National Institute of Environmental Research (NIER) has developed the Korean Reach File (KRF) for scientific and systematic analysis of variables related to water quality, pollutant sources and aquatic ecosystems in consideration of steam reach networks. The KRF provides a new framework for data production, storage, management and analysis for water related variables in the relation with spatial characteristics, connections, and topologies of stream reaches. However, the current version of KRF (ver.2) has a limited applicability because its nodes include not only the stream points based on topological characteristics but also those based on water quality monitoring stations, which may undermine its generality. In this study, a new version of KRF (ver.3) was designed and established to overcome the weak point of the version 2. The version 3 is a generalization of the old KRF graphic data and it integrates the attribute data while separating it from the graphic data to minimize additional work that is needed for data association and search. We tested the KRF (ver.3) by applying it to actual cases and its convenience and adaptability for each particular application was verified. Further research should focus on developing a database link model and real-world applications that are targeted to process event data.
Key Words
Korean Reach File (KRF), Spatial Network Analysis, Spatial Network Data, Spatial Database, Water Environment Information System (WEIS)
A Study on Comparison of Phycocyanin Extraction Methods for Hyperspectral Remote Sensing of Cyanobacteria in Turbid Inland Waters
하림 Rim Ha , 신현주 Hyunjoo Shin , 남기범 Gibeom Nam , 박상현 Sanghyun Park , 강태구 Taegu Kang , 송현오 Hyunoh Song , 이혁 Hyuk Lee
Phycocyanin (PC) is one of the water-soluble accessory pigments of cyanobacteria species, and its concentration is used to estimate the presence and relative abundance of cyanobacteria. In laboratory experiments PC content of field data were determined using Sarada`s freeze-thaw method in algal bloom season. The effectiveness of three selected extraction methods (repeated freeze-thaw method, homogenization, power control) for PC. It was found that the extraction efficiency of phycocyanin was the highest (of the methods compared) when a single freezing-thawing cycle was followed by pre-sonication. Applying this optimized method to surface water of Korean inland waters, the average concentration distribution was estimated 2.9~51.9 mg/m3. It has been shown that the optimized pre-sonication method is suitable to measure cyanobacteria PC content for the characterization of inland waters. The approach and results of this study provides the potential of effective methods for remote monitoring and management water quality in turbid inland waters using hyperspectral remote sensing.
The purpose of Total Pollution Load Control at Tributary is to get the maximum improvement effect of the water quality through finding the most impaired section of water-body and establishing the proper control measure of pollutant load. This study was implemented to find the optimal management of reach, period, condition, watershed, and pollution source and to propose appropriate reduction practices using the Load duration curve (LDC) and field monitoring data. With the data of measurement, LDC analysis is shown that the most impaired condition is reach V (G4~G5), E group (flow exceedance percentile 90~100%) and winter season. For this reason, winter season and low flow condition should be preferentially considered to restore water quality. The result of pollution analysis for the priority reach and period is shown that agricultual nonpoint source loads from onion and garlic culture are most polluting one. Therefore, it is concluded that agricultural reuse of surface effluent (storm-water runoff with non-point sources) and low impact farming including reducing fertilization and controling the height of drainage outlet are efficient water quality management for this study watershed.
In order to cope with the new and strict government regulations for turbid water discharge from construction sites, this study tested whether synthetic fiber filters can replace conventional best management practices. The filter efficiency was about 10 to 60% with a varying filter depth of 5 to 15cm, presuming extreme storm flow conditions to be in the range of 800 to 1500m/day of filtration rates. Fiber filter acts exactly like a granular filter, i.e. the separation efficiency is directly and inversely proportional to filter depth and rate, respectively. Based on the operational data, we suggested the Log-Log design relationship, which can be used to determine the filter depth and area. Compared to the widely used gravel filter which treats the turbid water at the construction site, about 20% higher efficiency was obtained under similar operating conditions. Cleaning the filter through a simple hand-washing method at the time of break-through, achieved about 90% soil recovery.
