• Journal of the Korean Society of Marine Environment & Safety
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• v.27 no.5
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• pp.605-617
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• 2021

The recovery of the sedimentary environment around a fallowing shellfish farm during its rest period after 20 years of long-running operation, was explored in Tongyeong Bay of Korea. Seasonal survey on macrobenthos community was conducted from July 2016 to September 2018 at five stations, which included the fallowing shellfish farm after 20-year operation (FF), a newly installed shellfish farm (NF), a shellfish farm for comparison around the closed shellfish farm (CF), and control stations with no farming activities (Con1, Con2). The total number of species and the density of macrobenthos were higher at the shellfish farm stations than the non-shellfish farm station, and their seasonal changes were significant. The dominant species at the shellfish farm stations was Capitella capitata while Paraprionospio patiens was dominant at the non-shellfish farm stations. The two dominant species were potential organic contamination indicators usually inhabiting the areas with dense organic matter. This suggests that the overall survey area was highly polluted with organic matters. Multivariate analysis showed that the macrobenthic community of CF changed to a level similar to that of Con1 immediately after the investigation, but not to a state above the Con1 level. Furthermore, the changes in NF were not significant when compared to those in CF.

• Korean Journal of Soil Science and Fertilizer
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• v.40 no.2
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• pp.164-171
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• 2007

This experiment was conducted to investigate heavy metal speciation and bioavailability from soil to the edible parts of water dropwort near industrial complex. The soils and water dropwort were collected from the paddies cultivating water dropwort(10 sites), stream sediments(5 sites), and background soils(3 sites) near industrial complex. The total concentrations of Cd Cu, and Ni were higher than those of permissible level for soil contamination(Cd 3, Cu 100, Ni $50mg\;kg^{-1}$ in soil) suggested by Kloke(1979). Dominant chemical forms of Cd in paddies cultivating water dropwort and stream sediments were exchangeable form(49.1-56.3%), and those of Cu, Zn, and Ni were Fe and Mn oxide bound and residual forms. The mobility factor of heavy metals in paddies cultivating water dropwort and stream sediments was in the order Cd>Zn>Ni>Cu>Pb, specially, the mobility factor of Cd (62-72%) were relatively higher than that of other metals in soils. The total concentrations of Cd in soils showed significant positive correlation with the ratios of exchangeable and Fe and Mn oxide bound forms, while correlated negatively with residual form. Heavy metal contents in root parts were higher than those in top parts of water dropwort. The bioavailability of water dropwort varied considerably between the different parts and heavy metals. Cd, Cu and Ni contents in water dropwort were correlated with each fractions in soils. Specially, the exchangeable form of Cd and Ni in soils showed significant positive correlation with the those contents of water dropwort.

• Economic and Environmental Geology
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• v.34 no.3
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• pp.283-299
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• 2001

The middle cover soils and clay liners collected from the Kumheung landfill in Gongiu City were analysed for As, Ba, Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, Sr, Ti and Zn concentrations using 0.] N HCl digestion and total/sequential extraction experiments followed by ICP-AES determination. The uncontaminated soil and sediment samples were also analyzed for the comparison. The results of sequential extraction showed that Cu was dominant in the oxidizable fraction, and As, Ni, Sr, Ba, and Mn were in the exchangeable fraction. Zinc and Mn occurred mostly in association with reducible, residual and carbonate fractions. Most of Cd and Pb were bound to the reducible and oxidizable fractions. The main carrier of Co, Cr, Fe and 11 was the residual fraction and another important carrier was the reducible fraction. The percentage of the metals of organically-bound form in the middle cover soils and clay liner was in the order of Cu(48%) > Ti(42%) > Pb(27%) > As(25%) > Cd(20%). As deduced from sequential extraction analysis, potential order of metal mobility in the middle cover soils and clay liner from the landfill was proposed: Cd > Sr > As > Ni > Mn > Ba > Cu > Pb > Zn » Co > 11 > Fe > Cr. Based on the 'geoaccumulation index' and the 'enrichment factor' normalized to A], the level of contamination of Cu, Ni and C1' was significant in the samples from Kumheung landfill and surrounding farmland. Their enrichments were attributed partly to anthropogenic pollutions.

• Journal of the Korea Organic Resources Recycling Association
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• v.28 no.4
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• pp.53-68
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• 2020

The concentrations of ammonia, hydrogen sulfide and fine dust were measured in the compost facility of a full-time Hanwoo breeding farms. The experiments were conducted in stack type composting facility(T1) and mechanical-stirred composting facilities(T2, T3). In the stack type composting facility, the highest temperature of compost pile was 46℃, and in the two mechanical-stirred composting facilities, it rose to 63℃ and 68℃, respectively. The concentrations of PM2.5 at T1, T2 were 15 ㎍/㎥ and 5~10 ㎍/㎥, respectively. And the concentration of PM2.5 at T3 was below 10 ㎍/㎥. The highest concentration of ammonia generated at T1 was 4 ppm, but no hydrogen sulfide was detected. The ammonia concentrations at T2 and T3 were 3 ppm and 4 ppm, respectively. However, hydrogen sulfide was not detected in both facilities. At T3, the ammonia concentration increased to 65 ppm at the point where the compost was stirred with a mechanical agitator. During composting period, the pH of the compost pile decreased from 9.06 to 8.94 and then increased to 9.14 as the composting period elapsed. The NaCl content of compost was 0.09% after composting process was complete. Moisture content of compost decreased from 65.9% to 62% as composting progressed. As composting proceeded, the content of volatile solids decreased from 65.6% to 64.7% and the content of TKN decreased from 1.327% to 1.095%.

