• Korean Journal of Ecology and Environment
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• v.56 no.4
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• pp.339-347
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• 2023

Dissolved organic matter (DOM) is a key component in the biogeochemical cycling in freshwater ecosystem. However, it has been rarely explored, particularly complex river watershed dominated by natural and anthropogenic sources, such as various effluent facility and livestock. The current research developed a new analytical method for TOC/TN (Total Organic Carbon/Total Nitrogen) stable isotope ratio, and distinguish DOM source using stable isotope value (δ¹³C-DOC) and spectroscopic indices (fluorescence index [FI] and biological index [BIX]). The TOC/TN-IR/MS analytical system was optimized and precision and accuracy were secured using two international standards (IAEA-600 Caffein, IAEA-CH-6 Sucrose). As a result of controlling the instrumental conditions to enable TOC stable isotope analysis even in low-concentration environmental samples (<1 mgC L^-1), the minimum detection limit was improved. The 12 potential DOM source were collected from watershed, which includes top-soils, groundwater, plant group (fallen leaves, riparian plants, suspended algae) and effluent group (pig and cow livestock, agricultural land, urban, industry facility, swine facility and wastewater treatment facilities). As a result of comparing characteristics between 12 sources using spectroscopic indices and δ¹³C-DOC values, it were divided into four groups according to their characteristics as a respective DOM sources. The current study established the TOC/TN stable isotope analyses system for the first time in Korea, and found that spectroscopic indices and δ¹³C-DOC are very useful tool to trace the origin of organic matter in the aquatic environments through library database.

• Journal of the Korea Organic Resources Recycling Association
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• v.32 no.3
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• pp.19-29
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• 2024

Total organic carbon (TOC) represents the total amount of organic carbon contained in water and is a key water quality parameter used, along with biochemical oxygen demand (BOD) and chemical oxygen demand (COD), to quantify the amount of organic matter in water. In this study, a model to predict TOC was developed using XGBoost (XGB), a representative ensemble machine learning algorithm. Independent variables for model construction included water temperature, pH, electrical conductivity, dissolved oxygen concentration, BOD, COD, suspended solids, total nitrogen, total phosphorus, and discharge. To quantitatively analyze the impact of various water quality parameters used in model construction, the feature importance of input variables was calculated. Based on the results of feature importance analysis, items with low importance were sequentially excluded to observe changes in model performance. When built by sequentially excluding items with low importance, the performance of the model showed a root mean squared error-observation standard deviation ratio (RSR) range of 0.53 to 0.55. The model that applied all input variables showed the best performance with an RSR value of 0.53. To enhance the model's field applicability, models using relatively easily measurable parameters were also built, and the performance changes were analyzed. The results showed that a model constructed using only the relatively easily measurable parameters of water temperature, electrical conductivity, pH, dissolved oxygen concentration, and suspended solids had an RSR of 0.72. This indicates that stable performance can be achieved using relatively easily measurable field water quality parameters.

• Environmental Analysis Health and Toxicology
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• v.5 no.3_4
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• pp.19-28
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• 1990

Nitroarenes are ubiquitous environmental pollutants displaying potent mutagenicity in bacteria and carcinogenicity in mammal. In this study, the concentration of nitroarenes in coarse and fine particles and mutagenicity of POC$\_$N/ fraction was investigated in suspended particulates at the Shinchon and Bulkwang area of Seoul. The suspended particulates were collected bimonthly by a high volume cascade impactor air sampler from July 1987 to May 1988. Extractable organic matter was obtained by ultrasonic extraction on diethly ether/cyclohexane (8/2, v/v). Neutral fraction was obtained by liquid-liquid extraction. Polar neutral organic compounds (POC$\_$N/) was fractionated by thin-layer chromatography. Finally, the concentrations of nitroarenes in POC$\_$N/ fraction were measured and determined by capillary gas chromatography. Direct and indirect mutagenicity of POC$\_$N/ fraction were measured using Salmonella typhimurium TA 98. The result were as follows: 1) Major nitroarenes at the Shinchon area was 1-nitropyrene and at the Bulkwang area it was 2,7-dinitro-9-fluorenone during the year. 2) Average concentration of total nitroarenes measured was 67.26 ng/m$^3$in fine particles which was 1,3 folds higher that in coarse particle (52.30 ng/m$^3$). 3) Annual pattern of nitroarenes concentrations revealed that concentration during heating season (Feb., Jan., Mar.) was 2.2 folds higher than that in non heating season (May, Jul., Sep.). Concentration of each season has 157.68 ng/m$^3$and 80.39 ng/m$^3$. 4) The mutagenic activity of POC$\_$N/ fraction from fine particles was higher compared to that of coarse particles and was increased when metabolically activated, with 59 mixture. Mutagenicities, Metabolically activated, were significantly different between Shinchon and Bulkwang area, 322.8 rev/250 $\mu\textrm{g}$/plate and 286.8 rev/250 $\mu\textrm{g}$/plate, respectively. 5) Annual pattern of mutagenicity of POC$\_$N/ fraction revealed that mutagenicity during the heating season was 1.7 folds higher at Shinchon area and 1.2 folds higher at Bulkwang than during the non heating season. The variable contents and levels of nitroarenes in suspended particulates may affect human health significantly. Further studies such as risk assessment should be conducted on the basis of these kind of studies.

