• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
• /
• 2003.09a
• /
• pp.342-345
• /
• 2003

비소로 오염된 폐광산주변 하천 퇴적토 오염 복원을 위한 토양세척법의 복원효율을 규명하였다. 세척액에 대한 비소제거 효율을 규명하기 위해 오염된 3종류의 하천 퇴적토에 대하여 초산, 구연산, 염산 각 0.01, 0.05, 0.1, 0.5, 1N 수용액과 증류수(pH 5.41)에 대한 세척실험을 실시하였다. 실험결과 세척 효율은 염산과 구연산 용액의 경우 0.05N 이상에서 저농도의 구연산을 제외하고 99.9% 이상의 제거효과를 나타내었다. 초산의 경우 1N의 경우에도 36%와 71%의 낮은 세척 효율을 보였으며, 증류수로 세척한 경우에는 20% 내외의 세척 효율을 나타내었다. 이러한 세척 효율은 본 오염지역의 복원목표를 토양오염 우려기준의 40% 농도(2.4mg/kg)로 설정하여 하천퇴적토를 복원할 수 있음을 나타내고 있으며, 결론적으로 오염 퇴적토의 농도 분포에 따라 적절한 세척액을 선택한다면 세척 효과를 훨씬 증대시킬 수 있으리라 사료된다. 본 연구를 통한 세척효율 결과는 연구지역을 포함한 전국 각지의 폐광산 복원공정 설계에 중요한 자료로 활용될 수 있을 것으로 판단된다.

• Journal of Soil and Groundwater Environment
• /
• v.12 no.4
• /
• pp.16-24
• /
• 2007

An investigation on the polluted sediments in the Lake Sihwa and the benthos that inhabited on the sediments was conducted. Cost effective remediation alternatives were derived form the results of the investigation. The sediment samples taken from four sampling points out of thirteen showed relatively high heavy metal (particularly copper) concentrations which exceeded the Effects Range Low (ERL) of the National Oceanic and Atmospheric Administration, USA. The four sampling points were located in front of industrial complexes. Although the heavy metals appeared to have affected the growth of the benthos, the concentration of it did not exceed the criteria of dredging that were developed by Netherlands or the State of Washington, USA. However, contamination by organic matters and sulfur compounds was severe, which exceeded the criteria of dredging that were established in Japan. The sediments taken from the four sampling points which were contaminated with heavy metals showed higher organic matter content in general. The organic matters in the sediments depleted oxygen in summer, which appeared to be fatal to the benthos. A comprehensive analysis on the sediments, benthos, and other environmental impact from the contaminated sediments drew a conclusion that the benthonic environment of the Lake Sihwa needed a stepwise remediation, giving a particular emphasis on the clean up of the sediments upstram of the Lake which could cause odor problems to the nearby residential area.

• Economic and Environmental Geology
• /
• v.37 no.1
• /
• pp.121-131
• /
• 2004

Removal efficiencies of soil washing and soil improvement processes to remediate farmland soils and stream deposits around Goro abandoned mine were investigated with batch and column experiments. For As-contaminated farm-land soils around Goro mine, batch tests to quantify As extraction rate from contaminated soils and lime treated contaminated soils were performed. The contaminated soil mixed with lime decreased As extraction rate less than one fourth, suggesting that the soil improvement method mixed with lime dramatically decrease As extraction rate. A storage dam will be constructed in the lower part of the main stream connected to Goro abandoned mine and the amount of As extracted from the bottom soils of reservoir could be the main source to contaminate water of reservoir. The decrease of As extraction amount from the bottom in reservoir, caused by the application of the soil improvement method was investigated from the physically simulated column experiment and results showed that As extraction rate decreased to one forty when 1％ lime mixed soil improvement was applied to contaminated soils. For contaminated stream deposits connected Goro mine, the removal efficiency of the soil washing method was investigated with batch experiments. Hydrochloric acid, citric acid, acetic acid and distilled water were used as soil washing solution and 0.01, 0.05, 0.1, 0.5, 1.0 N of washing solution were applied to extract As. When washing with 0.05 N of hydrochloric acid or citric acid, more than 99.9% of As was removed from stream deposits, suggesting that As contaminated stream deposits around Goro mine be successfully remediated with the soil washing process. Total volumes of contaminated soils and deposits needed for remediation were calculated based on three different reme-diation target concentrations and the operation cost of soil washing for calculated soil volumes was estimated. Results from this research could be directly used to make a comprehensive countermeasure to remediate contaminated area around Goro mine and also many contaminated areas similar to this research area.

