• Journal of the Korean Society of Radiology
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• v.17 no.1
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• pp.25-30
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• 2023

As 3D printing technology is used in the medical field, interest in metal materials is increasing. The Department of Radiation Oncology uses a shielding block to shield the patient's normal tissue from unnecessary exposure during electron beam therapy. However, problems such as handling of heavy metal materials such as lead and cadmium, reproducibility according to skill level and uncertainty of arrangement have been reported. In this study, candidate materials that can be used for metal 3D printing are selected, and the physical properties and radiation dose of each material are analyzed to develop a customized shielding block that can be used in electron beam therapy. As candidate materials, aluminum alloy (d = 2.68 g/cm³), titanium alloy (d = 4.42 g/cm³), and cobalt chromium alloy (d = 8.3 g/cm³) were selected. The thickness of the 95% shielding rate point was derived using the Monte Carlo Simulation with the irradiation surface and 6, 9, 12, and 16 energies. As a result of the simulation, among the metal 3D printing materials, cobalt chromium alloy (d = 8.3 g/cm³) was similar to the existing shielding block (d = 9.4 g/cm³) in shielding thickness for each energy. In a follow-on study, it is necessary to evaluate the usefulness in clinical practice using customized shielding blocks made by metal 3D printing and to verify experiments through various radiation treatment plan conditions.

• Journal of Environmental Health Sciences
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• v.48 no.4
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• pp.236-243
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• 2022

Background: In the case of multiple exposures to different types of heavy metals, such as the conditions faced by residents living near a smelter, it would be preferable to group hazardous substances with similar characteristics rather than individually related substances and evaluate the effects of each group on the human body. Objectives: The purpose of this study is to evaluate the utility of factor analysis in the assessment of health effects caused by exposure to two or more hazardous substances with similar characteristics, such as in the case of residents living near a smelter. Methods: Heavy metal concentration data for 572 people living in the vicinity of the Janghang smelter area were grouped based on several subfactors according to their characteristics using factor analysis. Using these factor scores as an independent variable, multiple regression analysis was performed on health effect markers. Results: Through factor analysis, three subfactors were extracted. Factor 1 contained copper and zinc in serum and revealed a common characteristic of the enzyme co-factor in the human body. Factor 2 involved urinary cadmium and arsenic, which are harmful metals related to kidney damage. Factor 3 encompassed blood mercury and lead, which are classified as related to cardiovascular disease. As a result of multiple linear regression analysis, it was found that using the factor index derived through factor analysis as an independent variable is more advantageous in assessing the relevance to health effects than when analyzing the two heavy metals by including them in a single regression model. Conclusions: The results of this study suggest that regression analysis linked with factor analysis is a good alternative in that it can simultaneously identify the effects of heavy metals with similar properties while overcoming multicollinearity that may occur in environmental epidemiologic studies on exposure to various types of heavy metals.

• Journal of Nutrition and Health
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• v.55 no.4
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• pp.430-440
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• 2022

Selenium is an important trace mineral that plays an essential role in maintaining the body's immunity with oxidative stress defense and antioxidant activity, immunity, thyroid hormone control, defense against drug or heavy metal harm, and reducing the risk of chronic diseases. A selenium deficiency increases the risk of various chronic diseases, such as cancer, cardiovascular disease, diabetes, neurological disease, osteoarthritis, muscle necrosis and weakness, thyroid disease, and inflammatory diseases. This paper explains the criteria for establishing and revising selenium in the 2020 Dietary Reference Intake for Koreans (KDRIs) and reviews the current status of the selenium database and suggestions for setting the 2025 KDRIs in the future. In the 2020 KDRIs, the selenium intake with the maximum plasma selenoprotein P level was used as the criteria. The weight and coefficient of the variation were applied to the Chinese' reported values. Compared to 2015 KDRIs, there were some revisions in the selenium dietary reference intakes by gender and age according to the change in reference weight. To improve and revise selenium dietary reference intakes in the future, a selenium intervention study is needed to determine the maximum level of plasma selenoprotein P in Koreans. In addition, a revision of the selenium database of the nutritional assessment program (CAN-Pro 5.0) is needed. An analysis of the selenium content of foods should be expanded to assess the selenium intake accurately. In addition, research on the relationship between selenium intake and the biological indicators in the body is required for healthy people and subjects of special environments, such as patients and athletes with various oxidative stress.

