• Title/Summary/Keyword: organic geochemistry

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Environmental geochemistry of persistent organic pollutants in the Pearl River Delta

  • Peng Ping'an;Fu Jiamo;Sheng Guoying;Xiao Xianming;zhang Gan;Wang Xinming;Mai Bixian;Ran Rong;Cheng Fanzhong
    • Proceedings of the KSEEG Conference
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    • 2002.04a
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    • pp.8-10
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    • 2002
  • POPs in sediments and soil in the PRD are comparable to or much higher than those reported in other regions. Some sites may be classified as POPs- polluted with high ecological risks. Large-scale land transform in the process of regional urbanization may facilitate the transfer of POPs in the soil to the sedimentary system by enhancing the soil run-off. Urban atmospheric PCBs in PRD are found to be less than some of the North American or European urbans, but PAHs are significantly higher. The center of the PRD has been the major source area of PAHs and organochlorine pesticides in the PRD. The northern part of the PRD serves as a regional sink for the air particulates and affiliated POPs.

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The role of organic matter associated with uranium mineralization (우라늄 광화작용(鑛化作用)에 기여(寄與)하는 유기물질(有機物質)의 역할(役割))

  • Oh, Chun-Hyuck;Kim, Jong-Hwan
    • Economic and Environmental Geology
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    • v.21 no.3
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    • pp.319-329
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    • 1988
  • As a factor which can help to understand the genesis of (mata) sedimentary and/or hydrothermal uranium depisits, an interpretation of the role of organic matter associated with uranium mineralization, was attempted with the literature published up to the end of 1986. Laboratory studies, in which diageneis and metamorphism are artificially simulated, can help to elucidate how uranium with particular organic materials are formed and destroyed. Similarly, research involving a variety of techniques is needed to characterize both the soluble organic extracts (bitumen) and the insoluble organic matter (kerogen), separated from uranium ores and associated rocks. In the presence of clay minerals and amorphous oxy-hydroxde minerals, an understanding of the role of organic matter must be prudent and may require the incorporation of multidisciplinary approach (mineralogy, inorganic geochemistry ...).

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Sequential Extraction of Heavy Metals in Soils and A Case Study (토양중의 중금속 연속추출방법과 사례연구)

  • Jung, Myung Chae
    • Economic and Environmental Geology
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    • v.27 no.5
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    • pp.469-477
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    • 1994
  • Many researchers have investigated most representative sequential extraction method using various reagents for determining the chemical forms of metals in soils and sediments. In this paper, a newly modified method for sequential extraction scheme based on Tessier's method by Environmental Geochemistry Research, Centre for Environmental Technology, Imperial College, was introduced and examined. In comparison with Tessier's method, originally designed for sediment analysis by Atomic Absorption Spectrophotometry (AAS), the sequential extraction scheme has been developed for the multi-element analysis by Inductively Coupled Plasma Atomic Emission Spectrometry (ICP-AES). The partitioning of particulate trace elements was classified into five fractions: (i) exchangeable, (ii) bound to carbonates or specially adsorbed, (iii) bound to Fe and Mn oxides, (iv) bound to organic matter and sulphides and (v) residuals. The experimental results of the pilot study for in-house reference material (HRM2) and certified international standard reference material (SRM2711) using the modified method showed not only reasonable precision and accuracy but also acceptable overall recovery rates. In addition, mine dump soils sampled in the Dalsung Cu-W mine, Korea were prepared and sequentially extracted using the method. Most of Cu was bound to organic matter/sulphides and residual fractions. The dominant fraction of soil Pb and Zn in the study area was found in the residuals. The fraction of Cd showed a wide variation between samples and could be found bound to the carbonates or specially adsorbed, oxides, organic fraction and residuals. The recovery rates of Cd, however, were poor due to relatively low Cd concentrations in soils. The heavy metals in these mine dumps appear to be in the more inert forms and should not be readily bioavailable. The soils, however, had very low pH values (average 4.1) and had sandy textures; consequently, rapid infiltration of rainfall may increase leaching of Zn and Cd which were found to be around 5 to 10% of the exchangeable fraction. As a result of the investigation of this study, it has been strongly recommended that these mine waste materials should still be considered a significant contaminant source and will need environmental remediation to prevent pollutants from being released into the environment.

