• Journal of Environmental Science International
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• v.14 no.7
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• pp.649-655
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• 2005

Microcystis aeruginosa is common form of cyanobacteria (blue-green algae) capable of producing toxic heptapeptide (microcystin) that cause illness or death. The comparison of molecular genetic method with the morphological characteristics of cyanobacteria was conducted. We have designed PCR primers (JJM98F, JJM1141R) for cyanobacterial 16S rRNA and phycocyanin intergenic spacer (PC-IGS) gene domain. To confirm the production of microcystins, PCR primers for the N-methyltransferase (NMT) domain of microcystin synthetase gene mcyA were designed using 21 cyanobacteria strains Most of isolated strains from the Nakdong River was classified as Microcystis aeruginosa and the similarities were $99\%$ with M. aeruginosa AF 139292. $38.1\%$ of isolated strains contained microcystin synthesis gene. NMT (N-methyltransferase) were not detected in isolated strain in several strains, which means non-toxic. However, the NMTs of the strains were detected during the cultivation.

• Journal of Environmental Science International
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• v.24 no.9
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• pp.1123-1129
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• 2015

This research was performed by means of several different virgin granular activated carbons (GAC) made of each coal, coconut and wood, and the GACs were investigated for an adsorption performance of iodine-131 in a continuous adsorption column. Breakthrough behavior was investigated that the breakthrough points of the virgin two coals-, coconut- and wood-based GACs were observed as bed volume (BV) 7080, BV 5640, BV 5064 and BV 3192, respectively. The experimental results of adsorption capacity (X/M) for iodine-127 showed that two coal- based GACs were highest (208.6 and $139.1{\mu}g/g$), the coconut-based GAC was intermediate ($86.5{\mu}g/g$) and the wood-based GAC was lowest ($54.5{\mu}g/g$). The X/M of the coal-based GACs was 2~4 times higher than the X/M of the coconut-based and wood-based GACs.

• Journal of Korean Society on Water Environment
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• v.29 no.1
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• pp.97-106
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• 2013

The temporal and spatial variations of water quality in a stratified reservoir are fully dependent on the characteristics of inflow loading from its watershed and the transport regimes of pollutants after entering the reservoir. Because of the meteorological and hydrological conditions in Korea, the pollutants loading to reservoirs are mostly occur during rainfall events. Therefore it is important to understand the characteristics of pollutants loading from upstream rivers and their spatial propagation through the stratified reservoir during the rainfall events. The objectives of this study were to characterize the water quality variations in upstream rivers of Imha Reservoir during a rainfall event, and the transport and spatial variations of pollutants in the reservoir through extensive field monitoring and laboratory analysis. The results showed that the event mean concentration (EMC) of SS, BOD, $COD_{Mn}$, T-N, T-P, $PO_4-P$ are 8.6 ~ 362.1, 2.5 ~ 5.1, 1.5 ~ 5.1, 1.1 ~ 1.9, 8.3 ~ 57.1, 5.6 ~ 25.7 times greater than the mean concentrations of these parameters during non-rainfall period. The turbidity and SS data showed good linear correlations, but the relationships between flow and SS showed large variations because of hysteresis effect during rising and falling periods of the flood. The ratio of POC to TOC were 12.6 ~ 14.7% during the non-rainfall periods, but increased up to 28.2 ~ 41.7% during the flood event. The turbid flood flow formed underflow and interflow after entering the reservoir, and delivered a great amount of non-point pollutants such as labile and refractory organic matters and nutrients to the metalimnion layer of reservoir, which is just above the thermocline. Spatially, the lateral variations of most water quality parameters were marginal but the vertical variations were significant.