• Korean Journal of Clinical Laboratory Science
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• v.54 no.4
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• pp.298-306
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• 2022

This study sought to evaluate the mechanism of cellular injury caused by ferrous sulfate (FeSO₄) and the protective effects of Parnassia palustris L. (PP) extract against FeSO₄-induced cytotoxicity of cultured C6 glioma cells. FeSO₄ is known to cause neurotoxicity and induce Parkinson's disease. The antioxidative effects of PP, such as superoxide dismutase (SOD)-like and superoxide anion-radical (SAR)-scavenging activities, as well as effects on cell viability, were studied. FeSO₄ significantly decreased cell viability in a dose-dependent manner and the XTT₅₀ value, the concentration of FeSO₄ which reduced the cell viability by half, was measured at 63.3 μM in these cultures. FeSO₄ was estimated to be highly cytotoxic by the Borenfreund and Puerner toxicity criteria. Quercetin, an antioxidant, significantly improved cell viability, damaged by FeSO₄-induced cytotoxicity. While evaluating the protective effects of the PP extract on FeSO₄-induced cytotoxicity, it was observed that the extract significantly increased cell viability compared to the FeSO₄-treated group. Also, the PP extract showed superoxide dismutase (SOD)-like and superoxide anion radical (SAR)-scavenging activities. Based on these findings, it can be concluded that FeSO₄ induced oxidative stress-related cytotoxicity, and the PP extract effectively protected against this cytotoxicity via its antioxidative effects. In conclusion, natural antioxidant sources such as PP may be agents useful for preventing oxidative stress-related cytotoxicity induced by heavy metal compounds such as the FeSO₄, a known Parkinsonism inducer.

• Journal of Environmental Health Sciences
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• v.48 no.6
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• pp.306-314
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• 2022

Background: Due to the rapid aging of the South Korean population, neurological diseases such as dementia are increasing. Many studies have reported that the incidence of dementia is associated with environmental factors along with age. Objectives: This study analyzed the association between cognitive function and ten heavy metals in the body: arsenic, aluminum, chromium, manganese, cobalt, nickel, iron, copper, zinc, and lead. Methods: From 2018 to 2019, a total of 120 participants who suffered from cognitive impairment were recruited for this study. Blood and urine samples were collected and analyzed for heavy metal concentrations using an inductively coupled plasma mass spectrometer. Demographic information was obtained through face-to-face questionnaires completed by a trained investigator. Cognitive function was evaluated with the Korean version of the Mini-Mental State Examination and the Korean version of the Boston Name Waiting Test. The associations between cognitive function scores and heavy metal concentrations were analyzed using multiple logistic regression analysis. Results: The average age of the 120 participants was 72.7 years, and 69.2% were female. The mean of the MMSE-K and K-BNT scores were 22.9 and 37.9, respectively. The geometric mean of aluminum (Al) was 8.42 ㎍/L. MMSE-K was associated with iron (Fe), but the significance was removed in the logistic regression based on 24 points. K-BNT was significantly associated with aluminum and the odds ratio for K-BNT above 38 decreased by 45% as the aluminum concentration increased. Conclusions: The association between aluminum and the K-BNT score indicated that aluminum is associated with language-related cognitive decline. Based on this result, further study will be conducted by considering co-exposure effects of heavy metals including aluminum.

• Journal of Food Hygiene and Safety
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• v.38 no.3
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• pp.158-163
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• 2023

This study aimed to determine mercury (Hg), methylmercury (MeHg), and selenium (Se) levels in deep-sea fishes distributed in Gyeonggi-do, South Korea. Concentrations of Hg, MeHg, and Se were measured by using a mercury analyzer and Inductively Coupled Plasma - Mass Spectrometry (ICP-MS). The average content (mg/kg) in the seafood samples was as follows: Hg, 0.7647 (0.0182-5.3620), MeHg, 0.0764 (0.0096-0.8750), and Se, 0.4728 (0.1075-3.5100). All the levels of MeHg were below the recommended standards of the Ministry of Food and Drug Safety i.e., <1.0 mg/kg. Recent studies have shown that Se prevents Hg toxicity. The average daily intake in humans was 3.3 ㎍/kg, which was lower than the recommended amount (50-200 ㎍/person/day). The weekly intake of Hg and MeHg was calculated to be 6.07% and 1.90%, respectively, of the provisional tolerable weekly intake (PTWI). This study showed that the weekly intake of Hg and MeHg from abyssal fish was less than the PTWI recommended by the Joint FAO/WHO expert committee on food additives. Therefore, the levels reported in this study are presumed to be adequately safe.

• Applied Chemistry for Engineering
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• v.35 no.1
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• pp.54-60
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• 2024

The present study was aimed to evaluate the removal of the trace pollutants (heavy metals and microplastics) in the sewage treatment plant by using the jellyfish Extract at Immunity reaction (JEI) of Aurelia coerulea. The experiment was conducted on two different scales: the lab scale using a Jar-tester and the Pilot system scale equipped with two newly developed devices in the laboratory, the active tube connection mixed system and the concentration integrated separation device. Compared to anionic polymers currently used in the field, JEI showed similar or higher efficiency to remove the trace pollutants. When JEI was added to the effluent through the Pilot system, the combination of JEI and the trace pollutants was maximized through two mixing processes, and as a result, the removal rate of the trace pollutants was greatly improved. Based on these results, we propose the present technology as an alternative to removing trace pollutants that can reduce ecosystem risk and minimize the generation of inorganic waste, away from the existing method.

