• Economic and Environmental Geology
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• v.40 no.3 s.184
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• pp.277-293
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• 2007

Seasonal and spatial variations in the concentrations of trace elements, pH and Eh were found in a creek watershed affected by mine drainage and leachate from several waste rock dumps within the As-Pb-rich Indae mine site. Because of mining activity dating back to about 40 years ago and rupture of the waste rock dumps, this creek was heavily contaminated. Due to the influx of leachate and mine drainage, the water quality of upstream reach in this creek was characterized by largest seasonal and spatial variations in concentrations of Zn(up to $5.830 mg/{\ell}$), Cu(up to $1.333 mg/{\ell}$), Cd(up to $0.031 mg/{\ell}$) and $SO_4^{2-}$(up to $173 mg/{\ell}$), relatively acidic pH values (3.8-5.1) and highly oxidized condition. The most abundant metals in the leachate samples were in order of Zn($0.045-13.909 mg/{\ell}$), Fe($0.017-8.730mg/{\ell}$), Cu($0.010-4.154mg/{\ell}$) and Cd($n.d.-0.077mg/{\ell}$), with low pH(3.1-6.1), and high $SO_4^{2-}$(up to $310 mg/{\ell}$). The mine drainage also contained high concentrations of Zn, Cu, Cd and $SO_4^{2-}$ and remained constantly near-neutral pH values(6.5-7.0) in all the year. While the leachate and mine drainage might not affect short-term fluctuations in flow, it may significantly influence the concentrations of chemicals in the stream. The abundance and chemistry of Fe-(oxy)hydroxide within this creek indicated that the Fe-(oxy)hydroxide formation could be responsible for some removal of trace elements from the creek waters. Spatial and seasonal variations along down-stream reach of this creek were caused largely by the influx of water from uncontaminated tributaries. In addition, the trace metal concentrations in this creek have been decreased nearly down to the background level at a short distance from the discharge points without any artificial treatments after hydrologic mixing in a tributary. The nonconservative(i.e. precipitation, adsorption, oxidation, dissolution etc.) and conservative(hydrologic mixing) reactions constituted an efficient mechanism of natural attenuation which reduces considerably the transference of trace elements to rivers.

• The Journal of Engineering Geology
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• v.14 no.4 s.41
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• pp.469-485
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• 2004

The purpose of this study is to investigate the hydrochemical characteristics of groundwater in the Umsung area, and to elucidate the effect of host rock type, well depth and mineralization zone on the groundwater chemistry. The geology of the study area consists of Jurassic granite and Cretaceous sedimentary rocks, which are bounded by a fault. Most of shallow groundwaters exploited in the Jurassic granite area are used for agricultural purpose, whereas the deep groundwaters in the Cretaceous sedimentary rocks are used for a drinking water. The shallow groundwater shows weak acidic pH, the electrical conductivity ranging from $142\;to\;903\;{\mu}S/cm$, and the chemical type of $Ca-HCO_3\;to\;Ca-Cl(SO_4,\;NO_3)$. A few of shallow groundwaters are contaminated by nitrate, and show high concentration of Fe, Mn and Zn, that reflects the effect of a mineralization zone. The deep groundwater shows neutral to weak alkaline pH, higher electrical conductivity than that of shallow groundwater, and the chemical type of $Ca-HCO_3$. The seepage water from the abandoned mines does not have the characteristics such as acidic pH, high concentration of heavy metals and high sulfate content. The hydrogen and oxygen isotopes of groundwater indicates an altitude effect of the recharge area between deep groundwater and shallow groundwater. In conclusion, the chemical composition of groundwater complicately reflects the effects of their host rocks, well depth, agricultural activity and mineralization zone in the study area.

• Journal of the Korean Society of Groundwater Environment
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• v.4 no.1
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• pp.20-26
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• 1997

