• Korean Journal of Soil Science and Fertilizer
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• v.49 no.4
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• pp.293-299
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• 2016

The chemical properties of paddy fields in Gangwon province were monitored every 4 years from 2003 to 2015 in order to provide basic information for soil fertility management of paddy fields. In 2015, the soil chemical properties of paddy fields were 5.9 in pH, $22g\;kg^{-1}$ in organic matter (OM), and $123mg\;kg^{-1}$ in available (Avail.) phosphate $P_2O_5$. Exchangeable (Exch.) potassium (K), calcium (Ca) and magnesium (Mg) were 0.39, 4.8 and $0.9cmolc\;kg^{-1}$, respectively, and Avail. $SiO_2$ was $170mg\;kg^{-1}$. In the long-term analysis, the contents of Avail. $SiO_2$, Exch. K and pH of paddy soils showed increasing tendency. However, Avail. $P_2O_5$, Exch. Ca and Mg tended to decrease, and there were no significant changes in the contents of OM. Soil OM, Avail. $P_2O_5$ and $SiO_2$ were not different among the different topographical sampling sites. However, the mean value of Exch. K and Ca were different among the different topographical sampling sites, and exceeded optimal values in the fluvio-marine plains. Different soil texture resulted in different soil pH, while no difference for OM, Avail. $P_2O_5$ and $SiO_2$. Paddy soil samples within appropriate pH range increased from 65% in 2003 to 77% in 2007, 68% in 2011, and 71% in 2015. In case of Avail. $SiO_2$, soil samples within appropriate range increased from 20% in 2003, to 37% in 2007, 29% in 2011, and 45% in 2015. Meanwhile, Cd and Pb were distributed to less than 5% of soil pollution standards. Cu, As and Zn were distributed to less than 10%, 15% and 20%, respectively. Therefore, paddy soil in Gangwon Province was judged to be safe. As a result, paddy fields with more or less in nutrient level need to be fertilized based on the soil analysis. And the application of silicate fertilizer is strongly recommended to those of paddy fields in need. In addition, soil management including the cultivation of green manure crop or application of rice straw is necessary to increase the organic matter content of paddy soil.

• The Korean Journal of Malacology
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• v.30 no.1
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• pp.41-49
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• 2014

This study was conducted to investigate the effects of cadmium (Cd) exposure on biochemical factors in the hemolymph and hepatopancreas of the abalone, Haliotis discus hannai. The abalone were exposed to 0, 5, 10, 20 and 40 ${\mu}g/L$ Cd for 4 weeks. The phenoloxidase (PO) activity was decreased in hemolymph of abalone exposed to 40 Cd ${\mu}g/L$ for 4 weeks compared to the control (P < 0.05). The hemolymph enzymes, alkaline phosphatase (ALP), aspartate aminotransferase (AST) and alanine aminotransferase (ALT) activities were markedly elevated in 40 Cd ${\mu}g/L$ after 4 weeks. The hemolymph calcium concentrations were significantly decreased in 20 and 40 Cd ${\mu}g/L$ for 4 weeks. Hepatopancreas superoxide dismutase (SOD) and catalase (CAT) activities were significantly increased by Cd. SOD was increased in both 20 and 40 Cd ${\mu}g/L$ and CAT, in 40 Cd ${\mu}g/L$ after 2 weeks (P < 0.05). These results suggested that the abalone SOD and CAT including PO may serve as a protective mechanism against oxidative stress by Cd. We conclude that a Cd concentration, 40 ${\mu}g/L$ in water may curtail hemolymph homeostasis and anti-oxidative reactions in abalone hepatopancreas. From these results, these biochemical factors may represent a convenient method of monitoring heavy metal pollution in coastal areas.

• Journal of Environmental Science International
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• v.24 no.7
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• pp.917-925
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• 2015

Styela clava tunic is generated in large amounts as a waste from S. clava processing plants and leads to environmental problems. It destroys the beach scenery and causes a bad smell and pollution by trashing on the seashore. Therefore, purpose of this study was to investigate antioxidant and antihypertensive activities of different solvent extracts from S. clava tunic for recycling of fishery waste. Antioxidant and antihypertensive activities of all extracts were concentration-dependent. Of extracts, hot water extract showed the highest DPPH radical scavenging activity with the lowest effective concentration ($EC_{50}$) value (0.733 mg/ml). Chloroform extract exhibited the highest metal chelation activity with the lowest $EC_{50}$ value (2.696 mg/ml). Autoclaved water extract showed the highest NO radical scavenging activity with the lowest $EC_{50}$ value (0.491 mg/ml) and n-hexane extract showed the highest reducing power ($A_{700}=1.897$ at 100 mg/ml). And n-butanol extract showed the highest SOD-like activity with the lowest $EC_{50}$ value (19.116 mg/ml) and ACE inhibition activity with the lowest inhibitory concentration($IC_{50}$) value (0.149 mg/ml). These results indicate that extracts obtained from S. clava tunic may potential candidate to reduce diseases caused by various oxidative stresses and hypertension.

