• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
• /
• v.24 no.4
• /
• pp.535-547
• /
• 2019

In this study, the heavy metal analysis in sediments (surface sediments, sediments cores and settling particles) from Shihwa Lake has been carried out to evaluate the changes of metal pollution levels in sediments after the operation of Tidal Power Plant (TPP). The average concentrations of metals in surface sediments sampled in 2015 were 8% (Cd)~31% (Zn, Hg) lower than in 2009 before TPP operation. Results of calculating the pollution load index (PLI) with 8 metals, the PLI value in 2015 showed a 18% decrease compared to 2009. However, Cu, Zn, Pb concentrations of surface sediments in 2015 at the upper region around industrial complex still exceeded the TEL (threshold effect level) values for sediment quality guideline in Korea. After the operation of TPP, the metal contaminated depths were increasing from 15 cm to 30 cm at S6 site and from 8 cm to 20 cm at S7 site, respectively. Our data showed that the mean concentration of heavy metals in core samples decreased but the contaminated depth increased. The average of the total sedimentation flux for particulate matter increased by 3.2 times from 32.5 g/㎡/d in 2009 to 103.5 g/㎡/d in 2015. This showed that the bottom sediments were resuspended by the operation of TPP, resulting in an increase of particulate matter in the water column. These results suggest that the sediments contaminated with heavy metals seem to be resuspended and relocated due to the water current caused by the operation of TPP. Cr, Cu, Zn, Pb and Cd were highly exceeding the TEL values in the upstream region and accumulated more than 40 cm of sediment depth, indicating that heavy metal contamination through industrial activity were still a serious environmental problem of Shihwa Lake. Although the metal pollution of Shihwa Lake has been slightly reduced, the contaminated sediments with heavy metals inside of Shihwa Lake might be discharged to outer sea after the resuspension by TPP operation. It is necessary for the advanced scientific approach and political decision to drastically reduce the heavy metal pollution of the study region.

• Korean Journal of Environmental Agriculture
• /
• v.40 no.1
• /
• pp.60-66
• /
• 2021

BACKGROUND: The concern over heavy metal(loid)s in arable land and agricultural products increases for public health in recent years. This study aims to identify transition characteristics of heavy metal(loid)s and to assess dietary risk in barley grown at the major producing districts in Korea. METHODS AND RESULTS: The soil and barley samples were collected from 38 locations around the major producing districts at Jeollabuk-do in Korea for the propose of examining the concentrations of heavy metal(loid)s. The 34 barley samples were separately purchased on the market for the same survey. The average concentration and range of arsenic (As), cadmium (Cd) and lead (Pb) in barley grown at the major producing districts in Korea were 0.037 (0.016-0.094), 0.028 (0.004-0.083) and 0.137 (0.107-0.212) mg kg-1, respectively. Currently, the maximum allowable level for barley Pb is set at 0.2 mg kg-1 in Korea, and the monitoring results suggested that some samples exceeded the maximum allowable level and required appropriate farming management. Bio-concentration factor values by heavy metal(loid)s in barley were high at Cd, copper (Cu) and zinc (Zn), similar to other crops, while As and Pb were low, indicating low transferability. CONCLUSION: Human exposure to As, Cd and Pb through dietary intake of barley might not cause adverse health effects due to relatively low concentrations, although the Pb in some barley was detected higher than the maximum allowable level. Further study on uptake and accumulation mechanism of Pb by barley might be required to assess the human health risk associated with soil contamination.

• Journal of the Korean Crystal Growth and Crystal Technology
• /
• v.4 no.4
• /
• pp.388-394
• /
• 1994

A Hg(0.79)Cd(0.21)Te single crystal has been grown by the Traveling Heater Method(THM). Its zinc blend cubic structure is identified from the X-ray diffraction patterns and its lattice constant is determined to be $6.464 {\AA}$ using the least-square method of Cohen. From the values of the lattice constant, the composition x is determined to be 0.21. The electron density is calculated from the relative intensities of the scattered X-ray and compared with the theoretically calculated values. From the electron density distribution, it is shown that the crystal binding of Hg(1-x)Cd(x)Te(MCT) is mainly covalent and has tetrahedron bonds between adjacent atoms.

