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송다희,박선화,전상호,황종연,김문수,조훈제,김덕현,이경미,김기인,김태승,김태승,정현미 한국토양비료학회 2017 한국토양비료학회지 Vol.50 No.4
In this study, we monitored 4 volatile organic compounds (VOCs) such as chloroform, dichloromethane,1,2-dichloroethane, and tetrachloromethane in groundwater samples to determine the detection frequency andtheir concentrations and evaluated the health risk level considering ingestion, inhalation, and skin contact. 75groundwater wells were selected. 24 wells were from monitoring background groundwater quality level and51 wells were from monitoring groundwater quality level in industrial or contamination source area. In theresults, the detection frequency for chloroform, dichloromethane, 1,2-dichloroethane, and tetrachloromethanewas 42.3%, 8.1%, 6.0%, and 3.4%, respectively. The average concentrations of VOCs were high in theorder of chloroform (1.7 μg L-1), dichloromethane (0.08 μg L-1), tetrachloromethane (0.05 μg L-1), and1,2-dichloroethane (0.05 μg L-1). Chloroform had the highest detection frequency and average detectionconcentration. In the contaminated groundwater, the detection frequency of VOCs was high in the order ofchloroform, dichloromethane, 1,2-dchloroethane, and tetrachloromethane. The average concentrations forchloroform, dichloromethane, 1,2-dichloroethane, and tetrachloromethane were 2.23 μg L-1, 0.08 μg L-1, 0.07μg L-1, and 0.06 μg L-1, respectively. All the 4 compounds were detected at industrial complex and storagetank area. The maximum concentration of chloroform, dichloromethane, and 1,2-dichloroethane was detectedat industrial complex area. Especially, the maximum concentration of chloroform and dichloromethane wasdetected at a chemical factory area. In the uncontaminated groundwater, the detection frequency of VOCs washigh in the order of chloroform, dichloromethane, and 1,2-dchloroethane and tetrachloromethane was notdetected. The average concentrations for chloroform, dichloromethane, and 1,2-dichloroethane were 0.57 μgL-1, 0.07 μg L-1, and 0.03 μg L-1, respectively. Although chloroform in the uncontaminated groundwater wasdetected the most, the concentration of chloroform was not exceeding water quality standards. By land use,the maximum detection frequency of 1,2-dichloroethane was found near a traffic area. For human riskassessment, the cancer risk for the 4 VOCs was 10-6~10-9, while the non-cancer risk (HQ value) for the 4VOCs is 10-2~10-3.
송다희,박선화,전상호,김기인,황종연,김문수,조훈제,김덕현,이경미,김혜진,김태승,정혜미,김현구 한국토양비료학회 2017 한국토양비료학회지 Vol.50 No.5
For this study, groundwater samples for 3 years from 2011 through 2013 were collected at 106 groundwater monitoring sitein Korea. These groundwater samples were analyzed for 13 pesticides such as cabofuran, pentachlorobenzene, hexachlorobenzene,simazine, atrazine, lindane (gamma-HCH), alachlor, heptachlor, chlordane (total), endosulfan (1, 2), dieldrin,endrin, 4,4-DDT. The objectives of this study were to determine the detection frequency and their concentrations of 13pesticides and evaluate the health risk level considering ingestion, inhalation, and skin contact using concentrations of 13pesticides in groundwater samples. An analysis was used for the simultaneous determination for 13 pesticides using GC-MS. GC-MS was performed on HP-5ms, using helium (1 ml min-1) as carrier gas. The average recoveries of the pesticides werefrom 92.8% to 120.8%. The limits of detection (LODs) were between 0.004 μg L-1 and 0.118 μg L-1 and the limits ofquantification (LOQs) were between 0.012 μg L-1 and 0.354 μg L-1. 106 groundwater wells were selected. 54 wells werefrom well to monitor background groundwater quality and 52 wells were from well to monitor groundwater quality inindustrial or contamination source area. Eight pesticides including pentachlorobenzene, lindane (Gamma-HCH), heptachlor,chlordane (total), Endosulfan (1, 2), dieldrin, endrin, and 4,4-DDT were not detected in groundwater samples. The detectionfrequency for hexachlorobenzene, alachlor, carbofuran and simazine was 23.4%, 11.4%, 7.3%, and 1.0%, respectively. Atrazine was detected once in 2011. The average concentrations were 0.00423 μg L-1 for carbofuran, 0.000243 μg L-1 foralachlor, 0.00015 μg L-1 for simazine, and 0.00001 μg L-1 for hexachlorobenzene. The detection frequency of hexachlorobenzenewas high, but the average concentration was low. In the contaminated groundwater, the detection frequency forhexachlorobenzene, alachlor, carbofuran, simazine and atrazine was 26.1%, 21.3%, 7.1%, 1.9% and 0.3%, respectively. Inthe uncontaminated groundwater, detection frequency for hexachlorobenzene, carbofuran and alachlor were 20.2%, 7.5%,and 1.9% respectively. Simazine and atrazine were not detected at uncontaminated groundwater wells. According to thepurpose of groundwater use, atrazine was detected for agricultural groundwater use. Hexachlorobenzene showed highdetection frequency at agricultural groundwater use area where the animal feeding area and golf course area were located. Alachlor showed more than 50% detection frequency at cropping area, pollution concern river area, and golf course area. Atrazine was detected in agricultural water use area. By land use, the maximum detection frequency of alachlor was foundnear an orchard. For human risk assessment, the cancer risk for the 5 pesticides was between 10-7 and 10-10, while thenon-cancer risk (HQ value) was between 10-4 and 10-6. For conclusion, these monitoring study needs to continue because ofthe possibility of groundwater contamination based on various purpose of groundwater use.