• Korean journal of applied entomology
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• v.18 no.1 s.38
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• pp.49-53
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• 1979

Paddy lands around industrial areas in Gyeonggi and Jeonbuk provinces are increasingly concerned about pollution by heavy metals. This stimulated the quantitative analysis of copper, zinc, lead and cadmium in the soil from the aress concerned. Results obtained are summarized as follows: 1. Heavy metal contents of the soil from Sue-Myun, Siheung-Gun, Gyunggi province were 20.95 ppm of Cu, 226.46 ppm of Zn, 84.17 ppm of Pb, and 2.62 ppm of Cd, respectively. Those of Anyang, Kimpo, and Jeonbuk areas were as low as the natural background levels, about 10 ppm. 2. The contentration of heavy metals of the river valley soils tended to increase from upper stream to the lower. This seemed to be caused by the fact tat disposed water from plants flows to the lower stream and metals contained in the water accummlate in the soils around the lower stream. 3. Cadmium content was exceptionally lower than 0.2 ppm in all the areas tested. The present concentartion of cadmium is not of the extent to which any injury could occur to rice plants.

• Membrane Journal
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• v.27 no.5
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• pp.425-433
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• 2017

As the problems related to the environmental pollution such as carbon dioxide emission are emerging, the need for the renewable energy and environmentally friendly energy is getting intense. Fuel cells are eco-friendly energy generation devices that generate electrical energy and produce water as a sole by-product. Compared to the traditional proton exchange membrane fuel cell (PEMFC), anion exchange membrane alkaline fuel cell (AEMAFC) has a main advantage of possibility to use low cost metal catalysts due to its faster kinetics. The AEM, which conducts $OH^-$ ions, should possess high ion conductivity as well as high chemical stability at high pH conditions. We hereby introduce a crosslinked poly(2,6-dimethyl-1,4-phenylene oxide) having a spacer-type conducting group as novel AEM, and report a high ion conductivity ($67.9mScm^{-1}$ at $80^{\circ}C$) and mechanical properties (Young's modulus : 0.53 GPa) as well as chemical stability (6.8% IEC loss at $80^{\circ}C$ for 1,000 h,) for the developed membrane.

• Journal of the Mineralogical Society of Korea
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• v.21 no.1
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• pp.57-65
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• 2008

The geochemical partitioning of arsenic in contaminated soils from a of wet land and tailing of the abandoned mine is examined. Chemical analysis and sequential extraction method by ultrasound-sonication extraction are applied to investigate the mobility and chemical existence conditions of arsenic as well as heavy metals. The results of this study showed that heavy metals concentration of tailings showed as a following order: Fe > As > Cu > Pb > Cr. The highest metal concentration was recognized in samples less than $63\;{\mu}m$ fraction in their particle sizes. Exchangeable and carbonate fractions in soil samples showed following Cu > As > Pb > Fe > Cr for tailings, and Fe > Pb > Cu > As > Cr for reservoir soils, respectively. Arsenic was bound as exchangeable fraction in tailings and its concentration appeared higher than those of the other metals. Thus, As can be easily dispersed into soil and water environments. The obtained results can be used to design soil remediation plan in the study area and require further detailed study to investigate severe environmental pollution of surface water as well as rivers with respect to heavy metals in terms of speciation analysis of toxic elements such as As and Cr.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.39 no.2
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• pp.106-117
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• 2006

We measured the concentrations of organic matter and metallic elements (Al, Fe, Cr, Mn, Ni, Cu, Zn, As, Cd, Pb and Hg) in the surface sediments of Masan Harbor (in the southern sea, Korea) to evaluate the geochemical characters of sediment and the pollutions by organic matter and metallic elements. The mean grain size of the surface sediments in the study area ranged from $5.6{\phi}$ to $7.8{\phi}$, indicating silt sediment. The water content of the surface sediments exceeded 60% except at some stations. The contents of ignition loss (IL), total organic carbon (TOC) and total nitrogen (TN) ranged from 7.2-14.3%, 1.2-3.2%, and 0.10-0.28%, respectively. Based on the C/N ratios, the organic matter in the surface sediments of Masan Harbor may originate from terrigenous sources including fluvial inputs (mainly sewage in urban areas). The chemical oxygen demand (COD) and acid volatile sulfide (AVS) ranged from $11.3-29.9\;mgO_2/g\;dry$ and 0.20-4.47 mgS/g dry, respectively, and low concentrations were observed near a shipping route. In addition, the concentrations of metallic elements showed large spatial variations in Masan Harbor and the distributions of metallic elements were also comparable to those of organic matter. This implies that the distributions of organic matter and metallic elements in the surface sediments of Masan Harbor are mainly controlled by biogenic matter and artificial action (mainly dredging). In addition, we calculated the enrichment facto. (EF) and geoaccumulation index (Igeo) in order to evaluate pollution by metallic elements. The enrichment of metallic elements relative to Al was three to eighteen times higher at the study sites, compared to levels in the Earth's crust except for Fe, Ni and Mn. In addition, the Igeo class indicated that the surface sediments in the study area were moderately to strongly polluted in terms of metallic elements.

