• Korean Journal of Ecology and Environment
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• v.49 no.4
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• pp.343-353
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• 2016

Oligochaetes distribute widely in freshwater ecosystem, and some species are used as bioindicators for water quality assessment because they are tolerant to organic enrichment. They are acknowledged for potential for environmental health recovery of organic polluted environment. There are a lot of studies on ecology and toxicity assessment using oligochaetes in aquatic environment. In this study, we reviewed literature on ecotoxicology of aquatic oligochaetes. We searched literature from a database 'google scholar' by using keywords such as aquatic, oligochaete, and toxicity. The literature were summarized according to publication years, species, test methods, and chemicals. We obtained 133 articles published from 1953 to 2015 from the database. Among them, 58 papers(43.6% of total) have been published in 1990s. Three species(Lumnbriculus variegatus, Tubifex tubifex, and Limnodrilus hoffmeisteri) have been used most frequently in the study. Different species displayed different toxicological responses to different toxic chemicals. The results on the ecotoxicological study with aquatic oligochaetes revealed the possibility of the development for early warning system using aquatic oligochaetes to monitor aquatic ecosystem disturbance.

• Journal of environmental and Sanitary engineering
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• v.21 no.2 s.60
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• pp.20-29
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• 2006

Analysis of benthic macroinvertebrate community and biological estimation of water quality by the benthic macroinvertebrates were conducted at Olympic Park at its nearby waters in Seoul from December, 2004 to September, 2005. The benthic macrovertebrates were 49 species. Among them, 39 species of aquatic insects were included 11 species in odonata, 9 species in diptera, 7 species in hemiptera, 6 species in coleoptera, 3 species in ephemeroptera, 2 species in trichoptera and 1 species in lepipdoptera, and 10 species of non-insects were 6 species in mollusca, 2 species in hirudinea and 2 species in oligochaeta. Species number of lakes, Seongnae Stream within and outside the Olympic Park was 25 species, 35 species and 33 species, respectively. Individual number of lakes, Seongnae Stream within and outside the Olympic Park was $131\;inds/2.5m^2\;239\;inds/2.5m^2\;556\;inds/2.5m^2$, respectively. Mean dominance indices of lakes, Seongnae Stream within and outside the Olympic Park was 0.74, 0.61 and 0.72, respectively. According to the saprobic system based on the ESB index(Ecological score of benthic macroinvertebrate community), all survey sites are $\beta-mesosaprobic$ waters. To increase of abundance of benthic macroinvertebrates, regular interval monitoring has to be enforced and standard of water quality for the ecological ponds of Olympic Park has to be prepared.

• Journal of Korean Society on Water Environment
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• v.35 no.5
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• pp.432-438
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• 2019

The purpose of this study is to predict Trophic Diatom Index (TDI) in tributaries of the Han River watershed using the random forest algorithm. The one year (2017) and supplied aquatic ecology health data were used. The data includes water quality(BOD, T-N, $NH_3-N$, T-P, $PO_4-P$, water temperature, DO, pH, conductivity, turbidity), hydraulic factors(water width, average water depth, average velocity of water), and TDI score. Seven factors including water temperature, BOD, T-N, $NH_3-N$, T-P, $PO_4-P$, and average water depth are selected by the Correlation Feature Selection. A TDI prediction model was generated by random forest using the seven factors. To evaluate this model, 2017 data set was used first. As a result of the evaluation, $R^2$, % Difference, NSE(Nash-Sutcliffe Efficiency), RMSE(Root Mean Square Error) and accuracy rate show that this model is compatible with predicting TDI. To be more concrete, $R^2$ is 0.93, % Difference is -0.37, NSE is 0.89, RMSE is 8.22 and accuracy rate is 70.4%. Also, additional evaluation using data set more than 17 times the measured point was performed. The results were similar when the 2017 data set were used. The Wilcoxon Signed Ranks Test shows there was no statistically significant difference between actual and predicted data for the 2017 data set. These results can specify the elements which probably affect aquatic ecology health. Also, these will provide direction relative to water quality management for a watershed that must be continuously preserved.

