• 환경분석과 독성보건
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• 제21권4호
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• pp.292-303
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• 2018

The particle sizes and heavy metal concentrations (Pb, Zn, Cu, Cd, Hg, As, Cr, Ni, Li, Al) of surface sediments of the Yeongsan River were analyzed to assess the distribution and pollution level of heavy metals. The distribution of particle sizes was dominated by sand in the upstream sites (MS1-MS7) and by silt loam in the downstream sites (MS8-ML3), but MS3 and MS6, located slightly upstream of the two weirs, were found to be loamy sand and silt loam, respectively. The concentrations of Pb, Zn, Cu, Cd and Hg were higher at the upstream sites, while As, Cr, Ni and Li were higher at the downstream sites. The heavy metals of crustal origin (As, Cr, Ni and Li) were strongly correlated with particle size, while the other heavy metals (Pb, Zn, Cu, Cd and Hg) were weakly correlated with particle size. Considering their concentrations, most of heavy metals were evaluated as having almost no toxic effects on benthic organisms, at all sites. In addition, anthropogenic contamination by the $I_{geo}$, EF and CF were found to have no impact at most sites, with only low levels of pollution at the others. Using the PLI method, the MS2 and MS3 sites, located upstream, were assessed to be affected by anthropogenic contamination. Most importantly, Zn, Cu and Hg were found to be the elements responsible for most pollution, and they were highest at the upstream sites, implying pollution by domestic sewage and urban discharge.

• 한국환경과학회지
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• 제25권1호
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• pp.41-56
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• 2016

In recent localized heavy rainfalls have been arising from abnormal climate change. People are concerning about damages with increasing the frequency of flooding. Therefore, we need to understand river hydraulic characteristics and management to reduce damage from flooding. To study hydraulic characterization of Sincheon experimental catchment HEC-RAS (Hydrologic Engineering Center River Analysis System) model which provided by U.S Army Corps of Engineers (USACE) was applied. This study analyzed and compared water level the frequency flood for 100 years and 200 years by clark unit Hydrography. The change of the water level of Daejeon bridge, Sincheon bridge and Singi bridge showed increased for all conditions. The flow rate for the Daejeon bridge and the Sincheon bridge showed an increase, but the Sinki bridge showed a decreasing flow rate overally, except for 1hour-100 years. The verification result showed that the model was able to simulate the water level with 0.4709 coefficient of determination and error ration ranging from 1 to 3%.

• 한국물환경학회지
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• 제34권6호
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• pp.688-702
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• 2018

Since the 1970s regulations against the pollution of drinking water have been introduced in Lake Paldang watershed area. To understand the effects of water environment management policies and the impacts of climate changes on Lake Paldang, a long-term comprehensive study of this watershed and the changes in its water environment is required. In this study, we analyzed changes in the weather, hydrology, sources of pollution, water quality, and algal development from 2000 to 2015 year based on the statistical data provided by several national information systems. While the population and amount of sewage in the Lake Paldang watershed increased by about 1.5 times, the amount of animal manure showed a decreasing trend during the same period. The wastewater also increased by about 1.5 times while the amount of water intakes rose by about 1.14 times. The water quality in front of the Paldang Dam, which is the representative monitoring site of the Lake Paldang, was stable. The annual average BOD concentration remained within 2 mg/L, which is a "Good (lb)" level according to the environment standards of Republic of Korea. The development of phytoplankton and harmful cyanobacteria were largely influenced by meteorological factors.

• 한국물환경학회지
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• 제35권6호
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• pp.510-519
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• 2019