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Characteristics of Molluscan Community Structure and Relationship between the Structure and Environmental Variables in Abyssal Plain of the East Sea (동해 심해저 연체동물 군집구조 특성 및 군집구조와 환경요인과의 상관성)

  • Son, Min Ho;Jung, Jik Young;Kim, Chang Joon;Choi, Ki Young
    • The Korean Journal of Malacology
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    • v.32 no.4
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    • pp.289-295
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    • 2016
  • Study on characteristics of the molluscan community structure and relationship between the structure and environmental variables in the abyssal plain of the East Sea was carried out for 5 years, starting from 2009 until the end of 2015 except 2010 and 2011. The water depth at the study site is approximately 1,600 m at minimum, and maximum depth of 2,000 m and a total of 16 molluscan species including Aplacophora, Gastropoda and Bivalvia were observed. Species with the highest biomass was Thyasira tokunagai, followed by Yoldiella philippiana which were observed at 9 sampling stations every year. Among 4 sampling stations having various depths (1,600/ 1,700/ 1,800/ 2,000 m), the highest diversity for species was observed at water depths of 1,600 m and 1,700 m, but found the lowest at 1,800 m. Both abundance and biomass were found to be negative correlations with water depth (p < 0.05), however, showed a positive correlation with the concentrations of organic matters (p < 0.01, p < 0.05). However, it is interesting to note that both Thyasira tokunagai (biomass, 82.6%; abundance, 44.1%) and Yoldiella philippiana (biomass, 15.9%; abundance, 4.7%) did not show distinctive correlations with water depth as well as concentrations of organic matters (p > 0.05). Therefore, it could be concluded that community structure of both Thyasira tokunagai and Yoldiella philippiana did not appear to be affected by water depth and concentrations of organic matters but geographical characteristics.

Assessment of Persistent Organic and Heavy Metal Contamination in Busan Coast: Application of Sediment Quality Index (부산 연안해역의 잔류성 유기오염물질과 중금속 오염평가: 퇴적물 오염지수 적용)

  • Han, Gi Myung;Hong, Sang Hee;Shim, Won Joon;Ra, Kong Tae;Kim, Kyung Tae;Ha, Sung Yong;Jang, Mi;Kim, Gi Beum
    • Ocean and Polar Research
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    • v.38 no.3
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    • pp.171-184
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    • 2016
  • In order to assess the level of contamination and identify the priority contaminants in the Busan coast, intensive sediment sampling was conducted and persistent organic pollutants and heavy metals were analyzed. The Sediment Quality Index (SQI) was derived based on the contaminant data by comparing with Sediment Quality Guidelines (SQGs) established in Korea, Canada, and Australia/New Zealand. Toxic contaminants were found to be widely distributed across the coast. Among organic contaminants, PAHs showed the highest concentration, followed by butyltins, nonylphenols, PBDEs, DDTs, PCBs, HCHs and CHLs. Heavy metals were also abundantly detected with the highest concentration of Zn followed by Cu > Cr > Pb > Ni > As > Cd > Hg. Compared to organic contaminants, most heavy metals, except for Cu and Hg, were homogeneously distributed along the coast in a good relationship with total organic carbon of sediment particles. In general, the concentrations of organic compounds and heavy metals were highest at the inner part of harbor areas with a tendency to decline from inside areas to the outside, indicating the high loading of pollutants from harbors. A high exceedance for low-SQGs and high-SQGs was found for TBT, p'-DDT, p,p'-DDD, Cu and Zn. The SQI scores calculated from low-SQGs and high-SQGs were in the range of 18-100 and 54-100, respectively. The inner part of Busan Harbor, Dadaepo Harbor, and Gamcheon Harbor were observed as being regions of concern. Overall, TBT, Cu, and p,p'-DDT were the chemicals most frequently exceeding SQGs and influencing SQI scores.

