• Fisheries and Aquatic Sciences
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• v.6 no.4
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• pp.225-227
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• 2003

Acetylcholinesterase (AChE) activity is a potential biomarker for phenanthrene exposure in aquatic organisms. Olive flounder (Paralichthys olivaceus) were exposed to three different concentrations (0.5, 1.0 and 2.0, uM) of phenanthrene for four weeks. AChE activities in the brain, heart and eyes were documented. Inhibition of AChE activity was found significant in flounder treated with a concentration greater than $1.0 {\mu}M$ of phenanthrene. This indicates that a chronic exposure to phenanthrene induces damage in various organs (brain, heart and eyes) and changes of AChE activities might be a useful biomarker to assess the impacts induced by polycyclic aromatic hydrocarbon (PAH). Evidence from this study confirms that the measurement of AChE in the brain and eyes of flounder is a valuable tool that along with other biomarkers can maximize an ecotoxicologists' confidence in assessing the impacts of oil and PAH pollution in the aquatic environment.

• Korean Journal of Ecology and Environment
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• v.52 no.1
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• pp.1-8
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• 2019

River water quality and organisms have a very close relationship with the human living environment and health, so it is very important to ensure and maintain the ecological integrity of the aquatic ecosystem. In that sense, benthic diatoms have relatively little mobility, can explain the effects of long-term exposed pollution sources, and are very suitable indicator organisms for river ecosystem evaluation. Diatom ecologists have been developed various diatom indices to assess water quality and stream ecosystem over the world. However, they so far have insufficient identification of taxa, are strongly regional, and are difficult to apply as they are domestically. Unfortunately, there has not been developed an independent diatom index suitable for the Korean stream. Therefore, management of water quality and aquatic ecosystem suitable for domestic rivers can be made, and development or improvement of comprehensive multivariate diatom index for the integrated assessment of water quality and aquatic ecosystem is urgently needed.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.34 no.6
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• pp.666-671
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• 2001

To investigate the food organisms and feeding selectivity of slimy (Leiognathus nuchalis) during the postlarval stage, the gut contents of the fish, captured in Kwangrang Bay in 1995, were observed. The food organisms in the gut were composed of copepod egg and nauplius, Tintinnopsis spp. and Codonellopsis sp. The indices of relative importance (IRI) indicated that Tintinnopsis spp. was the most dominant food item ($80.6\%$), and copepod nauplius was the next ($18.5\%$). Tintinnopsis spp. was the most favorite food item: it occupied $73.8\%$ of gut contents, though it did $39.2\%$ of microzooplankton in the surrounded water. The composition of copepod nauplius was higher in the larvae shorter than 2.0 mm NL. As slimy larvae grew, the size of food organisms in the gut was not changed, and their number increased, and the selectivity for food items increased.

• Fisheries and Aquatic Sciences
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• v.4 no.4
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• pp.219-228
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• 2001

Surface sediments (0- 5 cm), mussels (Mytilus coruscus and M. edulis) and oysters (Crassostrea gigas) were sampled at 20 stations in Korean coast during a period of February to July 2000. Samples were analyzed for polycyclic aromatic hydrocarbons (PAHs) content using gas chromatography coupled to mass spectrometer detector (GC/MSD). The sediment $\sum PAH$ concentration varied from 7 to 1,214 ng/g dry weight and the level of carcinogenic PAHs of six species ranged from 1 to 563 ng/g dry weight in surface sediments. In organisms, the levels of $\sum PAH$ were in the range of 63-876 ng/g dry weight and the concentrations of carcinogenic PAHs of six species were in the range of 4-582 ng/g dry weight. The highest PAH concentrations in sediments and organisms were in samples from Station 5 in Pohang coast and Station 8 in Jinhae coast, respectively. $\sum PAH$ concentrations in sediments and organisms collected from Korean coast were slightly low or comparable to those in other countries. The contribution of ring aromatic groups to sum of 16 PAHs in sediments and organisms showed a similar pattern for most stations. In sediments, the predominant contributions were four and five ring aromatics like fluoranthene, pyrene, benzo[a]anthracene, chrysene, benzo[b]fluoranthene, benzo[k]fluoranthene and benzo[a]pyrene. In the organisms, four ring aromatics like fluoranthene, pyrene, benzo[a]anthracene and chrysene were predominant PAH species. Several molecular indices such as phenanthrene/anthracene, fluoranthene/pyrene and LMW/HMW ratio were used to identify the origin of PAH contamination in sediments. The results indicate that PAHs of Korean coast were mainly of pyro1ytic contaminants with slight petrogenic input. A high correlation within individual PAH compound in marine sediments was observed, while correlation in organisms showed a highly significant relationship for heavier molecular weight PAHs.

