• Journal of Korean Society of Environmental Engineers
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• v.33 no.12
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• pp.861-867
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• 2011

In order to understand the extent of contamination of the sediments on the Mankyoung and Dongjin Rivers flowing into the Saemangeum Reservoir, the concentrations of ignition loss (IL), COD, total nitrogen (T-N), total phosphorus (T-P), and heavy metals (As, Cd, Cr, Pb, Zn) were measured. The average concentrations of IL, COD, and T-P were 2.40 (${\pm}2.18$)%, 2.97 (${\pm}3.06$) mg/g sediment, 0.370 (${\pm}0.351$) mg/g sediment, respectively, showing the extent of contamination is not serious. However, the concentrations of these parameters in the samples taken in year 2009 were higher than those in year 2008, indicating the contamination of sediments goes on gradually. The concentrations of T-N were in the range of 0.59~13.11 mg/g sediment with variation of locations and seasons. It was determined that the T-N contamination is serious when the concentrations were compared with the dredging guidelines of sediments in the Korean freshwaters, indicating the countermeasures are required to maintain the water quality of the Saemangeum Reservoir. The concentrations of heavy metals except chromium did not exceed the worrisome level of soil contamination stipulated by the Soil Environment Conservation Act of Korea. The high concentration of chromium to be concerned in some samples from the upstream of Mankyoung River requires source analysis and countermeasure to control the contamination.

• Journal of the Korean Society of Marine Environment & Safety
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• v.26 no.4
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• pp.392-402
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• 2020

We investigated the concentrations of acid volatile sulfide (AVS), ignition loss (IL), total organic carbon (TOC), total nitrogen (TN), and metallic elements (As, Cd, Cr, Cu, Fe, Hg, Mn, Pb, and Zn), in August 2015, to determine the spatial distribution and pollution status of organic matter and metals in the surface sediment of Jinju Bay, a spraying shellfish farming area, Korea. The concentrations of organic matter and metallic elements were significantly higher in the southern part of the bay than in the mouth and center of the bay. The C/N ratio (5.7~8.0) in the sediment represents the dominance of organic matter of oceanic origin in the surface sediment of the study area. The concentrations of AVS, TOC, and metals (As, Cd, Cr, Cu, Hg, Pb, and Zn) were much lower than the values of the sediment quality guidelines applied in Korea. Based on the results of the pollution load index (PLI) and ecological risk index (ERI), the metal concentrations in the surface sediment of Jinju Bay have a weakly negative ecological effect on benthic organisms although the sediments with high metal pollution status are distributed in the southern parts of the bay, with high dense shellfish farming areas. Thus, the surface sediments in Jinju Bay are not polluted with organic matter and are slightly polluted with metallic elements.

• Korean Journal of Ecology and Environment
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• v.38 no.3 s.113
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• pp.372-381
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• 2005

This study was conducted to test the efficiency of water quality improvement using the dissolved air flotation (DAF) technique in a shallow eutrophic reservoir. The application of DAF was followed by the addition of a chemical coagulant (poly aluminum chloride; PAC). The experiment was conducted in the mesocosm scale (wide ${\times}$ length ${\times}$ depth: 6 m ${\times}$ 6 m ${\times}$ 3 m). Suspended solids (SS) and volatile SS (VSS) concentration decreased by 54 ${\sim}$ 71% and 57 ${\sim}$ 79% of the initial concentrations, respectively. Total phosphorus and Chl- a concentration also decreased by 74 ${\sim}$ 92% and 54 ${\sim}$ 98%, respectively. BOD decreased by>86% while COD decrease ranged 29 ${\sim}$ 63%. Dissolved inorganic P (DIP) and dissolved total P (DTP) concentration decreased by 34 ${\sim}$ 88% and 62 ${\sim}$ 88%, respectively. After DAF application further onto the sediment, DIP-release rates from the sediment decreased by 17% (0.82 ${\to}$ 0.68 mg $m^{-2}$$day^{-1}$ in the oxic condition and 23% (2.27 ${\to}$ 1.76 mg $m^{-2}$$day^{-1}$) in the anoxic condition, compared to the release rate from the untreated sediment. DTP-release rate from both the oxic and anoxic sediments also decreased by 33% (5.62 ${\to}$ 3.78 mg $m^{-2}$$day^{-1}$) and 20% (6.23 ${\to}$ 4.99 mg $m^{-2}$$day^{-1}$), respectively. These results suggest that the DAF application both to the water column and onto the sediment be effective to improve water quality by removing particulate matters in the water column as well as reducing P-release from the sediment.

