• Title/Summary/Keyword: range of contamination

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Recent Progress in Membrane based Colorimetric Sensor for Metal Ion Detection (색 변화를 활용한 중금속 이온 검출에 특화된 멤브레인 기반 센서의 최근 연구 개발 동향)

  • Bhang, Saeyun;Patel, Rajkumar
    • Membrane Journal
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    • v.31 no.2
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    • pp.87-100
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    • 2021
  • With a striking increase in the level of contamination and subsequent degradations in the environment, detection and monitoring of contaminants in various sites has become a crucial mission in current society. In this review, we have summarized the current research areas in membrane-based colorimetric sensors for trace detection of various molecules. The researches covered in this summary utilize membranes composed of cellulose fibers as sensing platforms and metal nanoparticles or fluorophores as optical reagents. Displaying decent or excellent sensitivity, most of the developed sensors achieve a significant selectivity in the presence of interfering ions. The physical and chemical properties of cellulose membrane platforms can be customized by changing the synthesis method or type of optical reagent used, allowing a wide range of applications possible. Membrane-based sensors are also portable and have great mechanical properties, which enable on-site detection of contaminants. With such superior qualities, membrane-based sensors examined in the researches were used for versatile purposes including quantification of heavy metals in drinking water, trace detection of toxic antibiotics and heavy metals in environmental water samples. Some of the sensors exhibited additional features like antimicrobial ability and recyclability. Lastly, while most of the sensors aimed for a detection enabled by naked eyes through rapid colour change, many of them investigated further detection methods like fluorescence, UV-vis spectroscopy, and RGB colour intensity.

The Uranium Removal in Groundwater by Using the Bamboo Charcoal as the Adsorbent (대나무 활성탄을 흡착제로 활용한 오염지하수 내 우라늄 제거)

  • Lee, Jinkyun;Kim, Taehyoung;Lee, Minhee
    • Economic and Environmental Geology
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    • v.51 no.6
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    • pp.531-542
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    • 2018
  • Batch sorption experiments were performed to remove the uranium (U) in groundwater by using the bamboo charcoal. For 2 kinds of commercialized bamboo charcoals in Korea, the U removal efficiency at various initial U concentrations in water were investigated and the optimal sorption conditions to apply the bamboo charcoal were determined by the batch experiments with replicate at different pH, temperature, and reaction time conditions. From results of adsorption batch experiments, the U removal efficiency of the bamboo charcoal ranged from 70 % to 97 % and the U removal efficiency for the genuine groundwater of which U concentration was 0.14 mg/L was 84 %. The high U removal efficiency of the bamboo charcoal maintained in a relatively wide range of temperatures ($10{\sim}20^{\circ}C$) and pHs (5 ~ 9), supporting that the usage of the bamboo charcoal is available for U contaminated groundwater without additional treatment process in field. Two typical sorption isotherms were plotted by using the experimental results and the bamboo charcoal for U complied with the Langmuir adsorption property. The maximum adsorption concentration ($q_m:mg/g$) of A type and C type bamboo charcoal in the Langmuir isotherm model were 200.0 mg/g and 16.9 mg/g, respectively. When 2 g of bamboo charcoal was added into 100 mL of U contaminated groundwater (0.04 ~ 10.8 mg/L of initial U concentration), the separation factor ($R_L$) and the surface coverage (${\theta}$) maintained lower than 1, suggesting that the U contaminated groundwater can be cleaned up with a small amount of the bamboo charcoal.

Polarimetry of solar system small bodies using the Seoul National University 61cm telescope and TRIPOL