• Journal of Environmental Impact Assessment
• /
• v.17 no.6
• /
• pp.321-333
• /
• 2008

Considering risks and artificial enrichments of metals in the soils of the study area, the study aims to analyze geology, grain size and geochemistry. Geology is mainly composed of gneisses and phyllites of metamorphic rocks, sandstones, siltstones, shales, tuffs of sedimentary ones and granites and andesites of igneous ones in the area. In the area, mean contents of metals are not meaningful in accordance with petrogenesis. The soil textures of the area are of S, lS and sL of sandy soil, L, scL, cL of loam and C, zC and sC of clayey soil. Mean contents of Ni, Cr, Co and Cu are meaningfully high in loam and clayey soil relative to sandy soil, whereas Ni, Zn, Cd contents are higher in clayey soil than in loam. Those differences imply the metallic contents are dependent to grain size. Based on the metal contents in the soils of the study area, Cu and Zn in loams and Pb in sandy soils are corresponded to soil contamination warning standards, and As showing 75mg/kg of maximum content in loams is assigned to soil contamination countermeasure standards, respectively. Artificial enrichment factor minimized wall rock and grain size relations is over 1 in Cr, Ni and Cu, but the factor is below 1 in average of other metals.

• Applied Chemistry for Engineering
• /
• v.28 no.6
• /
• pp.655-662
• /
• 2017

Sulfide photocatalysts, CdS and CdZnS, were synthesized using a simple precipitation method and their photocatalytic activities were evaluated by the degradation of rhodamine B under visible light irradiation. The effects of four inorganic salt additives, KCl, NaCl, $K_3PO_4$, and $Na_3PO_4$, on the photocatalytic reaction were examined and the role of $K^+$, $Na^+$, $Cl^-$ and $PO_4{^{3-}}$ ions during photocatalytic reaction was discussed. The added inorganic salts were shown to have a remarkable effect on the photocatalytic reaction. It was also found that the anions in inorganic salts have a much more profound effect on the reaction rate, as compared to the cations. Under the present experimental conditions, $PO_4{^{3-}}$ revealed a significant inhibitory effect on the degradation rate whereas $Cl^-$ enhanced the rate slightly. This work pointed out that the consideration of additive effects is needed in the photocatalytic reaction for wastewater treatment.

• Journal of Sensor Science and Technology
• /
• v.6 no.5
• /
• pp.423-429
• /
• 1997

We fabricated PLT thin films on ITO substrate for flat pannel display and investigated the characteristics, then we applicated to electroluminescent device and investigated application possibility. When we fabricated PLT thin films with substrate temperature of $500^{\circ}C$, and pressure of 30 mTorr, the relative deielectric constant and breakdown electricfield of PLT thin films were 120 and 3.2MV/cm. The electric resistivity was $2.0{\times}10^{12}{\Omega}{\cdot}cm$. PLT thin films had polycrystal structure of perovskite and pyrochlore at the higher substrate temperature than $450^{\circ}C$, and had good crystallinity at higher pressure. To use PLT insulator film and ZnS:Mn phosphor, we fabricated thin film electroluminescent device of ITO/PLT/ZnS:Mn/PLT/Al structure. At the result, threshold voltage was $35.2V_{rms}$ and brightness was $2400cd/m^{2}$ at $50V_{rms}$ and 1kHz. Maximum luminescence efficiency was 0.811m/W.

• Progress in Medical Physics
• /
• v.28 no.4
• /
• pp.226-231
• /
• 2017

The aim is to investigate the spectra responsibilities of QD (Quantum Dot) for the innovation of new dosimetry application for therapeutic Megavoltage X-ray range. The unique electrical and optical properties of QD are expected to make it a good sensing material for dosimeter. This study shows the spectra responsibility of toluene based ZnCd QD and PPO (2.5-diphenyloxazol) mixed liquid scintillator. The QDs of 4 sizes corresponding to an emission wavelength (ZnCdSe/ZnS:$440{\pm}5nm$, ZnCdSeS:470, 500, $570{\pm}5nm$) were utilized. A liquid scintillator for control sample was made of toluene, PPO. The Composition of QD loaded scintillators are about 99 wt% Toluene as solvent, 1 wt% of PPO as primary scintillator and 0.05, 0.1, 0.2 and 0.4 wt% of QDs as solute. For the spectra responsibility of QD scintillation, they were irradiated for 30 second with 6 MV beam from a LINAC ($Infinity^{TM}$, Elekta). With the guidance of 1.0 mm core diameter optical fiber, scintillation spectrums were measured by a compact CCD spectrometer which could measure 200~1,000 nm wavelength range (CCS200, Thorlabs). We measured the spectra responsibilities of QD loaded organic liquid scintillators in two scintillation mechanisms. First was the direct transfer and second was using wave shifter. The emission peaks from the direct transfer were measured to be much smaller luminescent intensity than based on the wavelength shift from the PPO to QDs. The emission peak was shifted from PPO emission wavelength 380 nm to each emission wavelength of loaded QD. In both mechanisms, 500 nm QD loaded samples were observed to radiate in the highest luminescence intensity. We observed the spectra responsibility of QD doped toluene based liquid scintillator in order to innovate QD dosimetry applicator. The liquid scintillator loading 0.2 wt% of 500 nm emission wavelength QD has most superior responsibility at 6 MV photon beam. In this study we observed the spectra responsibilities for therapeutic X-ray range. It would be the first step of innovating new radiation dosimetric methods for radiation treatment.