• Journal of the Korean Society of Food Science and Nutrition
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• v.40 no.8
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• pp.1121-1127
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• 2011

We evaluated the quality characteristics of adzuki bean sediment according to variety. The moisture, crude protein, and crude ash contents of the various adzuki bean varieties were 8.2~11.1, 15.4~20.6 and 3.3~3.6 g/100 g, respectively. The potassium contents of Chilbo-pat (CB) and Hongeon-pat (HE) were 875.1 and 873.1 mg/100 g, respectively. The calcium contents of Jungbu-pat (JB) and Kumsil-pat (KS)were 73.6 and 73.2 mg/100 g, respectively. A high level of magnesium (131.4 mg/100 g) was found in Yeonkeum-pat (YK). The yields of adzuki bean sediment according to variety were no different either wet (188.3~204.7%) or dry (62.1~66.0%). The L-values on sediment of YK and KS were 67.0 and 68.0, respectively; however, the CB L-value was low at 54.0. A high level of a- (6.6) and b-value (12.8) was found in YK; however, the values for CB were much lower at 3.8 and 5.9, respectively. There was no difference in particle-size distribution, water binding capacity, and solubility of adzuki bean sediment according to variety. High levels of peak (3.79 RVU), trough (3.75 RVU), final (7.33 RVU), and setback viscosity (3.54 RVU) were found in JB. The sensory properties of products in food processing are important, and the variety of adzuki bean sediment should be chosen depending on desired product characteristics.

• Environmental Engineering Research
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• v.19 no.3
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• pp.223-228
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• 2014

We investigated seasonal algae variability and its influence on water quality in an agricultural reservoir. We observed that maximal total phosphorus (TP) loads were 1,715 kg from farmland in September, which changed the ecosystem in the reservoir. At this time, Dictyosphaerium pulchellum as green algae dominated. Aulacoseira ambigua as diatom became the most dominant from November 2010 to May 2011. The diatom was sensitive to water temperature. Microcystis spp. and Oscillatoria spp. as cyanobacteria were dominant during summer and fall, and sank down to the sediment during winter and spring. Increasing water temperature during summer causes anaerobic conditions in the sediment, leading to regrowth of cyanobacteria. With regard to the ratio of total nitrogen (TN) to TP, green algae and cyanobacteria were dominant at TN:TP ratios less than 20-30. Diatoms were dominant at TN:TP ratios greater than 30-40. Statistical analysis indicated that diatom growth was dependent on water temperature and TN concentration. TP concentration and water temperature were the key factors for the growth of cyanobacteria and green algae. From these results of this study, the management of land-use was an important parameter for improving water quality in the agricultural reservoir.

• Journal of The Korean Society of Agricultural Engineers
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• v.54 no.3
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• pp.91-101
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• 2012

This study is to assess the runoff characteristics of nonpoint source pollution loads for Jecheon and Jangpyeong stream watersheds located in the upstream of Chungju lake. The SWAT (Soil and Water Assessment Tool), a physically based distributed hydrological model was calibrated and verified using 5 years (2006 to 2010) streamflow and water quality data. The Nash-Sutcliffe model efficiency for streamflow was 0.60~0.92 and the determination coefficients for sediment, Total Nitrogen (T-N), and Total Phosphorous (T-P) were 0.53~0.71, 0.51~0.91 and 0.38~0.85 respectively. The results showed that the Sediment, T-N, and T-P of Jangpyeong stream were 40.0~60.9 %, 34.8~64.1 % and 76.5~83.9 % higher than Jecheon stream watershed during wet days. The results evaluated high NPS loads at Jangpyeong stream because the percentage of urban and upland crop cultivation area Jangpyeong stream watershed was higher than Jecheon stream watershed.

