• Parasites, Hosts and Diseases
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• v.21 no.2
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• pp.193-204
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• 1983

The Jinyang Lake is dammed up Nam River, and surrounded by Jinju city and four counties; Jinyang, Sanchong, Hading, and Sachon in kyongsang-Nam-Bo, Korea. The areas around this man-made lake have been known as an endemic focus of clonorchiasis in Korea. The present study was first aimed to know the distribution of freshwater mollusks including medically important snails, and larval trematodes shed from Parafossarulus manchouricus and Semisulcospira libertina. In addition to above studies, water analyses in each snail habitat were carried out in order to figure out a part of their environmental factors. This malaco-ecological survey was done at the sirs areas around upper, middle and lower parts of the lake for 4 months, August-November, 1983. Total nine species of freshwater mollusks were collected throughout the study: 4 species of gastropods: Semisulcospira libertina, Cipangopaludina chinensis, Parafossarulus manchouricus and Radin auricularia, and 5 species of bit.alves; Unio dcuglasiae, Ancdonta woodiana, Lamprotula gottschei, Corbicula yuminea and Limncperma lucustris. Out of nine species of freshwater mollusks, three species of gastropods; S. Zibertina, p. manchouricus and R. auricularia were medically important in terms of the transmission of digenetic trematodes to humans. P. manchouricus and R. auricularia were mainly collected from the shallow ponds and the irrigation channels with the muddy basin, but S. libertine and the bivalves were only collected from the stream of Nam River where the gravels and rocks were dominant. The levels of dissolved oxygen (D.O.) and biochemical oxygen demand \(B.O.D._5)\ of the water specimens sampled from the study areas ranged from 6.0 to 9.6 ppm and from 0.4 to 1.6 ppm respectively. As a result, it is considered that water system around the Jinyang Lake might be relatively clean without any heavy pollution of aquatic microorganisms and organic materials during the period of this study. On the other hand, eight metalic constituents from the water samples were also assayed, and all metalic ions detected were remarkably low below the legal criteria. However, calcium ion in the water samples from the habitats of P. manchouricus was considerably higher than others. Infection rates of digenetic trematodes in the snails were 6.9% in P. manchouricus and 4.8% in S. libertine, respectively. P. manchouricus snails harboring with thc cercariae of Clonorchis sinensis were only 0.14% among the snails examined, and other trematode cercariae except cercaria of C. sinensis were: furcocercus cercariae, cercaria of Loxogenes liberum type I and II. S. libertine snails parasitized with the cercariae of Metagonimus yokogawai were 1, 5% out of the snails examined, and no cercaria of Paragonimus westermani was found in S. libertine snails in the present study. Digenetic trematode cercariae other than M. yokogawai observed in S. libertina snails were: Cercaria yoshidae (B type) , Cercaria cristata, Cercaria innominatum, Cercaria of Centrocestus formosanus and Cercaria nipponensis.

• Journal of Environmental Science International
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• v.27 no.6
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• pp.411-423
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• 2018

To investigate the distribution characteristics of grain size and organic matter of surface sediments from the Nakdong-Goryeong Mid-watershed, surface sediments were collected and analyzed. The samples were collected from six sited at four different times between May 2013 and May 2014. The were analyzed for grain size, water content, ignition loss, chemical oxygen demand, total organic carbon and total nitrogen. The surface sediments were mainly composed of medium sand (mean 44.7%) and coarse sand (mean 32.8%) and became coarser in May 2014. Fine sediments at the site NG-2 were poorly sorted and positively skewed, and occur in a tributary environment that is relatively low-energy compared with the other sites. The water content at the studied sites (15.3 ~ 34.9%) averaged 20.25%, and ignition loss (0.4 ~ 5.8%) and total nitrogen (274 ~ 2493 mg/kg) averaged 1.33% and, 696 mg/kg, respectively. These values indicated that the sediments were not seriously contaminated when compared with the sediment pollution evaluation standard of the National Institute of Environmental Research. The chemical oxygen demand (mean 0.17%) was at the non-polluted level compared with United States Environmental Protection Agency sediment quality standards. The total organic carbon (mean 0.18%) at all sites except site NG-2 (lowest effect level) was the no effect level of the Ontario sediment quality guidelines. The COD/IL (0.02 ~ 0.20) and C/N (0.73 ~ 6.76) were less than 1 and 10, respectively. Organic matter in the study area produced naturally from aquatic organisms. Results of principal component analysis showed that fine sediments (very fine sand and silt) were significantly affected by organic matters (ignition loss, chemical oxygen demand, total organic carbon and total nitrogen). In addition, the highest organic matters content in the study area occurred at the site with the finest sediments (NG-2).

