A sea/land breeze circulation system and a regional scale circulation system are formed at a region which has complex terrain around coastal area and affect to the dispersion and advection of air pollutants. Therefore, it is important that atmospheric circulation model should be well designed for the simulation of regional dispersion of air pollutants. For this, Local Circulation Model, LCM which has an ability of high resolution is used.
To verify the propriety of a LCM, we compared the simulation result of LCM with an exact solution of a linear theory over a simple topography. Since they presented almost the same value and pattern of a vertical velocity at the level of 1 ㎞, we had a reliance of a LCM.
For the prediction of dispersion and advection of air pollutants, the wind field should be calculated with high accuracy. A numerical simulation using LCM will provide more accurate results over a complex terrain around coastal area.
This study was conducted to develop the questionnaire for the measurement of environmental attitudes and test its reliability and validity. Development and validation of the 46 survey items that measure environmental attitudes were described. The total of 3 surveys were conducted and the total of 510 persons including diverse sample groups were questionnaired. The SAS PC+ package program was used in both the reliability analysis and the validity analysis of surveyed data. Results revealed the very high reliability and the high validity of the questionnaire. The reliability of the finalized questionnaire was increased to the level of Cronbach-α 0.92 after the repeated reliability analyses and revisions of the firstly and secondly designed questionnaires. The validity of our questionnaire was sufficiently affirmed through the use and application of factor analysis and known-groups technique.
This study was carried out to determine the antimutagenic effects of genistein on the somatic mutagenicity induced by aflatoxin B1 (AFB1), using Drosophila wing spot test system. Mutagen alone or mutagen with genistein were administered to the heterozygous(mwh/+) third instar larvae by feeding, and somatic cell mutations were detected in adult fly wing hairs.
Genistein did not show any mutagenicity with the feeding concentrations of 5∼15% in the test system. As the feeding concentrations of genistein increased, genistein inhibited the mutagenicity induced by AFB1 (14.6%∼62.2% inhibition rate), while as the concentrations of AFB1 increased, small mwh spots that arise mostly from chromosome deletion and nondisjunction were more strongly suppressed by genistein than the large mwh spots from chromosomal recombination. In each group of different AFB1 concentrations, the rate of inhibition for total mwh spots was dependent on the dose of genistein.
These results indicate that genistein have inhibitory effect on the mutagenicity induced by a mutagen, AFB1. It seems to suggest that genistein may exert inhibitory effects to mutagenic and/or carcinogenic properties of DNA damaging agents.
From the environmental aspects, primary productivity of phytoplankton plays the most important role in enhancement of marine culture oyster production. This study may be divided into two branches; one is estimation of maximum oyster meat production per unit facility(Carrying Capacity) under the present environmental conditions in Kamak Bay, the other is improvement of carrying capacity from increase of primary productivity by changing the environmental conditions that cause not to form an unfavorable environment such as the formation of oxygen deficient water mass using the eco-hydrodynamic model. By simulation of three-dimensional hydrodynamic model and ecosystem model, the comparison between observed and computed data showed good agreement. The results of sensitivity analysis showed that phytoplankton maximum growth rate was the most important parameter for phytoplankton and dissolved oxygen. The estimation of mean primary productivity of Wonpo, Kamak, Pyongsa, and Kunnae culture grounds in Kamak Bay during culturing period were 3.73gC/㎡/d, 2.12gC/㎡/d, 1.98gC/㎡/d, and 1.26gC/㎡/d, respectively. Under condition not to form the oxygen deficient water mass, four times increasing of pollutants loading as much as the present loading from river increased mean primary productivity of whole culture grounds to 4.02gC/㎡/d. Sediment N, P fluxes that allowed for 35% increasing from the present conditions increased mean primary productivity of whole culture grounds to 3.65gC/㎡/d. Finally, ten times increasing of boundary loadings from the present conditions increased mean primary productivity of whole culture grounds to 3.95gC/㎡/d. The maximum oyster meat production per year and that of unit facility in actual oyster culture grounds under the present conditions were 6,929ton and 0.93ton, respectively. This 0.93ton/unit facility is considered to be the carrying capacity in study area, and if the primary productivity is increased by changing the environmental conditions, oyster production can be increased.
