• Journal of Radiation Protection and Research
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• v.28 no.3
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• pp.155-163
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• 2003

The groundwater flow and contaminant transport numerical models have been established for analyzing the movements of pollutants in subsurface soil at Daeduk site. The groundwater flow and concentration of U-234 using the numerical models were simulated around Daeduk nuclear facilities. The computed groundwater flow was mainly advected toward the direction of east and southeast around HANARO in the site. The radioactive material entered into the subsurface soil was transported along the same direction with groundwater flow. The radioactive material deposited on the surface from the calculated concentration distributions was not affected by surrounding environment of the site.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.14 no.4
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• pp.331-341
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• 2016

To evaluate the physicochemical and radiological properties of raw materials and by-products in domestic distribution, about 220 samples with 16 species were prepared. We measured the energy spectrum and the chemical content, such as U, Th, and K, using a $LaBr_3$ scintillation detector and ED-XRF. In addition, HPGe detector was used to analyze the radioac-tivity of $^{234}Th$, $^{234}mPa$, and $^{214}Bi$ in uranium decay series and $^{228}Ac$, $^{212}Pb$, and $^{208}Tl$ in thorium decay series, and $^{40}K$. The correlation between characteristic variables, such as the count rate in several ROIs, chemical content, and radioactivity, was assessed to infer the radioactivity of natural radionuclides through a rapid screening method. Based on the results, a characteristic database for raw material and by-product in domestic distribution was established and it will provide useful information in the analysis procedure and improve the accuracy and reproducibility in the analysis of natural radionuclides.

• Clinical and Experimental Pediatrics
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• v.49 no.10
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• pp.1037-1041
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• 2006

Purpose : The prevalence of obesity and nonalcoholic steatohepatitis(NASH) was increased in adolescents. This study was performed to observe the prevalence of elevated aminotransferase levels in adolescents and to assess the correlations between aminotransferase levels and obesity related parameters(body mass index, waist circumference, hip circumference, waist to hip ratio and insulin level). Methods : We obtained weight, height, waist circumference and hip circumference from 2,417 male and 1,219 female adolescents. Mean age was $15.7{\pm}0.7$ years old. We measured fasting insulin, aspartate aminotransferase(AST) and alanine aminotransferase(ALT). Obese and overweight were defined as body mass indices(BMI) of more than the 95th, and 85th-94th percentiles, respectively, for age and sex. Results : The number of adolescents with obesity is 324(8.9 percent). 414(11.4 percent) subjects belonged to the overweight group. The average ALT level of obese, overweight and control groups were significantly different(obese : $32.1{\pm}34.3U/L$, overweight : $19.6{\pm}13.6U/L$, control : $12.7{\pm}6.7U/L$, P<0.001). The average AST level was also different according to group(obese : $27.8{\pm}16.5U/L$, overweight : $22.8{\pm}8.6U/L$, control : $20.8{\pm}8.5U/L$, P<0.001). AST and ALT were correlated with anthropometric parameters and insulin level. After multiple regression analysis, waist circumference was the significant predictive value for AST(r=0.234, P<0.001). Waist circumference, BMI and insulin levels were significant predictive values for ALT(r=0.435, P<0.001). Conclusion : The prevalence of abnormal aminotransferase was higher in the obese and overweight groups than control group. Waist circumference was useful to predict abnormal aminotransferase levels.

• Journal of Environmental Health Sciences
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• v.30 no.5 s.81
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• pp.469-480
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• 2004

The radon concentrations were measured to survey distribution of radon concentrations in Seoul subway stations. The radon concentrations in air and water were measured at seventeen subway stations(Mapo, Chungjongno, Sodaemun, Kwanghwamun, Chongno3ga, Ulchiro4ga, Tangdaemun, Sangildong on Line 5;Nowon, Chunggye, Hagye, Kongnung, Taenung, Mokkol, Chunghwa, Sangbong, Myomok on Line 7) using the $RAdtrak^{TM}$ radon gas detector, Pylon AB-5 continuous passive radon detector and liquid scintillation counting method from January to May 1999. The major results obtained from this study were as follows: The long-term mean concentrations of radon were $61.8\;Bq/m^3$ in office, $78.9\;Bq/m^3$ in platform, $38.2\;Bq/m^3$ in concourse and $20.1\;Bq/m^3$ in outdoor, respectively. These levels were less than the action level ($148\;Bq/m^3$) of the U.S. EPA. The highest level of short-term mean concentrations was $116.55\;Bq/m^3$ at Chongno3ga station on the 5th line subway stations, while the lowest mean concentration was $19.55\;Bq/m^3$ at Mokkol station on the 7th line subway stations. The highest concentration of radon in the road water and storing underground water in the subway stations was $234.7\;KBq/m^3\;and\;155.5\;KBq/m^3$ in Sodaemun subway station, respectively. The results suggest that radon concentration in subway stations seems to be affected by ventilation and radon concentratin in underground water in the subway stations.

• Korean Journal of Agricultural and Forest Meteorology
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• v.6 no.1
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• pp.38-48
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• 2004

Tropospheric ozone data in Korea for 1998-2002 were analyzed to assess the impact on vegetation. SUM06(sum of hourly concentrations at or above 0.06 ppm) and AOT40(accumulated exposure over a threshold of 40 ppb), widely used as ozone indices in the U.S. and Europe, were calculated based on hourly ozone concentration in 612 areas during 1998-2002 in Korea. SUM06 of the highest 30 areas were 5-12 ppm/hr which were almost the same levels of the U.S. average, and a crop loss of 5% would be expected. Ozone pollution in Seoul during 1998-2002 had decreased compared to that for 1990-97 except in the Northern area; however, ozone pollution in Kyunggi during 1998-2002 had been increased twice compare to the previous 5 years. Korea was divided into four regions: Seoul Metropolitan area, Jungbu, Honam, and Youngnam. Ozone pollution in the Seoul Metropolitan area was much higher during 1998-2000 than the other areas, but ozone pollution during 2001-2002 was almost the same in all four regions. Chunnam-Kwangyang na Kyungbuk-Gumi, famous industrial complexes in southern Korea, were significant ozone pollution areas. However, other industrial complexes, such as Incheon, Ulsan, and Kyunggi-Sihwa, were not polluted compared to their neighbors. Comparing all ozone indices, SUM06(yr), SUM06(3mon), AOT40(yr), AOT40(3mon), number of hours exceeding 100 ppb, 95 percentile, 99 percentile, and maximum concentration, it was determined reasonable to use SUM06(3mon), AOT40(3mon) and number of hours exceeding 100 ppb for evaluation of the chronic impact of ozone on vegetation.