• Journal of the Korean Society of Marine Environment & Safety
• /
• v.28 no.2
• /
• pp.212-223
• /
• 2022

For the remediation and restoration of contaminated sediment at the West Sea-Byeong dumping site, dredged materials was dumped in 2013, 2014, 2016, and 2017. The physicochemical properties and benthic fauna in surface sediments of the capping area (5 stations) and natural recovery area (2 stations) were analyzed annually from 2014 to 2020 to evaluate the capping effect of the dredged materials. The natural recovery area had a finer sediment with a mean particle size of 5.91-7.64 Φ, while the sediment in the capping area consisted of coarse-grained particles with a mean particle size of 1.47-3.01 Φ owing to the capping effect of dredged materials. Considering that the contents of organic matters (COD, TOC, and TN) and heavy metals in the capping area are approximately 50 % lower (p<0.05) than that in the natural recovery area, it is judged that there is a capping effect of dredged materials. As a result of analyzing macrobenthic assemblages, the number of species and ecological indices of the capping area were significantly lower than that of the natural recovery area (p<0.05). The number of species and ecological indices at the capping area were increased for the first four years after the capping in 2013 and 2014 and then tended to decrease thereafter. It is presumed that opportunistic species, which have rapid growth and short lifetime, appeared dominantly during the initial phase of capping, and the additory capping in 2016 and 2017 caused re-disturbance in the habitat environment. In the natural recovery and capping areas, Azti's Marine Biotic Index (AMBI) was evaluated as a fine healthy status because it maintained the level of 2^nd grades (Good), whereas Benthic Pollution Index (BPI) remained at the 1^st and 2^nd grade. Therefore, capping of dredged materials for remediation of contaminated sediment in the dumping site has the effect of reducing the pollution level. However, in terms of the benthic ecosystem, it is recommended that the recovery trend should be monitored long-term. Additionally, it is necessary to introduce an adaptive management strategy when expanding the project to remediate the contaminated sediment at the dumping area in the future.

• Journal of Soil and Groundwater Environment
• /
• v.14 no.1
• /
• pp.68-77
• /
• 2009

For the reservoir sediment highly contaminated with total Cr, Pb, and Cd, the applicability of electrokinetic remediation method was evaluated. Also, BCR sequential extraction method was adopted to compare the heavy metal speciation in between before and after electrokinetic reaction that is operated under constant current condition for the sediment. After reaction, total Cr and Pb moved toward the direction of anode, while Cd tended to cathode and stayed highest in the midst of sediment specimen. From the BCR sequential extraction analysis, it was known that for total Cr and Pb the residual fraction that showed high fraction before reaction decreased and changed to the oxidation fraction. On the other hand, for Cd the fraction of exchangeable/carbonate that dominated most fractions before reaction changed to the residual and oxidation fractions.