• Journal of Korean Society on Water Environment
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• v.31 no.3
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• pp.319-327
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• 2015

The present study was carried out to develop biological criteria for aquatic ecosystem health assessment using composition and diversity of collected species. The sampling sites were a total of 67 sites in the Han River (29 sites) and the Nakdong River (38 sites), May and September 2012. During the survey period fish were collected totally 93 species. In each water system, 73 and 61 species were collected in the Han River and the Nakdong River respectively. The current composition of fish species between the Han River and Nakdong River showed similar pattern. The dominant species was Zacco platypus of the Han River, and the Nakdong River was Opsariichthys uncirostris. In particular, ecological characteristics of O. uncirostris frequently appeared in general polluted waters. In conclusion, in the Nakdong River, average value of FAI (Fish Assessment Index) was averaged 41.3, indicating a "poor condition", and the Han River was 53.1, indicating a "poor condition". The aquatic health of the Nakdong River assessed based on FAI was considered to be worse than that of the Han River.

• Korean Journal of Environment and Ecology
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• v.22 no.5
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• pp.544-550
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• 2008

This study conducted a survey on the ecosystem of Wonju stream from May until November in 2004 and made an health assessment of Wonju stream using family biotic indices(FBI) and physical habitat assessment(PHA) of the aquatic insects. Through this survey, aquatic insects covering 8 orders, 37 families, 62 genuses, and 92 species were observed at 9 stations along Wonju stream. In terms of family biotic indices, it was confirmed that station 1,2 and 3 were maintaining the healthiest stream ecosystem with the value ranging from 4.55 to 4.82. In addition, station 2 was found to have the best habitat environment in the correlation between physical habitat assessment and family biotic indices with its value of 100 and 4.82, respectively. However, station 7 and 9 showed the lowest habitat environment with the value of 45, 6.17 and 45, 6.97, respectively. posing the need for improvement in PHA; further, station 7 and 9 showed inverted correlationship between PHA and FBI.

• Korean Journal of Ecology and Environment
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• v.45 no.4
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• pp.474-481
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• 2012

This study was performed to investigate the degree of long-term pollution at the mainstream of the Han River by comparing the concentration of BOD and COD from 1975 to 2011. The long-term annual average BOD and COD concentration at the mainstream of the Han River showed an increasing trend as it flowed downstream from Paldang Dam to Gayang. The concentration of BOD ($r^2$=0.646) and COD ($r^2$=0.260) showed a consistent decreasing trend for 37 years. In the case of Paldang Dam, BOD has maintained a decreasing trend, whereas the COD value showed an increasing trend after the 1990s. Therefore, a control of non-biodegradable materials in areas around Paldang Dam is required. The result of the seasonal variations of BOD and COD is as follows: spring>winter>summer and fall (p<0.001). The time series analysis revealed a strong correlation for every 12-month period. Also, the amount of water discharge at Paldang Dam has to be systematically controlled because the amount of water discharge from the dam influences the water quality at the mainstream of the Han River.

• Journal of Ecology and Environment
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• v.38 no.4
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• pp.541-544
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• 2015

We report the status of wetland vascular plant species in Korea including the whole peninsula and its adjacent islands. This analysis was based on database from our previous categorized list. In all, 4,050 taxa have been reported, including 3,769 native and 281 naturalized. Of these, 479 taxa (12%) are considered as wetland vascular indicator species: 240 obligate wetland plants (OBW) and 239 facultative upland plants (FACW). Approximately 31% of those 479 taxa, i.e., 149 taxa, are labelled as aquatic macrophytes. Wetland plants, mostly herbaceous but some woody, inhabit aquatic bodies and wet meadows. Except for two OBW and six FACW taxa, the rest of the plants are summer-green only. The information provided here is valuable for making assessments of wetland ecosystem health, as well as for developing management plans to preserve and restore wetlands and their resident plant species while also creating artificial wetland environments.