• Economic and Environmental Geology
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• v.34 no.5
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• pp.461-470
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• 2001

The Shihung mine was restored in the early 90's after abandonment for 20 yews since 1973. Although disposed mine tailings were removed and the site was replaced by an incineration plant, still some residual mine tailings remain in the places including the old mine tailing ditposal area and the adjacent agricultural area. These residual mine tailings are prone to impose an adverse impact on the soil and groundwater and needs investigation for the potential contamination. Mine tailing samples were collected from the old tailing disposal area and the iii paddy. The porewater from the mine tailing were extracted and analysed to investigate chemical changes along the reaction path. Batch leaching tests were also carried out in the laboratory to find any supporting evidence found in the field analysis. Evidence of elemental leaching was confirmed both by the mine tailing and the porewater chemistry in them. The element concentrations of Cu, Cd, Pb, Zn in the porewater exceed the standard for drinking water of Korean government and US EPA. Leaching of heavy metals from the mine tailing seem to be responsible for the contamination. In batch leaching test. heavy metals were either continuous1y released or declined rapidly. Combining the information with porewater variation with depths and the geochemical meodeling results, most of elements are controlled by dissolution and/or precipitation processes, with some solubility controlling solid phases (Cu, Pb, Fe and Zn). Batch leaching test conducted at fixed pH 4 showed much higher releases for the heavy metals up to 400 times (Zn) and this area is becoming more vulnerable to soil and groundwater pollution as precipitation pH shifts to acidic condition.

• Economic and Environmental Geology
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• v.43 no.2
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• pp.123-136
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• 2010

In order to remediate heavy metal contaminated Nong island, Maehyang-ri shooting range soils through the batch reactor scale washing were evaluated. The experiment texture soil of N3 in the Nong island at north side incline was (g)mS containing 12.9% gravel, 47.0% sand, 35.1% silt and 5.0% clay. And the N3 soil area was contaminated with Cd($22.5\pm1.9$ ppm), Cu($35.5\pm4.0$ ppm), Pb($1,279.0\pm5.1$ ppm) and Zn($403.4\pm9.8$ ppm). The EDTA(ethylene diamine tetra acetic acid, $C_{10}H_{16}N_2O_8$) in the N3 soil was observed as most effective extractants among the 5 extractants(citric acid, EDTA, phosphoric acid, potassium phosphate and oxalic acid) tested. And chemical partitioning of heavy metals after washing N3 soil with EDTA was evaluated. Removal efficiency of residual fractions was higher than that of non-residual fractions. To choose EDTA extractant which is the most effective in soil washing technology using batch reactor process cleaning Pb and Zn contaminated sits; Pb and Zn removal rates were investigated 92.4%, 94.0% removal(1,000 mM, soil:solution=5, $20^{\circ}C$, 24 hour shaking, pH=2, 200 RPM), respectively. The results of the batch test showed that the removal efficiency curve was logarithmic in soil was removal. Thus, EDTA washing process can be applied to remediate the Pb and Zn contaminated soil used in this study.

• Journal of Korea Water Resources Association
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• v.56 no.2
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• pp.103-113
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• 2023

The river confluence is a section in which two rivers with different topographical and hyrodynamic characteristics are combined into one, and it is a section in which rapid flow, inflow of sediments, and hydrological topographic changes occur. In the confluence section, the flow of fluid occurs due to the difference in density due to the type of material or temperature difference, which is called a density flow. It is necessary to accurately measure and observe the confluence section including a certain section of the main stream and tributaries in order to understand the mixing behavior of the water body caused by the density difference. A comprehensive analysis of this water mixture can be obtained by obtaining flow field and flow rate information, but there is a limit to understanding the mixing of water bodies with different physical properties and water quality characteristics of rivers flowing with stratigraphic flow. Therefore, this study attempts to grasp the density flow through the water temperature distribution in the confluence section. Among the extensive data of the river, vertical data and water surface data were acquired, and through this, the stratification phenomenon of the confluence was to be confirmed. It was intended to analyze the mixed pattern of the confluence by analyzing the water mixing pattern according to the water temperature difference using the vertical data obtained by measuring the repair volume by installing the ADCP on the side of the boat and measuring the real-time concentration using YSI. This study can supplement the analysis results of the existing water quality measurement in two dimensions. Based on the comparative analysis, it will be used to investigate the current status of stratified sections in the water layer and identify the mixing characteristics of the downstream section of the river.