Gas Permeation of Y2O3-SiC Composite Membrane
송다희,정미원 한국세라믹학회 2015 한국세라믹학회지 Vol.52 No.4
Y2O3-SiC composite membrane was dip-coated using Y2O3 sol solution; this membrane was compared with a non- coated one. Each membrane was characterized by XRD, FE-SEM and BET techniques. Hydrogen and CO permeation were tested with selfmanufactured Sievert's type equipment. Y2O3 coating was enhanced for the selectivity of the membrane (H2 versus CO). The hydrogen permeation was measured at 1 bar with increasing temperatures. In case of the coated membrane, hydrogen permeation was found to be 1.24 x 10-7 mol/m2sPa with perm-selectivity of 4.26 at 323 K.
전상호,박선화,송다희,황종연,김문수,조현제,김덕현,이경미,김기인,김혜진,김태승,정현미,김현구 한국토양비료학회 2017 한국토양비료학회지 Vol.50 No.5
To establish new metal groundwater standard, 5 metals such as aluminum, chromium, iron, manganese, andselenium were evaluated by Chemical Ranking Of groundWater pollutaNts (CROWN) including possibilityof exposure, toxicity, interest factor, connection standard for other media, and data reliability. 430groundwater samples in 2013 and 2014 were collected semiannually from 110 groundwater wells and theywere analyzed for selenium, manganese, iron, chromium, and aluminum. For this study, 430 groundwatersamples were categorized into 3 geological distribution features, such as igneous, metamorphic, andsedimentary rock region and geological background levels were divided by pre-selection methods. For theresults, the average concentrations of aluminum, chromium, iron, manganese, and selenium in 430 groundwatersamples were 0.0008 mg L-1, 0.0001 mg L-1, 0.174 mg L-1, 0.083 mg L-1, and 0.0004 mg L-1, respectively. Inaddition, among various geologies, average concentration of selenium was the highest in igneous rock region,average concentrations of chromium, manganese and aluminum were the greatest in sedimentary rock region,and average concentration of iron was the most high in metamorphic rock region. As a result of the geologicalbackground concentration with pre-selection method, background concentrations of selenium and aluminumin groundwater samples were the highest from sedimentary rock as 0.0010 mg L-1 and 0.0029 mg L-1 andbackground concentrations of manganese and iron in groundwater samples were the greatest from metamorphicrock as 0.460 mg L-1 and 1.574 mg L-1, and no chromium background concentration in groundwater sampleswas found from all geology.
이민후,김영석,송다희 한국지질과학협의회 2017 Geosciences Journal Vol.21 No.3
Numerical estimation of physical properties from digital pore microstructures has drawn great attention and is being used for quantifying interrelation between various physical properties. The pore microstructures are commonly obtained by the Xray microtomographic technique, which can give fairly accurate pore geometry. However, there is minor distortion due to the limited resolution or smoothing. This distortion can cause errors in estimating physical properties by pore-scale simulation techniques. Among the properties, seismic velocity would have relatively large errors since a small amount of change in grain contacts can cause significant over-estimation. In this paper, we analyzed the errors in seismic velocity by resolution and smoothing of pore geometry using three samples: an unconsolidated sand pack and two medium-porosity sandstones with different degrees of consolidation. As the resolution becomes poor, the calculated velocity increases linearly, while smoothing gives nonlinear trends; higher errors in the early stage of smoothing. As we expected, soft rocks have higher sensitivity, since the grain contacts are small and are sensitive to minor distortion. Within similar ranges, the resolution causes larger errors than smoothing. In addition, smoothing does not cause velocity over-estimation once the resolution becomes poor, while the resolution can create considerable errors in velocity even after significant smoothing. We conclude that the resolution should be considered in the first place when obtaining digital pore microstructures to minimize errors in velocity estimation. We can also suggest that a good care should be taken when applying smoothing filters, if a sample is suspected to be poorly-consolidated or to have high porosity.