• Journal of Korean Society of Environmental Engineers
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• v.28 no.8
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• pp.843-851
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• 2006

Although the detected amounts of those disease-causing(oo)cysts were high at each point in 2001, the detected amounts of Cryptosporidium and Giardia had decreased at low levels below 10(oo)cysts until 2004. Considered the detection results of each season, the most highly detected amounts of(oo)cysts were mostly recorded in summer and late summer(from June to September), while the site which the biggest amount was detected, was the point at Goryeung. The relation of Cryptosporidium with the water quality items was low, but the relations of Cryptosporidium and Giardia with turbidity were high($R^2$=0.4914, $R^2$=0.6176 respectively). And the detected amounts of Cryptosporidium and Giardia were relatively high, 20(oo)cysts/20L when the turbidity was more than 20 NTU. It was also found that the relation between the distribution of Cryptosporidium and Giardia was high, $R^2$=0.8432 and the density of Giardia was generally higher than that of Cryptosporidium. And Cryptosporidium and Giardia were simultaneously detected at each point. The primary sources that affected the density of those(oo)cysts were the livestock waste water and sewage.

• Journal of Wetlands Research
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• v.18 no.3
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• pp.250-261
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• 2016

The Philippines is a naturally water-rich archipelago capable of sustaining its ecological goods and providing services and needs of its people. Several waterbodies have been declared as natural wetlands in the country supporting the needs of community like water and food. In this study, 65 natural wetlands were considered including six sites that were identified as 'Wetlands of International Importance' such as Naujan Lake National Park, Agusan Marsh Wildlife Sanctuary, Olango Island Wildlife Sanctuary, Tubbataha Reefs Natural Park, Las $Pi{\tilde{n}}as-Para{\tilde{n}}aque$ Critical Habitat and Ecotourism Area and Puerto Princesa Subterranean River National Park. There are 22 wetland types presented in this research categorizing the Philippine wetlands. Philippine wetlands are now facing tremendous challenges such as land use conversion, abuse of resources, pollution coming from domestic, industrial and agricultural activities, and climate change. This paper provides an overview of Philippine wetlands in terms of their characteristics and components, impacts in the ecosystem, and the challenges they are dealing with. Moreover, the preservation measures that the government and private agencies implements to these wetlands were discussed and assessed. The enforcement of local and national laws concerning wetlands is found to be inadequate resulting in poor quality wetlands. The preservation and utilization of these wetlands can be maximized with a voluntary participation of whole Philippine community.

• Korean Journal of Ecology and Environment
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• v.45 no.2
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• pp.210-217
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• 2012

This study investigated the water quality of effluents from the wastewater treatment plants, located at the Gumi Complex 4, Gumi, and Wonpyong, in Gumi. DOC accounted for higher than 70% of TOC, and oxidation efficiencies, calculated from carbon, were 13~43% for BOD and 37~73% for CODMn, respectively. Based on the biological decomposition experiments, R-DOC account for higher than 70% of DOC, mostly being occupied by refractory organic matters. This indicated that the biodegradable organics occupied more proportions of organic loadings than the refractory organics. The effect of the organics from a discharge of a sewage treatment plant on rivers, Gumi industrial Complex 4, Gumi, and Wonpyong on lower streams of the Nakdong River were found to be 15%, 6% and 16% respectively. The ratio of 15% suggests that comparatively, no large portions of TOC loadings are occupied, but the problem is that the biodegradable organic matters occupy a lot more proportions than that of the refractory organic matters. Thus, it is highly estimated that the refractory organics can gradually increase the pollution level of organics and precursors of disinfection by-products to the down-stream water treatment plants.