  • Jin, Sunho;Ishiguro, Masateru;Kwon, Yuna Grace;Geem, Jooyeon;Bach, Yoonsoo P.;Seo, Jinguk;Sasago, Hiroshi;Sato, Shuji
    • The Bulletin of The Korean Astronomical Society
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    • v.44 no.1
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    • pp.64.2-64.2
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    • 2019
  • It is known that lights scattered by comets and asteroids are partially polarized. From polarimetric observations of those objects, we can investigate physical properties, such as albedos, sizes of cometary dust particles and regolith of asteroids. Since the polarization degrees of those objects highly depend on their phase angles (Sun-object-observer's angles), long-term monitoring observations are required. Moreover, comets show unforeseeable activations (i.e., outbursts) which need follow-up observations to understand the mechanism. In order to realize such monitoring and transient observations, we installed the Triple-Range Imager and POLarimeter (TRIPOL) on the 61cm telescope of Seoul National University (Hereafter, SNU) Gwanak campus. With this combination, we can obtain g', r', i' bands photopolarimetric images simultaneously with $8.0^{\prime}{\times}8.0^{\prime}$ field of view and pixel resolution of 0.94" pixel-1. Here, we make a presentation regarding the photometric and polarimetric performances of TRIPOL on the SNU 61cm telescope. In addition, we introduce initial polarimetric results of asteroid and comets with the instruments. First, we determine the limiting magnitudes (defined as magnitudes for S/N=5) of $15.17{\pm}0.06$ (g'-band), $15.68{\pm}0.01$ (r'-band), $16.24{\pm}0.03$ (I'-band), respectively, with total 240-seconds exposure (four 60-seconds exposure images, each was taken at different rotation angle for the half-wave plate). Second, we found that the instrumental polarization is negligibly small, ($-0.32{\pm}0.04%$ in the g', $-0.36{\pm}0.05%$ in the r' and $-0.21{\pm}0.04%$ in the i'-bands), while the polarization efficiencies are large enough to maximize the performance (i.e., $97.52{\pm}0.03%$ in the g', $98.83{\pm}0.02%$ in the r' and $99.15{\pm}0.02%$ in the i'-bands). With the instruments, we made observations of three Jupiter-family comets, 21P/Giacobini-Zinner, 38P/Stephan-Oterma, and 46P/Wirtanen and plan to observe one near-Earth asteroid, (433) Eros, on a trial basis. Especially for comets, we discriminate signals from dust and gas to eliminate gas contamination, which are known to change observed degree of linear polarization, using multi-band images. We confirm that the phase angle dependency of these comets are consistent with previous observations, probably because polarimetric property of Jupiter-family comets are broadly homogeneous unlike asteroids. We will also describe future observation plans using TRIPOL and SNU 61cm telescope.

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A Color Analysis on Working Clothing in Domestic Machine and Heavy Industry

  • Park, Hye-Won;Bae, Hyun-Sook;Park, Jin-Ah;Kim, Jie-Kwan
    • Journal of Fashion Business
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    • v.13 no.6
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    • pp.61-75
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    • 2009
  • The objective of this research is to the enhance the color function of work clothing : to research and analyze the hue and tone of work clothing colors to be used for machinery and heavy industries in national industrial complexes, Through this research, the color using problems which related with safety workers will be revealed. For this project, total 42 sets of work suits were sampled from 12 different companies in the machinery and construction industries in the national industrial complexes of Gyeongsang Namdo Province and 16 sets of work suits currently being sold in the market. The collected work suits samples were classified according to item types and design. Color measurements were taken thus: After calibration according to ASTM D1729 specifications of standardized configuration settings to match standardized luminous source D65(Daylight 6500K) in color cabinet BOTECK SuperLight-VI, the RGB values of the work suits were calculated using PANTONE Color Cue TX. The RGB values of the colors thus derived were converted into V/C values using the Munsell Conversion 9.0.6 and analyzed with Munsell's 10-color system and PCCS. The results were presented according to Munsell's color wheel and color and brightness distributions were expressed in table form, as well as presented as a tone map. Following analysis, color hue distribution was found to be concentrated around PB, and brightness distribution toward the low end and mid range of the scale. Saturation values were distributed mostly around the low end of the scale. Following color tone analysis according to PCCS, it became apparent that colors were mainly distributed around dkg, ltg, and g, at low- and mid-brightness and low-saturation. Therefore, it may be concluded that colors used in work suits in the machinery and heavy industries are mainly cool colors, at low- and mid-brightness and low saturation. It is conjectured that such colors were applied uniformly in the workplace in order to serve certain functions, such as concealment of stains and contamination. Therefore, it follows that the utilization of colors, among other functions served by working clothings, must be taken into consideration in order to enhance safety and efficiency.

Development of a Diagnostic System for the Detection of the Cowpea mild mottle virus Specific Gene in Quarantine (Cowpea mild mottle virus 특이유전자 검출을 위한 검역진단시스템 개발)

  • Lee, Siwon;Lee, Jin-Young;Moon, Bo Yeong;Kim, Chang Soo;Shin, Yong-Gil;Rho, Jae-Young
    • Microbiology and Biotechnology Letters
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    • v.43 no.3
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    • pp.296-299
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    • 2015
  • Cowpea mild mottle virus (CPMMV) has a wide range of hosts, such as the pea family and tomato. CPMMV is a non-reported virus in Korea, and is domestically designated as a controlled virus associated with plant quarantine. In this study, a rapid diagnostic method for the detection of CPMMV at quarantine sites was developed. For the development of a user-based system, the PCR compositions and conditions use existing methods of quarantine for the viruses. Two sets of RT-PCR and nested PCR were developed in this study that could be amplified from 579 → 298 dp and 638 → 252 bp, respectively. Furthermore, a sequence inserted positive control plasmid was developed, which is able to identify false-positives resulting from laboratory contamination. The findings of this study are important for the diagnosis of CPMMV in imported crops held in plant quarantine.

