• Journal of Korean Society on Water Environment
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• v.38 no.2
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• pp.63-71
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• 2022

This study aimed to maximize the potential of fluorescence 3D excitation-emission matrix (EEM) for predicting the trihalomethane formation potential (THMFP) of DOM with various sources. Fluorescence spectroscopy is a useful tool for characterizing dissolved organic matter (DOM). In this study, differential spectroscopy was applied to EEM for the prediction of THMFP, in which the difference between the EEM before and after chlorination was taken into account to obtain the differential EEM (DEEM). For characterization of the original EEM or the DEEM, the maximum intensities of several different fluorescence regions in EEM, fluorescence EEM regional integration (FRI), and humification index (HIX) were calculated and used for the surrogates for THMFP prediction. After chlorination, the fluorescence intensity decreased by 77% to 93%. In leaf-derived and effluent DOM, there was a significant decrease in the protein-like peak, while a more pronounced decrease was observed in the humic-like peak of river DOM. In general, leaf-derived and effluent DOM exhibited a relatively lower THMFP than the river DOM. Our results were consistent with the high correlations between humic-like fluorescence and THMFP previously reported. In this study, HIX (r= 0.815, p<0.001), FRI region V (r=0.727, p<0.001), humic-like peak (r= 0.827, p<0.001) from DEEM presented very high correlations with THMF P. When the humic-like peak intensity was converted to a logarithmic scale, a higher correlation was obtained (r= 0.928, p<0.001). This finding suggests that the humic-like peak in DEEM can serve as a universal predictor for THM formation of DOM with various origins.

• Journal of Korean Society of Environmental Engineers
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• v.28 no.9
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• pp.940-948
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• 2006

Fluorescence measurements of dissolved organic matter(DOM) have the superior advantages over other analysis tools for applying to water quality management. They are simple and fast and require minimal pretreatment of samples. Fluorescence index($F_{450}/F_{500}$), synchronous spectra, and fluorescence excitation-emission matrices(EEM) of various DOM samples were investigated to discriminate autochthonous/allochthonous composition, protein-like fluorescence, fulvic-like fluorescence, humic-like fluorescence, terestrial humic-like fluorescence by comparing among the real DOM samples of different origins with the help of literature. The samples used included standard purified DOM, lake, river and wastewater treatment effluent. The relative distribution of various DOM composition was derived from the ratios of each fluorescence region. The results were very consistent with those expected from the sample properties. Allochthonous and terrestrial humic-like fluorescence were more prominent in the samples with abundant soil-derived DOM components. In addition, the protein-like fluorescence property was more pronounced in the samples where strong algal or microbial activities were expected. It was also shown that the ratio of protein-like/terrestrial humic-like fluorescence obtained from synchronous spectrum and fluorescence EEM could be used as an indicator for the evaluation of wastewater treatment on the downstream water quality of rivers and for the prediction of the degree of algal/microbial activities in lakes. It is expected that the results of this study will provide the basic information to develop the future water quality management techniques using DOM fluorescence measurements.

• Progress in Medical Physics
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• v.12 no.1
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• pp.9-17
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• 2001

The prior purpose of this study is to introduce a optical biopsy and evaluate whether the optical biopsy, real-time, non-invasive technique, is a reliable tool to assess response to radiotherapy Four healthy volunteers, and four patients with inflammatory conditions of the oral cavity participated on the study. was obtained from each person enrolled in the study. Using FastEEM(Ercited Emission Matrix) as a optical biopsy tool, normal and tumor spectra are taken from the normal and the tumor regions. And then second optical biopsy are taken from the tumor regions in 4 patients with time delay at 7days.. Using a diagnostic algorithm, made by Gillenwater based on spectra excited at 337nm The Optical Biopsy turned out to be more suited for tumor diagnostic resulting in significant difference fluorescence spectra. The fluorescence intensity of cancerous tissue showed a higher position. The second fluorescence intensity of optical biopsy of cancerous oral tissue has more smaller than the first result. I conclude that optical biopsy, which technique don't need to remove tissue sample from body, and is a real time , and non-invasive measurement is a reliable tool to access to radiotherapy because FastEEM can do measure the variation of the tissue composition chemical, biological, and morphological after radiotherapy. Based on the fluorescence spectrum are taken from the optical biopsy in normal and tumor spectra as well as tumor spectra after 7days.