• 한국해양학회지
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• v.5 no.2
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• pp.59-64
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• 1970

The purpose of the study was to gather basic bacteriological data regarding the quality of Korean surface waters. Total coliforms, fecal coliforms and fecal Streptococci survey in the water of Lake Eui-Am were undertaken by the membrance filter technique. A total of 37 samples were collected in August 14, 1970. Total coliforms were detected in all samples, fecal coliforms and fecal Streptococci were detected in 68% and 82% of samples, respectively. Bacterial densities of the lake water were varied by station and depth. The numbers of bacteria per 100ml of the lake water were; 8-225(65.3 average) for the total coliforms, 0-112(26.2 average) for the fecal coliforms, 0-77(25.8 average) for the fecal Streptococci, and 8-302 (91.1 average) for the total number of total coliforms and fecal Streptococci. These results suggest that the Eui-Am lake water is only lightly polluted and indicate that the lake water, properly maintained, is a source of raw water of good bacteriological quality. Three forms of fecal pollution bacteria tend to increase with depth. This is believed that the suspended matter with conglomerated bacteria plays an important role in regulating of bacterial densities in summer season.

• Journal of the Korean Society of Marine Environment & Safety
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• v.15 no.4
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• pp.275-282
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• 2009

PAHs(Polycyclic Aromatic Hydrocarbons) compounds may enter into the marine environment in a number of ways, and PAHs in coastal area and estuary adjacent to urban area and industrial activities region are mainly introduced into marine environment via atmosphere or river. The field surveys to evaluate the pollution of PAHs in rivers of Jinhae bay were carried out in August, 2008. The water samples collected from seven main rivers and Deokdong WWTP(Waste water Treatment Plant) which lead to Jinhae bay. 16 PAHs which had been selected as priority pollutants by EPA were analyzed. The range and mean of dissolved Total PAHs concentrations in the rivers and Duckdong WWTP that lead to Jinhae bay were shown to be 9.79~128.25(mean 36.94)ng/L, while the range and mean of Total PAHs concentrations in SPM(Suspended Particulate Matter) were shown to be 1,81434~8,893.37(mean 4,657.73)${\mu}g$/kg dry wt. The dissolved Total PAHs and Total PAHs in SPM were shown to be high concentrations in the Semhocheon which leads to Masan bay that is the most polluted area of Jinhae bay, while those were shown to be low concentrations at rivers which lead to the west area of the bay. The ranges and means of the loading fluxes from rivers and Duckdong WWTP were calculated at 0.06~12.05(mean 1.86)g/day for dissolved Total PAHs and at 0.12~16.00(mean 2.41)g/day tor Total PAH in SPM. The loading flux of Total PAHs from Duckdong WWTP was shown to be the greatest, occupying more than 80% of Total loading flux from all rivers and WWTP to Jinhae bay. The composition patterns of PAHs compound by the number of benzene ring between dissolved PAHs and PAHs of SPM were different each other. Low molecuar weight PAHs of dissoloved compounds were in high concentration, while high molecular weight PAHs of SPM were in high concentration. These results were due to physical and chemical characteristics of PAHs and were similar to those of other studies. The total PAHs concentrations of dissolved and SPM in this study are lower than those of other studies. The extent of PAHs pollution appeared to be not serious in reverine waters of Jinhae bay.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.5
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• pp.64-71
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• 2018

The purpose of this study is to investigate the characteristics of the substrate of dairy wastewater through aerobic biodegradation and to use the results as the basic data for the efficient treatment of dairy wastewater. The SCODcr of the part of the matter that consisted of readily biodegradable organics (Ss) was 84.2%, which is higher than those of seafood processing wastewater (75.8~77.9%) and pigpen wastewater (58.2%). The proportion of non-biodegradable organics (SI) ranged from 5.6% to 6.4%, and the proportion of inert organics (SIi) generated by microbial metabolism ranged from 3.6 to 3.7%. The content coefficient (YI) of the non-biodegradable dissolved organic matter was in the range of 0.092 to 0.099, and the generation coefficient (Yp) of the inert substance produced by the microbial metabolism was in the range of 0.039 to 0.040. The analysis results of the organic component coefficient showed that approximately 91.0% of the dissolved organic matter of the dairy wastewater was biodegradable, and approximately 92.5% of the dissolved organic matter was the Ss component. Furthermore, the proportion of biodegradable organic matter in the total organic matter (TCODcr) was 89.3%. The proportions of non-biodegradable organics (SI) and non-biodegradable suspended organics (XI) were 3.0% and 7.7%, respectively, which are lower than those in similar wastewater. This means that the milk processing wastewater has a high aerobic biodegradability.