• Economic and Environmental Geology
• /
• v.36 no.2
• /
• pp.89-101
• /
• 2003

River deposits and farmland soils were analyzed to investigate the pollution level of heavy metals in the vicinity of the Goro abandoned Zn-mine. Surface (0-40 cm) and subsurface (40-100 cm) soils were collected around a main river located at the lower part of the Goro mine, and analyzed by ICP-MS for Cd, Cu, Pb, Zn and Cr after 0. 1N HCI extraction and by AAS for As after IN HCI extraction. Concentrations of cadmium and lead at the surface river deposits close to the mine were over the Soil Pollution Warning Limit (SPWL), and 43% of sample sites (6 of 14 samples) were over SPWL for As suggesting that river deposits were broadly contaminated by arsenic. Results from farmland soil analysis showed that surface soils were contaminated by heavy metals, while only arsenic was over SPWL at 50% of sampling sites. Main pollution mechanism around the Goro mine was the discharge of mine tailing and waste rocks from the storage site to the river and to adjacent farmland during flood season. Pollution Grades for sample locations were prescribed by the Law of Soil Environmental Preservation, suggesting that the pollution level of heavy metals around the Goro mine was serious, and the remediation operation fur arsenic and the isolation of mine tailing and waste rocks from river and farmland should be activated to protect further contamination. The area needed to clean up was estimated from pollution distribution data and the remediation methods such as a soil washing method and a soil improvement method were considered as the further remediation operation for arsenic contaminated soils and river deposits around the Goro abandoned mine.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2009.05a
• /
• pp.801-805
• /
• 2009

하천의 골재는 도로, 항만, 주택건설 등 다양한 건설재료로 이용되어 왔으며 급속한 산업화와 더불어 국가건설사업, 지방자치단체의 수익사업으로 인해 골재 수요가 급격히 증가해 왔다. 그러나 체계적인 조사 및 연구가 없이 무분별하게 행해진 하천준설은 하상저하, 하천의 불안정, 하상의 장갑화 등 물리적 영향뿐만 아니라 주변 하천의 식생, 저서생물의 서식처 등 수서생태계의 파괴, 하천정화능력 저하, 교각의 노출 등 생물적 경제적인 측면에서 악영향을 미치고 있다. 본 연구에서는 하천준설사업이 꾸준히 진행 중에 있는 낙동강 유역의 감천을 연구대상지역으로 선정하여, 2차원 수치모형인 RMA-2를 이용하여 준설에 따른 동수역학적 흐름특성의 변화를 모의하고, SED2D를 이용하여 단기하상변동을 예측하였다. 지형자료는 수치지도 및 실측자료를 토대로 하여 구축하였으며, 준설 전 후의 하상변동을 모의해 비교 분석한 결과, 하도중심에서의 흐름특성은 준설전에 비해 수위가 평균 0.85 m 저하되었고, 하상은 평균 0.56 m 저하되었다. 대상유역의 수위와 유속은 준설전에 비해 준설후에 안정적인 특성을 나타냈다. 또한, 준설전 후 전반적으로 하상상승이 발생하였으며 이는 상류에서의 유사유입량이 많아 퇴적이 많이 일어난 것으로 판단되며, 준설후는 준설전에 비해 하류에서의 퇴적량이 적게 나타났으며 이는 준설구간에서의 퇴적으로 인해 하류 유사이송이 적게 일어난 것으로 판단된다. 본 연구의 결과는 하천준설에 따른 하천환경 및 물리적 영향을 최소화하고, 교란하천의 복원 및 관리 등에도 활용될 수 있을 것이다.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2011.05a
• /
• pp.205-205
• /
• 2011

우리나라의 중소하천에는 하상경사 조정과 농업용수 확보 등의 목적으로 많은 보가 설치되어 있다. 하천에 보를 설치하면 보를 기준으로 상 하류의 흐름특성이 변하고, 홍수시 소통이 원활하지 않아서 제방이 붕괴되는 등의 피해를 발생시킨다. 또한 유입유사의 흐름을 차단하여 상류단에 퇴적이, 하류단에는 침식을 발생시켜 하상변동이 일어나게 된다. 하상변동은 단기적으로는 하천에서의 취수, 배수와 주운 등 하천관리에 직접적인 영향을 주고, 장기적인 면에서는 하천 시설물의 안정, 홍수위 및 지하수위의 변화, 하천부지의 변화 등 하천 및 유역관리에 광범위한 영향을 주고 있다. 따라서 하천의 유황 및 하상재료의 인위적인 변화에 의한 하상변동을 예측하고 분석하는 것은 하천계획 및 운용 관리면에서 매우 중요하다. 본 연구는 경안천 유역에 설치된 보를 대상으로 설치 전의 지형자료 및 수리학적 자료를 이용하여 모델링을 하였고, 이를 토대로 설치 후의 수리학적 특성 및 하상변동을 분석하였다. 모델링은 종 횡단으로 모의할 수 있는 2차원 유한요소모형인 RMA-2를 이용하여 보를 설치하기 전 후의 수위, 유속 등의 흐름특성을 모의하였고, SED-2D를 이용하여 하상변동 특성을 비교 분석하고자 하였다. 그 결과 경안천 유역에 설치된 보로 인해 보의 상류단에서는 수위가 상승하고 유속이 감소하는 경향을 나타내고, 유사의 퇴적으로 인해 하상 상승이 발생하였다. 또한 보의 하류단에서는 보월류시 유속이 증가하여 수위가 하강하는 흐름특성을 보였고 침식이 발생하였다.

