• Journal of Korean Society on Water Environment
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• v.39 no.2
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• pp.162-174
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• 2023

In order to prevent water pollution caused by organic matter, Total Organic Carbon(TOC) has been adopted indicator and monitored. TOC can be divided into Dissolved Organic Carbon(DOC) and Particulate Organic Carbon(POC). POC is largely precipitated and removed during stream flow, which making DOC environmentally significant. However, there are lack of studies to define spatio-temporal distributions of DOC in stream affected by various land use. Therefore, it is necessary to estimate the past DOC concentration using other water quality indicators to evaluate status of watershed management. In this study, DOC was estimated by correlation and regression analysis using three different organic matter indicators monitored in mixed land-use watersheds. The results of correlation analysis showed that DOC has the highest correlation with TOC. Based on the results of the correlation analysis, the single- and multiple-regression models were developed using Biochemical Oxygen Demand(BOD), Chemical Oxygen Demand(COD), and TOC. The results of the prediction accuracy for three different regression models showed that the single-regression model with TOC was better than those of the other multiple-regression models. The trend analysis using extended average concentration DOC data shows that DOC tends to decrease reflecting watershed management. This study could contribute to assessment and management of organic water pollution in mixed land-use watershed by suggesting methods for assessment of unmeasured DOC concentration.

• Journal of the Korean Society of Marine Environment & Safety
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• v.29 no.1
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• pp.24-35
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• 2023

Rapid industrialization and urbanization have led to severe marine pollution. A Water Quality Index (WQI) has been developed to allow the effective management of marine pollution. However, the WQI suffers from problems with loss of information due to the complex calculations involved, changes in standards, calculation errors by practitioners, and statistical errors. Consequently, research on the use of artificial intelligence techniques to predict the marine and coastal WQI is being conducted both locally and internationally. In this study, six techniques (RF, XGBoost, KNN, Ext, SVM, and LR) were studied using marine environmental measurement data (2000-2020) to determine the most appropriate artificial intelligence technique to estimate the WOI of five ecoregions in the Korean seas. Our results show that the random forest method offers the best performance as compared to the other methods studied. The residual analysis of the WQI predicted score and actual score using the random forest method shows that the temporal and spatial prediction performance was exceptional for all ecoregions. In conclusion, the RF model of WQI prediction developed in this study is considered to be applicable to Korean seas with high accuracy.

• Korean Journal of Ecology and Environment
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• v.41 no.4
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• pp.441-448
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• 2008

The purpose of this study was to analyze chemical water quality, fish trophic guilds, tolerance indicators, and fish community conditions in the Gap Stream and to compare the stream conditions between the unimpacted site and impacted site. This study was conducted in the physically stable season (May 2008) to minimize physical impacts such as flow and hydrological disturbance, and applied the study in the Gap Stream with two sites of unimpacted upstream site (Unim-S), mainly surrounded by forested area and impacted site (Im-S), influenced by the wastewater disposal plants and industrial complex in the urban region. Chemical data analysis showed that the degree of organic matter pollution, based on BOD, and COD, was $2{\sim}3$ fold greater in the Im-S than the Unim-S, and that TP, as eutrophication indicators, was 4.7 fold greater in the Im-S. Also, $NH_3-N$ was in 8.2 fold greater in the Im-S ($6.25\;mg\;L^{-1}$) than the Unim-S ($0.76\;mg\;L^{-1}$), indicating a massive influence of wastewater from the disposal plant. Similar results were found in other chemical parameters. Thus, chemical impacts in the Im-S were evident, compared to the unimpacted site. Evaluations of tolerant indicator species indicated that sensitive species were dominant in the Unim-S (23.9%) and tolerant species were dominant (97.8%) in the Im-S. Condition factor (CF) was averaged 0.95 ($0.68{\sim}1.18$) in the Unim-S and 1.08 ($0.93{\sim}1.22$) in the Im-S. Fish community in the Unim-S and Im-S was categorized as Zacco-community and Hemibarbus-community, respectively, and the community diversity index (H') was significantly (p<0.05) higher in the Unim-S (0.810) than the Im-S (0.466). Overall, our results suggest that the comparison approach of various chemical and ecological indicators provide important information in identifying multiple stressors in the stream ecosystems.