• Journal of Environmental Health Sciences
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• v.50 no.1
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• pp.25-35
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• 2024

Background: There are concerns about the health effects of various environmental pollution exposures among residents living near coal-fired power plants (CFPP). Objectives: This study attempted to compare the concentrations of heavy metals in blood and urine and those of urinary volatile organic compound (VOC) metabolites according to the residential separation distance. Methods: Participants in the study totaled 334 people who have lived for more than 10 years in areas within 10 km of a CFPP. The separation distance was analyzed in quartiles by dividing it into Q1 (88 people), Q2 (89 people), Q3 (89 people), and Q4 (68 people). We explained the purpose of this study to the participants and collected blood and urine after obtaining signatures on a participation agreement. Results: The study participants were 102 males (30.5%) and 232 females (69.5%), with an average age of 71. The average length of residence and distance were 43.8 years and 4,800 meters. The geometric mean concentrations of Pb, Cd, and Hg in blood and As and Cd in urine were respective 1.35 ㎍/dL, 1.43 ㎍/L, 3.16 ㎍/L. They were 167.88 ㎍/g for creatinine and 1.58 ㎍/g creatinine. The metabolite concentrations of VOCs were 50.67 ㎍/g creatinine in t, t-muconic acid (t, t-MA), 10.73 ㎍/g creatinine in benzyl mercapturic acid, 317.05 ㎍/g creatinine in phenylglyoxylic acid, 123.55 ㎍/g creatinine in methylhippuric acid, and 190.82 ㎍/g creatinine in mandelic acid. The concentration of Pb in the blood and Cd and t, t-MA in the urine of residents within affected area of the CFPP showed statistically significant differences among distance groups. Conclusions: The concentration of urinary VOCs metabolites, especially t, t-MA, differed according to the distance groups of residents within the affected area of CFPP (p<0.05).

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.13 no.2
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• pp.147-155
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• 2008

A series of experiments were conducted to find standard test organisms and to develop test protocols for sediment toxicity tests using indigenous amphipods inhabited in Korean coastal environments. The indigenous amphipods Mandibulophoxus mai and Monocorophium acherusicum were well associated with various sediment substrates from sand to mud. The tolerance limits to various physico-chemical factors affecting bioassay results such as temperature, salinity and total ammonium as well as the sensitivities to contaminants in water and sediments were investigated using M. mai and M. acherusicum in the present study. These amphipods were tolerable to the adequate ranges of salinity ($10{\sim}30\;psu$), temperature ($10{\sim}25^{\circ}C$) and ammonia (<50 ppm). They have relevant sensitivities to the reference toxicants, dissolved cadmium as well as other metals and organic pollutants, when compared to the standard test species used in other countries. Field-sediment toxicity tests revealed that M. mai would be more sensitive to sediment-associated pollutants than M. acherusicum, while the sensitivity of M. acherusicum was comparable to those of other sediment test species in other countries. Overall results of this first attempt to develop an amphipod sediment toxicity test protocol in Korea indicated that M. mai and M. acherusicum should be applicable in the toxicity assessment of contaminated sediments, following the further evaluation encompassing various ecological and toxicological evaluation and the standardization of test method.

• Korean Journal of Environmental Agriculture
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• v.30 no.1
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• pp.24-30
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• 2011

BACKGROUND: High input to the arable land is contributed to increasing productivity with causing the global environmental problems at the same time. Rapeseed cultivation has been forced to reassess its positive point for utilization of winter fallow field. The Objective of this study was performed to assess the environmental impact of rapeseed cultivation with double-cropping system in paddy rice on Yeonggwang district using life cycle assessment technique. METHODS AND RESULTS: For assessing each stage of rapeseed cultivation, it was collected raw data for input materials as fertilizer and pesticide and energy consumption rate by analyzing the type of agricultural machinery and working hours by 1 ton rapeseed as functional unit. Environmental impacts were evaluated by using Eco-indicator 95 method for 8 impact categories. It was estimated that 216 kg $CO_2$-eq. for greenhouse gas, 3.98E-05 kg CFC-11-eq. for ozone lazer depletion, 1.78 kg SO2-eq. for acidification, 0.28 kg $PO_4$-eq. for eutrophication, 5.23E-03 kg Pb-eq. for heavy metals, 2.51E-05 kg B(a)p-eq. for carcinogens, 1.24 kg SPM-eq. for smog and 6,460 MJ LHV for energy resource are potentially emitted to produce 1 ton rapeseed during its whole cultivation period, respectively. It was considered that 90% of these potential came from chemical fertilizer. For the sensitivity analysis, by increasing the productivity of rapeseed by 1 ton per ha, potential environmental loading was reduced at 22%. CONCLUSION(s): Fertilization affected most dominantly to the environmental burden, originated from the preuse stage, i.e. fertilizer manufacturing and transporting. It should be included and assessed an indirect emission, which is not directly emitted from agricultural activities. Recycling resource in agriculture with reducing chemical fertilizer and breeding the high productive variety might be contribute to reduce the environmental loading for the rapeseed cultivation.