Key Words
Construction sites, fiber filter, turbid water
Effects of Capping with Recycled Aggregates and Natural Zeolite on Inhibition of Contaminants Release from Marine Sediment
In this study, the capping with recycled aggregate and natural zeolite on marine sediment was accomplished to investigate the inhibition effect on pollutants release from sediment to seawater. An experiment was accomplished by capping with amendments for 60 days, and organic matter (COD), nitrate, phosphate and metallic elements (Ni, Zn, Cu, Pb, Cd, As, and Cr) concentrations were measured. Two capping materials effectively suppressed pollutants release. Recycled aggregate showed better capability for organic pollutants, nitrate and phosphate release. Meanwhile, natural zeolite was effective for metallic elements. As a result, recycled aggregate and natural zeolite can be considered as cheap capping material candidates. Also, the capping material can be selected according to target pollutants.
For the prediction of hydrologic phenomenon, predicting future land use change is very important task. This study is intended to compare and analyze between the two different land use change models namely CLUE-S and SLEUTH3-R. The analysis of two models are performed based on the MSR value such that the model having more reliable MSR value can be recommended as an appropriate land use change prediction model. The model performance was examined by applying them to the Gapcheon A watershed. Land use map of the study area of year 2007 obtained from the Ministry of Environment was compared with the predicted land use map obtained from the two different models separately and the result from both the models showed somewhat similar results. The MSR value obtained from CLUE-S was observed to be 0.564 while that from SLEUTH3-R was 0.586. But when land use map of 2010 was compared with predicted land use map obtained from the two models in same manner, the MSR value obtained from CLUE-S` was observed to be 0.500 while that from SLEUTH3-R was decreased to 0.397 which is almost 32.3% decrease from previous value of 2007. Moreover, SLEUTH3-R was seen more sensitive in conversion of urban areas compared to other land use types. Therefore, for the prediction of future land use change, CLUE-S model is reliable than SLEUTH3-R.
Key Words
CLUE-S, Land use change, Modeling, Modified Success Rate (MSR), SLEUTH3-R
The Effect of Connected Bioretention on Reduction of Surface Runoff in LID Design
전지홍 Ji-hong Jeon , 서성철 Seong-cheol Seo , 박찬기 Chan-gi Park
Recently Low Impact Development (LID) is recently used in Korea to control urban runoff and nonpoint source pollution. In this study, the effect of connecting three bioretention as LID-BMP on reduction of surface runoff from study area was evaluated. Estimating surface runoff and storage volume of bioretention is used by Curve Number (CN) method. In this study, storage volume of bioretention is divided by volume of surface runoff and precipitation which enter directely into bioretention. The ratio of captured surface runoff volume by bioretention to storage volume of bioretention is highly influenced by the ratio of drainage area to surface area of bioretention. The high bioretention surface area-to-drainage area ratio could capture much more surface runoff. The ratio of 1.2 captured 51~54% of total surface runoff with ranged from 5-30 cm of bioretion depth whereas 6.2 captured 81~85%. The connecting three bioretentions could capture much more runoff volume showing ranged from 35.8~167.3 m3 than the case of disconnecting three bioretentions at maximum amount of precipitation with non-effluent from the connecting three bioretentions. Therefore, connecting LID-BMPs could improve the removal efficiencies of surface runoff volume and nonpoint source pollution.
A watershed model was constructed using Hydrological Simulation Program Fortran to predict the water quality, especially chlorophyll-a, at major tributaries of Nakdong River basin, Korea. The BOD export loads for each land use in HSPF model were estimated to 1.47~8.64 kg/km2/day, which of values were similar to the domestic monitoring export loads. The T-N and T-P export loads were estimated to 0.618~3.942 kg/km2/day and 0.047~0.246 kg/km2/day, slightly less than the domestic monitoring data but within the range of foreign literature values. The model was calibrated at major tributaries for a three-year period (2008 to 2010). The deviation values ranged from -31.5 to 1.6% of chlorophyll-a, -24.0~2.2% of T-N, and -5.7~34.8% of T-P and root mean square error (RMSE) ranged from 4.3~44.4 ug/L of chlorophyll-a, -0.6~1.5 mg/L of T-N, and 0.04~0.18 mg/L of T-P, which show good calibration results. The operational water quality forecasting results for chlorophyll-a presented in this study were in good agreement with measured data and had a similar accuracy with model calibration results.