Hydro-geochemical Nature and Nitrates Contamination Charecters of Groundwater in the Youngdong, Chungbuk Province (충북 영동지역 지하수의 수리지화학적 특성 및 질산염 오염 특성)

  • Lee, In-Gyerong;Choi, Sang-Hoon
    • Economic and Environmental Geology
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    • v.45 no.1
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    • pp.23-30
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    • 2012
  • Major ions and nitrogen isotopic analyses were performed to determine the geochemical characters and to identify the source of nitrate of the shallow groundwater around agricultural field in the Youngdong area. The pH value of groundwater ranges from 60. to 8.2 (pH 7.2, mean). The average of EC, Eh and DO is 369 ${\mu}S/cm$ (70~729 ${\mu}S/cm$), 165.6 mV (29~383.2 mV), 4.3 mg/L (1.8~8.0 mg/L) respectively. The ion concentraion of groundwater was in the order of $Ca^{2+}$>$Na^{2+}$>$Mg^{2+}$>$K^{2+}$ and ${HCO_3}^-$>${NO_3}^-$>${SO_4}^{2-}$>$Cl^-$>$F^-$. Most of groundwater is Ca-$HCO_3$ type. The groundwater was affected by water-rock interaction in the shallow depth. Some groundwater is Ca-Cl or Na-$HCO_3$ (2.5%) type that was due to agricultural activities. The $NO_3$_N concetration of grondwater range from 10.2 mg/l to 26.9 mg/l, which show that this area is under nitrate pollution. ${\delta}^{15}N-NO_3$ value of the groundwater is the origins of are a combination of animal wastes and man-made fertilizers.

Petrology of the Cretaceous volcanic rocks in northern Yucheon Minor Basin, Korea (북부 유천소분지에 분포하는 백악기 화산암류에 대한 암석학적 연구)

  • Sang Wook Kim;Sang Koo Hwang;Yoon Jong Lee;Jae Young Lee;In Seok Koh
    • The Journal of the Petrological Society of Korea
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    • v.7 no.1
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    • pp.27-36
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    • 1998
  • The volcanic piles in the northern Yucheon Minor Basin area are the Hagbong basaltic rocks, the Chaeyaksan basaltic rocks, the Jusasan andesitic rocks, the Unmunsa rhyolitic rocks, and the Tertiary voicanics. Stratigraphically, from the lowermost, (1) the Hagbong basaltic rocks are composed mainly of basaltic tuff with two olivine basalt flows intercalated, (2) the Chaeyagsan basaltic rocks are predominantly in tuffs and agglomerate with 3 basaltic flow interlayers, (3) the Jusasan andesitic rocks consist of thick piles of alternated sequences of 4 andesite flows and 5 andesitic tuffs and tuffaceous sediments and (4) the Unmunsa rhyolitic rocks which embed some rhyolite and obsidian are dominant in tuffs such as ash flow and crystal welded tuff. These volcanics reveal distinguishable characteristics in petrochemistry. In discriminating by major elements, the Hagbong and the Chaeyagsan basaltic rocks are alkaline, whereas the latter is also spilitic. In comparison, the volcanic rocks of the Jusasan andesitic rocks and the Tertiary sequences are characteristically calc-alkaline although their distribution is spatially separated. On the other hand, the variations in immobile trace elements indicate that the Hagbong basaltic rocks range from alkaline to calc-alkaline and from WPB/VAB transition to VAB, whereas the Chaeyagsan basaltic rocks are calc-alkaline WPB/VAB transition type and the two others calc-alkaline VAB. In order to show such a variety in their rock series of the volcanic rocks, the environment during their magma generation, magma rising, and post-eruption alteration could be positively considered.