• Korean Journal of Environmental Biology
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• v.17 no.2
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• pp.159-168
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• 1999

The ophemeropterans such as Epeorus pellucidus, Uracanthella rufa and Drunella uculea were dominated in station 1. It was generally showed the stable aquatic communities with low dominance index values throughout the year in station 2. The first dominant species in station 3 were all mayflies with the average DI value of 0.38. The first dominant species of Uracanthella rufa known as relatively tolerant species in station 4. A crustacean species Gammarus spp. have frequently occurred as the 1st or 2nd dominant species in station 5. Limnodrilus socialis, and Chironomus spp. were dominated in stations 6 and 7 Station 1, 2 and 3 were classified as oligosaprobic status according to their average diversity index values ranging from 3.46 to 3.52. Station 7 showed $\alpha$-mesosaprobic water condition with the overall average diversity value of 1.26. In general, the equitability and species richness values in the same sampling areas had close relations with their diversity values. The dendrogram drawn by dissimilarity values among 7 sampling sites indicates that the macrobenthic communities were divided into 3 groups： stations 1, 2, 3 and 4； stations 6 and 7； and station 5 alone.

• Korean Journal of Environmental Biology
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• v.31 no.4
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• pp.362-369
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• 2013

Phytoplankton and zooplankton communities were investigated from 8 weir sites of the Nakdong River system to provide basic information on plankton community after weir construction and to estimate its effects on major water quality parameters. The relationship between plankton community structure and environmental factors was analysed with CCA (Canonical Correspondence Analysis). The results suggested that discharge and total phosphorus and nitrogen concentrations are important factors determining the phytoplankton species composition. For zooplankton community, the difference in discharge between September and October induced different distribution pattern of zooplankton community with more homogeneous distribution with extreme dominance of rotifers during the high discharge season. Chlorophyll a concentration representing phytoplankton biomass has been suggested as the main environmental factor affecting zooplankton community followed by COD and total nitrogen concentration.

• Journal of Korea Water Resources Association
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• v.55 no.9
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• pp.679-686
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• 2022

As the occurrences of flash floods have increased due to climate change, faster and more accurate precipitation observation using X-band radar has become important. Therefore, the Ministry of Environment installed two dual-pol X-band radars at Samcheok and Uljin. The radar data used in this study were obtained from two different elevation angles and composed to reduce the shielding effect. To obtain quantitative rainfall, quality control (QC), K_DP retrieval, and Hybrid Surface Rainfall (HSR) methods were sequentially applied. To improve the accuracy of the quantitative precipitation estimation (QPE) of the X-band radar, we retrieved parameters for the relationship between rainfall rate and specific differential phase, which is commonly called the R-K_DP relationship; hence, an empirical approach was developed using multiple rain gauges for those two radars. The newly suggested relationship, R = 27.4K^0.81_DP, slightly increased the correlation coefficient by 1% more than the relationship suggested by the previous study. The root mean square error significantly decreased from 3.88 mm/hr to 3.68 mm/hr, and the bias of the estimated precipitation also decreased from -1.72 mm/hr to -0.92 mm/hr for overall cases, showing the improvement of the new method.

• Korean Journal of Ichthyology
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• v.34 no.4
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• pp.262-269
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• 2022

A distribution survey was conducted from 2018 to 2020 to evaluate the distribution status, habitat characteristics, and extinction threat of the short ninespine stickleback Pungitius kaibarae (Gasterosteidae). Literature reports of P. kaibarae distribution have been sorted by each period, 1980~1996, 1997~2005, and 2007~2017, and the samples were collected in 32, 43, and 64 stations for each period. Among the 75 streams and 193 sampling sites investigated during the study period, 1,400 P. kaibarae individuals were collected from 26 streams at 39 sites. The main habitat of P. kaibarae was downstream or brackish water zones with a low altitude, slow water velocity, and many aquatic plants. The main reasons for the decline in population size were assumed to be drought and flood, river work for flood restoration and river maintenance, bridges construction, and predation by the exotic fish species Micropterus salmoides. Previous evidence reported a 42.6% reduction in occupancy within 10 years, a decline in habitat quality, and the spread and impact of the exotic fish species Micropterus salmoides. Therefore, P. kaibarae is now considered a Vulnerable (VU A2ace) species based on the IUCN Red List categories and criteria. Therefore, P. kaibarae should be redesignated as an endangered species by the Ministry of Environment and systematically managed.