• Journal of Industrial Technology
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• v.22 no.A
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• pp.201-210
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• 2002

The object of this study is to evaluate the factors affecting the water quality and to propose the influence of dominant factor quantitatively. The correlation analysis was performed to know the correlationship among the water quality items As a result of partial correlation analysis, it was shown that the water quality items are affected by the rainfall item directly. The factor analysis was performed to grasp some number of factors on each point for deducing the items of similar variable characteristics. The four points were divided into different factor groups. It was grasped that $NH_3-N$ and $NO_3-N$ Items have different variable characteristics after comparing the items. The Multiple regression analysis can decrease the number of observation. In the deduced multiple regression formula, it was shown that the rate of T-N, $NH_3-N$ and $NO_3-N$ in the independent variable took about 60% among all the regression formulas.

• Journal of Korean Society on Water Environment
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• v.29 no.5
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• pp.630-640
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• 2013

It is one of the most critical steps identifying impaired waterbodies exactly in the selection of target water quality indicators for the management of Total Maximum Daily Loads (TMDLs). Excess ratio and excess level were applied and analyzed by the stream zone basis in order to evaluate water impairment for Nakdong, Geum, Youngsan and Seomjin rivers. Each river basin was divided into stream zones in the light of its watershed and waterbody characteristics. Selected water quality parameters discussed in this study were pH, DO, BOD, COD, SS, T-P, T-Coli and F-Coli. The excess ratios of the water quality parameters were used to discriminate water bodies that did not meet water quality standards. The excess levels were used to classify the degradation of water quality. The excess ratios and the excess levels to the water quality criteria of the medium influence areas were used for each stream zone. The results indicate that the excess ratios and the excess levels are varied on the stream zone in each river basin. Three parameters, pH, DO and SS, met water quality standards in all stream zones. The other five parameters indicated very high excess ratios in most waterbodies, and especially T-P and T-Coli revealed to be very high excess levels in some waterbodies. These parameters could be considered as major target indicators for the management of TMDLs.

• Journal of Korean Society on Water Environment
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• v.28 no.6
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• pp.786-795
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• 2012

Water quality management should be focused on the pollution concentrated area so that the improvement of water quality can be achieved effectively for the management of Total Maximum Daily Loads (TMDLs). It is necessary to consider discharge characteristics in the TMDL plan. This study analysed discharge characteristics such as pollution generation and discharge load density, and reduction potential by each unit watershed, and categorized the unit watershed into four groups according to its discharge load characteristics. This analysis can be used as helpful information for the prioritization of pollution reduction area and selection of pollution reduction measures in the development of TMDL plans.

• Journal of Environmental Impact Assessment
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• v.32 no.2
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• pp.134-145
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• 2023

Currently, the floodplains of major rivers are transforming into various types of waterfront spaces according to the increase in leisure activities and improved accessibility. In general, waterfront activities in river channels tend to be concentrated in summer, and the waterfront activities during this period directly affect water quality. Accordingly, it is necessary to accurately compare and evaluate the characteristics and water quality of waterfront activities during the period when waterfront activities are concentrated. In this study, the following research was conducted to compare and analyze the current status of waterfront activities of users of waterfront areas and the water quality of waterfront areas. First, three waterfront areas were selected for investigation using the information from the Ministry of Environment's water quality measurement network. Second, a survey was conducted on the satisfaction and types of waterfront activities targeting users of waterfront areas. Third, water quality grades were calculated based on monthly water quality measurement factors and compared. Fourth, statistical analysis (one-way analysis of variance) was conducted to see if there was a significant difference in water quality characteristics between periods of high waterfront activity and periods of low waterfront activity using water quality measurement data for the last 5 years. As a result of this analysis, the following conclusions were drawn in this study. First, the use of waterfront activities was investigated in the order of camping, water skiing, fishing, swimming, and rafting. Second, satisfaction factors for waterfront activities were investigated in the order of activity convenience, water quality, waterlandscape, transportation access convenience, and temperature. Third, it was found that satisfaction with water quality in waterfront areas was generally unsatisfactory regardless of the water quality grade presented by the competent authority. Fourth, as a result of comparing the water quality measurement network data of the Ministry of Environment by water quality grade, generally good grades were found, and in particular, there was a difference in grade frequency by season in the BOD category. Fifth, as a result of statistical analysis (one-way ANOVA) of water quality monitoring network data by season, there were statistically significant differences in COD, BOD, TP, and TOC except for DO. Considering the results of these studies, it is judged that it is necessary to prepare a comprehensive management system for water quality improvement in the waterfront zone and to improve water quality during periods of high waterfront activity, and to prepare a water quality forecasting system for waterfront areas in the future.