This paper examines the influences of mining activities on the concentrations of heavy metals in soils in the vicinity of the Dalsung Cu-W mine, Korea. Geochemical surveys were undertaken in the Dalsung mine area and sampling of surface and subsurface soils was carried out. Samples were prepared using 0.1 N HCI, HNO$_3$-HClO$_4$, and aqua regia, and analyzed for Cd, Cu, Pb and Zn by Atomic Absorption Spectrometry. In addition, soil samples were sequentially extracted to investigate the chemical speciation of heavy metals in soils. Heavy metals are highly contaminated in soils in the vicinity of mining area ranging up to 28 $\mu\textrm{g}$/g Cd, 5000 $\mu\textrm{g}$/g Cu, 2390 $\mu\textrm{g}$/g Pb and 930 $\mu\textrm{g}$/g Zn by the method using HNO$_3$-HClO$_4$. The pollution indices calculated with the permissible levels are up to 49 in surface and subsurface soils, which are considered sufficient to raise environmental problems. However, the heavy metal levels by the method using 0.1 N HCl are not higher than Korean standard for soil contamination. It suggests that analytical methods and soil standard should be re-examined. From the results of the sequential extraction methods for metal speciation, total Cu, Pb and Zn concentrations may be determined by analytical methods using HNO$_3$-HClO$_4$ or aqua regia, and exchangeable phase of those metals by the method using 0.1 N HCl.

• Economic and Environmental Geology
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• v.27 no.1
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• pp.101-113
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• 1994

Geochemical investigations based on measurements of water parameters and sampling of stream sediments have been carried out, in the Okdongcheon stream and its tributaries in the Sangdong area of South Korea. There are two main problems occurring in the Okdongcheon stream: an acid mine drainage in the upper reaches and toxic trace metal contamination of the stream sediments mainly in the lower reaches. Acid mine water originating from coal mining was neutralized at the confluence of the Cheonpyongcheon stream whilst suspended solids due to flocculation of iron in water caused turbidity which was undesirable. Sediments in the Okdongcheon stream have been contaminated by mining activites. Iron was heavily concentrated in sediments in the upper Okdongcheon whilst toxic trace metals including Pb, Cu, Zn, Co, Cd, As and Bi were accumulated in sediments at stations draining metallic mining areas and near the tailings dam. There is now a requrement to neutralise the acid mine drainage and to use site-specific analysis of biological communities to ensure the conservation and preservation of aquatic organisms.

• Economic and Environmental Geology
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• v.40 no.1 s.182
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• pp.15-28
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• 2007

The study is for contaminations of major, rare earth and trace elements of the farmland soils from the Boeunjeil mine area. The results are compared with the soils of Chungjoo, Deokpyeong, Boeun and Chubu areas. Fe and S contents of the contaminated area are high relative to those from the uncontaminated areas, Chungjoo and Boeun areas. Trace elements of the contaminated area are high relative to those from uncontaminated area, Chunajoo, Deokpyeong, Boeun and Chubu areas. The trace elements ares divided into Cd, Ni, Sr, U, V, Zn and As, Co, Cu, Mo, Pb, Sb, based on these dispersion and correlation. Two groups show the positive correlation. Enrichment factor of potentially toxic elements from contaminated area is >5 value, but <4 value in the uncontaminated area. In the geoaccumulation index of the minor elements, the contaminated area has >1 value and the uncontaminated area has <1 value except Mn. Enrichment index of potentially toxic elements(As, Cd, Co, Cu, Ni, U, Zn) ranges from 0.3 to 87.0 in the contaminated area and from 0.4 to 3.9 in the uncontaminated area. Overall results show that the high contents of farmland soils for the elements(Fe, S, As, Cd, Co, Cu, Ni, U, Zn) indicate the contamination by coal-related activities.

• Economic and Environmental Geology
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• v.34 no.6
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• pp.539-553
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• 2001

Geochemical data of the Han river water, including four tributary water samples in the main Han river are presented in this paper. The concentration of dissolved ions in the North Han river water decreases in order of Ca>Na>K>Mg and HCO$_3$>NO$_3$>SO$_4$>Cl, which it mainly affected by the chemical weathering of granite and gneiss in the drainage basin. Meanwhile, the South Han river water shows a decreasing order of Ca>Mg>Na>K and HCO$_3$>SO$_4$>NO$_3$>Cl, which is controlled by the bed rock geology of carbornate rooks and the inflow of acid mine drainage from the metal and coal mines in the Taebaegsan and Hwanggangri areas. The main Han river waters are characterized by unusually high concentration of Na, Cl and SO$_4$ (Ca>Na>K>Mg and HCO$_3$>SO$_4$>CI>NO), indicating a significant anthropogenic pollution by human activities in the metropolitan Seoul city. The geochemical data of the Han river waters from 1981 through 1996 to 1999 records a significant increase in SO$_4$ and NO$_3$, which responsible for the increasing arid mane drainage and municipal anthropogenic pollution.