• Korean Journal of Environmental Biology
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• v.37 no.2
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• pp.204-216
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• 2019

To evaluate the biological integrity of aquatic ecosystems, we developed Korean multimetric diatom index (KMDI) using metrics that many researchers have been previously described, and compared to single-metric diatom index such as trophic diatom index (TDI) and diatom assemblage index to organic pollution (DAIpo). For the biological and environmental data, we investigated the epilithic diatoms, water quality and the land-use for 923 sites in Korean streams between 2013-2017, and estuaries between 2010-2017, respectively. Five appropriate metrics were selected according to the following steps; 1) extraction of 300 potential metrics (biological, chemical, physical, and geographical) based on previous references, of these, 2) 46 samples having high separation power were selected, 3) the selected metrics were each tested for variability, redundancy, and sensitivity to the environments, finally 4) construction of multi-metric diatom index comprising single type metrics such as TDI, DAIpo, % motile diatoms, % Achnanthes / (Achnanthes+Navicula), and % number of Gomphonema species. The biological integrity of the 233 sites from the Geum River basin were independently investigated using KMDI. Collectively, the new KMDI showed high sensitivity and explanatory power for environmental factors such as land-use, biochemical oxygen demand, total nitrogen, and electric conductivity. However, it had slightly higher biological integrity for the same sites as compared to single type diatom metrics. Finally, more data accumulation from all over Korea and the development of acceptable diatom metrics were required.

• Journal of Environmental Impact Assessment
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• v.27 no.1
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• pp.83-91
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• 2018

Media (bio-stone), aquatic macrophytes (Oenanthe javanica) and herbivorous cladoceran (Daphnia similoides) have been used in artificial floating island (AFI) systems for water pollution control. Efficiency in chl-a concentration controlling of AFI was tested using different combinations of each device: G-BD-mixture bio-stone and Daphnia similoides, G-OB-mixture Oenanthe javanica and bio-stone, G-BOD-mixture bio-stone, Oenanthe javanica and Daphnia similoides, and the out-put water quality improvement was compared with G-C-control (no device was applied). We analyzed removal efficiency of chl-a concentration and nutrient concentrations in the artificially eutrophic water in the laboratory experimental facility. The results showed average removal rates of Chlorophyll a, TN and TP for different four groups: 69.24%, 16.61%, -0.61%; 68.39%, 14.11%, 10.52%; 78.30%, 6.69%, 25.09%; 35.42%, -3.47%, -25.18%, respectively. The results have suggested that the mixture of media, plants and zooplankton is the most efficient combination for Chlorophyll a control, while the mixture of macrophytes and bio-stone have better efficiency nutrient control.

• Korean Journal of Ichthyology
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• v.30 no.2
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• pp.100-106
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• 2018

The distribution aspect and extinction threat evaluation of the endangered species, Rhodeus pseudosericeus were investigated from 2012 to 2017 in Korea for the subject of this study. The number of appearance sites in the past literature of available and identified R. pseudosericeus was 26. During the study period, the samples of R. pseudosericeus were collected in 44 sites (Hangang River 35 sites, Sapgyocheon Stream 4 sites, Daecheoncheon Stream 5 sites) among the noted 214 sampling stations investigated. Among these, the newly appearance streams were Ilricheon Stream, Samsancheon Stream, Bangyecheon Stream and Hanpocheon Stream in the Hangang River. In addition, the habitats and populations in the upper Seomgang River (Hoengseong Dam), lower Heukcheon Stream, Muhancheon Stream and Daecheoncheon Stream decreased due to dam construction, river work, water pollution, and the spread of the exotic species Micropterus salmoides. The main habitat of R. pseudosericeus was the middle-upper stream of clean water with slow water velocity, sand-pebble bottoms and lots of aquatic plants. Given this evidence as noted for the 30.2% reduction in occupancy within 10 years, due to the qualitative decline of habitat, the overfishing risk of ornamental fish and the spread of M. salmoides, in this case R. pseudosericeus is considered to be Vulnerable (VU A2cde) based on the IUCN Red List categories and criteria.

