• Journal of Korean Society on Water Environment
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• v.36 no.2
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• pp.116-124
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• 2020

This study aims to identify the characteristics of organic matter and pollutant sources using water quality and stable isotope ratios (δ¹⁵N, δ¹³C) of the two inflow tributaries (Gulpo (GP) and Anyang (AY) streams). Water samples were analyzed in June and September 2018, and the results showed that the concentrations of nutrients, such as TN and NO₃-N, were increased at GP4, which is located at the downstream of sewage treatment facilities(STFs). TOC and TN ratios showed a strong positive correlation (R² = 0.77, p<0.01) at all points except for GP4. The results of GP's stable isotope ratio analysis do not appear to be a constant cluster compared to AY because GPs with large amounts of pollutants from the industry (metal processing companies, etc.) have less tributary, shorter waterway and significantly different external sources. This could be attributed to different sources of external inflow despite its smaller number of tributaries and shorter waterways than AY. In the first half of the year, the δ¹⁵5N of GP4 was affected by discharge of STFs, while AY3 seemed to have an influence of tributary than the discharge of STFs. Consequently, using water quality, stable isotope ratio and C/N, the sources of contamination in two streams with different contaminants were identified and origin was estimated.

• Ocean and Polar Research
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• v.35 no.4
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• pp.427-439
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• 2013

Carbon cycling and productivity within Weno Island of Micronesia enclosed by the coral reef may be likely self-maintained and insignificantly affected by the open ocean. Therefore, it is important to understand the role of the mangrove known as providing the organic matter and habitats for many organisms in this enclosed area. In order to trace the nutritional source of fauna (mostly invertebrates) in the mangrove forest of Weno island, we analyzed the fatty acid (FA) and carbon and nitrogen stable isotopes of potential nutritional sources (mangrove leaf & pneumatophore, seagrass leaf & root, surface sediment, and particulate organic matter (POM) in water) and consumers (4 gastropods and anomura). The mangrove and seagrass contained the abundance of 18:2${\omega}$6, and 18:3${\omega}$3, whereas FAs associated with phytoplankton and bacteria were accounted for a high proportion in the surface sediment and POM. FA composition of consumers was found to be similar to those of the surface sediment, mangrove, and seagrass. These were also confirmed through the mixing model of stable isotope for contribution of nutritional sources to consumers. Overall results with the feeding types of investigated mangrove fauna indicate that investigated mangrove fauna obtained their nutrition from the various sources, i.e. the mangrove for Littorina cf. scabra, the microalgae for Strombus sp., and omnivorous Pagurus sp. and Terebralia cf. palustris. However, it is obvious that the nutrition of most species living in the mangrove ecosystem is highly dependent on the mangrove, either directly or indirectly. More detail food-web structure and function of the mangrove ecosystem would be established with the analysis of additional fauna and flora.

• Korean Journal of Soil Science and Fertilizer
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• v.18 no.4
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• pp.392-406
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• 1985

The soil management practices before transplanting the ginseng plant were studied with two organic matter sources such as a traditional organic matter (wild grass) and commercial organic fertilizer (byproducts of amino acid fermantation) during the late spring to late autumn. During the soil management practices, the soil received 40kg N/10a from five different combination treatments with above two organic matter sources, a wild grass and a commercial organic fertilizer. After the application of the treatments, the soil were ploughed regularly at the interval of 20 days and the changes of physicochemical properties during the soil management practices were investigated. The next year after soil management practices, ginseng plants were transplanted to each treatment, growth and the content of some organic components of ginseng plant were measured for comparision of the different treatments. 1. The decrease in bulk density observed during the first 40 days of management was considered to be the effect of the improved physical conditions caused by ploughing, The decrease in bulk density observed after 40 days of management was considered to be the effect of organic matter. Similar results were observed in particle density, however porosity increased with time. 2. Soil pH tended to decrease during the first 40 days of management, after which period the pH increased and was stabilized. However, CEC increased with organic matter treatment and the exchangeable $NH^+_4-N$ and $NO^-_3-N$ increased in 20 and 40 days after the management practices, respectively, and after that period it became steady. 3. The decomposition rate of treated organic matter was measured by the incubation test in laboratory conditions. The rate of decomposition was rapid during the first 20 days of management, after which period it showed slight changes. 4. The weight of ginseng root significantly increased in the treatment of 10kg N/10a organic fertilizer and 30kg N/10a wild grass. 5. The saponin content of ginseng root was highest in the 40kg N/10a wild grass treatment. The addition of organic fertilizer at the rate of more than 20kg N/10a caused the decrease in the saponin content.