• ALGAE
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• v.26 no.3
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• pp.265-275
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• 2011

This study examined the bioaccumulation of the heavy metals copper (Cu) and zinc (Zn) by the giant kelp, Macrocystis pyrifera, by exposing meristematic kelp tissue to elevated metal concentrations in seawater within laboratory aquaria. Specifically, we carried out two different experiments. The first examined metal uptake under a single, ecologically-relevant elevation of each metal (30 ppb Cu and 100 ppb Zn), and the second examined the relationships between varying levels of the metals (i.e., 15, 39, 60, 120, 240, and 480 ppb Cu, and 50, 100, 200, 300, 500, and 600 ppb Zn). Both experiments were designed to contrast the uptake of the metals in isolation (i.e., when only one metal concentration was elevated) and in combination (i.e., when both metals' concentrations were elevated). Following three days of exposure to the elevated metal concentrations, we collected and analyzed the M. pyrifera tissues using inductively coupled plasma atomic emissions spectroscopy. Our results indicated that M. pyrifera bioaccumulated Cu in all treatments where Cu concentrations in the seawater were elevated, regardless of whether Zn concentrations were also elevated. Similarly, M. pyrifera bioaccumulated Zn in treatments where seawater Zn concentrations were elevated, but this occurred only when we increased Zn alone, and not when we simultaneously increased Cu concentrations. This suggests that elevated Cu concentrations inhibit Zn uptake, but not vice versa. Following this, our second experiment examined the relationships among varying seawater Cu and Zn concentrations and their bioaccumulation by M. pyrifera. Here, our results indicated that, as their concentrations in the seawater rise, Cu and Zn uptake by M. pyrifera tissue also rises. As with the first experiment, the presence of elevated Zn in the water did not appear to affect Cu uptake at any concentration examined. However, although it was not statistically significant, we observed that the presence of elevated Cu in seawater appeared to trend toward inhibiting Zn uptake, especially at higher levels of the metals. This study suggests that M. pyrifera may be useful as a bio-indicator species for monitoring heavy metal pollution in coastal environments.

• Journal of Environmental Science International
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• v.22 no.11
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• pp.1473-1479
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• 2013

Entropy is a measure of disorder or uncertainty. This terminology is qualitatively used in the understanding of its correlation to pollution in the environmental area. In this research, three different entropies were defined and characterized in order to quantify the qualitative entropy previously used in the environmental science. We are dealing with newly defined distinct entropies $E_1$, $E_2$, and $E_3$ originated from Shannon entropy in the information theory, reflecting concentration of three major green house gases $CO_2$, $N_2O$ and $CH_4$ represented as the probability variables. First, $E_1$ is to evaluate the total amount of entropy from concentration difference of each green house gas with respect to three periods, due to industrial revolution, post-industrial revolution, and information revolution, respectively. Next, $E_2$ is to evaluate the entropy reflecting the increasing of the logarithm base along with the accumulated time unit. Lastly, $E_3$ is to evaluate the entropy with a fixed logarithm base by 2 depending on the time. Analytical results are as follows. $E_1$ shows the degree of prediction reliability with respect to variation of green house gases. As $E_1$ increased, the concentration variation becomes stabilized, so that it follows from linear correlation. $E_2$ is a valid indicator for the mutual comparison of those green house gases. Although $E_3$ locally varies within specific periods, it eventually follows a logarithmic curve like a similar pattern observed in thermodynamic entropy.

• Korean Journal of Soil Science and Fertilizer
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• v.46 no.5
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• pp.327-332
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• 2013

This survey was conducted to obtain basic data about organic matter such as BOD (Biochemical Oxygen Demand), COD (Chemical Oxygen Demand), DOC (Dissolved Organic Carbon) and TOC (Total Organic Carbon) in agricultural water in Gyeongnam province. BOD and COD are currently used for water quality indices, but adoption of TOC is being suggested. The surface water samples were collected at 39 locations in Gyeongnam province in April, July and October. Average concentrations of BOD, COD, DOC and TOC were 1.6, 3.3, 5.3 and $5.7mg\;L^{-1}$, respectively. In July, average concentrations of BOD and COD were 2.4 and $3.9mg\;L^{-1}$, respectively, showing these values were higher than other months. Average concentrations of TOC in April, July and October were 4.8, 7.4 and $4.8mg\;L^{-1}$, respectively. This suggested that the highest value of TOC was in July. Average decomposition efficiencies for BOD-C/TOC and COD-C/TOC were 11.4 and 23.9%, respectively. Correlation coefficient of TOC and DOC was higher by 0.995, whereas that of TOC and COD was lower by 0.763. Especially, TOC and DOC were highly related than others.