• Journal of Environmental Health Sciences
• /
• v.30 no.1
• /
• pp.41-49
• /
• 2004

Attention Deficit Hyperactivity Disorder (ADHD) is one of the most general childhood problems occurs locally and internationally, but the causes of ADHD are not cleared yet. Therefore, this study tried to examine some parts of the causes of ADHD closely, and finally contribute to the medical treatment of ADHD and its precautionary measures, by measuring and comparing concentration of minerals in hairs of the patients of ADHD and their control group's children. which can analyze the relevance to ADHD and the mineral content in human bodies, and mutual relations between toxic minerals and essential minerals in human bodies. After collection of hairs from 200 children(5 to 7-year-old, boys: 159 girls:41) diagnosed as ADHD by medical specialists based on the standard of DSM-IV diagnosis and their control group's 177 children(boys: 138 girls:39), the mineral concentration of samples was measured through ICP-MS and compared. And correlations between toxic minerals and essential minerals in human bodies among patients group was analyzed. All the toxic minerals(Pb, Hg, Al, Cd, As) of hairs analyzed in the study showed more higher range of concentration in patients group in comparison with their control group. Among them, the concentration of Pb(3.27 $\pm$ 3.82 ppm) and As(0.16 $\pm$ 0.15 ppm) in patients group were significantly high compared to their control group. And in this study Pb among toxic minerals showed negative correlation with Zn(r = -0.43), Mg(r = -0.15) among essential minerals. Cd among toxic minerals showed negative correlation with Zn(r = -0.20) among essential minerals. As among toxic minerals showed negative correlation with Ca(r = -0.14) among essential minerals.

• Journal of Bio-Environment Control
• /
• v.12 no.4
• /
• pp.245-251
• /
• 2003

This study was cnducted ton investigate the effect of soil conditioner such as dolomite, slkudge and organic manure on changes of soil chemical properties of abandoned zinc mine area. Growth responses of Chrysanthemum azwadskii and Caryopteris incana (Tunb) Miq affected by the appication were also determined. In thejsoil of abandoned zinz mine area, total heavy metal contents espectially Cd, Cu, Pb and Zn were high and organic matter contents was low. Application of sludge for phytoremediation resulted in higher soil organic content that other treatments tested. Heavy metal concentrations after application of soil conditioners were not different among treatments. The growth of C. zawadskii and C. incana (Tunb) Miq were significantly higher in sludge treatment than those in other treatments The cholrophyll content, chlorophyll flouorescence, protein content, photosynthetic rate and transpiration were high in sludge treatment. The heavy metal contents of C. zawadskii were the lowest in sludge treatment while those of C. incana (Tunb) Miq was the highest in sludge treatment.

• Clinical and Experimental Reproductive Medicine
• /
• v.24 no.1
• /
• pp.67-81
• /
• 1997

To determine the concentration and the physiologic role of metal components in blood plasma and seminal plasma in relation to male infertility, the concentrations of twelve metal components in blood plasma and seminal plasma including Na, Mg, K, Ca, Cr, Mn, Fe, Cu, Zn, Se, Cd and Pb were measured by atomic absorbance spectrophotometery or ion selective electrode analysis. Semen and blood samples were obtained from a total of 110 men including 70 male infertility patients, 20 vasectomized persons and 20 fertility proven volunteers visited to the Male Infertility Clinic of Pusan National University Hospital. The concentrations of Ca, Zn, Mg, Cr and Cd in control group were higher in seminal plasma than in blood plasma, and additionally Pb were higher in infertility group. The concentrations of all metal components revealed no significant difference according to patients' age, resident, occupation, sperm density, motility and hormone level in blood plasma, but some metal components including Ca, Mg, Cu, Mn, Cd and Pb revealed a significant difference according to each these parameters except patient's age in seminal plasma. The concentrations of Mn, Cd and Pb in the vasectomy persons were higher than in the infertility group III including testicular and epididymal factors, but not in blood plasma. We conclude that the quantitative changes of metal components in the seminal plasma may have effects on not only spermatogenesis and sperm function, but also contribute to diagnostic parameter according to organ specificity of the metal in the male reproduction.