• 환경영향평가
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• 제22권2호
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• pp.135-145
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• 2013

The recycling of coal bottom ash generated from coal power plants in Korea has been limited due to heterogenous characteristics of the materials. The most common management option for the ash is disposal in landfills (i.e. ash pond) near ocean. The presence of large coarse and fine materials in the ash has prompted the desire to beneficially use it in an application such as fill materials. Prior to reuse application as fill materials, the potential risks to the environment must be assessed with regard to the impacts. In this study, a total of nine test cells with bottom ash samples collected from pretreated bottom ash piles and coal ash pond in a coal-fired power plant were constructed and operated under the field conditions to evaluate the leachability over a period of 210 days. Leachate samples from the test cells were analyzed for a number of chemical parameters (e.g., pH, salinity, electrical conductance, anions, and metals). The concentrations of chemicals detected in the leachate were compared to appropriate standards (drinking water standard) with dilution attenuation factor, if possible, to assess potential leaching risks to the surrounding area. Based on the leachate analysis, most of the samples showed slightly high pH values for the coal ash contained test cells, and contained several ions such as sodium, potassium, calcium, magnesium, chloride, sulfate, and nitrate in relatively large quantities. Three elements (aluminum, boron, and barium) were commonly detected above their respective detection limits in a number of leachate samples, especially in the early leaching period of time. The results of the test cell study indicate that the pollutants in the leachate from the coal ash test cells were not of a major concern in terms of leaching risk to surface water and groundwater under field conditions as fill materials. However, care must be taken in extending these results to actual applications because the results presented in this study are based on the limited field test settings and time frame. Structural characteristics and analysis for coal bottom ash may be warranted to apply the materials to actual field conditions.

• 한국식품과학회지
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• 제8권1호
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• pp.33-41
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• 1976

1. 유기질소원(有機窒素源)으로는 soybean meal, 무기질소원(無機窒素源)으로는 $(NH_4)_2SO_4$가 lipase생산(生産)에 가장 효과(效果)이었다. 2. 배양중(培養中) 배지(培地)의 pH저하(低下)를 이르키는 xylose, glucose, fructose, galactose, mannose, maltose, soluble starch, dextrin을 탄소원(炭素源)으로 첨가(添加)하였을 때 lipase 생산(生産)이 심(甚)하게 저해(沮害)되었다. sucrose는 lipase생산(生産)을 저해(沮害)하지 않았으나 첨가효과(添加效果)는 인정(認定)되지 않았다. 3. 인산염(燐酸鹽)으로서는 $K_2HPO_4$, 마그네슘염(鹽)으로서는 $MgSO_4{\cdot}7H_2O$가 lipase생산(生産)에 가장 효과적(效果的)이었다. 4. Olive유(油), 대두유(大豆油) 및 야자유(油)의 첨가(添加)는 lipase생산(生産)을 증가(增加)시켰으며 1% olive유(油) 첨가시(添加時) lipase생산(生産)이 50% 증가(增加)되었다. 5. yeast extract $0.05{\sim}0.07%$첨가시(添加時) lipase생산(生産)이 약간 증가(增加)되었다. 6. 본균(本菌)의 lipase생산(生産)에 가장 적합(適合)한 배지(培地)는 soybean meal 2%, $K_2HPO_4$ 0.5%, $(NH_4)_2SO_4$ 0.1%, $MgSO_4{\cdot}7H_2O$ 0.05%, yeast extract 0.05%, olive유(油) 1%의 조성(組成)의 것으로서 최적배양조건하(最適培養條件下)에서 48시간(時間) 배양시(培養時)에 lipase생산(生産)이 최고(最高)에 도달(到達)하였다.

• 한국균학회지
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• 제27권1호통권88호
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• pp.1-9
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• 1999

느타리버섯 8품종의 균사생장은 $25{\sim}30^{\circ}C$의 온도 범위와 $5.5{\sim}6.5$의 pH 범위에서 가장 우수하였다. 영양원의 선발시험에서 탄소원으로서는 황백당, 밀가루 및 옥수수가루가, 그리고 질소원으로서는 대두분이 공시균주의 균사생장이 가장 우수하였다. 농업적으로 이용성이 우수한 황백당 3%, 대두분 0.3%, 인산칼륨 0.05%, 황산마그네슘 0.05%를 배지 조성으로 하는 농업용 액체배지를 선발하였다. 삼각플라스크 배양에서는 250 ml의 erlenmeyer flask에서 보다는 250ml의 shake flask에서 직경 6 mm의 균사절편을 2개 접종하여 배양액량 100ml에서 배양했을 때 공시균주의 균사체 생산이 우수하였다. 그리고 erlenmeyer flask에서 배양방법을 달리하여 느타리버섯의 균사를 배양하였을 때, $45^{\circ}$ 경사배양한 처리구에서 균사체 생산이 가장 우수하였으며, 길이 $50mm{\times}$ 직경 10mm의 유리막대를 넣고 배양한 처리구에서는 균체량이 가장 적었지만 펄프형의 균사생육을 유도할 수 있었다.

