-spectrometer. The activity concentrations of $^{90}Sr$ and $^{90}Y$ in a radioactive equilibrium state were measured using a gas flow proportional counter. Results and Discussion: We found the annual average activity concentrations of $^{137}Cs$ in the surface seawater was $1.66-2.89mBq{\cdot}kg^{-1}$ in Guryongpo and $1.68-2.43mBq{\cdot}kg^{-1}$ in Jangho. The annual average activity concentrations of $^{90}Sr$ in the surface seawater was $0.83-1.98mBq{\cdot}kg^{-1}$ in Guryongpo and $0.82-1.57mBq{\cdot}kg^{-1}$ in Jangho. The annual average activity concentrations of $^{137}Cs$ in the deep seawater sites were $1.51-1.73mBq{\cdot}kg^{-1}$, $1.19-1.60mBq{\cdot}kg^{-1}$ and $0.87-1.15mBq{\cdot}kg^{-1}$ in TH, JD, and HP. The annual average activity concentrations of $^{90}Sr$ in the same deep seawater sites were $1.00-1.94mBq{\cdot}kg^{-1}$, $0.82-1.26mBq{\cdot}kg^{-1}$, and $0.79-1.32mBq{\cdot}kg^{-1}$. The effective half-life was calculated by analyzing change over time in the activity concentration in the surface seawater. The effective half-life of $^{137}Cs$ was $15.3{\pm}0.1years$ in Guryongpo and $102{\pm}3years$ in Jangho. The effective half-life of $^{90}Sr$ was $28.3{\pm}4.3years$ in Guryongpo and $16.6{\pm}0.1years$ in Jangho. The ratio of the average activity concentration ($^{137}Cs/^{90}Sr$) was 1.72 in the surface seawater, which is similar to the reported ratio of the global radioactive fallout. The ratio in the deep seawater was 1.24, which is somewhat low compared to the global ratio (1.6, 1.8). Conclusion: Activity concentrations of $^{137}Cs$ and $^{90}Sr$ in the seawaters of the East Sea were similar to the previously reported activity levels in the East Sea and northwestern Pacific as a result of global radioactive fallout following atmospheric nuclear weapon tests.

• Journal of the Korean Society of Food Culture
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• v.17 no.2
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• pp.141-152
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• 2002

This study provides a national examination on youths' 'understanding' of irradiated food. The 1,200 subjects of the survey were randomly sampled from male and female students throughout the nation, between grades five and eleven. The survey was conducted toward these samples in November 2000. The number of respondents with exposure to irradiated food was so small, amounting to only 4.0 percent of the whole sample. The core concept used in this study is 'impression'. An impression is information about a specific subject, which carries significance to an individual. The results show that the higher the grade was, the more value the contents of impression contained. Furthermore, impressions concerning atomic or nuclear energy, and radioactivity increased greatly among students in middle school and above. Providing information of effects and advantages of irradiated food was focused to increase positive impressions and decrease the negative ones more greatly than providing simple factual information. Youths showed less value-centered impressions of irradiated food and more impressions centered on fragmented facts than adults. Respondents previously exposed irradiated food were shown to acquire the most of their information from the television and newspaper media. Among six information sources presented in the survey, youths pointed out 'science and technology research institutes' as the most credible. International organizations and environmental/ consumer organizations were evaluated as having relatively high credibility. Providing simple factual information of irradiated food did not seem to bring about any difference to the intention of purchasing irradiated food. On the other hand, respondents provided with effects-included information showed an increase in such intention. Our research results of the youth show a notable difference with that of the adults. Thus, programs and strategies to enhance youths' understanding should differ from those concerning adults.

• Journal of Radiation Protection and Research
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• v.41 no.2
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• pp.173-178
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• 2016

Background: In situ gamma spectrometry has been used to measure environmental radiation, assumptions are usually made about the depth distribution of the radionuclides of interest in the soil. The main limitation of in situ gamma spectrometry lies in determining the depth distribution of radionuclides. The objective of this study is to develop a method for subsurface characterization by in situ measurement. Materials and Methods: The peak to valley method based on the ratio of counting rate between the photoelectric peak and Compton region was applied to identify the depth distribution. The peak to valley method could be applied to establish the relation between the spectrally derived coefficients (Q) with relaxation mass per unit area (${\beta}$) for various depth distribution in soil. The in situ measurement results were verified by MCNP simulation and calculated correlation equation. In order to compare the depth distributions and contamination levels in decommissioning KRR site, in situ measurement and sampling results were compared. Results and Discussion: The in situ measurement results and MCNP simulation results show a good correlation for laboratory measurement. The simulation relationship between Q and source burial for the source layers have exponential relationship for a variety depth distributions. We applied the peak to valley method to contaminated decommissioning KRR site to determine a depth distribution and initial activity without sampling. The observed results has a good correlation, relative error between in situ measurement with sampling result is around 7% for depth distribution and 4% for initial activity. Conclusion: In this study, the vertical activity distribution and initial activity of $^{137}Cs$ could be identifying directly through in situ measurement. Therefore, the peak to valley method demonstrated good potential for assessment of the residual radioactivity for site remediation in decommissioning and contaminated site.

• Journal of Radiation Protection and Research
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• v.21 no.1
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• pp.9-16
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• 1996

For the determination of radiostrontium, $^{89}Sr\;and\;^{90}Sr$ in environmental soil sample, a solvent extraction method for the separation of Ca and Sr from matrix using crown ether was investigated. In comparison with the existing fuming nitric acid method, the extraction method showed high chemical yield of strontium and provided simple and rapid analytical steps. The new analytical method applied to the determination of radiostrontium in some soil sample around a nuclear power station to show that the analytical procedure is readily applicable to the practical radioactivity monitoring.