• Korean Journal of Ecology and Environment
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• v.46 no.2
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• pp.175-184
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• 2013

Organic carbon and total nitrogen stable isotope ratios of suspended materials were determined at 3 stations (from Mongtan Bridge to Youngsan river estuary barrage) (n=6, each) from November 2008 to August 2009, in order to understand the origin of particulate organic matter at the Estuary of Youngsan River. Allochthonous organic matter, ammonia-N and silicate were increased after heavy rain (in August). Carbon isotope ratios were significantly different between stations in November and August, and it was possible to determine the origin of organic matter. The heavier nitrogen isotope ratios, as well as higher phosphate concentrations, were found in November than other sampling times. Livestock wastewater and farmland input was likely the main causes of these high values. In addition, YS3 station, the nearest site to estuary barrage, appears to be affected by a substantial amount of livestock wastewater and farmland input, considering that nitrogen isotope ratios were heavier than those at the upper sites. These results suggest that the analysis of stable isotope ratios is a simple but useful tool for the determination of organic matter origin in aquatic environments.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.23 no.2
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• pp.145-154
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• 1990

Amounts of total suspended matter(TSM) around the Kori waters have been monitored for two years to understand the dispersal pattern of fine-grained sediment. Average concentration of the TSM is $3\~4\;mg/\iota$ in the surface and $3.5\~5\;mg/\iota$ in the near-bottom water. Semi-quantitative analysis for the four major clay minerals in TSM is also performed. The average relative abundance of each clay mineral such as illite, kaolinite, chlorite, and smectite is $65\%,\;17\%,\;17\%$, and $1\%$, respectively. It seems that the majority of recent fine-grained sediment deposited around the Kori area is derived from the Nakdong River. The texture of surface sediment is also dominated by fine-grained fraction leading up to $90\%$ of silt and clay content. The grain size decreases seaward progressively.

• Environmental Engineering Research
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• v.24 no.2
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• pp.238-245
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• 2019

This study investigated the characteristic of aerobic granular sludge (AGS) process to treat the sewage having low carbon/nitrogen ratio (Biochemical oxygen demand ($BOD_5$):Total nitrogen (T-N), 4.5:1) in sequencing batch reactor (SBR). The removal efficiency of $BOD_5$, suspended solid (SS), T-N and phosphorus ($PO_4{^{3-}}$-P) were 92.6%, 64.3% and 90.1%. Concentration and size of AGS were changed in proportion to the organic matters and nitrogen concentration of the influent (Concentration and size of AGS: 1,700-3,000 mg/L, 0.5-1.0 mm). Mixed liquor suspended solid (MLSS) also changed with the concentration of AGS (MLSS: 2,000-3,500 mg/L). When the settling time was shortened from 15 min to 10 min, size and shape of AGS were maintained (Size of AGS: 1.0-1.5 mm). In addition, the concentration of AGS and MLSS increased (Concentration of AGS: 3,500 mg/L, MLSS: 4,000 mg/L). Concentration, size and shape of AGS were affected the settling time of the reactor more than the concentration of organic matter and nitrogen in the influent. In the results of removal efficiency and changes in AGS, we confirmed that the SBR process using AGS can be used to treat the sewage having low carbon/nitrogen ratio by applying short settling time.

• Tuberculosis and Respiratory Diseases
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• v.58 no.2
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• pp.167-173
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• 2005

Background : Airborne particles during Yellow Sand phenomena are known to be associated with the respiratory disease. The purpose of this study was to evaluate the concentration and metal component properties of Yellow Sand particles and compare with airborne microbial concentration and species in non Yellow Sand and Yellow Sand phenomena. Methods : Samplings were carried out in 2002 in Seosan, during non Yellow Sand and Yellow Sand phenomena. Samples were taken using the 8-stage Cascade impactor and metallic elements were analyzed by XRF. Those were culture on the media for bacterial and fungal culture and celline for virus. Results : The concentration of total suspended particulate matter were respectively $80.2{\mu}g/m^3$, $40.3{\mu}g/m^3$ in non Yellow Sand and Yellow Sand phenomena. The concentration of metallic elements such as Ca, Fe, Cu and Zn in Yellow Sand phenomena were higher than its in non Yellow Sand. Two bacteria, Bacillus species and Staphylococcus were grown in two periods. In both periods, several fungal spores(Mucor species, Cladosporum, Alternaria, Aspergillus, Penicillium, and Alternaria species) were identified. The differences of bacteria and fungus species not observed in Yellow Sand and non Yellow Sand. Any viruses were not isolated in between both periods. Conclusions : The concentration of total suspended particulate matter and some metallic elements in Yellow Sand phenomena were higher than its in non Yellow Sand. The difference of bacteria and fungus species was not observed in non Yellow Sand and Yellow Sand phenomena.