• Journal of Environmental Science International
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• v.2 no.2
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• pp.153-160
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• 1993

The problem of supply and transport of sediment from a mountainous catchment is very important in explaining dynamic geomorphology and the hydrological cycle. The discharge of suspended sediment is determined by a morphological system. Human interference to environment Is also an important, not negligible factor in sediment production. Moreover, growing concern in recent years for the problems of nonpoint pollution and for the transport of contaminants through terrestrial and aquatic ecosystems has highlighted the role of sediment-associated transport in fluvial systems. This study was conducted in forested and quarried catchments in order to clarify the different discharge process and the mechanism of suspended sediment dynamics for each catchment. As a forested catchment, the Yamaguchi River catchment which drains a $3.12km^2$ area was chosen. On the other hand, the Futagami River basin which is formed by three subbasins (1.07, 1.59 and $1.78km^2$), as a quarried catchment was selected. These catchments are situated to the north and east of Mt. Tsukuba, Ibaraki, Japan. The discharge pattern of suspended sediment from the Futagami River basin is more unstable and irregular than that from forested catchment, the Yamaguchi River catchment. Under the similar rainstorm conditions, suspended sediment concentration from quarried catchment during a rainstorm event increases from 43 to 27,340 mg/l. However, in the case of the forested catchment it changes only from nearly zero to 274 mg/l. Generally, the supply source of suspended sediment is classified into two areas, the in-channel and non-channel source areas. As a result of field measurements, in the case of the forested catchment the in-channel (channel bed, channel bank and channel margin) is the main source area of suspended sediment. On the other hand, remarkable sediment source area on the Quarried catchment is the non-channel that is unvegetated ground.

• Korean Journal of Ecology and Environment
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• v.36 no.2 s.103
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• pp.172-180
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• 2003

For a biological assessment of Pyeongtaek Reservoir and its major influent streams, an algal growth potential test (AGPT) was conducted with the blue-green algae Microcystis aeruginosa in March, June, September and December, 2000. The range and average value of AGPT were from 0 to 463 mg dw/l and 90 mg dw/l, respectively. For the influent streams in particular, the average of AGPT was the in the Hwangguchi Stream (343 mg dw/l). It decreased to 158, 66, 29, 21, and 21 mg dw/l in the Sojong Stream, Songhwan Stream, Osan Stream, Chinwi Stream, and Ansong Stream, respectively. The AGPT values in the reservoir ranged from 0 to 138 mg dw/1(mean 54 mg dw/1) with a tendency to increase in the upstream, which was close to the influent streams. In general, the AGPT values decreased further in the downstream. Immediately after the abrupt increase in influent discharge in summer, the AGPT value in the downstream almost doubled due to the proliferation of blue-green algae. The water quality of Pyeongtaek Reservoir and its influent streams further deteriorated during the drought period. Similarly, the AGPT value was the highest during this period. The AGPT values showed the closest correlation with the content of P (r = 0.999, p<0,001). Thus, it could be concluded that the content of P is highly effective in the growth of algae. In the Pyeongtaek Reservoir Watershed, the AGPT values varied in space and time. It was also closely related to the nutrient content of influent streams. The AGPT values revealed that the water quality state was hypertrophic (> 20 mg dw/1). Thus, control of the aquatic environment is essential. AGPT is very useful in evaluating the fertility and pollution state of the water as well as determining the nutrients that limit the growth of algae.