• Journal of Korean Society on Water Environment
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• v.35 no.6
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• pp.539-549
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• 2019

In 2016, Benthic Macroinvertebrates Streambed Index (BMSI) was proposed as an index to evaluate streams as benthic macroinvertebrate depending on the substrate type of streambed. However, orignal BMSI were selected without consideration of water quality. Analyzes without water quality do not constitute biological indices based solely on the substrate type of streambed. Therefore, in this study, the indicator value was improvement in consideration of water quality, and the distribution characteristics of benthic macroinvertebrates according to the substrate type of streambed were analyzed under relatively equal water quality conditions. We surveyed 20,155 sampling units in Korea from 2008 to 2018, and we re-estimated each lithophility of 191 taxa. As a result of estimating the streambed of each newly lithophilic value classification group considering the water quality, it was different from the original lithophilic value. Representative integer lithophilic values were newly calculated from 126 taxa among the 191 index taxa used in the analysis. The correlation between new constructed BMSI and community structure was compared and analyzed. It showed extreamely significance (p<0.001) in the dominance index, diversity index, abundance index, and evenness index of the community structure. Diversity index, abundance index, and evenness index showed positive correlation, and dominance index showed negative correlation. The correlation coefficient (r) was the highest in the richness index of about 0.664.

• Journal of Korean Society on Water Environment
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• v.24 no.2
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• pp.239-246
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• 2008

In this study, an optimized deterministic water-quality model was constructed to estimate water quality of a river and lake in the upstream basin of a dam. A stochastic water-quality analysis using reliability analysis technique was applied to the model. The model was tested in the 13.9 km reach from Maeil stage station of Kyechun to Hoengsung Dam of Sum River. After finding hydraulic characteristics from nonuniform flow analysis, Broyden-Fletcher-Goldfarb-Shanno (BFGS) optimization technique for model calibration was applied to determine optimum reaction parameters, and model verification was performed based on these. The stochastic model, using Mean First­Order Second­-Moment (MFOSM) and Monte-Carlo methods, was applied to the same reach as the deterministic study. Variations of discharge and water quality in headwater were considered, as well as variations of hydraulic coefficients and reaction coefficients. The statistical results of output variables from MFOSM were similar to those from the Monte-Carlo method. Risk analysis using MFOSM and Monte-Carlo methods presented the probabilities of some locations in the Hoengsung Lake violating existing water-quality standards in terms of DO and BOD.

• Journal of Wetlands Research
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• v.24 no.4
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• pp.301-311
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• 2022

The purpose of this study is to analyze the seasonal characteristics of water quality using long-term water quality monitoring data. Seasonal characteristics of water quality were analyzed using monitoring data from 34 tributaries where long-term monitoring was performed in the Nakdong River system, and average data analysis of water quality, coefficient of variation analysis, and trend analysis were performed for seasonal analysis. For seasonal analysis, average data analysis of water quality, coefficient of variation analysis, and trend analysis were performed. As a result of the evaluation of the coefficient of variation, tributaries were larger than main streams, and BOD, T-P, and TOC were larger in autumn and T-N were larger in spring. Trend analysis was analyzed using Mann-Kendall and Sen's Slope. BOD, T-N, and T-P tended to decrease, but TOC had a lot to increase. Through this study, it was possible to evaluate the availability of long-term water quality monitoring data and analyze seasonal characteristics, and to analyze the stabilization period of water quality and changes in pollutant sources for watershed management.