• The Journal of Engineering Geology
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• v.31 no.3
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• pp.295-306
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• 2021

This study used numerical modeling to investigate the stability of railway roadbed in areas with various underground cavities and rock conditions associated with mining activities. It compared combined loads from both passenger and freight trains with loads from only passenger trains. Stability was assessed with reference to the Korean government standards for railway subsidence allowance and railway warping repair. Sufficient stability regarding the railway subsidence allowance standard was not achieved when cavities were at depths of <5 m. The criteria for requiring railway warping repair were met when cavities were at depths of <15 m, depending on the rock fracture condition. This study provides the first report on systematic analysis land subsidence related to cavity size and rock fracture conditions associated with mining activities. We expect that this study could serve as an important reference for railway construction in mining areas.

• Economic and Environmental Geology
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• v.54 no.2
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• pp.299-308
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• 2021

Fe(II) released from mining activities is precipitated as various Fe(III)-oxyhydroxides when exposed to an oxidizing environment including mine drainage. Ferrihydrite, one of the representative precipitated Fe(III) minerals, is easy to adsorb heavy metals and other pollutants due to the large specific surface area caused by very low crystallinity. Ferrihydrite is transformed to thermodynamically more stable goethite in the natural environment. Hence, information on the transformation of ferrihydrite to goethite and the related mobility of heavy metals in the acid mine drainage is important to predict the behaviors of those elements during ferrihydrite to goethite transition. The behaviors of heavy metals during the transformation of ferrihydrite to goethite were investigated for core samples collected from an AMD treatment system in the Heungjin-Taemaek coal mine by using X-ray diffraction (XRD), chemical analysis, and statistical analysis. XRD results showed that ferrihydrite gradually transformed to goethite from the top to the bottom of the core samples. Chemical analysis showed that the relative concentration of As was significantly high in the core samples compared with that in the drainage, indicating that As was likely to be adsorbed strongly on or coprecipitated with iron oxyhydroxide. Correlation analysis also indicated that As can be easily removed from mine drainage during iron mineral precipitation due to its high affinity to Fe. The concentration ratio of As, Cd, Co, Ni, and Zn to Fe generally decreased with depth in the core samples, suggesting that mineral transformation can increase those concentrations in the drainage. In contrast, the concentration ratio of Cr to Fe increased with depth, which can be explained by the chemical bond of iron oxide and chromate, and surface charge of ferrihydrite and goethite.

• Journal of Korean Society of Environmental Engineers
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• v.34 no.5
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• pp.345-350
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• 2012

To investigate the exposure and health risk assessment for the residents near the D-asbestos mine in Chungbuk, Korea. We analyzed asbestos in the 20 ambient air and 23 activity based samples near the mine. The airborne sample results are showed that 8 of 20 samples ranged between 0.0025 to 0.0029 f/cc (fiber per cubic centimeter) and the others were below the detection limit by phase contrast microscopy (PCM). In addition, asbestos fibers were under the detection limit or not being by transmission electron microscopy (TEM). Based on interview and survey targeting the local residents, we made the activity based sampling (ABS) scenarios fit to the conditions of field. At the same time, we calculated the excess lifetime cancer risk (ELCR) of these ABS scenarios according to the ELCR average value and 95% upper confidence limit (UCL). At the case of weed whacking, soil digging and sweeping yard scenario, 95% UCL of ELCR exceeded the $1{\times}10^{-4}$, acceptable risk range for exposure. Based on our study results, it is necessary safety measures such as risk communication, abatement or management of naturally occurring asbestos (NOA).

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2001.11a
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• pp.67-68
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• 2001

우리 나라가 위치한 동북아 지역은 급속한 산업 및 경제활동 증가로 세계의 주요 오염 지역으로 대두되고 있다. 특히, 중위도 편서풍대 위치한 우리 나라는 주로 3월과 4월 황사의 영향을 받고 있다. 사막에서 발생한 모래먼지는 시정을 악화시키며 이들 중 미세한 입자(0.1~10$\mu\textrm{m}$)는 산란과 흡수를 통하여 대기의 복사평형과 기후변화에 커다란 영향을 미칠 수 있다(Carlson, 1980; Duce,1980; Shaw,1980). 이러한 현상은 주로 대기 중의 미세 입자의 광산란에 기인되는 것으로 도시 지역의 에어로졸의 분포 및 화학적인 성분과 밀접한 관계를 가진다. (중략)