• 한국미생물·생명공학회지
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• 제2권2호
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• pp.83-88
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• 1974

1) 폐액을 여과했을 때 잔사부분엔 조단백질 33.08%, 총당 19.96%, 회분 2.06% 이었으며, 여액부분은 환원당 1.54%, 조단백진 2.48%, 회분이 0.43%이었으며 1kg/㎤에서 15분간 2차 살균한 결과 그의 pH가 3.15이었다. 2) 여액을 기본배지로 하여 flask 상에서 Saccharomyces cerevisiae YF-1 의 최적배양조건을 구한 결과 배지 100m1 당 Urea 0.428g, KH$_2$PO$_4$ 0.439g, MgSO$_4$ㆍ5$H_2O$ 0.21g을 첨가한 뒤 pH 4.0, 3$0^{\circ}C$ 에서 24~28시간 배양함이 가장 좋았다. 이때 배지 100m1당 1.38g의 건조효모균체 (35$^{\circ}C$에서 24시간 진공건조)를 얻을 수 있었다. 3) 건조효모의 조성은 조단백질 56.96%, 지방 1.30%, 탄수화물6.53%. 회분 9.62%이었다. 본 연구는 문교부 학술연구조성비로 행한 것이다.

• 한국토양비료학회지
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• 제25권4호
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• pp.357-363
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• 1992

본(本) 시험(試驗)은 1954년(年)부터 동일비료연용(同一肥料連用)이 토양(土壤)의 양분변동(養分變動) 양상(樣相) 및 생산력에 미치는 효과를 구명(究明)하기 위(爲)하여 실시(實施)한 시험(試驗)에서 생산된 현미중(玄米中)의 화학성분(化學成分)을 분석(分析)하고 이들 성분(成分)과 미질(米質)과의 관계(關係)를 검토(檢討)한 것으로 이를 요약(要約)하면 다음과 같다. 1. 질소유형별(窒素類型別) 현미중(玄米中)의 복백미(腹白米) 생성량(生成量)은 질소(窒素)를 유안(硫安)으로 시용(施用)한 삼요소구(三要素區)에서 가장 많았고 유안단용구(柳安單用區), 요소단용구(尿素單用區), 완전무비구(完全無肥區)의 순(順)으로 낮았다. 2. 삼요소(三要素)를 시용(施用)하고 규산(珪酸) 또는 석회(石灰)를 각각(各各) 시용(施用)하였거나 이들 규산(珪酸) 및 석회(石灰)를 혼용(混用)하였을 때에는 삼요소(三要素)만을 시용(施用)하였을 때보다 복백미(腹白米) 생성량(生成量)이 크게 감소(減少)되었다. 그 정도(程度)는 석회시용구(石灰施用區)보다 규산시용구(珪酸施用區)에서 유의(有意)한 감소(減少)를 보였다. 3. 삼요소(三要素)를 동일(同一)하게 시용(施用)한 후(後) 퇴비(堆肥)를 시용(施用)하였거나 각(各) 개량제(改良劑)를 퇴비(堆肥)와 혼합(混合) 처리(處理) 하였을 때에는 삼요소(三要素) 단용구(單用區)에 비(比)하여 현미중(玄米中)의 복백미(腹白米) 생성량(生成量)이 크게 증가(增加)하였다. 특(特)히 삼요소(三要素)＋석회(石灰)＋퇴비구(堆肥區)에서는 삼요소(三要素) 단용구(單用區)에 비(比)하여 2배이상(培以上)의 높은 복백미(腹白米)가 생성(生成)되었다. 4. 복백미(腹白米) 생성량(生成量)이 적은 구(區)에서는 질소유형별(窒素類型別) 및 삼요소처리구(三要素處理區) 공(共)히 현미중(玄米中)의 전질소함량(全窒素含量)이 낮았으며 이들 각(各) 처리중(處理中)에서도 복백미(腹白米) 생성량(生成量)이 많았던 구(區)에서는 현미중(玄米中)의 전질소함량(全窒素含量)도 높았다. 5. 현미중(玄米中) Mg/K비율(比率)이 낮을 수록 복백미(腹白米) 생성량(生成量)은 많아지는 경향(傾向)이었으며, $Mg/K{\cdot}N$비율(比率) 역시(亦是) 낮은 구(區)에서 복백미(腹白米) 생성량(生成量)이 많았다.

