• 한국미생물·생명공학회지
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• 제24권4호
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• pp.519-524
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• 1996

The kinetics of growing microalga, Spirulina platensis was investigated to treat swine wastes with optimum growth conditions. Temperature was varied from 15 to 40$\circ$C at three different light intensities, 6 W/m$^{2}$, 12 W/m$^{2}$ and 24 W/m$^{2}$. The specific growth rate was increased as temperature increased up to 30$\circ$C. The activation energy was estimated as 13.5 kcal/mol by an Arrhenius relationship. 0.24 (1/day) of specific growth rate was obtained from batch cultivation with 30% swine wastes, compared to 0.31 (1/day) from clean culture. It was found that Spirulina platensis was able to reduce 70-93% of PO$_{4}$$^{3-}$ -P, 67-93% of inorganic nitrogen, 80-90% of COD and 37-56% organic nitrogen by adding various concentrations of swine wastes for 12 days of batch cultivation. Rate constants for removing nitrates and phosphates in treating swine wastes were estimated as 0.17 (1/day) and 0.14 (1/day) in the first order reaction, respectively. 1.52 (g/L) of maximum cell density was maintained at 0.20 (1/day) of dilution rate in continuous culture, adding 20% swine wastes for 30 days. The chemical composition of the biomass obtained from the process showed 58.7% of protein, 11.0% of lipid and 15.6% of ash.

• The Korean Journal of Ecology
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• 제18권1호
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• pp.1-15
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• 1995

Alakline phosphatase activity (AP A) as a phosphorus deficiency measurement in flowing waters and of microhabitats (rocks, wood, leaves, and sediments) was measured and its relationship to flux of nutrients and response to rainfall events were determined for two geologically different streams in west Alabama from August to November. Results indicated water column AP A in both streams had a low correlation with levels of orthophosphate, total organic phosphorus, nitrate, ammonia, dissolved organic carbon, and discharge (r=0.075-0.583; n=g-IU. Communities on rock surfaces showed a higher AP A level than those on wood and leaves. Sediment passed through a $106{\mu}m$ sieve showed 2-9 times higher AP A level than material passed through $425{\mu}m$ sieve. The first storm after drought at Yellow Creek introduced substantial quantities of DOC (2.5 times baseflow concentrations) and $N0_3-N$ (5.8 times baseflow concentrations) which did not affect AP A significantly. The second storm at Little Schultz Creek caused minor changes in nutrient cocentrations; however $N0_3-N$ levels and AP A were drastically lower due to the dilution effect. Retention of stream water AP A at Yellow Creek and Little Schultz Creek on $0.45{\mu}m$ filter (54 and 43%, respectively) and $0.22{\mu}m$ (83 and 77% of total APA. respectively) indicated more free dissolved portion of the enzyme was present at Little Schultz Creek. Little Schultz Creek (with carbonate and with a higher productivity and biomass) showed a consistantly greater AP A activity $(132{\pm}54\;{\mu}M{\cdot}1^{-1}{\cdot}min^{-I};\;n=g)$ than Yellow Creek $(41{\pm}23\;{\mu}M{\cdot}1^{-I}{\cdot}min^{-I}$, with a sandstone substrate; n=l1, $p{\leq}O.OO1)$. Overall, a greater APA on all microhabitats and the presence of more dissolved enzyme in Little Schultz Creek during the study period may indicates it is more P deficient than Yellow Creek.

• The Korean Journal of Ecology
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• 제3권1_2호
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• pp.1-10
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• 1980

This study was carried out to find out the correlation between plant groups and environomental gradient in the native grassfild near Kang Nam Express Terminal from August 26 to september 15, 1977. The correlations among plant species were calculated by using the method of x2 and the various relationships among soil environmental gradients were grouped by means of correlation coefficient. As a result, both the species and the soil environmental factors could be subdivided into four groups, and the four groups of the native grassfield were turned out to be correlated with the four groups of soil environmental factors. The first plant group (Panicum dichotomiflorum, Chenopodium album, Bidens forndosa, Humulus japonicus, Alopeculus amurensis, Potentilla fragarioides, Centipeda minima, Beckmannia erucaeformis) was formed in the releve 1∼10 reagions, organic matter by Turins's method, Total N, Exchange Ca and total of Exchange K, Na, Kg, Ca were abundent. The second plant group (Digitaria sanguinalis, Paltulaca oleracea, Echinochlea macrocrovi, Cyperus amuricus) was formed in the relve 11∼18 reagions, where Exchange Ca and total of Exchange K, Ng, Mg, Ca were little but Exchange A1 and sand were aburdent. In relve 19∼20 reagions, with much of Exchange Ca, total of Exchange K, Na, Mg, Ca, pH and a little Exchange Al, was found the third plant group (Pycreus sanguinoloentus, Cyperus amuricus, Ludwigia prostrata, Echinochloa echinata, Polygonum thunbergii, Salix glandulosa seedling) The fourth plant group (Cassia nomame, Polygnoum perfoliatum, Setaria viridis, Glocien ussuriensis, Lactuca indica, setaria glauca, Artemisia capill aris, Artmisia asiatica, Calamagrostis arundinacea, Kummerowia striata, Denothera odorata, Artemisia japonica, Carey laceolata) was formed in relve 21∼25 reagions, where organic matter by loss on ignition, Exchange Mg and Maximum water holding capacity were abundent but sand was a little. Thus it can be concluded that there is a close relationship between the vegetation group clasified by meaus of x2 and the environtal factors of soil devided by means of correlations coefficient.