• Journal of Wetlands Research
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• v.9 no.2
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• pp.57-69
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• 2007

This study focused on coastal water quality response to land-based and sediment pollution loads and estimation of the carrying capacity in Masan Bay using an ecological model with the data in summer of 2002. A residual current was simulated to have a slightly complicated pattern with ranging from 0.1 to 1.5 cm/s. In Masan Bay, pollutant materials cannot flow from the inner to the outer bay easily because of residual currents flow southward at surface and northward at the bottom. The simulation results of COD distribution showed high concentrations over 3 mg/L in the inner part of Masan Bay related pollutant discharge. For improvement seawater quality grade I in Masan Bay, it is necessary to reduce the organic and inorganic loads from point sources by more than 80%. For improvement seawater quality grade II, it is necessary to reduce the organic and inorganic loads from point sources by more than 50% and ameliorate severe polluted sediment. The carrying capacity for COD is 2.32 ton/day and 7.16 ton/day for each grade.

• Journal of the Korean Geotechnical Society
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• v.24 no.10
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• pp.105-111
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• 2008

To improve the stability of levee structure, it is required to use good quality fill materials, intensive management, appropriate hydraulic structure and construction of cut-off wall. In particular, the most important factor of levee construction technology is to use bed sediment for its safety. In this study, seepage model test and numerical analysis were performed based on a standard section of levee recommended in the river design standard of korea (2005). The results of test and analysis show that most of the bed soil is a sand (SP in USCS), which does not satisfy the permeability criteria for levee materials ($< k=10^{-3}cm/sec$), thus for the safety of levee it is required to adopt a stabilizing method such as good quality soil mixing, water content control.

• Analytical Science and Technology
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• v.14 no.2
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• pp.173-179
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• 2001

The study was carried out to analyze the pollutant Fe, Cu, Cr, Zn, Cd for sediments collected from lake in K river basin. Three analytical methods currently used in Korea, Japan, U.S.A, were compared. Pretreatment using microwave digestion showed higher analytical results for Fe, Cu, Cr, Zn, Cd than Korean Official Method(KOM) and American Toxicity Characteristic Leaching Procedure(TCLP) Method. Also, analytical results using microwave digestion, TCLP and KOM were as follows: 38.1-48.0 mgFe/kg, 10.2-15.9 mgFe/kg AND 3.5-12.6 mgFe/kg, 37.0-50.1 mgCu/kg, 0.06-0.24 mgCu/kg and 0.01-0.03 mgCu/kg, 137.0-152.0 mgZn/kg, 0.67-0.82 mgZn/kg and 0.3-0.5 mgZn/kg, respectively. From this result, a new analytical method for the determination of heavy metal in sediment should be developed for the accurate estimation of pollution degree in sediment.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.48 no.4
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• pp.542-554
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• 2015

Grain size, the content of ignition loss (IL), and the concentrations of chemical oxygen demand (COD), acid volatile sulfide (AVS), and trace metals (Fe, Mn, Cu, Pb, Zn, Cd, Cr, As, and Hg) in surface sediments from the Taehwa River estuary, Ulsan, were measured to evaluate pollution levels and potential ecological risks of organic matter and trace metals in estuarine sediment. The mean grain size (Mz) of sediments in the study region ranged from $-0.8-7.7{\varphi}$ (mean $2.8{\pm}2.4{\varphi}$). Surface sediments in the upstream region of the Taehwa River were mainly composed of coarse sediments compared to the downstream region. The concentrations of IL, COD, AVS and trace metals in the sediment were much higher at downstream sites of Myeongchon Bridge in the vicinity of industrial complexes than at upstream sites of those in the vicinity of the residential areas due to the anthropogenic input of organic matter and trace metals by industrial activities. On the basis of several geochemical assessment techniques [sediment quality guidelines (SQGs), enrichment factor (EF), geoaccumulation index ($I_{geo}$), pollution load index (PLI) and ecological risk index (ERI)], the surfaces sediments in the study region are not highly polluted for trace metals, except for As. However, the higher concentrations in downstream study regions of the Taehwa River could impact benthic organisms including shellfish (i.e. Manila clam) in sediments.