• Journal of Environmental Health Sciences
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• v.42 no.5
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• pp.293-301
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• 2016

Objectives: This paper presents the current development progress of environmental health indicators (EHIs) in the Republic of Korea and discusses the utilization, limitations and prospects of EHIs. Methods: The development process and assessment criteria of EHIs were established based on the DPSEEA (Driving force-Pressure-State-Exposure-Effect-Action) framework with reference to that of the World Health Organization-Europe. In order to explore the applicability of EHIs, a case study was performed to compare the atmospheric environmental health status between the Republic of Korea and European region countries using six indicators. Results: Through the development process, 23 indicators in five areas including air quality, indoor air quality, climate change, chemicals, and water quality were developed, mostly using national statistical data. As a result of the case study comparing environmental health indicators in air quality between the Republic of Korea and Europe, it could be useful to understand the different situation of air pollution source, emission, exposure and health effects. Conclusion: In order for EHIs to compare environmental health status and be used as an environmental health policy development tool for vulnerable areas and related factors, it is necessary to develop further indicators for various issues other than air quality and conduct additional research on their interpretation and related implications, such as policy implementation effects.

• Journal of Environmental Health Sciences
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• v.42 no.4
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• pp.280-292
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• 2016

Objectives: The objective of this study was to build COD regression models for the Han River and evaluate water quality. Methods: Water quality data sets for the dry season (as of January) during a four-year period (2012-2015) were collected from the database of the Han River automatic water quality monitoring stations. Statistical techniques, including combined genetic algorithm-multiple linear regression (GA-MLR) were used to build five-descriptor COD models. Multivariate statistical techniques such as principal component analysis (PCA) and cluster analysis (CA) are useful tools for extracting meaningful information. Results: The $r^2$ of the best COD models provided significant high values (> 0.8) between 2012 and 2015. Total organic carbon (TOC) was a surrogate indicator for COD (as COD/TOC) with high reliability ($r^2=0.63$ in 2012, $r^2=0.75$ for 2013, $r^2=0.79$ for 2014 and $r^2=0.85$ for 2015). The ratios of COD/TOC were calculated as 2.08 in 2012, 1.79 in 2013, 1.52 and 1.45 in 2015, indicating that biodegradability in the water body of the Han River was being sustained, thereby further improving water quality. The BOD/COD ratio supported these findings. The cluster analysis revealed higher annual levels of microorganisms and phosphorous at stations along the Hangang-Seoul and Hantangang areas. Nevertheless, the overall water quality over the last four years showed an observable trend toward continuous improvement. These findings also suggest that non-point pollution control strategies should consider the influence of upstreams and downstreams to protect water quality in the Han River. Conclusion: This data analysis procedure provided an efficient and comprehensive tool to interpret complex water quality data matrices. Results from a trend analysis provided much important information about sources and parameters for Han River water quality management.

• Journal of Environmental Science International
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• v.13 no.5
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• pp.479-488
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• 2004

Five sediment cores from the tidal flat of artificial Lake Shihwa are analyzed in terms of sedimentology and geochemistry to evaluate the heavy metal contamination and redox condition of surficial sediment following the Shihwa seawall construction. The variability of concentrations of various elements depends on the depositional environment, and reflects the various redox conditions and sediment provenances. The amounts of Ti and Al and their ratio of Ti/ Al with respect to Li clearly indicate that there is an anthropogenic contribution to the surficial sediment. The high concentrations of heavy metals suggest an anthropogenic contribution at ST. 34 and ST. 22. Concentrations of most elements (Cr, Cu, Zn and Pb) are higher near the Shihwa-Banwol industrial complex than in the central part of Lake Shihwa. Concentrations of heavy metal in surficial sediment near the Shihwa-Banwol industrial complex are two to eight times higher than in the center of Lake Shihwa. Enrichment factors (EF), which are normalized by the unpolluted shale, suggests a significant metallic contamination near the Shihwa-Banwol industrial complex (SBIC). The redox condition is divided into two anoxic and mixed oxi $c_oxic zones based on the carbon:sulfur (C/S) ratios of organic matter and elemental relationships. Correlations among geochemical elements Mn, U and Mo are significantly different from site to site, and may therefore be an indicator of the spatial redox condition. Controlling factors for switching anoxic/oxic conditions are thought to be water depth and the differences in industrial effluent supply. The variations of the Cu/Mn ratio in the sediments confirms above mentioned spatial differences of a redox condition in part, and therefore shows a location-dependence redox condition in sediments at four other sites. The redox condition of the surficial sediment characteristics of the Shihwa Lake are controlled by its geographic location and water depth.th.

• Journal of Environmental Impact Assessment
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• v.27 no.2
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• pp.105-113
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• 2018

The modeling of noise mapping and the evaluation of noise pollution based on the exposed population were frequently used as an indicator of environmental noise assessment to overcome the limitations of field survey and Tele-Monitoring System. Results from these methods were highly influenced by the setting of noise source, input data of prediction factors and analytical methods of predictive values. The population exposed to noise were estimated as M1-1>M2-1>Base>M2-2>M1-2 in both areas. The highest noise setting methods(M1-1, M1-2) were overestimated, being compared with the Base method.