• 한국환경과학회지
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• 제1권1호
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• pp.47-51
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• 1992

수중에 존재하는 휘발성 유기화합물은 샤워를 하는동안 공기로 방출되고 공기농도는 샤워 변수에 따라 달라지는데, 이는 휘발성 유기화합물의 호기농도의 변화를 야기 시킨다. 본 연구에서는 샤워를 하는 동안 공기중의 클로로포픔 노출에 영향을 미치는 주요한 샤워변수(물온다 및 노출시간)를 클로로포픔 호기농도를 측정하여 검토 하였다. 크롤로포름 호기농도는 물의 온도와 노출 시간이 증가함에 따라 증가 하였다. 가장 큰 클로로포름 호기농도 차이를 나타내는 두개의 흡기 노출 조건은 미지근한 물을 이용한 5분 동안의 노출과 더운 물을 이용한 15분 동안의 노출이었다. 클로로포름 호기농도는 후자의 노출후에 전자의 경우보다 거의 3배 정도 높았다. 주요 샤워변수와 수중농도로 조정된 호기농도 사이의 수학모델은 0.0001의 확률에서의 데이타와 훌륭한 일치되는 결과를 나타내었다.

• Safety and Health at Work
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• 제2권4호
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• pp.365-374
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• 2011

Objectives: This study was designed to investigate whether long-term, low-level exposure to monocyclic aromatic hydrocarbons (MAHs) induced insulin resistance. Methods: The subjects were 110 male workers who were occupationally exposed to styrene, toluene, and xylene. One hundred and ten age-matched male workers who had never been occupationally exposed to organic solvents were selected as a control group. Cytokines, which have played a key role in the pathogenesis of insulin resistance, and oxidative stress indices were measured. Assessment of exposure to MAHs was performed by measuring their ambient levels and their urinary metabolites in exposed workers, and the resulting parameters between the exposed group and non-exposed control groups were compared. Results: There was no significant difference in general characteristics and anthropometric parameters between the two groups; however, total cholesterol, fasting glucose, fasting insulin, and homeostasis model assessment of insulin resistance levels were significantly higher in the exposed group. Phenylglyoxylic acid levels showed significant association with tumor necrosis factor-${\alpha}$, total oxidative status, and oxidative stress index via multiple linear regression analysis. Further, there was a negative correlation between methylhippuric acid levels and total anti-oxidative capacity, and there was a significant relationship between MAHs exposure and fasting glucose levels, as found by multiple logistic regression analysis (odds ratio = 3.95, 95% confidence interval = 1.074-14.530). Conclusion: This study indicated that MAHs increase fasting glucose level and insulin resistance. Furthermore, these results suggested that absorbing the organic solvent itself and active metabolic intermediates can increase oxidative stress and cytokine levels, resulting in the changes in glucose metabolism and the induction of insulin resistance.

• 한국토양비료학회지
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• 제36권3호
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• pp.145-153
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• 2003

조사지역의 평균 토양화학성은 pH 5.93, 유기물함량 $25.9g\;kg^{-1}$, 유효인산 $742mg\;kg^{-1}$, $NO_3-N$ $44.7mg\;kg^{-1}$ 이었으며, 토양 1 g당 균근균 포자는 양파 12.1, 마늘 11.7, 고추 10.1로 작물별 큰 차이를 보이지 않았다. 토성에 따른 포자수는 식토와 미사질 식토에서 토양 1 g 당 15개 이상의 포자밀도를 보였으며, 토양 pH, OM, $NO_3-N$, Av. $P_2O_5$등 토양양분함량과 포자밀도는 유의성 있는 상관관계를 보이지 않았으나, 포자수는 양분농도와 관계없이 일정한 수준을 보였다. 종이 확인된 균근균 수집 포자는 Glomus속 2종과 Gigaspora속 3종으로 Glomus clarum, Glomus intraradices, Glomus etunicatum와 Gigaspora rosea, Gigaspora margarita 등 이었다.

• 유기물자원화
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• 제19권4호
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• pp.53-59
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• 2011

본 연구에서는 $AT_4$ 방법으로 매립 폐기물의 생물학적 안정화도를 평가하는데 있어서, 실험자가 상이함에 따라 결과가 달라지는 것을 방지하기 위해 표준화된 실험을 위한 실험조건을 제시하고자 하였다. $AT_4$ 실험에 있어서 초기 지연시간, $CO_2$ 흡수제의 교체시기, 산소소모량 측정주기, 유기성 폐기물 함량에 따른 $AT_4$ 측정값 변화 추이등을 살펴보고, 각각에 따른 영향인자에 대해 논의하였다. 매립폐기물의 불균질성과 측정상의 오차범위를 감안할 때 매립폐기물의 안정화 기준치는 $AT_4$ 기준으로 $10mg\;O_2/g\;DM$의 값을 제시하였다.