• Journal of Korean Society on Water Environment
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• v.38 no.1
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• pp.31-42
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• 2022

Dissolved organic matter (DOM), which changes according to various factors, is ubiquitously present from natural environments to engineered treatment systems. Only limited information is available regarding the environmental functions of DOM after bulk analyses are only applied for characterization. In this paper, latest DOM analytical techniques are briefly introduced, which include fluorescence excitation-emission matrix with parallel factor analysis (EEM-PARAFAC), size-exclusion chromatography with an organic carbon detector (SEC-OCD), carbon/nitrogen stable-isotope ratio, and Fourier transform-ion cyclotron resonance-mass spectroscopy (FT-ICR-MS). Recent examples of using advanced analyses to interpret the phenomena associated with DOM occurring in natural and engineered systems are presented here. Through EEM-PARAFAC, different components like protein-like, fulvic-like, and humic-like can be identified and tracked individually through the investigated systems. SEC-OCD allows researchers to quantify different size fractions. FT-ICR-MS provides thousands of molecular formulas present in bulk DOM samples. Lastly, carbon/nitrogen stable-isotope ratio offers reasonable tools for tracking the sources in environments. We also discuss the advantages and weakness of the above-mentioned characterizing tools. Specifically, they focus on single environmental factors (different sourced-DOM and interaction of sediment-pore water) or simple changes after individual treatment processes. Through collaboration with the advanced techniques later, they help the researchers to better understand environmental behaviors in aquatic systems and serve as essential tools for addressing various pending problems associated with DOM.

• Journal of Korean Society on Water Environment
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• v.40 no.2
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• pp.67-78
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• 2024

The introduction of a significant amount of phosphorous into aquatic environments can lead to eutrophication, which can in turn result in algal blooms. For the effective management of watersheds and the prevention of water quality problems related to nonpoint organic matter (OM) sources, it is essential to pinpoint the predominant OM sources. Several potential OM sources were sampled from upper agricultural watersheds, such as fallen leaves, riparian reeds, riparian plants, paddy soil, field soil, riparian soil, cow manure, and swine manure. Stream samples were collected during two storm events, and the concentrations of dissolved organic carbon (DOC) and phosphorous (DOP) from these OM sources and stream samples were assessed. DOM indicators using fluorescence spectroscopy, including HIX, FI, BIX, and EEM-PARAFAC, were evaluated in terms of their relevance in discerning DOM sources during storm events. Representative DOM descriptors were chosen based on specific criteria, such as value ranges and pronounced differences between low and high-flow periods. Consequently, the spectral slope ratio (S_R) paired with fluorescence index (FI) using end-member mixing analysis (EMMA) proved to be suitable for estimating the contribution of organic carbon (OC). The contribution of each organic phosphorous (OP) in stream samples was determined using the phosphorous-to-carbon (P/C) ratio in conjunction with the OC contribution. Notably, OP derived from swine manure in stream samples was found to make the most dominant contribution, ranging from 61.3% to 94.2% (average 78.1% ± 12.7%). The results of this research offer valuable insights into the selection of suitable indicators to recognize various OM sources and highlight the main sources of OP in forested-agricultural watersheds.

• Journal of Korean Society of Environmental Engineers
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• v.31 no.9
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• pp.803-810
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• 2009

This study is conducted to examine spatial variations of Dissolved Organic Matter (DOM) in stream and waste waters of the different watershed areas (agricultural, residential, and industrial complex area) by using fluorescence 3D-EEMs (3 Dimensional Excitation Emission Matrix Spectroscopy). Furthermore, the research investigates the changes of DOM characterization by synchronous and 3D-EEMs during a rainfall event. The characterizations of DOM obtained by 3D-EEMs show two noticeable peaks at humic and protein-like regions. Humic-like substances (HLS) are found in rural and urban areas, and humic and protein-like substances (PLS) are shown in industrial area. According to the fluorescence peak $T_1:C_1$ ratios, it is observed that high amount of HLS was discharged from Banweol Industrial Complex (3TG). Additionally, linear relationships (Regression rate, $r^2$=0.65, $r^2$=0.66) have been shown between PLS (peak $T_1,\;B_1$) and biochemical oxygen demand (BOD), which indicates the impact of sewage. For the rainfall event (30 mm), no remarkable difference of DOM was found at rural area except increment of fluorescence intensity comparing dry period. In contrast, HLS at urban area is highly discharged within 30 minutes from the beginning of rainfall. Also, there are high influences of HLS and PLS within 20 minutes at industrial complex (4TG). Fluorescence 3D-EEMs has not only verifies a watershed of DOM origination but also monitors diffuse and point source impacts.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.18 no.4
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• pp.497-508
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• 2020

In the geochemical field, the chemical speciation of hexavalent uranium (U(VI)) has been widely investigated by performing measurements to determine its luminescence properties, namely the excitation, emission, and lifetime. Of these properties, the excitation has been relatively overlooked in most time-resolved laser fluorescence spectroscopy (TRLFS) studies. In this study, TRLFS and continuous-wave excitation-emission matrix spectroscopy are adopted to characterize the excitation properties of U(VI) surface species that interact with amorphous silica. The luminescence spectra of U(VI) measured from a silica suspension and silica sediment showed very similar spectral shapes with similar lifetime values. In contrast, the excitation spectra of U(VI) measured from these samples were significantly different. The results show that distinctive excitation maxima appeared at approximately 220 and 280 nm for the silica suspension and silica sediment, respectively.

