• Journal of Korean Society for Atmospheric Environment
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• v.11 no.4
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• pp.351-359
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• 1995

In order to investigate geochemical behaviors of artificial radionuclide($^{137}$ Cs), the fallout deposition of arificial radioisotope($^{137}$ Cs) was measured from May to October in 1994 at the Korea Ocean Research & Development Institute(KORDI), Ansan, Kyunggido, Korea. And to study radioisotopic behavior and cumulative action in soil, soil samples were collected from Kwang-Leung Forest, Kyunggidom and artificial radioisotope ($^{137}$ Cs) and natural radioisotope($^{210}$ Pb) were identified. The amount of $^{137}$ Cs in atmosphere collected by wet deposition process in May was found to be 4.95 to 11.96mBq m$^{-2}$ whereas the amounts of $^{137}$ Cs by dry deposition process in May and October were found to be 4.0mBq g$^{-1}$ and 3.0mBq g$^{-1}$ , respectively. The amount of $^{137}$ Cs accumulated in soil was measured to be 311mBq cm$^{-2}$ , which contained 83% of the total inputs from atmospheric fallout (374 mBq cm$^{-2}$ ) since 1960s. In addition, the accumulation rate and the annual flux of $^{210}$ Pb into soils were 0.32cm yr$^{-1}$ and 34 mBq cm$^{-2}$ yr$^{-1}$ , respectively. Conclusively, it was found that arificial radioisotopes were mainly from the stratosphere and soil resupension of continental China through the troposphere.

• Economic and Environmental Geology
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• v.42 no.5
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• pp.479-486
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• 2009

In natural environments, manganese (Mn) exists in the valence of +2, +3, and +4 and plays a pivotal role as a strong oxidant or reductant in the geochemical cycles of elements. Especially, Mn forms varying (oxyhydr)oxides. The oxidation state of structural Mn is characteristic to each oxide and is one of the most important factors controlling its geochemical behaviors such as solubility, sorption capacity, and redox potential. Therefore, it is important to elucidate processes governing Mn oxidation state in predicting the fate and transport of many redox sensitive elements in the environment. X-ray photoelectron spectroscopy (XPS) is a very useful method to determine the oxidation state of various elements in solid phases. In this study, the oxidation states of structural Mn in MnO, $Mn_2O_3$, $MnO_2$ were assessed based on the binding energy spectra of $Mn2p_{3/2}$ and Mn3s using XPS and were compared with those reported elsewhere. $Mn2p_{3/2}$ binding energies were determined as 640.9, 641.5, 641.8 eV for MnO, $Mn_2O_3$, $MnO_2$, respectively, which indicates that the binding energy increased with increasing Mn oxidation state. It was also noted that Ar etching may cause changes in electronic structure configuration on surface of the original sample.

• Journal of Conservation Science
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• v.37 no.6
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• pp.748-766
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• 2021

The Iksan Ssangneung (twin tombs), a pair of tombs comprising the Daewangneung (large royal tomb) and the Sowangneung (small royal tomb), were constructed in the typical style of stone tunnel and chamber tombs in the Baekje Kingdom during the Sabi period (538 to 660 AD) of ancient Korea. Soil layers exposed during excavation of Sowangneung in a trench east of the tomb are: the bottommost layer, the ground level layer, the Panchuk (rammed earth) layer of the Baekje, the layer created by a grave robbery, and soil recovered during the Japanese colonial period. Soil samples were obtained by segmenting an easy stratigraphic horizon into sub categorized soil layers, and their material properties were analyzed; they are composed mainly of sandy loam based on the particle size distributions. In the site foundation, loamy sand is packed in the bottommost layer, and sandy loam with high sand and silty sand fills most of the overlying layer. The central and topmost portion of the Baekje layer is composed of loam with high clay content. All soil layers show geochemical behaviors similar to those of the bottommost layer. X-ray diffraction analysis verified kaolinite in all layers, also observed in soil layers displaying high crystallinity. Kaolinite and halloysite were identified by scanning electron microscopy. Thus, we conclude that the Baekje layer of the Sowangneung is composed of sandy loam containing kaolin procured from near the site. An impermeable middle to upper layer was created using viscous loam. The top of the tomb was closed tightly.

• Economic and Environmental Geology
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• v.55 no.5
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• pp.465-475
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• 2022

The seafloor massive sulfide deposits are important mineral resources for base and precious metals, and their ore genesis and metal contents are mainly controlled by wall-rock leaching process and/or magmatic volatile input from the underlying magma chamber. However, the contribution of two different metal sources to the seafloor hydrothermal mineralization significantly varies in diverse geological settings and thus still remains controversial. In this review, mineralogical and geochemical characteristics of SMS deposits from mid-ocean ridges (MORs) and volcanic arcs were investigated to understand the contribution from different metal sources and to suggest future challenges that need to be addressed. As a result, the genetic occurrences of enargite and cubanite, galena and barite indicate the effects of magmatic input and water-rock interaction, respectively. Also, the distributional behaviors of Co, As, and Hg in pyrite and FeS content of sphalerite could be useful empirical indicators to discriminate the significant roles of different metal sources between MOR and Arc settings. To date, as most studies have focused on sulfide samples recovered from the seabed, further studies on magmatic sulfides and sulfate minerals are required to fully understand the genetic history of SMS deposits.