• 한국물환경학회지
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• 제35권3호
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• pp.271-277
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• 2019

Korean Trophic State Index ($TSI_{KO}$) was developed in 2006, and was composed of COD ($COD_{Mn}$ based on permanganate method), Chlorophyll a (Chl.a) and total phosphorus (TP). However, $COD_{Mn}$ usually represents only 50-60% of total organic matter in stream or lake water due to low oxidizing power of permanganate. This study investigated the relationship between TOC and $COD_{Mn}$ based on the average data for the whole layer in 81 lakes in Korea, during the period 2013-2017. As a result, $COD_{Mn}$ was found to be 1.54 times more than TOC in 66 of the freshwater lakes and 3 brackish lakes (TOC measured using thermo-oxidation method). TOC was about a quarter of $COD_{Mn}$ in 8 coastal lakes (TOC measured using UV-persulfate oxidation method), and it appeared to be underestimated due to chloride interference. Using the data of 69 lakes with exception of 12 brackish lakes, $TSI_{KO}$(TOC) was developed based on the correlation between TOC and $COD_{Mn}$, while $TSI_{KO}$(COD) was replaced with $TSI_{KO}$(TOC). However, for trophic state assessment of brackish lakes, the $TSI_{KO}$(TOC) can only be utilized in case that TOC is measured through thermo-oxidation method. The determination coefficient of $TSI_{KO}$(Chl) to $TSI_{KO}$(COD) in 66 freshwater lakes and 3 brackish lakes was 0.83, while that to $TSI_{KO}$(TOC) was 0.68. This difference could be attributed to the recalcitrant organic part of TOC.

• Journal of Forest and Environmental Science
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• 제38권1호
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• pp.21-37
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• 2022

The present study was carried out to evaluate the chemical properties of soil in relation to forest structure and composition at different altitudes (900-2,600 m asl) in a part of Western Himalaya. The composite soil samples were taken from three (viz. upper, middle and lower) depths. The soils of the whole study area were acidic in nature (pH=4.90-5.51). Contents of Nitrogen (N), Phosphorus (P), Potassium (K), Carbon (C) and soil organic matter (SOM) showed much fluctuation during different seasons of year. Nitrogen content showed significant positive correlations with altitude (r=0.924, p<0.05) and different community parameters like species diversity (r=0.892, p<0.01) and species richness (r=0.941, p<0.05). Phosphorus exhibited direct correlations with carbon (r=0.637) while weak negative correlations with different community parameters like species richness & diversity, total basal cover (TBC), density and canopy cover. Carbon content and hence SOM showed direct correlations with Nitrogen (r=0.821, p<0.01); Phosphorus (r=0.637, ns) and Potassium (r=0.540, ns). But no significant relationship was observed between K content and species richness (p=0.30, r=-0.504); between K content and species diversity (p=0.14, r=-0.672); between P content and species diversity (p=0.29, r=-0.513) and species richness (p=0.23, r=-0.575). Among the different soil nutrients, only N showed a significant positive correlation with altitude while all others exhibited negative (but non-significant) correlation with it. The study revealed that the chemical properties affect and are reciprocally affected by forest structure and composition and that N rich soils of higher altitudes are best for the growth and development of forests.

• 유기물자원화
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• 제30권1호
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• pp.33-39
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• 2022

혐기성 소화 슬러지 탈리여액을 대상으로 마그네슘 공급원이 인산암모늄마그네슘(MAP) 결정화에 의한 인산염 회수에 어떠한 영향을 미치는지 알아보기 위해 회분식 실험을 실시하였다. 마그네슘 공급원으로 염화마그네슘, 수산화마그네슘 그리고 산화마그네슘을 사용하여 다양한 pH (7.5, 8.0 및 8.5) 조건 및 Mg/P 몰 비율(1.0, 1.5, 2.0 및 2.5)에서 인산염 회수를 실시하였다. 그 결과, 마그네슘 공급원과 관계없이 pH 조건과 Mg/P 몰 비율이 높을수록 인산염 회수율이 증가하였다. pH가 가장 낮은 7.5의 조건에서는 Mg/P 몰 비율이 증가할수록 인산염 회수율이 증가하였는데 산화마그네슘, 수산화마그네슘, 염화마그네슘의 순으로 높았다. 그러나 pH가 가장 높은 8.5의 조건에서는 Mg/P 몰 비율과 관계없이 모든 마그네슘 공급원에서 90% 이상의 높은 인 회수율을 얻을 수 있었다. 따라서 낮은 pH 조건에서도 높은 인산염 회수율을 얻을 수 있었던 수산화마그네슘과 산화마그네슘이 경제적인 측면뿐만 아니라 효율적인 측면에서도 염화마그네슘을 대체할 수 있을 것으로 기대된다.