• Environmental Engineering Research
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• 제13권4호
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• pp.165-168
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• 2008

Measurements of phosphatase activity in peatlands are made difficult by the low levels of activity and the characteristically high concentrations of dissolved organic matter within the sediments. These materials may cause high background absorbances in colorimetric assays, and quenching interference in fluorimetric assays. This review describes the development of a new approach which allows such problems to be overcome by using HPLC to separate the interferences from the products of enzymic hydrolysis. This approach is applicable to various environmental samples such as peat, wetland sediment, and sludge which may contain a large amount of interfering organic matters.

• 한국물환경학회지
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• 제25권4호
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• pp.589-596
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• 2009

The spectroscopic characteristics and chemical oxygen demand (COD) oxidation efficiencies were investigated for dissolved organic matters (DOM) from diverse sources, which may indirectly affect the concentrations and the quality of DOM found in watersheds. The DOM investigated for this study showed a wide range of the percent distributions of refractory organic matter (R-OM) from 8 to 100%. Relatively high R-OM distributions were observed for the DOM with the source of head water, sediments, paddy soils, field soils, and treated sewage whereas the DOM from livestock waste, reed, weeds, algae, and attached algae exhibited lower R-OM percent distributions. The percent distribution of R-OM had positive correlations with specific UV absorbance (SUVA) and humidification indices (HIX) of DOM. The investigated DOM was classified into four different source groups (i.e., biota, vegetables, soils, sediments) by comparing the synchronous fluorescence spectra. The DOM group from biota source was characterized by a prominent presence of protein-like fluorescence (PLF) whereas fulvic-like fluorescence (FLF) was additionally observed for vegetable-source DOM. FLF became significant for the DOM from both soils and sediments although no PLF was found for soil-derived DOM. A range of COD oxidation efficiency was observed for the various DOM, ranging from 36 to 94% and from 65 to 125% for $COD_{Mn}$ and $COD_{Cr}$, respectively. The results indicate that $COD_{Cr}$ reflects the higher OM concentration than $COD_{Mn}$. However, 95% confidence intervals of the COD oxidation efficiencies were similar for the two types of COD, suggesting that $COD_{Cr}$ may not be the superior OM index to $COD_{Mn}$ in terms of the variability of the oxidation efficiency. No significant correlations were obtained between COD oxidation efficiencies and the spectroscopic characteristics of DOM for this study.

• 한국환경과학회지
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• 제9권1호
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• pp.1-11
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• 2000

A study on the variational characteristics of water quality and phytoplankton biomass by principal component analysis(PCA) was carried out in Kogum-sudo from February to October in 1993. We analyzed PCA on biological factors such as chlorophyll a and phytoplankton cell numbers for centric and pennate diatoms, phytoflagellates, and total phytoplankton as well as physico-chemical factors as water temperature, salinity, transparency, dissolved oxygen(DO), saturation of DO, apparent oxygen utilization (AOU), chemical oxygen demand(COD), nutrient (ammonia, nitrite, nitrate, phosphate and silicate), N/P ratio and suspended solid(SS). The source of nutrients supply depended on the mineralization of organic matters and inputs of seawater from outside rather than runoff of freshwater. The phytoplankton biomass was changed within short interval period by nutrients change. And it was controlled by the combination of several environmental factors, especially of light intensity, ammonia and phosphate. The marine environmental characteristics were determined by the mineralization of organic matters in winter, by runoff of freshwater including high nutrients concentration in spring, by ammonia uptake and high phytoplankton productivity in summer, and phosphate supplied input seawater from outside of Kogeum-sudo in autumn. And Kogum-sudo was separated with 2 regions by score distributions of PCA. That is to say, one region was middle parts of straits which was characterized by the mixing seawater and the accumulated organic matters, other one region was Pungnam Bay and the water around Kogum Island which was done by high phytoplankyon biomass and productivity year-round.