• The Journal of Engineering Geology
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• v.29 no.4
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• pp.579-598
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• 2019

We investigated geochemical contaminants and Fe, Al behavior in precipitates of acid mine drainage (AMD) from the Donghae abandoned coal mine, Taebaek, Gangwon Province using aqueous chemical analyses, XRD, IR, and ²⁷Al NMR, Our results showed that water chemistry changed with pH and Eh, and saturation indices of chemical species in the AMD. According to saturation calculated by visual MINTEQ, the AMD was saturated with various Fe-, Al-oxyhydroxide minerals. Reddish brown precipitates are composed of schwertmannite, ferrihydrite, and goethite, whereas whitish precipitates are composed mostly of alumimous minerals such as poorly crystallized basaluminite with trace Al₁₃-Tridecamer. It is important to apply active treatment methods rather than simple storage pond and to control the precipitation and solubility of iron species and aluminous species for ensuring remediation and control for the AMD discharged from the Donghae abandoned coal mine.

• Journal of Environmental Science International
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• v.4 no.5
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• pp.103-103
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• 1995

In the Chinhae Bay, Korea, sedimentation rates and sedimentary record of anthropogenic metal loads were determined by $^{210}Pb$ dating and heavy metal analysis of four sediment cores . The sedimentation rates varied from 0.16g/$cm^2$/yr(3.1mm/yr) at Sta. Ct, located within narrow waterway to 0.24g/$cm^2$/yr(4.8mm/yr) at Sta. Cl, located in Haengam Bay. Maximum contents of Mn, Zn, Cu and Cr were observed at Sta. C2 located near the mouth of Masan Bay, while minimum contents were observed at Sta. CB. Mn/Fe ratios at Sta. C2 and Sta. C4 showed gradually increasing and decreasing downward, respectively, in the upper layer of sediment cores. This suggests that Mn may be diagenetically redistributed in highly reduced environment. At Sta. C2, the concentrations of Zn and Cu began to increase from 1920s by anthropogenic input and have been remarkablely increasing since mid 1960s. At Sta. C3, located near Sungpo, anthropogenic input of these two elements has also slightly increased after 1970s. However, pollution of these two elements was not significant in Haengam Bay(Sta. Cl) and Chiljun watenway(Sta. C4). The pollution of Co, Ni and Cr was not remarkable in all core samples except surface sediment of Sta. C2. The total input of anthropogenic Zn and Cu since 1920s was estimated to be 28∼792 ㎍/cm2 and 0∼168㎍/cm2, respectively. Sta. C2 showed remarkablely higher values relative to other stations: anthropogenic loads of Zn and Cu constituted 27% and 29% of the total sedimentary inventories at the present day, respectively. Fe, Ni, Cr and Co contents showed good correlation(r>0.8) with each other. Anthropogenic Zn and Cu also showed a very good positive correlation(>0.9). However, correlation between these two group of element was quite scattered, indicating different sources and geochemical behaviors.

• Journal of Environmental Science International
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• v.4 no.5
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• pp.489-500
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• 1995

In the Chinhae Bay, Korea, sedimentation rates and sedimentary record of anthropogenic metal loads were determined by $^{210}Pb$ dating and heavy metal analysis of four sediment cores . The sedimentation rates varied from 0.16g/$cm^2$/yr(3.1mm/yr) at Sta. Ct, located within narrow waterway to 0.24g/$cm^2$/yr(4.8mm/yr) at Sta. Cl, located in Haengam Bay. Maximum contents of Mn, Zn, Cu and Cr were observed at Sta. C2 located near the mouth of Masan Bay, while minimum contents were observed at Sta. CB. Mn/Fe ratios at Sta. C2 and Sta. C4 showed gradually increasing and decreasing downward, respectively, in the upper layer of sediment cores. This suggests that Mn may be diagenetically redistributed in highly reduced environment. At Sta. C2, the concentrations of Zn and Cu began to increase from 1920s by anthropogenic input and have been remarkablely increasing since mid 1960s. At Sta. C3, located near Sungpo, anthropogenic input of these two elements has also slightly increased after 1970s. However, pollution of these two elements was not significant in Haengam Bay(Sta. Cl) and Chiljun watenway(Sta. C4). The pollution of Co, Ni and Cr was not remarkable in all core samples except surface sediment of Sta. C2. The total input of anthropogenic Zn and Cu since 1920s was estimated to be 28~792 $\mu\textrm{g}$/cm2 and 0~168$\mu\textrm{g}$/cm2, respectively. Sta. C2 showed remarkablely higher values relative to other stations: anthropogenic loads of Zn and Cu constituted 27% and 29% of the total sedimentary inventories at the present day, respectively. Fe, Ni, Cr and Co contents showed good correlation(r>0.8) with each other. Anthropogenic Zn and Cu also showed a very good positive correlation(>0.9). However, correlation between these two group of element was quite scattered, indicating different sources and geochemical behaviors.