• Journal of Food Hygiene and Safety
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• v.17 no.3
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• pp.137-145
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• 2002

Tributyltin compounds have been increasingly used in the form of plastic stabilizers, catalytic agents, industrial agricultural biocides, antifouling paint, and pesticides. Among these organotin compounds, large amounts of tributyltin(TBT) and triphenyltin(TPT) have been used as antifouling agents because they have a superior ability to prevent marine organism from being encrusted on ship bottoms and in culturing nets. Environmental pollution by these organotin compounds in the aquatic environment were undertaken. The international maritime Organization's established a provisional tolerable daily intake(TDI) of 1.6[micro]g TBTO/kg/ B.W. The Food and Agiculture Organization (of the United Nations)/world Health Organization's (FAO/WHO) proposed a TDI of 0.5ug TPT/kg BW/d. This study is conducted monitoring of TBT on seafoods in Korea and risk assessment for exposure on TBT in seafoods. Total hazard index(using Reference Dose : 0.3 ug TBTO/kg B.W/day) of intake exposure on seafoods is 0.04 as the 50th percentile, 0.08 as the 95th percentile. This value is estimated by Monte-Carlo simulation using Crystal Ball(Decisioneering Co., 2001).

• Journal of the Korean Society of Environmental Restoration Technology
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• v.22 no.3
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• pp.15-30
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• 2019

Changpo Lake was created as a part of a land reclamation for refugee self-helping projects. It shows characteristics of a fresh water lake, and still retains the early appearance of reclamation that surrounding regions have not been developed into farm lands. Shallow wetland has formed around the lake, which provides great conditions for diverse lives, and surrounding earthiness is favorable for growth of vegetation and restoration of the ecosystem. However, as facilities of the Muan International Airport nearby Changpo Lake are expanding and barns are being constructed, artificialness is gradually increasing. Particularly, since pollution sources such as sport facilities, farm lands and barns are scattered around Changpo Lake, pollutants are flowing in constantly. Accordingly, the results for setting up management areas according to the spatial characteristics and creating natural ecological spaces near Changpo Lake, Taebongcheon stream and Hakgyecheon stream are as follows. First, the creation of a natural eco-friendly waterfront space should be promoted by securing the health of the aquatic ecosystem and restoring species and the ecosystem. In addition, a consultative body needs to be formed to lead local residents to participating in river investigation and monitoring, maintenance, and management through role sharing. Second, the basic direction of the spatial management plan is to keep the unique charm of Changpo Lake, maintain harmony with nature, create diverse waterfront areas, and secure the continuity of Changpo Lake and inflow streams. Moreover, the area should be divided into three zones such as a conservation zone, a restoration zone and a waterfront zone, and for each zone, the preservation of vegetation, the creation of ecological wetlands and restoration of the ecotone and ecological nature need to be promoted. Third, facilities and activity programs for each space of Changpo Lake should be operated for efficient management of protected areas. In order to suit the status of each space, biological habitats, water purification spaces, experiential and learning spaces, and convenience and rest spaces should be organized and designated as research, monitoring, education, and tourism areas. Accordingly, points of interest should be set up within the corresponding area. In this study, there are many parts that need to be supplemented for immediate implementation since the detailed plans and project costs for the promotion of programs by area are not calculated. Therefore, it is necessary to make detailed project plans and consider related projects such as water quality, restoration of habitats, nature learning and observation, and experience of ecological environments based on the categories such as research, monitoring, education and tourism in the future.

• Journal of Environmental Impact Assessment
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• v.30 no.1
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• pp.1-12
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• 2021

This study focused on verifying the identification of freshwater fish species in Korea using Environmental DNA (eDNA) technique. The research of DNA is increasing in the field of ecology, since this is more sensitive of identify rather than traditional investigation method. Which is difficult to detect species hidden in water and be easily influenced by diverse factors (sites, bad weather, researchers and so on). We applied the pilot test in aquarium (Freshwater Fish Ecological Learning Center in Yangpyeong, Gyeonggi Do), where freshwater fish species are inhabits. We conducted to sampling and analyzing the sixteen water samples (50 species from 7 orders and 13 families) using MiFish primer set. The results showed that 45 species (90%) was investigated by eDNA. It highlight that eDNA with universal primer is possible to detect freshwater fish species of Korean. However, the errors on species identification seems to be caused by the primer that be not suited perfectly and the pollution such as aquarium, sampling collectors.