Key Words
Chlorophyll-a, Forecast, HSPF, Nakdong River
Improving HSPF Model`s Hydraulic Accuracy with FTABLES Based on Surveyed Cross Sections
The hydrological simulation program-FORTRAN (HSPF) is a comprehensive watershed model that employs depth-area- volume-flow relationships knows as the hydraulic function table (FTABLE) to represent the geometric and hydraulic properties of water bodies. The HSPF model`s hydraulic representation mainly depends on the accuracy of the FTABLES and the hydraulic representation determines the respond time of water quality state variables and also control scour, deposition, and transport of sediments in the water body. In general, FTABLES are automatically generated based on reach information such as mean depth, mean width, length, and slope along with a set of standard assumptions about channel geometry and hydraulics, so these FTABLES can`t describe accurately the geometry and hydraulic behavior of rivers and reservoirs. In order to compensate the weakness of HSPF for hydraulic modeling, we have generated alternative methods to improve the accuracy of FTABLES for rivers using the surveyed cross sections and rating curves. The alternative method based on the hydraulics simulated by HEC-RAS using the surveyed cross sections and rating curves could improve significantly the accuracy of FTABLES. The alternative FTABLE could improve greatly the HSPF model`s hydraulic accuracy but had little effect on the hydrological simulation.
Implemented since 2004, TPLC (Total Pollution Load Control), the most powerful water-quality protection program have been implemented since 2004. Recently, uncertainty of prediction using steady state model increased as changes of water environment, and necessity of dynamic state model, especially watershed model came to the fore on TPLC. For application of watershed model on TPLC, the adjustment of relationship (mass-balance) between discharged loads estimated by technical guidance and arrived loads based on observed data at the watershed outlet should be possible. However, HSPF perform simulation as semi-distributed model (lumped model) in a sub-basin. Therefore, if the estimated discharged loads from individual pollution source is entered into RCHRES module directly (without delivery ratio) as point source data, the pollutant load couldn`t be reduced properly in the RCHRES module until they reached the outlet of sub-basin. The hypothetic RCHRES that generated using HSPF BMP Reach Toolkit was applied to solve this problem, although it is not original usage of Reach Toolkit. And the impact of discharged load according to spatial distribution of pollution sources in a sub-basin could be expressed by multi-segmentation of hypothetic RCHRES. The discharged pollutant load through hypothetic RCHRES could be adjusted easily by modification of infiltration rate or characteristics of flow control devices.
Key Words
BMP Web Toolkit, Delivery ratio, HSPF, TPLC, Watershed modeling
Determination of Antibiotic Residues: I. Extraction and Clean-up Methods for Solid Samples
김찬식 Chansik Kim , 류홍덕 Hong-duck Ryu , 정유진 Eu Gene Chung , 김용석 Yongseok Kim , 류덕희 Doug Hee Rhew
Korea is one of the countries with a large market of veterinary antibiotics, although antimicrobial resistance in bacteria is becoming a serious issue in many countries. Korean government started to be interested in estimation of effects of livestock manure on rivers and agricultural soils and in monitoring heavy metals, organic pollutants and antibiotics in the water and soil samples. In this paper, pre-treatment methods to separate the selected antibiotics from the solid samples were reviewed. It is essential to select an efficient and proper procedure for the pre-treatment due to the high portion of proteins and organics in biosolid samples. The pre-treatment consists of extraction followed by clean-up. Initially, homogenized samples were extracted by sonication, mechanical agitation or pressurized liquid extraction with methanol/acetonitrile/water mixture under acidic/base depending on compounds. However, aminoglycosides and colistin were extracted with 5% trichloroacetic acid and HCl, respectively. Since the β-lactams are easily decomposed in acidic and basic condition, these were extracted in neutral pH. Filtration with membrane (pore size, 0.2 μm) or solid phase extraction with HLB and methanol, as eluent, were normally applied for the clean-up. More than three pre-treatment procedures should be adopted to screen all the selected antibiotics in solid samples.