• Journal of Biosystems Engineering
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• 제35권5호
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• pp.343-349
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• 2010

Rapid on-site sensing of nitrate-nitrogen and potassium ions in hydroponic solution would increase the efficiency of nutrient use for greenhouse crops cultivated in closed hydroponic systems while reducing the potential for environmental pollution in water and soil. Ion-selective electrodes (ISEs) are a promising approach because of their small size, rapid response, and the ability to directly measure the analyte. The capabilities of the ISEs for sensing nitrate and potassium in hydroponic solution can be affected by the presence of other ions such as calcium, magnesium, sulfate, sodium, and chloride in the solution itself. This study was conducted to investigate the applicability of two ISEs consisting of TDDA-NPOE and valinomycin-DOS PVC membranes for quantitative determinations of $NO_3$-N and K in hydroponic solution. Nine hydroponic solutions were prepared by diluting highly concentrated paprika hydroponic solution to provide a concentration range of 3 to 400 mg/L for $NO_3$-N and K. Two of the calibration curves relating membrane response and nutrient concentration provided coefficients of determination ($R^2$) > 0.98 and standard errors of calibration (SEC) of < 3.79 mV. The use of the direct potentiometry method, in conjunction with an one-point EMF compensation technique, was feasible for measuring $NO_3$-N and K in paprika hydroponic solution due to almost 1:1 relationships and high coefficients of determination ($R^2$ > 0.97) between the levels of $NO_3$-N and K obtained with the ion-selective electrodes and standard instruments. However, even though there were strong linear relationships ($R^2$ > 0.94) between the $NO_3$-N and K concentrations determined by the Gran's plot-based multiple standard addition method and by standard instruments, hydroponic $NO_3$-N concentrations measured with the ISEs, on average, were about 10% higher than those obtained with the automated analyzer whereas the K ISE predicted about 59% lower K than did the ICP spectrometer, probably due to no compensation for a difference between actual and expected concentrations of standard solutions directly prepared.

• 약학회지
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• 제41권3호
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• pp.305-311
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• 1997

Sustained release-microspheres and immediate release-pellets were prepared to develop a controlled release multiparticulate system containing both water soluble and insoluble dr ug. Pseudoephedrin.HCl (EPD) and terfenadine (TRF) were used as model drugs, respectively. Sustained release-EPD microspheres were prepared by solvent evaporation method using Eudragit RL or RS as a matrix combined with pH-insensitive film coating. Smaller EPD microspheres were obtained when smaller amount of Eudragit as a matrix material or larger amount of magnesium stearate as a dispersing agent was used. However the obtained microspheres did not show syfficient sustained release characteristics. About 97% of EPD was released after 1 hr irrespective of matrix material used. Subsequent coating of the microspheres with pH-insensitive polymer such as Eudragit RS or ethylcelulose (EC) resulted good sustained in 37.5, 73.3 and 92.0% release of encapsulated EPD in distilled water after 1, 3 abd 7 hr, respectively. It corresponds to mean dissolution time (MDT) of 2.3 hr, which is much larger than that of un-coated EPD microspheres (0.0048 hr). Immediate release TRF pellets were prepared by spherically agglomerated crystallization using Eudragit E as an inert matrix and methylene chloride as a liquid binder. Using Eudragit E alone as a matrix resulted in satisfactory physical properties of the pellets such as sphericity, surface texture and flowability, but led to slower release of TRF from pellets than un-modified TRF powder (MDT of 1.70 vs 1.43 hr in pH 1.2 dissolution medium). Introducing propylene glycol or sodium lauryl sulfate as an emulsifier brought about faster release of TRF from pellets (MDT of 1.14 and 0.95 hr, respectively). In conclusion, microencapsulation by solvent evaporation combined with film coating and spherically agglomerated crystallization were successfully utilized to prepare controlled release multiparticulate system composed of sustained release EPD-microspheres and immediate release TRF pellets.

• 한국동물위생학회지
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• 제42권4호
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• pp.289-296
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• 2019