• Journal of Environmental Policy
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• v.10 no.4
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• pp.61-80
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• 2011

Through concentrated investments in environmental regulations centered around BOD, which is a biodegradable matter index, and basic environmental infrastructures, national BOD pollution level has continuously improved. Nonetheless, limitations of BOD management system has become evident through nation-wide stagnation and/or increases of refractory organic matters, such as COD, at main drinking water sources, and the need for a new index, which can easily indicate different environmental conditions, has increased. Therefore, this study suggests a new organic management index for a proper management of surface water. $COD_{Cr}$ and TOC were examined as candidates for surface water quality management index, and it was found that TOC was more appropriate than $COD_{Cr}$ as an organic matter management index. Through this study, it was found that TOC possesses following qualities: a more representative index; international acceptability; monitoring program is easier; better availability of analysis techniques; better accuracy and precision of analysis; less time required for analysis; ease of operation; management of disinfection byproducts; connection with present policies; existence of foreign and domestic application case studies; and correlation with water ecosystem.

• Journal of Korean Society of Environmental Engineers
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• v.33 no.2
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• pp.132-136
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• 2011

The Temporal variability in the food chain structure of bacteria in the sedimentary organic matter was investigated using stable isotope and fatty acid. Potential organic matter sources (Land plant, Marine POM, benthic microalgae, Riverine POM), sedimentary organic matter and bacteria were sampled in Gamo largoon and Nanakita estuary. The main objective of the present study was to determine food sources of bacteria along with temporal variability. Land plant (${\delta}^{13}C$ = -26.6‰ and ${\delta}^{15}N$ = 3.6‰) and Riverine POM (${\delta}^{13}C$ = -25.5‰ and ${\delta}^{15}N$ = 8.9‰) were isotopically distinct from benthic microalgae (${\delta}^{13}C$ = -16.3‰ and ${\delta}^{15}N$ = 6.2‰) and Marine POM (${\delta}^{13}C$ = -20.3‰ and ${\delta}^{15}N$ = 10.3‰). ${\delta}^{13}C$ values of sedimentary organic matter showed a distinct gradient in the range of -20.7‰ to -191‰. The stable carbon and nitrogen isotope values of bacteria in the study were -20.8‰ to -18.6‰ for ${\delta}^{13}C$ and 6.5‰ to 8.6‰ for ${\delta}^{15}N$. From this results based on stable isotope measurements showed that in the bacteria was found to be dominated by Marine POM and Benthicmicoralge during 0 to 20 day. Whereas, terrestrial plant and riverine POM showed little in fluence to bacteria during the experiment.

• Journal of Korean Society of Water and Wastewater
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• v.23 no.6
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• pp.727-733
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• 2009

This study was performed to investigate the physical characteristics like compressive strength, permeability, porosity and the water quality removal characteristics of permeable concrete pavement filled with microbial-soil sheet to remove SS, organic matter and nutrients in artificial rainfall. As a result, it can show the removal efficiency is SS 90~95%, COD 85~93%, BOD 80~83%, T-N 61~75%, T-P 71~78% on WAPS I(W1) and WAPS II(W2). Therefore, permeable concrete pavement filled with microbial-soil sheet shows higher removal efficiency(SS 10%, organic matter and nutrients 30%) than a conventional porous concrete(W3). By filling microbial-soil sheet to permeable concrete pavement, we confirm that the function and efficiency are improved significantly and that a naturally-friendly facility can be developed and applied to treat non-point sources.

• Journal of Korean Society of Water and Wastewater
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• v.22 no.1
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• pp.131-140
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• 2008

The application of magnetic ion exchange resin($MIEX^{(R)}$) is effective for natural organic matter(NOM) removal and for control of the formation of disinfection byproducts(DBPs). NOM removal is also enhanced by adding $MIEX^{(R)}$ with coagulant such as polyaluminium chloride(PACl) in conventional drinking water treatment systems. In the application of $MIEX^{(R)}$, it is important to understand changes of NOM characteristics such as hydrophobicity and molecular weight distributions with $MIEX^{(R)}$ or $MIEX^{(R)}$+coagulant treatment.To observe characteristics of NOM by treatment with $MIEX^{(R)}$ or $MIEX^{(R)}$+coagulant, four major drinking water sources were employed. Results showed that the addition of $MIEX^{(R)}$ to coagulation significantly reduced the amount of coagulant required for the optimum removal of dissolved organic matter(DOC) and turbidity in the all four waters. The DOC removal was also increased approximately 20%, compared to coagulant treatment alone. The process with $MIEX^{(R)}$ and coagulant showed that complementary removal of hydrophobic and hydrophilic fraction of DOC. The combined processes preferentially removed the fractions of intermediate (3,000-10,000 Da) and low (< 500 Da) molecular weight. The microfiltration test showed that membrane cake resistance was decreased for waters with flocs from $MIEX^{(R)}$+coagulant. A porous layer was formed to $MIEX^{(R)}$ on the membrane surface and the layer consequently inhibited settling of coagulant flocs, which could act on a foulant.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.39 no.2
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• pp.106-117
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• 2006