• Journal of Environmental Health Sciences
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• v.50 no.2
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• pp.93-101
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• 2024

Background: As pollutants caused by non-point sources flow into rivers, river water quality monitoring for fecal pollution is becoming increasingly important. Objectives: This study was conducted to investigate the distribution of microbial communities in the Yeongsangang River water system and sewage treatment plants in Gwangju and to evaluate their antibiotic resistance. Methods: In the experiment, samples were distributed to five selective media at each point and then cultured for 18 to 24 hours. When bacteria were observed, they were sub-cultured by size and shape and identified using MALDI-TOF MS equipment. When identification was completed, 17 types of antibiotic susceptibility tests were performed using VITEK II equipment, focusing on gram-negative dominant species among the identified strains. Results: During the study period, a total of 266 strains were isolated from 39 samples. Gram-positive bacteria were 37 strains in four genera, or 13.9% of the total, and Gram-negative bacteria were 229 strains in 23 genera, or 86.1% of the total. Antibiotic susceptibility testing of 23 strains, the major dominant species, showed that one strain (4.3%) was resistant to only one antibiotic, and two strains (8.7%) were 100% susceptible to the 17 antibiotics tested. The other 20 strains (87.0%) were multidrug resistant bacteria resistant to two or more antibiotics. There were various types of multidrug resistance. Among them, penicillin and cephalosporin series showed the highest resistance. Conclusions: Based on the results of this study, it was found that the bacterial community structure changed according to regional and environmental factors, and it was judged that continuous research such as genetic analysis of antibiotic-resistant bacteria present in natural rivers is necessary.

• Korean Journal of Ecology and Environment
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• v.36 no.3 s.104
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• pp.336-343
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• 2003

Two types of statistical models, simple and multivariate log linear models, were studied for continuity simulation and trend analysis of water qualities in incoming flows to Lake Paldang. Water quality is a function of one independent variable (flow) in the simple log linear model, and of three different variables (flow, time, and seasonal cycle) in multivariate model. The independent variables act as surrogate variables of water quality in both models. The model coefficients were determined by the monthly data. The water qualities included 5-day Biochemical Oxygen Demand ($BOD_5$), Total Nitrogen (TN), and Total Phosphorus (TP) measured from 1995 to 2000 in the South and the North branches of Han River and the Kyoungan Stream. The results indicated that the multivariate model provided better agreements with field measurements than the simple one in a31 attempted cases. Flow dependency, seasonality, and temporal trends of water quality were tested on the determined coefficients of the multivariate model. The test of flow dependency indicated that BOD concentrations decreased as the water flow increased. In TN and TP concentrations, however, there were no discernible flow effects. From the temporal trend analyses, the following results were obtained: 1) no trends on BOD at all three upstreams, 2) increase on TN at the South Branch and the Kyoungan Stream, 3)decrease on TN at the North Branch,4) no trends on TP at the North and the South Branches and 5) increase on TP at the Kyoungan Stream by 3 to 8% per years. The seasonality test showed that there were significant seasonal variations in all three water qualities at three incoming flows.

• The Korean Journal of Ecology
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• v.28 no.3
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• pp.129-134
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• 2005

The monthly variations of physico-chemical and microbiological water quality were investigate in the artificial Lake Geumgang near estuary barrage. Sixty heterotrophic bacteria were isolated and identified by amplification and sequencing of 16S rDNA. Water temperature, pH, and inorganic nutrients($NH_4$-N, $NO_2$-N, $NO_3$-N, $PO_4$-P) were measured. Concentrations of DO, BOD, and inorganic nutrients were lower than in the middle-stream of Geum river The population densities of heterotrophic bacteria and total coliforms varied from $4.1{\pm}1.0\times10^2$ to $6.7{\pm}1.1{\times}10^3\;cfu\;ml^{-1}$, and 0 to $2.3{\pm}0.6{\times}10^2\;cfu\;ml^{-1}$, respectively. Among the measured numbers of physiological groups of bacteria, cellulolytic bacteria showed higher population densities than those of other physiological groups. Bacterial community structure was analysed based on 16S rDNA partial sequencing. Among 60 isolates, dominant genus was Pseudomones (20 strains).