Rare earth element geochemistry of shelf sediments in the western part of Jeju Island, korea

  • Youn, Jeung-Su;Kim, Tae-Joung
    • 한국지구과학회:학술대회논문집
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    • 2010.04a
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    • pp.58-58
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    • 2010
  • The sediment geochemistry, including REE of surface and core samples in the western part off Jeju Island have been carried out in order to understand the provenance and hydrolic sorting. The sediment in the study area were primarily composed of coarse silt with a mean grain size of $2.8{\sim}82.8{\mu}m$. The ratios of TOC over total nitrogen (TN) showed that the study area sediments contained more organic matters of marine origin than those of terrigenous origin. The total A1203, Fe203, K20, MgO, and MnO contents and REE concentration of the fine sediments are higher than those of the coarse sediments. The higher Zr/Th and Zr/Yb ratios in coarse sediments relative to fine-grained detritus indicates sedimentary sorting. Grain size influence the REE concentrations of the study area sediment significantly. The < $63{\mu}m$ fraction of the sediment has higher REE concentration and different REE patterns when compared with those in bulk samples, due to the presence of REE-enrich heavy minerals. The REE distribution patterns of the western part of Jeju Island sediments are relatively enriched in most LREEs than the Yellow River sediment and depleted in the Changjiang River, but the LaN/YbN ratios are similar to the Changjiang sediment. The Eu/Eu* ratios ranged from 0.594~0.665(0.631) is much similar to the Yellow River sediment, possibly mixture of the sediments from these two rivers.

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The geochemical properties of phosphorus from sediments of Lake Shihwa (시화호 퇴적물에서 인의 지화학적 특성)

  • Shim Moo-Joon;Cho Sung-Rok;Na Kong-Tae;Shin Jin-Sun;Kim Eun-Soo
    • Journal of the Korean Society for Marine Environment & Energy
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    • v.4 no.3
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    • pp.16-27
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    • 2001
  • We have studied the phosphorus geochemistry in sediments from anoxic environments of Lake Shihwa. The dominant sedimentary phosphorus forms were detrital apatite P and Al-bound p, whereas the amount of Fe-bound P was low because of anoxic condition. Based on the correlation between TP(Total Phosphorus) and OC(Organic Carbon), the behavior of sedimentary phosphorus was influenced by organic matters. It shows that dissolved and solid phosphorus concentrations, the flux of phosphate and the correlation coefficients between sedimentary phosphorus and organic matter In St. Cl were higher than those in St. C2. The results indicate that the concentrations and distributions of phosphorus In sediments were controlled by organic matters.

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Isotope Geochemistry of Uranium Ore Deposits in Okcheon Metamorphic Belt, South Korea (옥천변성대내(沃川變成帶內)에 분포(分布)하는 우라늄광상(鑛床)의 동위원소(同位元素) 지구화학적(地球化學的) 연구(硏究))

  • Kim, Kyu Han
    • Economic and Environmental Geology
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    • v.19 no.spc
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    • pp.163-173
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    • 1986
  • Black and graphite slates from the Okcheon metamorphic belt contain enriched values of uranium (average 200~250ppm) and molybdenum (average 150~200ppm). Uranium mineralization is closely associated with quartz and sulfide veinlets which are formed diagenetically in graphite slate. The uranium minerals were concentrated in outer part of graphite nodules. The ${\delta}^{13}C$ values of organic carbon from the metasediments including uranium bearing graphite slate range from -15.2 to -26.1‰ with a mean of -23.5‰. Meanwhile, ${\delta}^{13}C$ values of coal and coaly shale from some Paleozoic coal fields of South Korea vary from -19.4 to -23.9‰ with an average of -22.5‰. Isotopic compositions of vein calcite in uranium bearing slate range from -13.4 to -15.4‰ in ${\delta}^{13}C$ and +11.3 to +15.1‰ in ${\delta}^{18}O$ could indicate a reduced organic carbon source isotopically exchanged with a graphite of biogenic origin. Metamorphic temperature determined by a calcite-graphite isotope geothermometer was 383~$433^{\circ}C$ which corresponded to greenschist facies by Miyashiro (1973) and is consistent with metamorphic facies estimated by mineral assemblages (Lee, et al., 1981, and Kim, 1971). The fixation of uranyl species by carbonaceous matter in marine epicontinental environment, and remobilization of organouranium by diagenetic processes have attributed to the enrichment of uranium and heavy metals in the graphite slate of Okcheon metamorphic belt.

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