• Journal of Environmental Health Sciences
• /
• v.42 no.1
• /
• pp.10-18
• /
• 2016

Objectives: Microcystin (MC) produced during cyanobacterial blooms is a worldwide problem presenting a serious health threats to humans and ecosystems. During July through October of 2013, the Ilwol Reservoir experienced a high biomass of phytoplankton (maximum $211.7mg/m^3$ of Chlorophyll-a) containing the toxigenic cyanobacterium Oscillatoria sp. The aim of this study is to analyze MC concentration in the reservoir water, as well as in representative fish species (Carassius cuvieri, Carassius auratus, Channa argus). We also evaluated the human health risk of exposure to MCs accumulated in the fish. Methods: Concentrations of MCs in the water and fish samples were analyzed by liquid chromatography with a triple quadrupole tandem mass spectrometer (LC/MS/MS) and enzyme-linked immunosorbent assay (ELISA). Results: The total levels of four MC variants, including MC-LR, MC-RR, MC-YR and MC-LA were below the WHO drinking water guideline limit (1 ug MC-LR per liter) both for the dissolved and particulate fraction present in the water samples. The mean MC concentrations in the livers of all species were significantly higher than in the gills (p < 0.01) and muscles (p < 0.05). The values of estimated daily intake of MCs in muscles, the edible part of the fish, would be only $0.005-0.015{\mu}g/kg{\cdot}day$, much lower than WHO's provisional tolerable daily intake of $0.04{\mu}g/kg{\cdot}day$. Conclusion: This study suggests that, owing to the spatial distribution or temporal variation of MC, there is a need for careful monitoring of cyanotoxin in reservoir water and aquatic animals to protect public health.

• Korean Journal of Ecology and Environment
• /
• v.42 no.3
• /
• pp.331-339
• /
• 2009

This study evaluated the potential human health risk on the basis of the level of bioaccumulation and EDI (Estimated Daily Intake) of microcystin-LR, one of hepatotoxic, in organs, including liver, muscle, viscera and gill, of fish from Lake Yeongeheon and Lake Daecheong when the cyanobacterial water-blooms broke out. The result has confirmed that Carassius cuvieri from Lake Yeongcheon contains higher level of microcystin-LR in its organs including liver. In Lake Daecheong, omnivorous Hemibarbus labeo and phytoplanktivorous Carassius cuvieri have shown high microcystin-LR level on average, especially higher for viscera, and Carassius cuvieri has appeared to contain higher level of microcystin-LR in the liver and the gill compared with other species. As a result of comparison between EDI of microcystin-LR from each organs and TDI (Tolerable Daily Intake) of WHO (Chorus and Bartram, 1999) to evaluate human health risk, the EDI levels from Carassius cuvieri's organs except museles have exceeded TDI level at the both lakes. Consequently, the study has proved that microcystin was bioaccumulated in the various parts of fish, and it can be ingested by human resulting in risking human health. Continuous monitoring and reducing consumption of fish, especially Carassius cuvieri, during the cyanobacterial water-blooming period will be needed to protect human health.

• Journal of Korean Society on Water Environment
• /
• v.30 no.5
• /
• pp.539-548
• /
• 2014

This study was carried out to investigate algal community structures and their correlations with environmental factors on five weir areas in the Nakdong River, South Korea. Water qualities, hydrodynamics, meteorological conditions and algal species compositions were observed in studied sites from May 2010 to Dec. 2013. Results showed that average total phosphorus concentration of 2013 was decreased by 52.4% in comparing with that from 2010 to 2011. Chlorophyll.a concentrations were positive significant with water temperature, pH, total phosphorus and total nitrogen, but is not significant with turbidity and suspended solids. Seasonal successions of algae were observed that Stephanodiscus sp. was dominant species with 65.3% of dominant frequency in studied site. Large algal biomass of the low temperature-adapted diatoms were observed during temperature range of $4{\sim}9^{\circ}C$, but large cyanobacterial biomass mainly during high temperature period ranged from $22^{\circ}C$ to $32^{\circ}C$. Microcystis sp. dominated during high water temperature in summer. The yearly correlations of algal biomass with accumulated solar radiations were not significant but seasonal correlations of summer from June to August were significant with correlation coefficient 0.33 (p<0.05). There were not significant correlations between turbidities and algal biomass. Turbidity and suspended solids concentrations were not significant correlation with algal biomass. According to the results, algal communities had strong correlation with water temperature and had partially correlation with solar radiation. For an effective management of algal blooms, water managers should survey with more long-term monitoring of various environmental factors and algal communities.

