• Journal of Korea Water Resources Association
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• v.57 no.10
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• pp.757-767
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• 2024

In the Hankyung-Daejeong watersheds of western Jeju Island, several groundwater wells showed abnormal measurements of high electrical conductivity (EC) and pH. To identify the causes of this abnormal water quality, we conducted borehole imaging, vertical EC logging, groundwater quality analysis, and SEM-EDS analysis of white suspended matter in the well. Most of the wells showing abnormal water quality had well-grouting below the water table, with borehole EC values ranging from 300 to 10,000 μS/cm. The wells exhibited higher ion concentrations compared to nearby wells and had a high pH range of 8.2 to 12.7, indicating a slightly to strong alkalinity. The primary components of the white-colored suspended matter were identified as oxygen and magnesium. These findings suggest that the abnormal water quality of the study wells is caused by the cement mortar used for grouting during well construction rather than by nitrate contamination or seawater intrusion. To prevent the influence of well-grouting on water quality during groundwater well development, an establishment of standards for groundwater development and utilization facilities is needed.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2003.04a
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• pp.77-81
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• 2003

일반세균, 질산성질소, 탁도로 오염된 지하수 관정의 2개공에 대해 수질개선을 시행하였다. 그 결과 2개공 모두 음용수 기준에 적합한 수질개선 효과를 가질 수 있음으로 하여 수질오염 발생의 주요 요인 중의 하나가 지하수 지표하부 오염방지 시설인 그라우팅이 부실함으로써 기인함을 규명할 수 있었다. 따라서, 본 연구를 통해 수질이 오염된 지하수 관정의 수질개선이 가능하다는 확인은 물론 또한, 지하수 관정내 지표수의 유입을 방지하기 위해서 지하수 상부오염방지 시설의 설치가 적극적으로 추진되어야 할 것이다. 지하수 오염을 예방하기 위해서는 지하수 개발 단계에서부터 지하수 지표하부 오염방지 시설이 연암 암반층까지 견실하게 적용되어져야 한다는 것을 확인할 수 있었다.

• Bulletin of Korea Environmental Preservation Association
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• v.29 s.372
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• pp.44-46
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• 2007

• The Journal of Engineering Geology
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• v.23 no.3
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• pp.293-304
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• 2013

Because the present groundwater law broadly regulates a simple and impractical guideline ignoring aquifer characters and geology, general purpose facilities for protection of groundwater contamination is still considered unsatisfactory to ensure groundwater resources. In recent, there have been growing attempts in the packer development as crucial techniques and devices for groundwater protection. This study investigated the application of packer grouting techniques to contaminated groundwaters of two well sites in the Andong and Yeongi areas, both of which revealed a satisfactory effect with improved water quality: 94% decrease in turbidity at the Andong area and 60% decrease in $NO_3$-N, respectively. Based on aquifer characters including geology, weathering depth, fracture pattern, hydraulic gradient, and the flow path of contaminants, the integrated properties of groundwater contamination should be evaluated and treated with the help of accurate analyses such as bore hole imaging and monitoring data. Packer grouting and casing on well to ensure the useful aquifer free of contaminant are expected to play important role in inhibiting the inflow of contaminants when adequately applied. Therefore it is concluded that these can serve as reliable tools in remediation and protection of contaminated groundwater as well as efficient utilization of groundwater.

• The Journal of Engineering Geology
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• v.10 no.2
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• pp.150-171
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• 2000

In the Cheju Island, there are high salinity water yield in the coastal area. There are various reason; the main reason is low-groundwater level by the structure of geology, and over-yielding etc. This study analysis water quality, the distribution of high salinity wells. 16 sample well logged the electronic geology survey. As result of distribution of Cl$^-$ is the East Area is high than other areas. Water quality test data divides 6 group by sea level of well bottom: over Om, Om~-1Om, -10~-20m, -20~-30m, -30~-40m, under -40m. According collect data of Kriging, and logged the electronic geology survey, and other survey are related chlorine(Cl$^-$). The map of Cl$^-$ distribution was made. Bukcheju Gun, Hallim Up, there are 2 wells prevent high salinity water. Both of well are effective grout sill salinity water intrusion aquifer.

• The Journal of Engineering Geology
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• v.29 no.4
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• pp.495-508
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• 2019

We measured the concentrations of natural radionuclides (uranium and radon) and major elements in groundwater collected from forty wells located in Wonju area to investigate the hydrochemistry and the occurrence of these radionuclides. The range of electrical conductivity (EC) value in the study area was 73~400 μS/cm. In addition to the increase of EC value, the content of cations and anions also tends to increase. Uranium concentrations ranged from 0.06~50.5 ㎍/L (median value, 1.55 ㎍/L) and radon concentrations ranged from 67~8,410 pCi/L (median value, 1,915 pCi/L). Uranium concentrations in 3 well, 7.5% of the samples, exceeded 30 ㎍/L, the maximum contaminant level (MCL) proposed by the US Environmental Protection Agency (EPA), based on the chemical toxicity of uranium. Radon concentrations in 9 wells, 22.5% of the samples, and 1 well, 2.2% of the samples, exceeded 4,000 pCi/L (AMCL of the US EPA) and 8,100 pCi/L (Finland's guideline level), respectively. Concentrations of uranium and radon related to geology of the study area showd the highest values in groundwater of the biotite granite area. Uranium and radon contents in the groundwater are comparatively low compared to those in other countries with similar geological settings. It is likely that the measured value was lower than the actual content due to the inflow of shallow groundwater by the lack of casing and grouting.

• Economic and Environmental Geology
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• v.51 no.6
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• pp.553-566
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• 2018

The occurrence of natural radionuclides like uranium and radon in groundwater was hydrochemically examined based on 40 well groundwaters in Mungyeong area. The range of electrical conductivity (EC) value in the study area was $68{\sim}574{\mu}S/cm$. In addition to the increase of EC value, the content of cations and anions also tends to increase. Uranium concentrations ranged from $0.03{\sim}169{\mu}g/L$ (median value, $0.82{\mu}g/L$) and radon concentrations ranged from 70~30,700 pCi/L (median value, 955 pCi/L). Only 1 out of 40 wells (2.5%) showed uranium concentration exceeding the maximum contaminant level (MCL; $30{\mu}g/L$) proposed by the US Environmental Protection Agency (EPA). Radon concentrations of eight wells (20%) exceeded AMCL(Alternative maximum contaminant level) of the US EPA (4,000 pCi/L). Four out of those eight wells even exceeded Finland's guideline level (8,100 pCi/L). When concentrations of uranium and radon were investigated in terms of geology, the highest values are generally associated with granite. The uranium and radon levels observed in this study are low in comparison to those of other countries with similar geological settings. It is likely that the measured value was lower than the actual content due to the inflow of shallow groundwater by the lack of casing and grouting.

• 한국지구물리탐사학회:학술대회논문집
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• 2000.09a
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• pp.54-69
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• 2000

There are groundwater trouble by high-salinity yield inducing sea-water intrusion in Cheju Island. It is used groundwater-GIS(Well-lnfo) in the maintenance and management of groundwater in Cheju Island to grasp groundwater trouble area and cause of high-salinity yield. For 16 wells certain to yield high-salinity, we logged specific electrical conductivity(EC) and tried to get hold of freshwater and saltwater relationship. As result of distribution of $Cl^-$ by depth, it is showed up groundwater trouble by high-salinity yield in the east coastal area and the partly north coastal area. The reason of high-salinity groundwater yield are low-groundwater level by the structure of geology and low-hydraulic gradient etc. There is necessity for management to development and use of groundwater in the high-salinity area, special management area.