The 'Stable Isotope Analysis in R' (SIAR), one of the Bayesian mixing models for stable isotopes, has been proven to be useful for source apportionment of nitrates in rivers. In this study, the contribution ratios of nitrate sources were quantified by using the SIAR based on nitrogen and oxygen stable isotope measurements in the Yeongsan River. From the measurements, it was found that the values of δ¹⁵N-NO₃ and δ¹⁸O-NO₃ ranged from -8.2 ‰ to +13.4 ‰ and from +2.2 ‰ to +9.8 ‰, respectively. We further analyzed the contribution ratios of the five nitrate sources by using the SIAR. From the modeling results, the main nitrate source was found to be soil N (29.3 %), followed by sewage (26.7 %), manure (19.6 %), chemical fertilizer (17.9 %) and precipitation (6.3 %). From the results, it was found that the anthropogenic sources, i.e., sewage, manure and chemical fertilizer contribute 64.2% of the total nitrate inflow from the watershed. Due to the significant correlation of δ¹⁵N-NO₃ and lnNO₃^- in this study, the fractionation factors reflecting the biogeochemical processes of stable isotope ratios could be directly obtained. This may make the contribution ratios obtained in this study more precise. The fractionation factors were identified as +3.64 ± 0.91 ‰ for δ¹⁵N-NO₃ (p<0.01) and -5.67 ± 1.73 ‰ for δ¹⁸O-NO₃(p<0.01), respectively, and were applied in using the SIAR. The study showed that the stable isotope method using the SIAR could be applied to quantitatively calculate the contribution ratios of nitrate sources in the Yeongsan River.

• 한국물환경학회지
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• 제32권3호
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• pp.261-270
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• 2016

We analyzed cyanobacterial community including akinete, resting cell, and benthic cyanobacteria in sediment of Bukhan, Namhan-River, Paldang-Lake, and Kyeongan-Stream and compared the physicochemical factors for water and pore water. We also performed cyanobacteria growth potential test through incubating sediment. As a result of physicochemical analysis, the concentrations of nutrients were similar for each depth of Bukhan-River. For Namhan-River and Lake Paldang sites, the concentrations of TP and DTN in bottom and deep water had higher levels. DTN in water body composed of NO3-N(73%) while DTN in pore water composed of NH3-N(77.8%). Benthic cyanobacteria in the sediment such as Oscillatoria tenuis, O. limosa, Phormidium tenue, Pseudanabaena limnetica, and Lyngbya sp. were dominant (between 0.0∼243.3×10³ cells/g, w/w). Cell densities of cyanobacteria in sediment depth of 0∼2 cm in most sites were higher compared to those in other depths. The cell density of cyanobacteria in sediment correlated with pH, conductivity, BOD5, TP, DTP, and chl. a. Increased phytoplankton and organic matters were found to be able to inhibit the growth of benthic cyanobacteria. Results of cyanobacteria growth potential test after incubating sediment revealed that harmful cyanobacteria (Anabaena, Aphanizomenon, Microcystis, and Oscillatoria) appeared at 7 days post culturing. Base on these results, the methods used in this study are considered to be able to determine the appearance of harmful cyanobacteria.

• 생태와환경
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• 제49권4호
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• pp.375-384
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• 2016

Phytoplankton community is one of the important factors for the management of aquatic environment due to generation of varying toxins by harmful algal species. This study was performed to examine the phytoplankton community structure (PCS) in the midstream of Geum River (GR) from January 2014 to December 2015. The water sampling was performed in five stations on 2014, and three stations on 2015. Subsequently, the morphological identification was performed by microscopic observation in laboratory condition. As results, total 265 species were identified and it was comprised of 40.8% of Bacillariophyceae, 9.1% of Cyanophyceae, 44.5% of Chlorophyceae, and the others (4.9%). During the investigation period, total average standing crop of phytoplankton was $12,948cells\;mL^{-1}$, and it was comprised of $7,702cells\;mL^{-1}$ of Bacillariophyceae, $2,821cells\;mL^{-1}$ of Cyanophyceae, $2,121cells\;mL^{-1}$ of Chlorophyceae, and $305cells\;mL^{-1}$ of others. To verify which tributaries of upstream area influence on PCS of midstream of GR, the phytoplankton standing crops of two stations including Mihocheon (MH) and Gapcheon (GC) were examined on 2014, and compared to result of on 2015. The results were shown that the MH station had more similar phytoplankton standing crops with midstream of GR than GC station. The relationship between environmental parameters and phytoplankton dynamics was studied at the investigated station. As results, whereas water temperature and total phosphorus were represented the positive correlation, N/P ratio was remarkably exhibited negative correlation. From the results, it is suggested that the PCS of midstream of GR was more affected by MH station than GC station, and the changes of temperature, phosphorus concentration, and N/P ratio may be important factors on the PCS formation of midstream of GR.

