• Journal of Environmental Health Sciences
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• v.35 no.5
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• pp.376-385
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• 2009

The characteristics of Lake Cheonhoji water and sediment were investigated in oder to utilize these as fundamental materials for the management of lake water quality. The hydrographic properties of Lake Cheonhoji which are relatively low chance of nutrients loading from the watershed and a long retention time of lake water, lead to the probability of high lake productivity. It was also observed that lake water showed stratification during summer and complete mixing during fall, even though water depth was relatively shallow. The trophic state was eutrophic to hypertrophic from summer to late fall. The overall properties of the sediment were oligohumic, high ignition loss and high composition of NAIP and Resid.-P, which might serve as potential pollution sources of lake water quality. In laboratory scale experiments, it was observed that leaching potential of nutrients in the sediment was greatly dependant upon water temperature and dissolved oxygen. Finally, water pollution in Lake Cheonhoji was considered to be largely due to the adverse cycle of uncontrollable eutrophication, which resulted in the subsequent occurrence of dead algae and animal plankton, organic sedimentation, reduction of dissolved oxygen and nutrients leaching, which again reinforced the cycle of eutrophication in the lake.

• Journal of Environmental Impact Assessment
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• v.7 no.2
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• pp.5-14
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• 1998

This study was performed to estimate interrelation between characteristics of sediment and nutrient releare from sediment in Dae-cheong lake. For the investigations, sediments were sampled in June and October 1997 at fish farms, embayment, and the main stream of Dae-cheong lake. Items for investigation are as follows; water content, weight loss on ignition(IG), porosity of sediment, Total Kjeldahl Nitrogen(TKN), content of element(H, N, C), nutrient release rate. Water content and porosity were measured to conjecture the physical trait and grain size. And weight loss on ignition was measured to determine the contents of organic substance. For the determination of nutrient release rate, $PO_4-P$ and $NH_4-N$ concentration of interstitial water and overlying water were measured. Release rate of nutrients which has direct influenced upon the water quality were 0.05-8.63mg-$P/m^2{\cdot}day$ and 4.99-36.56mg-$N/m^2{\cdot}day$. And it was found that release rate was measured higher in the 1st sampling than in the 2nd sampling. And for determination of the humus level of sediment, carbon and nitrogen content were measured by using elemental analyzer. Generally, C/N ratio is used to determine humus level of lake sediment. As a result of elemental analysis, C/N ratio was determined in the range of 7.64~11.55, so humus level of Dae-cheong lake sediment was estimated from mesohumic state to oligohumic state.

• Journal of Environmental Impact Assessment
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• v.8 no.1
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• pp.107-120
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• 1999

This study was performed to survey the general feature of reservoir sediment in Daecheong, Sapkyo and Kumkang reservoir. For investigations, sediments were sampled at four sites in Dae-Cheong and two sites in SapKyo and Kumkang in June and October. The items for investigation are as follows; water content, loss on ignition(IG), porosity of sediment, contents of element such as hydrogen, nitrogen, carbon, phosphorus contents and nutrient release rates. Loss on ignition was measured to determine the contents of organic substance. And its ranges were determined 2.4~16.2% in Daecheong reservoir, 5.6~27.9% in Sapkyo and 4.8~18.7% in Kumkang reservoir. And, total phosphorus contents in sediments were measured $677{\sim}5,238{\mu}g/g$ in Daecheong, $780{\sim}1,417{\mu}g/g$ in Sapkyo and $604{\sim}1,452{\mu}g/g$ in Kumkang reservoir. And release rates of nutrients were calculated $0.05{\sim}8.63mgP/m^2day$ and $4.99{\sim}36.56mgN/m^2day$ in Daecheong, $1.83{\times}10^{-3}{\sim}3.23{\times}10^{-2}mgP/m^2day$ and $1.97{\sim}.22mgN/m^2day$ in Sapkyo, $8.31{\times}10^{-3}{\sim}6.51{\times}10^{-2}mgP/m^2day$ and $0.89{\sim}4.42mgN/m^2day$ in Kumkang reservoir, respectively. And this study attempted to determine the humus level of sediments. As a result of elemental analysis, C/N ratio was determined 3.0~13.1 in Daecheong reservoir, 6.5~13.0 in Sapkyo and 3.6~12.6 in Kumkang reservoir, respectively. From the elemental analysis, humus levels of reservoirs were changed from mesohumic to oligohumic state in all reservoirs.