• Economic and Environmental Geology
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• v.40 no.4
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• pp.403-418
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• 2007

The objective of this research was to characterize the fate and transport of Cr(VI) contaminated groundwater in the Daejeon industrial area. Five subsidiary monitoring wells were newly installed and two existing wells were utilized for the investigation and the reduction process of Cr(VI) contaminated groundwater of the Daejeon(Mun-pyeong) national groundwater monitoring station. The Cr(VI) concentrations at the shallow aquifer well of the station were in the range of 3.2-4.5 mg/L indicating continuous contamination. However, Cr was not detected at the deep bedrock well and the other monitoring wells except MPH-1 and 3. The Cr(VI) concentrations of MPH-1 and MPH-3 were below the drinking water guideline value (0.05 mg/L). Therefore, the plume of the Cr(VI) contaminated groundwater was predicted to be confined within the narrow boundary around the station. The soluble/exchangeable Cr(VI) concentrations were below the detection limit in all core and slime samples taken from the five newly installed wells. Although the exact source of contamination was not directly detected in the study area, the spatial Cr(VI) distribution in groundwater and characteristics of the core samples indicated that the source and the dispersion range were confined within the 100 m area from the monitoring station. The contamination might be induced from the unlined landfill of industrial wastes which was observed during the installation of an subsidiary monitoring well. For the evaluation of the natural attenuation of Cr(VI), available reduction capacities of Cr(VI) with an initial concentration of 5 mg/L were measured in soil and aquifer materials. Dark-gray clay layer samples have high capacities of Cr(VI) reduction ranging from 58 to 64%, which is obviously related to organic carbon contents of the samples. The analysis of reduction capacities implied that the soil and aquifer materials controlled the dispersion of Cr(VI) contamination in this area. However, some possibilities of dispersion by the preferential flow cannot be excluded due to the limited numbers of monitoring wells. We suggest the removal of Cr(VI) contaminated groundwater by periodical pumping, and the continuous groundwater quality monitoring for evaluation of the Cr(VI) dispersion should be followed in the study area.

• Proceedings of the KSEEG Conference
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• 2007.04a
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• pp.585-587
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• 2007

• Journal of the Korean Society of Groundwater Environment
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• v.2 no.1
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• pp.9-13
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• 1995

In the stream-aquifer setting, this study evaluated the effects of spatial variability in nonpoint sources and hydraulic conductivity on groundwater outflow concentration history. Monte Carlo experiments based on the advection-dispersion equation were used to determine the statistical moments of groundwater outflow concentration history. The comparison between a spatially distributed model and spatially integrated model (SID) was made in order to examine the possibility of applying SID to the problems of nonpoint source groundwater pollution.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2004.04a
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• pp.459-462
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• 2004

This study assesses groundwater vulnerability to contaminants in 12 administrative districts of the city of Changwon, using DRASTIC technique. DRASTIC was originally applied to situations in which the contamination sources are at the ground surface, and the contaminants flow into the groundwater with infiltration of rainfall. However, groundwater contamination in urban areas can also be related to excessive pumping resulting in a lowering of the water level. The correlation coefficient between minimum DRASTIC indices and the degree of poor water quality for 10 districts is low as 0.40. The correlation coefficients between minimum DRASTIC indices and the groundwater discharge rate, and between minimum DRASTIC indices and well density per unit area are 0.70 and 0.87, respectively. Thus, to evaluate the potential of groundwater contamination in urban areas, it is necessary to consider other factors such as groundwater withdrawal rate and well density per unit area with ratings and weights as well as the existing six DRASTIC factors.

• Proceedings of the Korea Water Resources Association Conference
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• 2015.05a
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• pp.84-88
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• 2015

경인 아라뱃길은 국내에서 운영된 사례가 없는 기수역 운하로서 유량 및 수환경 관리 등을 포함한 수질관리 상황을 종합적으로 평가하기 위한 대책이 필요하다. 또한 경인 아라뱃길로 유입되는 오염원에 대한 현황 및 현장조사를 실시하고, 유입 오염원인을 정확히 파악하는 것이 중요하다. 따라서 경인 아라뱃길 유역의 수질조사 및 분석, 수질예측을 통해 수질관리 방안을 제시하였다. 분석결과, 홍수시 경인 아라뱃길로 유입되는 굴포천의 DO, BOD, SS는 삼정천의 영향으로 상승하였다. 삼정천은 굴포천 상류에서 부천시와 인천시의 관할 행정구역 면적에 비해 인구밀도가 높고 축산 농가 및 산업계로 인한 미처리 유출수에 의해 굴포천에 직 간접적인 영향을 미치고 있는 것으로 판단된다. 또한 굴포천 하수처리장 방류 이후 BOD, T-N, T-P의 경우 급상승하였다. 따라서 굴포천 중류의 부천시 삼정동과 인천시 계양구 내 하수 및 폐수를 하수처리장을 통해 배출할 수 있는 공동처리장 운영 등의 처리 방안이 필요하다. 또한 EFDC 모형을 이용한 해수와 담수의 성분비 변화에 대한 경인 아라뱃길의 수질을 예측한 결과, 해수가 많을수록 수질이 BOD, COD 등이 양호 한 것으로 나타났다. 그러나, 염분에 의한 지하수 및 주변환경 변화에 대한 영향을 고려하였을 때, 해수와 담수비를 조절하는 것보다 성분비를 유지하고 유입되는 양을 확대한다면, 경인 아라뱃길의 수질관리는 효과적일 것으로 판단한다.