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Arsenic species in husked and polished rice grains grown at the non-contaminated paddy soils in Korea (국내 비오염 논토양에서 재배한 현미와 백미 중 비소화학종 함량)

  • Kim, Da-Young;Kim, Ji-Young;Kim, Kye-Hoon;Kim, Kwon-Rae;Kim, Hyuck-Soo;Kim, Jeong-Gyu;Kim, Won-Il
    • Journal of Applied Biological Chemistry
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    • v.61 no.4
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    • pp.391-395
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    • 2018
  • There is an increasing concern over arsenic (As) contamination of paddy soil and rice with regard to food safety. This study was conducted to investigate total and inorganic As concentration in one hundred husked and polished rice samples collected at the non-contaminated paddy soil in Korea. Arsenic species in rice samples were extracted using 1% nitric acid ($HNO_3$) with a microwave oven and were measured using high performance liquid chromatography coupled with inductively coupled plasma-mass spectrometry. Mean concentrations of total As in husked rice and polished rice were 0.18 and $0.11mg\;kg^{-1}$, respectively. Also, average inorganic As concentrations in husked rice and polished rice were 0.11 and $0.07mg\;kg^{-1}$, respectively. These levels are lower than the standard guideline value 0.35 and $0.2mg\;kg^{-1}$ for inorganic As in husked and polished rice recommended by Codex Committee on Contaminants in Foods and Ministry of Food and Drug Safety, respectively. The mean of the inorganic As ratio for the total amount of As was 0.65 and 0.67 for husked rice and polished rice, respectively, and the range was from 0.08 to 1.0. For health risk assessment, the average value of cancer risk probability was $9.24{\times}10^{-5}$ and ranged from $2.30{\times}10^{-5}$ to $1.90{\times}10^{-5}$. Therefore, human exposure to As through dietary intake of surveyed rice samples might considered to be a low health risk.

Microbial Community Structures Related to Arsenic Concentrations in Groundwater Occurring in Haman Area, South Korea (함안지역 지하수의 비소(As) 함량과 미생물 군집 특성과의 연관성 검토)

  • Kim, Dong-Hun;Moon, Sang-Ho;Ko, Kyung-Seok;Kim, Sunghyun
    • Economic and Environmental Geology
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    • v.53 no.6
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    • pp.655-666
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    • 2020
  • This study evaluated the characteristics of arsenic production in groundwater through microbial community analysis of groundwater contaminated with high arsenic in Haman area. Groundwater in Haman area is contaminated with arsenic in the range of 0-757.2 ㎍/L, which represents the highest arsenic contamination concentration reported in Korea as natural groundwater pollution source. Of the total 200 samples, 29 samples (14.5%) showed higher arsenic concentration than that of 10 ㎍/L, which is the standard for drinking water quality, and 8 samples (4%) found in wells with 80-100 m depth were above 50 ㎍/L. In addition, seven wells with arsenic concentration more than 100 ㎍/L located in the northern part of Haman. As a result of microbial community analysis for high arsenic-contaminated groundwater, the microbial community compositions were significantly different between each sample, and Proteobacteria was the most dominant phyla with an average of 61.5%. At the genus level, the Gallinonella genus was predominant with about 12.8% proportion, followed by the Acinetobacter and Methermicoccus genus with about 7.8 and 7.3%, respectively. It is expected that high arsenic groundwater in the study area was caused by a complex reaction of geochemical characteristics and biogeochemical processes. Therefore, it is expected that the constructed information on geochemical characteristics and microbial communities through this study could be used to identify the origin of high arsenic groundwater and the development of its controlling technology.

A Survey of the Presence of Aflatoxins in Food (식품 중 아플라톡신 오염도 조사)

  • Park, Min-Jung;Yoon, Mi-Hye;Hong, Hae-Geun;Joe, Tae-Suk;Lee, In-Sook;Park, Jeong-Hwa;Ko, Hoan-Uk
    • Journal of Food Hygiene and Safety
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    • v.23 no.2
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    • pp.108-112
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    • 2008
  • A survey of total aflatoxin levels was conducted on 158 samples (nuts, fermented foods and their processed products) collected in local markets in Gyeonggi-do and Domestic Internet Site. The total aflatoxins were quantified by the immunoaffinity column clean-up method followed by high performance liquid chromatography (HPLC)-fluorescence detector (FLD). Aflatoxins were found in 45(28.5%) samples including 34 nuts and nut products, 7 soybean pastes, 1 meju, 1 bean product and 2 corn snacks with a range of $0.02{\sim}3.96\;{\mu}g/kg$. These results show that the contamination level of aflatoxin in foods consumed in Korea is low compared with the standard in Korea Food Code($10\;{\mu}g/kg$ as aflatoxin $B_1$). Aflatoxin $B_1$ content was increased in peanuts and com snacks during storage but it was decreased in doenjang (soybean paste).