• 상하수도학회지
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• 제18권2호
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• pp.242-246
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• 2004

Dissolved air flotation (DAF) is an effective solid/liquid separation process for low density particles, such as algal flocs, humus materials and clay particles produced from low turbidity water. The fraction of humic substances for natural organic matters (NOMs) are considered problematic in water because it can readily react with chlorine to form harmful by-products (trihalomethanes) and can be exposed to undesirable color, tastes and odors in drinking water. A broad class of NOMs includes fulvic acid, humic acid and humin. This paper will discuss the results from a study that performed with a DAF pump process using synthetic wastewater contained humic substance. Batch jar tests were performed to evaluate coagulant dose and recycle ratio on flotation efficiency.

• 대한환경공학회지
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• 제36권7호
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• pp.492-497
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• 2014

해수담수화 시설에서 전처리와 역삼투막(reverse osmosis, RO) 공정의 유기물 제거특성을 살펴보고, 유기물의 특성변화가 막오염 지수에 미치는 영향을 조사하였다. 연구에서 비교된 전처리 공정은 다중여재여과(dual media filter, DMF), 가압형 정밀여과(MF), 침지형정밀여과(SMF) 이다. 유기물의 특성변화를 알아보기 위해 원수와 공정별 처리수의 탁도, $UVA_{254}$, DOC, size exclusion chromatography (SEC), fluorescence excitation emission matrix (FEEM), transparent exopolymer particles (TEP) 등을 분석하였다. 이온성 물질과 무기물 항목은 전처리 공정의 종류에 관계없이 처리되지 않았고 RO공정을 거치면서 99% 이상 제거되었다. 유기물에 의한 막오염에 큰 영향을 미치는 소수성 유기물은 전처리를 통해 상대적으로 제거가 용이하였다. 전처리 공정의 유기물 제거율은 막여과 공정(MF, SMF)이 기존 DMF 공정에 비해 높았다. 처리수내 유기물의 농도가 감소할수록 막오염지수 중 하나인 silt density index (SDI) 값도 감소하였다. MF로 전처리한 경우 SDI값이 가장 낮게 나타났는데, 처리수 내의 $0.1-0.4{\mu}m$ TEP 농도가 MF와 SMF 막오염지수의 차이와 상관관계를 보였다.

• 한국물환경학회지
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• 제26권6호
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• pp.976-985
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• 2010

In this study, characteristics of dissolved organic matter (DOM) from Lake Paldang and seven other DOM sources (lake plankton, plants, soil, composite, treated sewage) were studied using XAD resin fractionation and 28-day microbial incubation experiment. Distribution patterns of DOM-fractions, which include hydrophilic acids (HiA), hydrophilic bases (HiB), hydrophilic neutrals (HiN), hydrophobic acids (HoA), hydrophobic neutrals (HoN) and the extent of DOM biodegradation (i.e., biodegradability) were different depending on the origins of the DOM samples. The DOM distribution pattern and the biodegradability were found to be effective for distinguishing the different DOM sources. The biodegradability (%) had negative correlations with the content (%) of hydrophobic fractions (Ho) and specific UV absorbance of DOM, which indicate that the Ho fractions contain more aromatic carbon structures and relatively stable during biodegradation, irrespective of the sources. To gain additional insight into the microbial transformation of the DOM, we also investigated the changes in the fraction's distribution for plankton, leaf litter and composite samples after the incubation. The results showed that biodegradation of hydrophilic fraction (Hi) causes an increase in the proportion of Ho (HoA, HoN), while biodegradation of HoA increases the HoN production.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2005년도 Proceedings of ISRS 2005
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• pp.445-449
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• 2005

Various methods to detect the phytoplankton/red tide blooms in the oceanic waters have been developed and tested on satellite ocean color imagery since the last two and half decades, but accurate detection of blooms with these methods remains challenging in optically complex turbid waters, mainly because of the eventual interference of absorbing and scattering properties of dissolved organic and particulate inorganic matters with these methods. The present study introduces a new method called Red tide Index (Rl), providing indices which behave as a good measure of detecting red tide algal blooms in high scattering and absorbing waters of the Korean South Sea and Yellow Sea. The effectiveness of this method in identifying and locating red tides is compared with the standard Ocean Chlorophyll 4 (OC4) bio-optical algorithm applied to SeaWiFS ocean imagery, acquired during two bloom episodes on 27 March 2002 and 28 September 2003. The result revealed that OC4 bio-optical algorithm falsely identifies red tide blooms in areas abundance in colored dissolved organic and particulate inorganic matter constituents associated with coastal areas, estuaries and river mouths, whereas red tide index provides improved capability of detecting, predicting and monitoring of these blooms in both clear and turbid waters.