• Proceedings of the Korea Water Resources Association Conference
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• 2008.05a
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• pp.800-804
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• 2008

하수처리수의 농업용수 재이용에 따른 영향을 평가하기 위해 논의 관개용수 수질에 따른 토양심도별 영양물질 분석을 시행하였다. 시험지구는 경기도 수원시 병점에 위치하며, 실험에 사용한 관개용수는 1) 지하수(TP#1), 2) 하수처리수(TP#2), 3) 재이용수(TP#3; 하수처리수+여과+UV소독)로 분류하여 관개하였다. 토양은 표토를 포함하여 20 cm 간격으로 60 cm까지 토양 심도별로 샘플링하였으며. 총질소(TN)와 총인(TP) 항목을 분석하였다. 분석결과 표토에서는 관개용수 수질의 차이에 의해 하수처리수 및 재이용수를 관개한 처리구 토양에서 영양물질의 함량이 높게 나타났다. 그러나 심도가 증가할수록 관개용수 수질에 의한 영향이 줄어들어 하수처리수의 농업용수 재이용으로 인해 관개용수 내 영양물질의 함량이 높아져도 심토까지는 영향을 미치지 못하는 것으로 나타났다.

• Journal of the Korean Society of Groundwater Environment
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• v.5 no.3
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• pp.129-140
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• 1998

In this study two sites were selected to investigate groundwater contamination and spatial relationship between pollution level and its source. One is the Asan area, agricultural district where pollution sources are scattered. The other is the Gurogu area of Seoul city, industrial district where industrial complex and residential areas are located. Groundwater samples collected from these districts were analysis for chemical constituents. The attribute value files of the chemical constituents of groundwater and the spatial layers have been constructed and the pollution properties have been investigated to find out spatial relationships between the groundwater constituents and pollution sources using CIS. Relatively high contents of Si and HCO$_3$ in groundwater from the Asan area reflect the effect of water-rock interaction, whereas high contents of Cl, NO$_3$, SO$_4$and Ca in groundwater from the Gurogu area are due to the pollution of various sources. Pollution over the critical level of Korean Dinking Water Standard has been investigated from 15 sampling sites out of 40 in the Asan area, and 33 sampling sites out of 51 in the Gurogu area. There is pollution of NO$_3$, Cl, Fe, Mn, SO$_4$and Zn in groundwater from the Gurogu area, and that of NO$_3$, SO$_4$and Zn in groundwater from the Asan area. Principal pollution in both areas is NO$_3$contamination. Deep groundwater from the Asan area is not contaminated with NO$_3$except for one site and most of shallow groundwater near the potential point sources such as factory and stock farm is contaminated seriously. Groundwater from the Gurogu area has been already polluted seriously considering the fact of contamination of deep groundwater. This study reports a spatial relationship between the pollution level and pollution source using GIS.

• Journal of Environmental Impact Assessment
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• v.12 no.3
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• pp.199-209
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• 2003

The withdrawal method for protecting the uncontaminated part from the spread of contaminants was suggested by a simultaneous equation. The formulation of them is based upon the build up of the ridge part between the contaminated and uncontaminated parts that resulted from the efficient use of barrier wells. The quality in the withdrawn groundwater depends upon the heads at wells no. 5 and 6. The determination of pumping rates and qualities with changing the heads at wells no. 5 and 6 should be given by considering the demand for water use and the capacity and cost for removing the contained contaminants. The results of this study should be used in taking a plan for supplying water use as well as preventing the spread of contaminants from some known contaminated sources.

• The Journal of Engineering Geology
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• v.23 no.1
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• pp.1-17
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• 2013

It is sometimes necessary to change the location of the collection conduit, which is constructed in shallow sediments in a stream, if the concentrations of $Fe^{2+}$ and $Mn^{2+}$ become too high for water treatment. A total of nine wells, including four shallow wells with a depth of 3 m and five deeper wells with a depth of 6 m, were installed in the study area at Naeseong-cheon in Yecheon-gun. The change in hydrogeochemical features of groundwater and the concentrations of $Fe^{2+}$ and $Mn^{2+}$ were examined at the wells during 5 hours of pumping. As pumping was performed, the velocity of groundwater flow was increased around the pumping well and aeration conditions were developed to precipitate iron and manganese oxides in an oxidizing environment. In addition, the concentrations of $Ca^{2+}$ and $Cl^-$ at the pumping well were increased following the mixing of surface water and groundwater. It is suggested that the center region of the stream would be more suitable for a new collection conduit, considering the concentrations of $Fe^{2+}$ and $Mn^{2+}$ in groundwater and their reducing effect during pumping. The installation of a collection conduit based on field tests performed to ensure water quality enables a reduction in the construction and management costs at water treatment facilities.

• Journal of Food Hygiene and Safety
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• v.34 no.6
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• pp.551-556
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• 2019

Recently, due to the fact that the mineral content in the wash water of the GAP-certified melon exceeds the GAP wash water standards, there are cases where the certification cannot be maintained. Therefore, agricultural industry demand requesting relaxation of the inorganic elements standard for water quality has been increasing, taking into account the consumption characteristics of Korean melon, which is eaten after removing the peel. This study was conducted to evaluate the human risks of four inorganic materials (fluorine, arsenic, iron and manganese) based on the water quality data of 142 samples of groundwater that was used for washing GAP-certified Korean melon in Seongju area from 2017 to 2019. As a result, the HQ of four minerals in Koreans who consumed groundwater used for washing GAP-certified Korean melons in the Seongju area was below 0.10 on average. In particular, in the case of iron and manganese which are esthetic influence substances, the average HQ was 0.00. The overexposure group showed 0.01, which was lower than the HQ (average 0.01, overexposure group 0.03) of the group that consumed Korean melon. Based on all the results, even if the groundwater of the Seongju area is used to wash GAP-certified Korean melon, the impact from these four inorganic materials, including iron and manganese, for Korean population consuming Korean melon will be minimal.