• The Journal of Engineering Geology
• /
• v.23 no.2
• /
• pp.95-104
• /
• 2013

This study proposes an efficient management plan for improving the water quality of agricultural reservoirs. Hongdong reservoir is located in an area that includes farmland, forest, residential housing, and livestock farms. The levels of pollutants in Hongdong reservoir were investigated with the aim of improving the water quality in the reservoir. The potential concentrations of total nitrogen (T-N) and total phosphorus (T-P) in Hongdong reservoir were 1.06-3.67 and 0.52-1.12 $g/m^2-d$, respectively. An analysis of leaching characteristics was performed under anaerobic conditions for 72 hours at $20^{\circ}C$. The concentrations of T-P and $PO_4$-P were measured by general leaching for a set period. In the case of T-P, the leaching was measured by irregular leaching due to denitrification of nitrite nitrogen ($NO_2$-N) and nitrate nitrogen ($NO_3$-N). A very small amount of $NH_3$-N on nitrogen ($N_2$) was measured due to the low pH in the column, as a consequence of the anaerobic conditions.

• Economic and Environmental Geology
• /
• v.36 no.6
• /
• pp.457-467
• /
• 2003

Soil Precise Investigation(SPI) for river deposits and farmland soils around Goro abandoned Zn-mine, Korea was performed to assess the pollution level of heavy metals(As. Pb, Cd, Cu) and to estimate the remediation volume for contaminated soils. Total investigation area was about 950000 $m^2$, which was divided into each section of 1500 $m^2$ corresponding to one sampling site and 545 samples for surface soil(0-10cm in depth) and 192 samples for deep soil(10-30cm in depth) from the investigation area were collected for analysis. Concentrations of Cu, Cd, Pb at all sample sites were shown to be lower than Soil Pollution Warning Limit(SPWL). For arsenic concentration, in surface soils, 20.5% of sample sites(104 sites) were over SPWL(6mg/kg) and 6.7%(34 sites) were over Soil Pollution Counterplan Limit(SPCL: 15mg/kg) suggesting that surface soils were broadly contaminated by As. For deep soils, 10.4% of sample sites(18 sites) were over SPWL and 0.6%(1 site) were over SPCL. Four pollution grades for sample locations were prescribed by the Law of Soil Environmental Preservation and Pollution Index(PI) for each soil sample was decided according to pollution grades(over 15.0 mg/kg, 6.00-15.00 mg/kg, 2.40-6.00 mg/kg, 1.23-6.00 mg/kg). The pollution contour map around Goro mine based on PI results was finally created to calculate the contaminated area and the remediation volume for contaminated soils. Remediation area with over SPWL concentration was about 0.3% of total area between Goro mine and a projected storage dam and 0.9% of total area was over 40% of SPWL. If the remediation target concentration was determined to over background level concentration, 1.1% of total area should be treated for remediation. Total soil volume to be treated for remediation was estimated on the assumption that the thickness of contaminated soil was 30cm. Soil volume to be remediated based on the excess of SPWL was estimated at 79,200$m^3$, soil volume exceeding 40% of SPWL was about 233,700 $m^3$, and soil volume exceeding the background level(1.23 mg/kg) was 290,760 TEX>$m^3$.