We measured the concentrations of organic matter and metallic elements (Al, Fe, Cr, Mn, Ni, Cu, Zn, As, Cd, Pb and Hg) in the surface sediments of Masan Harbor (in the southern sea, Korea) to evaluate the geochemical characters of sediment and the pollutions by organic matter and metallic elements. The mean grain size of the surface sediments in the study area ranged from $5.6{\phi}$ to $7.8{\phi}$, indicating silt sediment. The water content of the surface sediments exceeded 60% except at some stations. The contents of ignition loss (IL), total organic carbon (TOC) and total nitrogen (TN) ranged from 7.2-14.3%, 1.2-3.2%, and 0.10-0.28%, respectively. Based on the C/N ratios, the organic matter in the surface sediments of Masan Harbor may originate from terrigenous sources including fluvial inputs (mainly sewage in urban areas). The chemical oxygen demand (COD) and acid volatile sulfide (AVS) ranged from $11.3-29.9\;mgO_2/g\;dry$ and 0.20-4.47 mgS/g dry, respectively, and low concentrations were observed near a shipping route. In addition, the concentrations of metallic elements showed large spatial variations in Masan Harbor and the distributions of metallic elements were also comparable to those of organic matter. This implies that the distributions of organic matter and metallic elements in the surface sediments of Masan Harbor are mainly controlled by biogenic matter and artificial action (mainly dredging). In addition, we calculated the enrichment facto. (EF) and geoaccumulation index (Igeo) in order to evaluate pollution by metallic elements. The enrichment of metallic elements relative to Al was three to eighteen times higher at the study sites, compared to levels in the Earth's crust except for Fe, Ni and Mn. In addition, the Igeo class indicated that the surface sediments in the study area were moderately to strongly polluted in terms of metallic elements.

• Journal of the Korean Society of Marine Environment & Safety
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• v.23 no.6
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• pp.699-709
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• 2017

We measured the grain size, total organic carbon (TOC), total nitrogen (TN), and heavy metals (As, Cd, Cr, Cu, Fe, Hg, Mn, Pb, and Zn) in order to understand the spatial distribution and pollution level of organic matter and metals in surface sediment around Goseong Bay, a shellfish farming area, Korea. The surface sediments were composed of finer sediments such as mud and clay. The concentration of TOC, TN, and heavy metals were much higher in the innermost bay than in the mouth and outside of bay. The spatial distribution of organic matter and heavy metals and C/N ratio (5-10) in sediment showed that the organic matter and heavy metals in sediment of the study region were significantly influenced by oceanic origin organic matter and anthropogenic sources, respectively. Based on the results of four assessment techniques (sediment quality guideline, geoaccumulation index, pollution load index, ecological risk index), the sediments around the Goseong Bay were a little polluted for heavy metals and the high metal concentrations in the northern region of bay could adverse impact on benthic organisms in sediment. Thus, the systematic management plan for the improvement of water and sediment environment and the concentrated monitoring of pollutants for sustainable aquaculture and seafood safety around Goseong Bay are necessary in the future.

• Korean Journal of Soil Science and Fertilizer
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• v.48 no.6
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• pp.736-743
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• 2015

Organic matter plays important roles in soil ecosystem in terms of carbon and nitrogen cycles. Due to recent concerns on climate change, carbon sequestration in agricultural land has become one of the most interesting and debating issues. It is necessary to understand behavior of soil carbon for evaluating decomposition or sequestration of organic matter and analyzing potential carbon decomposition pattern about the kinds of organic matter sources to cope with well. In order to evaluate decomposition of soil carbon according to organic material during cultivating rice in paddy field, we treated organic material such as hairy vetch, rice straw, oil cake fertilizer, and manure compost at $50{\times}50{\times}20cm$ blocks made of wood board, and analyzed carbon contents of fulvic acid and humic acid fraction, and total carbon periodically in 2013 and 2014. Soil sampling was conducted on monthly basis. Four Kinds of organic matter were mixed with soil in treatment plots on 2 weeks before transplanting of rice. The treatment of animal compost showed the highest changes of total carbon, which showed $7.9gkg^{-1}$ in May 2013 to $11.6gkg^{-1}$ in October 2014. Fulvic acid fraction which is considered to easily decompose ranged from 1 to $2gkg^{-1}$. Humic acid fraction was changed between 1 to $3gkg^{-1}$ in all treatments until organic material had been applied in 2014. From May to August in the second year, the contents of humic acid fraction increased to about $4gkg^{-1}$. The average of humic fraction carbon at treatments of animal compost was recorded highest among treatments during two years, $2.1gkg^{-1}$. The treatment of animal compost has showed the lowest ratio of fulvic acid fraction, humic acid fraction compared with other treatments. The average ratio of fulvic fraction carbon in soil ranged from 16 to 20%, and humic fraction carbon ranged from 19 to 22%. In conclusion, animal compost including wood as bulking agent is superior in sequestrating carbon at agricultural land to other kinds of raw plant residue.