• Korean Journal of Ecology and Environment
• /
• v.56 no.2
• /
• pp.127-139
• /
• 2023

Daechung Reservoir has been suffering from severe cyanobacterial blooming periodically due to the water pollutants from the watershed, especially nutrients from nonpoint sources. As a countermeasure, an artificial wetland was constructed to mitigate the pollutant load from the watershed by utilizing the vegetation. We investigated the water quality of the influent and outflow of the wetland during years 2014~2020 to evaluate the performance of pollutant removal through the wetland. Major pollutants (e.g. BOD, COD, SS, T-N, and T-P) were largely reduced during the retention in the wetland while nutrients removal was more efficient than that of organic matters. Pollutant removal efficiency for different inflow concentrations was also investigated to estimate the wetland's capability as a way of managing nonpoint sources. The efficiency of water treatment was significantly higher when inflow concentrations were above 75^th percentile for all pollutant, implying the wetland can be applied to the pre-treatment of high pollution load including initial rainfall runoff. Furthermore, the yearly variation of removal efficiency for seven years was analyzed to better understand long-term trends in water treatment of the wetland. The annual treatment efficiency of T-P was very high in the early stages of vegetation growth with high concentration of inflow water. However, it was confirmed that the concentration of inflow water decreased, vegetation stabilized, and the treatment efficiency gradually decreased as the soil was saturated. The findings of the study suggest that artificial wetlands can be an effective method for controlling harmful algal blooms by alleviating pollutant load from the tributaries of Daechung Reservoir.

• Journal of Microbiology and Biotechnology
• /
• v.11 no.3
• /
• pp.504-507
• /
• 2001

The partial 16S gene sequences of six filamentous cyanobacterial strains, Oscillatoria lmosa KCTC AG10168, Oscillatoria princeps KCTC AG10153, Oscillatoria sp. KCTC AG 10184, Phormidium tenue KCTC AG10158, Phormidium parchydematicum KCTC AG10164, and Lyngbya hieronymusii KCTC AG10199, which were isolated in the late summer at Daecheong Reservoirs, were determined and assigned their phylogenetic and taxonomic position among taxa of order Ocillatoriales whose partial 16S rRNA gene sequences aligned in this suty, were very heterogeneously clustered with other taxa. The two strains, Oscillatoria limosa KCTC AG10168 and O. princeps KCTC AG10153, formed a cluster with O. sancta PCC7515, which supported 64% of the bootstrap trees with high similarity (19-96.15%). Strain Oscillatoria sp. KCTC AG10184, that was known to produce a nasty substance, was closely related to the toxic Oscillatoria group. The study on morphological variation in various environments and toxin production will confirm the taxonomic status of these species. Phormidium tenus KCTC AG10158 and Phormidium parchydematicum KCTC AG10164 made a cluster with other oscillatorian species of Phormidium, Oscillatoria, and Leptolynbya, which supproted 100% of the bootstrap trees with a very high sequence smilarity (96.8-99.8%) in thsi study. The sequence analysis in this study also supported that taxa of oscillatoriales are not monophyletic. Some of the fractures, such as the presence or absence of sheath and cell shape, which were used to define them, would be inadequate and should be reconfirmed. We suggest that sequences of partial 16S rRNA gene fragments aligned in this study should be more useful than morphological features in the identification and reconfirmation of the taxonomic status of these oscillactorian cyanobacteria.

• Korean Journal of Ecology and Environment
• /
• v.47 no.4
• /
• pp.292-301
• /
• 2014

Akinete germination may be a starting point of some akinete-producing cyanobacterial blooms in eutrophic freshwater systems. This study examined germinability of akinete of a cyanobacterium Anabaena circinalis isolated from the sediment of the North Han River (Cheongpyung Dam), Korea, under several environmental factors such as temperature ($5{\sim}25^{\circ}C$), light ($0{\sim}100{\mu}mol\;photons\;m^{-2}\;s^{-1}$), nutrients (nitrogen and phosphorus) and pH (5~12). The high germination rate appeared at high temperature: >55% at $25^{\circ}C$, followed by 15% at $15^{\circ}C$, $10^{\circ}C$ and 10% at $5^{\circ}C$. Low light intensity was favorable for akinete germination. Over 45% of germination occurred at low light intensities (5, 15 and $30{\mu}mol\;photons\;m^{-2}\;s^{-1}$), while less than 10% of germination occurred at both 50 and $100{\mu}mol\;photons\;m^{-2}\;s^{-1}$. No germination occurred in the dark condition. Akinete germination rate increased with nutrient (phosphorus and nitrogen) enrichment, and nitrogen addition showed greater effect on the germination compared to phosphorus addition. Akinetes germinated well at neutral or slightly alkaline pH condition (pH 7 and pH 8: >55%), but no germination was observed at pH 11~12. The present study demonstrates some favorable ambient conditions of Anabaena circinalis germination, which could provide useful information to study the germination conditions of other Anabaena species or akinete-forming algae and predict its bloom in eutrophic freshwaters.