• Korean Journal of Environmental Agriculture
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• v.2 no.1
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• pp.13-17
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• 1983

The influence of planting time and age of reclaimed fields on the contents of heavy metals in vegetable crops in suburban areas was investigated. Investigated crops were 4 radish cultivars, Chinese cabbage, spinach, Garland chrisanthemum, and Welsh onion. Cd, Pb, Cu, and Zn were analyzed. The results obtained were as follows. 1) For radishes except Altari-mu and Welsh onion, the highest concentrations of heavy metals were recorded in roots whereas, for Chinese cabbage and Garland chrisanthemum, the highest concentration was appeared in leaves. 2) For lettuce, radishes, and spinach, the lowest concentrations of heavy metals were recorded in winter and the concentrations were the same between spring and autumn. 3) In lettuce difference of concentrations of heavy metals were not appeared between field age after reclamation with sewege sludge. 4) The concentrations of heavy metals observed was not harmful to human health.

• Korean Journal of Environmental Biology
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• v.17 no.1
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• pp.59-69
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• 1999

Bacterial population, signal compounds of pollution, bacterial productivity, heterotrophic activity and the activities of extracellular enzymes were analyzed four times from July 1994 to April 1995 at Daejin, Galnam, Pohang, and Ulsan in the coastal area of Bast Sea in order to investigate the state of eutrophication. The population of heavy metal resistant bacteria in Pohang was the highest among all stations. The bacterial populations which could utilize C -P compounds (phosphonate) showed the highest at Pohang that was expected for the industrial and agricultural effluents to inpour. It could be useful as an index of expectation about the influx of industrial sewages and agricultural effluents. The activities of extracellular enzymes for the degradation of organic matter were the highest in the Ulsan Chuyongam, but low in Daejin. These results showed positive relationship with the population of heterotrophic bacteria and bacterial productivity The ratio of poly-P and DNA in Pohang was the highest, and that in Ulsan, Galnam, and Daejin consecutively, corresponding with the distribution of heterotrophic bacteria. In case of the heterotrophic activities, each of the stations gives difference of seasonal variation in heterotrophic activities. Bacterial productivity seemed to be dependent on seasons; the highest in summer and the lowest in fall and winter. These seasonal variations of bacterial productivity seems to be similar with those of heterotrophic bacteria. It is suggested that the state of eutrophication could be evaluated by the criteria of the population sizes and the productivities of microorganisms, the amount of poly-P, heterotrophic activity, the activities of extracellular enzymes, etc.

• Journal of Preventive Medicine and Public Health
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• v.14 no.1
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• pp.111-116
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• 1981

Economic development of Korea brought rapid progress and expansion of her industries. Accordingly, number of workers who have been exposed to hazardous metals are increasing. For better understanding the significance of on the job human metal pollution, a total of 22 solderers among autoworkers and 28 controls among medical students was purposively selected as samples of the study. From their blood, concentrations of cadmium and lead were measured with atomic absorption spectrophotometer, and to compare with statistical indices of controls those of solderers were sumarized as follows. 1. Each frequency distribution of cadmium and lead concentration in blood of solderers was more positively skewed showing non-Gausian distribution. 2. Interindividual variation of lead concentration in blood of solderers was markedly revealed. 3. Each mean of cadmium and lead concentration in blood of solderers was higher than that of controls(Cd;p<0.01, Pb;p<0.01). 4. Relative ratio of cadmium concentration in blood of solderers to that of controls was 1.36 by arithmatic mean and 1.39 by geometric mean. Relative ratio of lead concentration in blood of solderers to that of controls was 1.53 by arithmatic mean and 1.30 by geometric mean. 5. It was shown that concentration of lead is slightly correlated with that of cadmium both in solderers and controls(solderers; p<0.1, controls;p<0.1).