• Journal of Korean Society on Water Environment
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• v.32 no.1
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• pp.98-107
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• 2016

This study examined the effects of environmental conditions and the presence of refractory organic matter on oxidation rates of total organic carbon (TOC) measurements based on high temperature combustion and ultraviolet-sulfate methods. Spectroscopic indices for prediction of oxidation rates were also explored using the UV spectra and fluorescence excitation-emission matrix (EEM) of humic acids. Furthermore, optimum TOC instrument conditions were suggested by comparing oxidation rates of a standard TOC material under various conditions. Environmental conditions included salts, reduced ions, and suspended solids. Salts had the greatest influence on oxidation rates in the UV-sulfate method. However, no effect was detected in the high temperature combustion method. The UV-sulfate method showed lower humic substance oxidation rates, refractory natural organic matter, compared to the other methods. TOC oxidation rates for the UV-sulfate method were negatively correlated with higher specific-UV absorbance, humification index, and humic-like EEM peak intensities, suggesting that these spectroscopic indices could be used to predict TOC oxidation rates. TOC signals from instruments using the UV-sulfate method increased with increasing chamber temperature and increasing UV exposure durations. Signals were more sensitive to the former condition, suggesting that chamber temperature is important for improving the TOC oxidation rates of refractory organic matter.

• Journal of Korean Society on Water Environment
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• v.23 no.4
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• pp.482-489
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• 2007

Fluorescence properties and carbohydrate content were investigated using ultrafiltrated size fractions of dissolved organic matters (DOM) originated from different sources. The materials included a treated sewage, an algal organic matter, and a soil leachate, all of which are major constituents of dissolved organic matter in a typical urban river. Four different size fractions were separated from the three sources of each DOM. The size distribution demonstrated that a higher molecular weight fraction was more present in soil leachate compared to two other source DOMs. A higher content of carbohydrates was observed in the following order - algal DOM > treated sewage > soil leachate. A wide range of specific UV absorbance was observed from size fractions of a single source DOM, indicating that aromatic carbon structures are heterogeneously distributed within one source of DOM. The structural heterogeneity was the most pronounced for the soil leachate. The fluorescence index ($F_{450}/F_{500}$) of the treated sewage was similar to that (2.0) typically obtained from autochthonous DOM, suggesting that the treated sewage exhibited autochthonous organic matter-like properties. No protein-like fluorescence intensities were observed for all of the soil leachate size fractions whereas they were observed with two other source DOMs. Based upon the fluorescence peak ratios from fluorescence excitation-emission matrix (EEM), two discrimination indices could be suggested to distinguish three different source DOMs. It is expected that the suggested discrimination indices will be useful to predict the sources of DOM in a typical urban river affected by treated sewage.

• Journal of Korean Society on Water Environment
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• v.38 no.2
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• pp.72-81
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• 2022

Numerous studies have investigated the occurrence and fate of microplastics in the environment; however, only limited effort has been devoted to exploring the characteristics of dissolved organic matter (DOM) leached from microplastics. In microplastic (MP)-contaminated environment, MPs are typically mixed with naturally-occurring particles, which interferes with their detection in the environment. Thus, it is necessary to distinguish between the DOM leached from MPs and those leached from natural particles and also to characterize their properties. This study investigated DOM leaching behavior from MPs (polystyrene: PS, polyvinylchloride: PVC) and natural particulates (forest soil: FS, litter leaves: LL) under light, which is considered one of the main weathering processes that affect MPs in the environment. The leached DOM concentrations and fluorescence characteristics were compared under dark versus light conditions. Regardless of the origins, UV light promoted DOM release from all the particulates. More DOM was released from natural particles than from MPs under both conditions. However, the effect of promoting DOM release by UV was more pronounced for MPs than for natural particles. It was observed from fluorescence spectra that the intensity of the humic-like region was substantially reduced when MP-derived DOM was exposed to UV light, whereas the change of intensity was very little for natural particles. Under light conditions, the ratio of protein-like to humic-like fluorescence of MP-derived DOM was higher than that of DOM from natural particles. This study implies that a substantial amount of DOM could be leached from MPs even in MP-polluted environment under UV irradiation. Protein/humic fluorescence ratio could be utilized as a fast probing indicator to separate the two sources of particles under light.