A novel rapid procedure with liquid chromatography tandem mass spectrometry (LC-MS/MS) detection has been developed by changing various conditions including sample preparation such as QuEChERS (Quick, Easy, Cheap, Effective, Rugged and Safe) methodology. This work has been involved the optimization and validation of detection method for fluoroquinolones which are widespread used in livestock especially in the chicken. Five grams of homogenized chicken muscle were extracted with QuEChERS EN and acetonitrile containing 5% formic acid and cleaned with anhydrous magnesium sulfate and C₁₈ sorbent. The separation was performed on Acquity UPLC HSS T3 (2.1 mm×100 mm, 1.8 ㎛) column. The mobile phase A and B were composed of water containing 0.1% formic acid and acetonitrile containing 0.1% formic acid, respectively. Flow rate was 0.25 mL/min and column temperate was 40℃. LC-MS/MS with multiple reaction monitoring has been optimized for ten fluoroquinolones (ciprofloxacin, danofloxacin, difloxacin, enrofloxacin, marbofloxacin, norfloxacin, ofloxacin, orbifloxacin, pefloxacin and sarafloxacin). The method developed in this study has been presented good linearity with correlation coefficient (R²) of 0.9971~0.9998. LOD and LOQ values ranged from 0.09 to 0.76 ppb and from 0.26 to 2.29 ppb, respectively. The average recoveries were from 77.46 to 111.83% at spiked levels of 10.0 and 20.0 ㎍/kg. Relative standard deviation (%) ranged 1.28~11.90% on intra-day and 3.10~8.38 % on inter-day, respectively. This analysis method was applicable to the livestock residue laboratories and was expected to be satisfactory for the residue surveillance system.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2004년도 임시총회 및 추계학술발표회
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• pp.121-121
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• 2004

The groundwater in the Pocheon area occurs from both a fractured bedrock aquifer in igneous and metamorphic rocks and an alluvial aquifer with a thickness of <50 m, and forms a major source of domestic and agricultural water supply. In this study, we performed a hydrogeochemical study in order to identify the control of geochemical processes on groundwater quality. For this study, groundwater level and physicochemical parameters (EC, Eh, pH, alkalinity) were monitored once a month from a total of 150 groundwater wells between June 2003 to August 2004. A total of 153 water samples (13 surface water, 66 alluvial groundwater, 74 bedrock groundwater) were also collected and analyzed in February 2004. Groundwater chemistry in the study area is very complex, depending on a number of major factors such as geology, degree of chemical weathering, and quality of recharge water. Hydrochemical reactions such as the leaching of surficial and near-solace soil salts, dissolution of calcite, cation exchange, and weathering of silicate minerals are proposed to explain the chemistry of natural groundwater. Alluvial groundwaters locally have very high TDS concentrations, which are characterized by their chloride(nitrate)-sulfate-bicabonate facies and low Na/Cl ratio. Their grondwater levels are highly fluctuated according to rainfall event. We suggest that high nitrate content and salinity in such alluvial groundwaters originates from the local recharge of sewage effluents and/or fertilizers. Likewise, high concentrations of nitrate were also locally observed in some bedrock groundwaters, suggesting their effect of anthropogenic contamination. This is possibly due to the bypass flow taking place through macropores. Tile degree of the weathering of silicate minerals seems to be a major control of the distribution of major cations (sodium, calcium, magnesium, potassium) in bedrock groundwaters, which show a general increase with increasing depth of wells. Thermodynamic interpretation of groundwater chemistry shows that the groundwater in the study area is in chemical equilibrium with kaolinite and Na-montmorillonite, which indicates that weathering of plagioclase to those minerals is a major control of hydrochemistry of bedrock groundwater. The interpretation of the molar ratios among major ions, as well as the mass balance calculation, also indicates the role of both dissolution/precipitation of calcite and Ca-Na cationic exchange as bedrock groundwaters evolves progressively.

• 한국환경농학회지
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• 제39권3호
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• pp.246-252
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• 2020

BACKGROUND: Pesticides are broadly used to control weeds and pests, and the residues remaining in crops are managed in accordance with the MRLs (maximum residue limits). Therefore, an analytical method is required to quantify the residues, and we conducted a series of analyses to select and validate the quick and simple analytical method for tolpyralate in five agricultural products using QuEChERS (quick, easy, cheap, effective, rugged and safe) method and LC-MS/MS (liquid chromatography-tandem mass spectrometry). METHODS AND RESULTS: The agricultural samples were extracted with acetonitrile followed by addition of anhydrous magnesium sulfate, sodium chloride, disodium hydrogencitrate sesquihydrate and trisodium citrate dihydrate. After shaking and centrifugation, purification was performed with d-SPE (dispersive-solid phase extraction) sorbents. To validate the optimized method, its selectivity, linearity, LOD (limit of detection), LOQ (limit of quantitation), accuracy, repeatability, and reproducibility from the inter-laboratory analyses were considered. LOQ of the analytical method was 0.01 mg/kg at five agricultural products and the linearity of matrix-matched calibration were good at seven concentration levels, from 0.0025 to 0.25 mg/L (R²≥0.9980). Mean recoveries at three spiking levels (n=5) were in the range of 85.2~112.4% with associated relative standard deviation values less than 6.2%, and the coefficient of variation between the two laboratories was also below 13%. All optimized results were validated according to the criteria ranges requested in the Codex Alimentarius Commission (CAC) and Ministry of Food and Drug Safety (MFDS) guidelines. CONCLUSION: In conclusion, we suggest that the selected and validated method could serve as a basic data for detecting tolpyralate residue in imported and domestic agricultural products.