• Korean Journal of Environmental Agriculture
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• v.36 no.2
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• pp.80-86
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• 2017

BACKGROUND: Pesticides is exposed in an aquatic environment and effected to benthic animals. Especially, sediment-associated pesticides is required for determination of sediment toxicity on aquatic organisms. This study was conducted to evaluate the impact of six pesticides (chlorfluazuron, difenoconazole, dithianon, flufenoxuron, flutianil, pendimethalin) on Chironomus riparius in aquatic ecosystems. METHODS AND RESULTS: Chlorfluazuron, difenoconazole, dithianon, flufenoxuron, flutianil and pendimethalin were used as a model compounds, which have a sediment-associated potential ($K_{oc}$>3). Acute and chronic toxicity tests on Chironomus riparius were performed at six concentrations of each pesticide with four replicates of each based on OECD test guideline 235 and 218. The calculated 48-h $EC_{50}$ values of chlorfluazuron, flutianil, pendimethalin, difenoconazole, dithianon and flufenoxuron were 6.72, 2.55, 2.27, 0.77, 0.30 and 0.11 mg/L, respectively. Flufenoxuron was the lowest 48-h $EC_{50}$ value in this study. The No Observed Effective Concentration (NOEC) and the Lowest Observed Effect Concentration (LOEC) of flufenoxuron for Chironomus riparius in 28-days test were 30 and $60{\mu}g/kg$, respectively. CONCLUSION: Pesticides of the sediment-associated have the potential effect for Chironomus riparius in aquatic ecosystems. Therefore, sediment toxicity assessment of these pesticides should be further investigated to evaluate the impact to benthic organisms.

• Korean Journal of Environmental Biology
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• v.36 no.2
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• pp.99-106
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• 2018

Extensive monitoring of aquatic organisms in rice paddy fields has been difficult due to laborious sampling methods such as quadrat sampling using a hand net. This study aimed to analyze temporal and regional community compositions of aquatic organisms collected with a less time-consuming sampling method. This method involved using submerged funnel traps in rice paddy fields. Submerged funnel traps were useful for capturing taxa containing species that are indicative of environmental changes and highly mobile species that feed on waterbirds. Fifteen taxa including Ampullariidae, Cobitidae, Chironomidae, Hydrophilidae and Dytiscidae determined the community compositions. Among the major taxa, only Chironomidae resistant to environmental disturbances represented temporal variations of aquatic organism communities in rice paddy fields. Ampullariidae, Dytiscidae, and Hydrophilidae, which are prone to be affected by anthropogenic activities, differed among regions.

• Proceedings of the Korea Society of Environmental Toocicology Conference
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• 1993.06a
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• pp.4-5
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• 1993

Toxicity tests in our laboratory are conducted usually with mass-reared organisms. They are under the same environmentel conditions throughout seasons and are supplied at specific age. A total of 38 species of aquatic organisms are being reared. We have attempted to establish pruified strains or to select clones of various parthenogenic organisms. The merits or demerits of our culturing test organisms are discussed. The differences in the susceptibility among clones or strains of test organism are also discussed. For a single species test, algae, daphnia, fish are often used. However, we usually use early stages, but occasionally, adults fish are used for reproduction tests. As an another important aspect, the toxicity through food chains has been studied. In this study, we select a pair of species belonging different trophic levels. The differences between single species tests and multispecies tests will be discussed. Even a single species test intends to assess the effects of chemicals on ecosystem levels, however, this idea is not applicable to ecosystems. Single species tests with standard organisms and multispecies tests are contradictory in concept. One type of multispecles tests is indoor microcosms being composed of severel species artificially assembled, and another is composed of natural components (both indoor and outdoor). We have used three types of outdoor mesocosms using ponds and three types of artificial streams. The mesocosms is useful to not only to analyze the floral or faun61 changes but also to study the fate or behaviour of chemicals in naturd environments. Lastly, usefulness of the field observation or experiments or semi-field experiments will be discussed. This will enhance the exploitation of early warning systems utilizing indicator organisms or animal behaviour.aviour.

• Proceedings of the Korean Society of Toxicology Conference
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• 2003.10b
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• pp.106-106
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• 2003

Many polycyclic aromatic hydrocarbons (PAH) are acutely toxic to fish and other aquatic organisms in the presence of environmentally realistic intensities of solar ultraviolet radiation (SUVR). The phototoxicity of polycyclic aromatic hydrocarbons (PAHs) occurs through photodynamic activation of PAH compounds. Oxygen molecules react as quenchers with excited triplet states of PAHs producing reactive oxygen species (ROS).(omitted)

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2019.05a
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• pp.355-356
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• 2019

• Journal of Korean Society on Water Environment
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• v.24 no.5
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• pp.592-597
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• 2008

Current water quality standard (WQS) in Korea is based on the protection of human health, not considering the protection of aquatic organisms. Most of chemicals can be toxic to ecological biota as well as human. Health of aquatic biota is closely related to the human health via food chain, therefore ecological risk based-WQS needs to be developed to protect the aquatic ecosystem. In this study, we selected the 31 chemicals in the Project entitled 'Development of integrated methodology for evaluation of water environment'. The methodology for calculating water quality criteria was derived from the Australian and New Zealand processes for deriving guideline trigger value for aquatic ecosystem. The available ecotoxicity data were collected from US EPA's ECOTOXicology Database (ECOTOX), TOX-2000 Database, European Chemicals Bureau (ECB)'s International Uniform Chemical Information Database (IUCLID) and Environmental Protection Agency (US EPA)'s report 'Ambient Water Quality Criteria (AWQC)'. The aquatic toxicity data for the Korean species were selected for risk assessment to reflect the Korean water environment. The monitoring values were calculated from the water quality monitoring data four main Korean rivers. We suggested the order of priorities of chemicals based on ecological risk assessment. We expect that these results can be useful information for establishing the WQS for the protection of aquatic ecosystem.