• Journal of Korean Society on Water Environment
• /
• v.35 no.3
• /
• pp.257-270
• /
• 2019

Followingthe Four Rivers Project, cyanobacterial blooms have been frequently observed in the upstream of the installed weirs. The aim of this study was to characterize the major environmental factors that are associated with the cyanobacteria dominance in Baekje Weir (Geum River) and Juksan Weir (Youngsan River) based on intensive experiments and systematic data mining methods. The factors related to the cyanobacteria dominance include7-days cumulative rainfall (APRCP7), 7-days averaged flow (Q7day), water temperature (Temp), stratification strength (${\Delta}T$), electronic conductivity (EC), DO, pH, $NO_3-N$, $NH_3-N$, TN, TP, $PO_4-P$, Chl-a, Fe, BOD, COD, TOC, and $SiO_2$. The most highly correlatedfactors to the dominant cyanobacteria were found to be EC, Temp, Q7day, $PO_4-P$ in theBaekje Weir. On the other hand, those dominant in the Juksan Weir were ${\Delta}T$, TOC, Temp, EC and TN. The EC showed a strong correlation with cyanobacteria dominance in both weirs because a high EC represents a persisted low flow condition. The cyanobacteria dominance was as high as 56 % when the EC was equal or greater than $418{\mu}S/cm$ in Baekje Weir. It was as high as 63% when the ${\Delta}T{\geq}2.1^{\circ}C$ in the Juksan Weir. However, nutrients showed a minor correlation with cyanobacteria dominance in both weirs. The results suggest that the cyanobacteria dominate in astate where the water flow rate is low, water temperature is high and thermal stratification is strengthened. Therefore, the improvement of flow regimes is the most important to prevent persistent thermal stratification and formation of cyanobacteria bloom in theBaekje and JuksanWeirs.

• Journal of Korean Society of Water and Wastewater
• /
• v.35 no.1
• /
• pp.1-14
• /
• 2021

Eutrophication and algal blooms can lead to increase of taste and odor compounds and health problems by cyanobacterial toxins. To cope with these eco-social issues, Ministry of Environment in Korea has been reinforcing the effluent standards of wastewater treatment facilities. As a result, various advanced phosphorus removal processes have been adopted in each wastewater treatment plant nation-widely. However, a lot of existing advanced wastewater treatment processes have been facing the problems of expensive cost in operation and excessive sludge production caused by high dosage of coagulant. In this study, the sedimentation and dissolved air flotation (SeDAF) process integrated with sedimentation and flotation has been developed for enhanced phosphorus removal in wastewater treatment facilities. Design and operating parameters of the SeDAF process with the capacity of 100 ㎥/d were determined, and a demonstration plant has been installed and operated at I wastewater treatment facility (located in Gyeonggi-do) for the verification of field applicability. Several empirical evaluations for the SeDAF process were performed at demonstration-plant scale, and the results showed clearly that T-P and turbidity values of treated water were to satisfy the highest effluent standards below 0.2 mg/L and 2.0 NTU stably for all of operation cases.

• Korean Journal of Ecology and Environment
• /
• v.46 no.2
• /
• pp.301-309
• /
• 2013

Between May and August 2012, a massive cyanobacterial bloom with Anabaena has been occurred throughout the North Han River. Sampling was conducted at one station on each lake, L. Uham, L. Cheongpyung, and L. Paldang, where occurred a dense bloom, in 13 July. According to the microscopic examination, the blooms was dominated by one specific filamentous cyanobacterium Anabaena and other phytoplankton. Morphologically, previous literature proven that this Anabaena species is A. crassa (Lemmermann) Komark.-Legn. & Cronberg. However, identification of species in a mixed population is complicated due to limited morphological differences. Therefore, with live sample including trichome, akinete and heterocyst, the sequences of 16S rRNA gene of Anabaena isolates were cloned and analyzed, and three 16S rRNA gene sequences of 1188~1520 bp in length were obtained. It was shown from the homologous analysis results that the obtained 16S rRNA sequences were highly homologous to the relevant sequences of A. crassa in GenBank. The 16S rRNA sequences of 63 species were retrieved from GenBank, and the phylogenetic tree was constructed by using these sequences.

• Korean Journal of Ecology and Environment
• /
• v.47 no.spc
• /
• pp.1-9
• /
• 2014

Lake Suwa is a natural lake which is well-known for sightseeing and fisheries. It had suffered severe eutrophication during 1960s and 1970s with the occurrence of cyanobacterial blooms and the extinction of some benthic animals. Since 1980 water quality has been improved due to efforts of local government, scientists, and citizens. Of various methods that were attempted to improve the water quality of Lake Suwa biological methods received much attention, because it can improve the lake ecosystem integrity and fisheries in addition to the water quality. The aim of this paper is to introduce the biological methods for water quality improvement that had been employed in Lake Suwa, Japan, and their contribution to the economic benefit of local residents. Until now a significant restoration of water quality has been achieved, but there are insufficient recovery of the sediment and biota due to anoxic hypolimnion of the lake. This study proposed suspended cage culture of bivalves as a feasible method of water quality improvement. Increased grazing by bivalves will contribute to the improvement of water quality and fisheries production, which will contribute both to the ecological restoration and economy of local residents.