• Journal of Environmental Health Sciences
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• v.37 no.2
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• pp.113-123
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• 2011

Objectives: Industrial development in Korea results in a rapid increase in the number of chemicals, some of which may be responsible for toxicity to aquatic ecosystems. In addition, the types of hazardous chemicals included in industrial effluents have gradually increased. Therefore, chemical analysis alone is not enough to assess ecological effects of toxic chemicals in wastewater. Methods: In response to new regulations as whole effluent toxicity (WET) tests for effluent discharge of 15 publicly owned treatment works (POTWs) and 25 industrial effluent treatment plants in Gyeonggi-do, which will be effective from 2011, a necessity of studies emerges that investigates toxicity levels. Results: In case of the public treatment plants, none of them had exceeded the criteria for ecotoxicity. As for individual wastewater discharge facilities, on the other hand, two types were found to exceed the criteria: pulp and paper manufacturing facilities and pharmaceutical manufacturing facilities. For the pulp and paper manufacturing facilities, monitoring results could not help determine the exact toxicant identification. However, Daphnia magna inhibition effect or death was found to leave white plums, suggesting that suspended solids treated and the polymer used in coagulant dose. In case of pharmaceutical manufacturing facilities, the general water quality parameters cannot affect Daphia magna. However, conductivity and salinity can have an effect to be 14,000 ${\mu}s/cm$, 8.1‰ by salts, respectively. Toxicity Identification Evaluation (TIE) and Toxicity Reduction Evaluation (TRE) procedures results appeared to be effective for identifying toxic compounds in $Cl^{-}$ and $SO_4^{2-}$. Conclusions: It is necessary to develop control measures for water treatment chemicals and salts used for processes such as coagulation in individual wastewater discharge facilities in order to achieve the goal to protect aquatic ecosystems in public waters.

• Korean Journal of Ecology and Environment
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• v.56 no.4
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• pp.414-419
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• 2023

Aquatic ecosystem is composed of various organic and inorganic matters. Its health is essential for sustaining its members such as vegetations, mammals, birds, fishes and invertebrates. Samcheonpo stream is one of candidate streams in Sacheon area of ecological restoration. For this reason, this study conducted to build up a data base for future comparison. The results shows that biodiversity of Epilithic Diatoms and Invertebrates is below average which means that human impacts such as artificial structures and activities have been negatively related to stream health. Consequently, we suggest several key factors when ecological restoration is performed in the stream.

• Korean Journal of Ecology and Environment
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• v.51 no.4
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• pp.311-321
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• 2018

The purpose of this study is to investigate effect of stream channel naturalness on ecological health by using environmental factors and Fish Assessment Index (FAI) in the Han River of South Korea. These samples and data have been released from the research project titled Stream/River Ecosystem Survey and Health Assessment, which was conducted in 444 sites in the Han river watershed from 2008 to 2016. All samples were classified into five groups according to a degree of morphological changes of stream. Water chemistry analyses indicated a decline in water quality by decreasing stream channel naturalness, it is assumed that channelized stream was vulnerable to aquatic pollution compared to the natural meandering stream. In the result of frequency of dominant species, sensitive species and insectivore such as Zacco koreanus, Rhynchocypris kumgangensis and Pungtungia herzi were frequently dominated in the natural meandering stream while tolerant species and omnivores such as Carassius auratus and Cyprinus carpio were more dominated in the channelized streams. The FAI in the channelized stream shows decline to average of $46{\pm}25$ compared with that of the natural meandering stream ($80{\pm}20$). The decrease in FAI was highly influenced by changes in matrixes of fish assemblage structure such as number of sensitive species (M3), portion of omnivores (M5) and insectivores (M6). Moreover, annual average FAIs from 2008 to 2016 were significantly correlated with water chemistry, especially TN, TP and BOD ($r^2=0.59$, p<0.0001). Taken together, all the results suggest that the stream channelization could negatively impact on the water quality and fish assemblage structure, leading to degradation in aquatic ecosystem health.