• 한국물환경학회지
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• 제33권6호
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• pp.640-649
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• 2017

The purpose of this study is the analysis of the water quality spatial characteristics for the main stream of Nakdong River in consideration of the tributary inflow. The flow and water quality (BOD, TOC, TP) data for 32 monitoring stations located in the main stream and the tributaries of Nakdong River were collected from 2003 to 2016. From the results of the flow and water quality analyses for each site, a status map of the flow and the water quality for Nakdong River was produced. The water quality of each river section was classified according to seven river-environment standards. The water quality changes in the main stream before and after the confluence were analyzed spatially. As a result, the water quality of Kumho River, in particular the Kumho B to Kumho C section, is the worst among the tributaries. In addition, the water quality grades of the lower streams such as Nam River and Miryang are worse than that of the upper streams of the Nakdong River. In the case of the main stream, the water quality grades of the sections between the Wicheon and Nam River confluences and the section from Nakbon L to Nakbon N are relatively poor.

• 한국물환경학회지
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• 제23권3호
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• pp.348-355
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• 2007

We investigated temporal changes of composition, habitat area, growth rate and elements content of hydrophytes at the artificial vegetation island (AVI) in Kyungan Stream within Lake Paldang. We also assessed nutrient removal rate through cutting off the emergent part of hydrophytes. The kinds of hydrophytes have increased from four species (P. australis, P. japonica, T. angustifolia and the Z. latifolia) at initial stage of installation to more than 29 species for 6-year operation. P. japonica was most dominant species at the AVI in 2006. The habitat area of have increased about 2.5 times compared to the initial planting area, occupying 63% of AVI's vegetation area. The incoming species of S. fluviatilis and B. frondosa have adapted successively and expanded habitat area in the AVI. The relative growth rate of P. japonica and P. australis was highest in spring sprouting period. Their hights and weights have increased until summer, by the time they were cutting off the emergent part. They started regrowth immediately after cutting and continued to grow until September and withered away in November. The carbon contents of P. japonica and P. australis have increased during growth phase, on the contrary, the nitrogen and phosphorus contents have decreased. By cutting off and removing the emergent part (leaves and branches) of hydrophytes twice from AVI, $17.6gN/m^2/y$ of nitrogen and $1.3gP/m^2/y$ of phosphorus was removed from AVI in 2006.

• 한국물환경학회지
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• 제25권2호
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• pp.235-244
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• 2009

The purpose of this study is to offer information about the current river conditions and basic data of streams in Busan city, by selecting 20 underground streams and evaluating their multilateral stream assessment. Concerning the evaluation of streams, 4 sections including the general index, the bank index, the river characteristic index, and the ecological environment characteristic index were evaluated. Ahead of the evaluation, the study divided Busan city into 4 zone for a systematic river investigation. Then, the study allocated code names to each river, and conducted literature research and a field survey of streams. Based on this, the study applied the evaluation of multilateral stream assessment. As a result, out of 4 entire grades, there was no grade 1 or grade 2. Instead, 35% were grade 3, 60% were grade 4, and 5% were grade 5. When looking into the evaluation results by Zone, the Dongbusan Zone showed the highest index, and the Suyeonggang Zone, the Jungbusan Zone, and the Nakdonggang Zone followed, in order.

• 환경영향평가
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• 제23권1호
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• pp.19-27
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• 2014

The purpose of this study is to provide a base line data to improve the water quality in the Yeongsan River basin. As the major factor that affects the water quality of Yeongsan River is nonpoint pollution source, in order to find a resolve to improve the quality, a study was conducted to identify the correlation between the stream water quality and that of the land use. The study showed that the concentration of the contents in the water from the agricultural land environment was found to be higher as oppose to that found in the content of the water from the forest land. As a result, it can be deducted that agricultural land deteriorates water quality whereas that of the forest land is of much better quality. Therefore, it is highly recommended to take advanced improved care of agricultural land close to a water source to improve the quality of Yeongsan River basin.