• Ocean and Polar Research
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• 제41권2호
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• pp.63-77
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• 2019

In order to investigate the behavior and seasonal variability of Mn as one of the bio-essential metals in the Amundsen sea, which is known as the most biologically productive coastal area around the Antartica, seawaters were collected using a clean sampling system for 10 stations (96 ea) in 2014 (ANA04B) and for 12 stations (139 ea) in 2016 (ANA06B) surveys of RV ARAON. Dissolved and particulate Mn concentration varied in the range of 0.15-4.43 nmol/kg and <0.01 to 2.42 nM in 2014 and in the range of 0.25-4.15 nmol/kg and 0.01-2.64 nM in 2016, respectively. From the sectional distribution of dissolved and particulate Mn, it might be suggested that dissolved/particulate Mn was provided from iceberg melting and diffusion/resuspension from sediments, respectively. Although this sea is highly productive, there was little evidence regarding the biological origin of dissolved Mn, but particulate Mn only in sea ice and offshore areas could be explained as originating from organic matters, e.g. phytoplanktons. And it could be suggested that the subsurface maximum of dissolved Mn was formed by isopycnal transport of melting materials from ice wall to offshore. Compared to early (2014) summer, temperature, salinity, biomass, dissolved and particulate Mn in late (2016) summer indicated that temporal variations might be resulted from the reduction of ice melting and mCDW flow, which induced a reduction in resuspension. In addition, in the late summer, particles including biomass were reduced, which brought about a reduction in the removal rate of dissolved Mn.

• 한국해양환경ㆍ에너지학회지
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• 제12권2호
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• pp.75-83
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• 2009

2003년부터 2006년 사이의 새만금 방조제 내측 표층 해역에서 입자성 부유물질(suspended particulate matter), 입자성 유기탄소(particulate organic carbon) 그리고 용존 유기탄소(dissolved organic carbon)의 분포 변화를 조사하였다. 하천을 통해 새만금 방조제 내측으로 유입되는 입자성 물질과 유기탄소는 대부분 풍수기인 여름철에 집중 되었고, 이는 2006년 4월 최종 물막이 공사 완료 후 폐쇄 환경이 된 새만금 내측 해역에 많은 양의 유기물 부하가 단기간에 집중될 수 있음을 시사하였다. 한편, 2003년 이후 제4호 방조제 완공으로 막혀진 만경강 하구역에서 새만금 방조제에 이르는 해역에서 입자성 물질과 유기탄소의 표층 농도가 증가하는 것이 관찰되었다. 특히 부영양화(eutrophication)로 인한 식물 플랑크톤의 증가로 입자성유기탄소를 비롯, 생물기원의 유기탄소가 증가하였다. 이러한 표층의 과도한 입자성 유기탄소의 증가는 향후 저층 퇴적 환경으로 침전되었을 경우 용존 산소 고갈에 큰 영향을 미칠 것으로 판단된다.

• Ecology and Resilient Infrastructure
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• 제6권2호
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• pp.128-135
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• 2019

본 연구는 하수종말처리장의 용존성 방류수 유기물질이 비스페놀 A (BPA)의 흡착과 에스트로겐 활성에 미치는 영향을 조사하였다. 특이적 자외선 흡수 (SUVA)와 형광 지수 (FI) 분석 결과, 방류수 유기물질은 참조물질로 사용한 스와니강 자연 유기물질과는 달리 미생물 기원의 비휴믹성 유기물질 특성을 나타내었다. Langmuir와 Freundlich 모델 모두 방류수 및 자연 유기물질에 대한 BPA의 흡착을 잘 설명하였다. 방류수 유기물질은 자연 유기물질 보다 더 높은 BPA 흡착능을 보여주었고, 이에 따라 에스트로겐 활성 역시 더 많이 감소시켰다. 이러한 결과들은 유기물질의 기원에 따라 BPA 흡착능과 에스트로겐 활성 저감이 크게 영향을 받는 다는 것을 제시한다.