• Journal of the Korean Society of Radiology
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• v.11 no.6
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• pp.531-538
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• 2017

Agricultural products produced in the agricultural area around the nuclear power plant are radioactive contamination, which can cause radioactive contamination to the human body. The purpose of this study was to investigate the limit of the radioactivity concentration $^{90}Sr$ for the internal exposure dose evaluation by ingesting the agricultural products collected around the nuclear power plant. The results of the gamma-isotope element analysis were freshly <0.0166-0.0336 Bq / kg for all samples and for artificial radionuclides not detected, and fresh <0.00586-0.0421 Bq / kg for Chinese cabbage, The freshness was 0.106 Bq / kg, and the freshness was 0.0114-0.0901 Bq / kg. 0.0177%, 0.0222%, 0.0376% and 0.00243%, respectively, for Chinese cabbages and large roots, which is lower than the legal standard value of $1mSv/yr{\cdot}man%$. It is considered that the formulas need to be broadly evaluated for the foods consumed by children and adults, taking into consideration the age of the food and the diet

• Journal of Radiation Protection and Research
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• v.45 no.2
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• pp.53-68
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• 2020

Background: International organizations such as the World Health Organization (WHO) and the United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) reported public exposure doses due to radionuclides released in the Fukushima nuclear accident a few years after the event. However, the reported doses were generally overestimated due to conservative assumptions such as a longer stay in deliberate areas designated for evacuation than the actual stay. After these reports had been published, more realistic dose values were reported by Japanese scientists. Materials and Methods: The present paper reviews those reports, including the most recently published articles; and summarizes estimated effective doses (external and internal) and issues related to their estimation. Results and Discussion: External dose estimation can be categorized as taking two approaches-estimation from ambient dose rate and peoples' behavior patterns-and measurements using personal dosimeters. The former approach was useful for estimating external doses in an early stage after the accident. The first 4-month doses were less than 2 mSv for most (94%) study subjects. Later on, individual doses came to be monitored by personal dosimeter measurements. On the basis of these measurements, the estimated median annual external dose was reported to be < 1 mSv in 2011 for 22 municipalities of Fukushima Prefecture. Internal dose estimation also can be categorized as taking two approaches: estimation from whole-body counting and estimation from monitoring of environmental samples such as radioactivity concentrations in food and drinking water. According to results by the former approach, committed effective dose due to ¹³⁴Cs and ¹³⁷Cs could be less than 0.1 mSv for most residents including those from evacuated areas. Conclusion: Realistic doses estimated by Japanese scientists indicated that the doses reported by WHO and UNSCEAR were generally overestimated. Average values for the first-year effective doses for residents in two affected areas (Namie Town and Iitate Village) were not likely to reach 10 mSv, the lower end of the doses estimated by WHO.

• Toxicological Research
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• v.13 no.4
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• pp.359-365
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• 1997

Many factors are known to be responsible for cerebral ischemic injury, such as excitatory neurotransmitters, increased intraneuronal calcium, or disturbance of cellular energy metabolism. Recently, oxygen free radicals, formed during ischemia/reperfusion, have been proposed as one of the main causes of ischemia/reperfusion injury. Therefore, to investigate the role of oxygen free radical during ischemia/reperfusion, in the present study the effect of endogenous oxygen free radical scavenger, superoxide dismutase / catalase(SOD / catalase) on the release of [$^3$H]-5-hydroxytryptamine([$^3$H]-5-HT) during hypoxia/reoxygenation in rat hippocampal slices was measured. The hippocampus was obtained from the rat brain and sliced 400 gm thickness with manual chopper. After 30 min's preincubation in the normal buffer, the slices were incubated for 20 min in a buffer containing [$^3$H]-5-HT(0.1 $\mu$M, 74 $\mu$Ci) for uptake, and washed. To measure the release of [$^3$H]-5-HT into the buffer, the incubation medium was drained off and refilled every ten minutes through a sequence of 14 tubes. Induction of hypoxia for 20 min (gassing it with 95% N$_2$/5% CO$_2$) was done in the 6th and 7th tube, and oxygen free radical scavenger, SOD / catalase was added 10 minutes prior to induction of hypoxia. The radioactivity in each buffer and the tissue were counted using liquid scintillation counter and the results were expressed as a percentage of the total activity. When slices were exposed to hypoxia for 20 min, [$^3$H]-5-HT release was markedly decreased and a rebound release of [$^3$H]-5-HT was observed on the post-hypoxic reoxygenation period. SOD / catalase did not changed the release of [$^3$H]-5-HT in control group, but inhibited the decrease of [$^3$H]-5-HT release in hypoxic period and rebound increase of [$^3$H]-5-HT in reoxygenation period. This result suggest that superoxide anion may play a role in the hypoxic-, and reoxygenation-induced change of [$^3$H]-5-HT release in rat hippocampal slices.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.6 no.4
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• pp.387-398
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• 2008

To obtain base-line data in the low- and intermediate-level radioactive waste disposal facility, radiological environment investigation is required at least two years prior to the facility operation near the disposal facility. The investigation has been performed since January 2007 for the Wolsong LILW disposal center. In this paper, investigation procedure and detailed information obtained for six months in 2008 are described. Based on the current results, future investigation planning is also discussed for the radiological environment management of the disposal facility.