Increased attention has been paid to occurrence of veterinary antibiotics in various environmental matrices due to their toxicological behavior in the ecosystem and development of antibiotic-resistant strains of pathogenic bacteria. In this paper, 37 target antimicrobials were selected based on annual sales of antibiotics for livestock in South Korea 2014. Also, extraction and clean-up methods for the determination of the antibiotic residues in liquid samples including water, milk and honey were comprehensively reviewed in the literature. Solid-phase extraction (SPE) was commonly used as pre-treatment method for the samples. Most of the analytes were extracted in acidic conditions (2.5~4.0) except aminoglycosides in neutral (7.0~8.0). b-Lactams showed the highest recoveries in neutral pH due to their degradation characteristics in acidic media. Starta-X, Oasis HLB and Oasis MCX were frequently applied as a SPE cartridge and Oasis HLB showed the highest recoveries for the majority of antibiotic classes. The homogenized honey and milk were extracted by mixing with acids for deproteinization. Solids and interferences in the extract were eliminated by centrifugation followed by membrane filtration or SPE before injection into HPLC.
This study explored the analytical conditions regarding 21 veterinary antibiotics which have popularly sold in South Korea, 2013 but were not targeted in EPA method 1694 yet. Most of the selected antibiotics were separated by a reverse-phase C18 column with the combination of (bufferized) water and organic polar solvent, which were commonly methanol and acetonitrile in the gradient elution mode. Volatile additives such as formic acid, ammonium acetate and ammonium formate were usually added to the mobile phases to minimize asymmetrical and tailing of antibiotics` peaks and to increase ionization of them in mass spectrometry. The analytical methods of aminoglycoside antibiotics were distinct from those of the other antibiotics in terms of adoption of ion-pair chromatography (IPC) and hydrophilic interaction chromatography (HILIC) capable of retaining and separating extremely polar compounds due to their hydrophilicity. Trifluoroacetic acid or heptafluorobutyric acid was frequently added to the mobile phase as an ion-pair reagent for the IPC. Tandem mass spectrometry was numerously applied to the detection of antibiotics using positive electrospray ionization (ESI) and the selected reaction monitoring (SRM) mode. All reviewed analytical methods have been validated by evaluating recovery, limits of detection and quantification, decision limit or detection capability of the methods.
In this study, 16 antibiotics selected from top 30 veterinary antibiotics sold in South Korea, 2014 as well as among the pharmaceuticals in EPA method 1694. In order to determine trace levels of antibiotics in environmental samples including surface water, soils, animal producing foods, and manures, LC-MS/MS was heavily used. In the chromatography for the detection of the selected antibiotics, the C18 column was mostly used at the temperature of 30~40°C. Water and methanol/ acetonitrile were commonly chosen as a non-polar and a polar mobile phase, respectively. Gradient elution was applied to separate multi-class antibiotics. Volatile additives such as formic acid, acetic acid, and ammonium acetate were mixed with the mobile phase to improve the ionization efficiency of analytes and the sensitivity in MS detection. Electrospray ionization (ESI) was widely used in the LC-MS/MS and positive ionization was preferred to determine the selected antibiotics. Protonated [M+H]+ molecule was selected as a precursor ion and its two transitions were analyzed: one for quantitative determination and the other for confirmation. This study were reviewed linearity of the calibration curve, recovery, repeatability, method detection limits (MDLs) and method quantification limits (MQLs) for each target compound used to validate the developed analytical methods.