• The Journal of Engineering Geology
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• v.29 no.2
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• pp.163-183
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• 2019

We investigated acid mine drainage (AMD) of Bongyang abandoned coal mine, Danyang, Chungbuk Province with emphasis on geochemical contaminants in AMD and precipitates using chemical analyses, XRD, SEM, IR, and $^{27}Al$ NMR. Water chemistry changes with pH and oversaturation of chemical species. According to calculation of saturation index, the AMD is saturated with various Fe, Al minerals. Orange or orcher precipitates are composed of schwertmannite and goethite, associated with Leptothrix orchracea bacteria, whereas whitish precipitates are composed mostly of alumimous minerals such as basaluminite with poor crystallinity. The whitish precipitates include trace $Al_{13}$-Tridecamer. It is important to control the precipitation and solubility of aluminous species for ensuring remediation and control for the AMD discharged from the Bongyang abandoned coal mine.

• The Journal of Engineering Geology
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• v.12 no.4
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• pp.471-484
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• 2002

Alluviums in the Keum River watershed cover an areal extent of $3,029{\;}\textrm{km}^2$ and contain about 8.1 billion tons of groundwater. However, the waters are severely polluted by nitrate, possibly due to the application of nitrogen fertilizer (>250 N kg/ha) on agricultural land. This paper aims to elucidate the pollution status and behaviors of nitrate in alluvial groundwaters in the Keum River watershed area, based on regional hydrogeochemical study. Most of the collected samples (n = 186) are polluted by nitrate (average = 42.2 mg/L, maximum = 295 mg/L). About 29% of the samples have the nitrate concentrations exceeding Korean Drinking Water Standard (44 mg/L $NO_3$). The distribution of nitrate concentrations in the study area is largely dependant on geochemical environments of alluvial aquifers. In particular, the decrease of redox potential of alluvial groundwaters showed a good correlation with the decreases of nitrate, iron, and manganese concentrations. Thus, the change of redox state in alluvial aquifers, likely reflecting their sedimentary environments, controls both the behavior and fate of nitrogen compounds and their natural attenuation (denitrification) in aquifers. A carbon-rich, silty layer within alluvium strata forms a reducing condition and possesses a buffering capacity on nitrate pollution.

• Economic and Environmental Geology
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• v.39 no.3 s.178
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• pp.213-227
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• 2006

The geochemical evolution of mine drainage and leachate from waste rock dumps and stream water in Pb-As-rich abandoned Sechang mine area was investigated to elucidate mechanisms of trace metals. Total and sequential extractions were applied to estimate the distribution of trace metals in constituent phases of the waste rocks and to assess the mobility of trace metals according to physicochemical conditions. These discharged waters varied largely in chemical composition both spatially and temporally, and included cases with significant]y low pH (in the range 2.1-3.3), and extremely sulphate (up to 661 mg/l and metal contents (e.g. up to 169 mg/l for Zn, 27 mg/l for As, 3.97 mg/l for Pb, 2.99 mg/l for Cu, and 1.88 mg/l for Cd). Arsenic and heavy metal concentrations at the down-stream of Sechang mine have been decreased nearly to the background level in downstream sites (sites 8 and 16) without any artificial treatments. The oxidation of Fe-sulfides and the subsequent hydrolysis, of Fe(II), with precipitation of poorly crystallized minerals, constituted an efficient mechanism of natural attenuation which reduces considerably the transference of trace metals (i.e. Fe and As) to rivers. The dilution of drainage by mixing with pristine waters provoked an additional decrease of trace metal concentrations and a progressive pH increase. On the other hand, the most soluble cations (i.e. Zn) remained significantly as dissolved solutes until the pH was raised to approximately neutral values. With respect to ecotoxicity, it is likely that the Zn pollution is of particular concern in Sechang mine area. This was confirmed by the sequential extraction experiment, where Zn in wet waste-rock samples occurred predominantly in the exchangeable fraction (65-89% of total), while Pb was the highest in the reducible and carbonate fractions, and Cd, Cu and As in the residual fraction. Pb concentration in the readily available exchangeable fraction (34-48% of total) was dominated for dried waste rock samples. Considering the proportion of metals bound to the exchangeable and carbonate fractions, the comparative mobility of metals probably decreased in the order of Zn>Pb>Cd>As=Cu.