The purpose of this study was to identify the controlling factors to construct tidal flat ecosystems having similar characteristics as natural ones. We transplanted the soil in a constructed tidal flat to a natural one and vice versa. Parameters monitored after these transplantations were silt content, organic matter, bacterial population and oxidation-reduction potential. Moreover, the relationship among silt content, organic matter and bacterial population was investigated by laboratory column experiment.
The silt content, organic matter, bacterial population and vertical profile of oxidation-reduction potential in the soil transplanted from the constructed tidal flat to the natural one changed to similar values to those in the natural one. On the contrary, all the parameters for the soil transplanted from the natural tidal flat to the constructed one changed to similar values as those in the constructed one. The silt contents in these two transplanted soils were in proportion to the organic carbon contents and bacterial population. Similarly, the bacterial population in laboratory column experiment increased with the increase in silt and organic matter contents.
It seemed to be important to select a place to enhance accumulative of silt and/or to maintain the silt content by hydrodynamic control of seawater in order to construct a tidal flat having similar characteristics as natural one.
In order to determine the changes of sediment facies and metal levels in surface sediments after the construction of Shiwha Lake, surface sediments were sampled at 8 sites located on the main channel monthly from June, 1995 to August, 1996 and analysed for 12 metals (Al, Fe, Mn, V, Cr, Co, Ni, Cu, Zn, Cd, As and Pb) by ICP/AES and ICP/MS.
Two groups of sampling sites (the inner lake with 3 sites and the outer lake with 5 sites) are subdivided by the surface morphology; the inner lake is a shallow channel area with a gentle slope, while the outer lake is relatively deep and wide channel with a steep slope which has many small distributaries.
After the construction of dam, fine terrestrial materials were deposited near the outer lake, which resulted in the change of major sediment facies from sandy silt to mud. With the deposition of fine sediments in the outer lake, anoxic water column induced the formation of sulfide compounds with Cu, Cd, Zn and part of Pb. Metal (Cr, Ni, Cu, Zn and Cd) contents in sediments increased up to twice within 2 years after the construction of dam. This is due to the direct input of industrial and municipal wastes into the lake and the accumulation of metals within the lake. In addition, frequent resuspension of contaminated sediments in a shallow part of the lake may make metal-enriched materials transport near the outer lake with fine terrestrial materials. As the enrichment of Cu, Zn, Cd and part of Pb in the Shiwha Lake may be related to the formation of unstable sulfide compounds by sulfate reduction in anoxic water or sediment column, the effect of mixing with open coastal seawater is discussed.
This study has been performed to evaluate mineral water quality by using four parameters [Mg]/[Ca], [Na]/[K], [Mg]+[Ca]/[Na]+[K] and total hardness(as CaCO3 ㎎/ℓ). The four parameters has been ploted in a general scale and logarithmic scale, respectively. The method of general scale is not applicable for evaluation on several parameters. Therefore, The logarithmic scale is applied instead to settle the problem. The evaluation of the water quality is based on standard sample S, and the results of the 6 domestics and 5 overseas sample evaluation are as follow. At present, evaluation of the water quality on the mineral water can be done by using four parameters calculated from only cation concentration printed on the bottle's marking.
The odor removal of landfill site leachate was carried out using pyroligenous liquid. The constituent elements of pyroligenous liquid and leachate were also analysed, employing Atomic Absorption Spectroscopy(AAS). Before order removal, the heavy metal ions such as Pb, Zn, Cu, Mn, Fe and Ni, in pyroligenous liquid were detected with ultra trace level. However, in this liquid, other metal ions such as As, Hg and Cd were not observed.
The optimum condition for removing odor from the leachate was observed in 15 times dilution of pyroligenous liquid. Also, the degree of outlet odor was 1. Furthermore, the concentration of odor constituent compounds, e.g. H2S, NH3, NH2 and CO2 in the leachate was remarkably reduced. Finally, water quality of the leachate was improved,
The diagnostic software for the wastewater treatment plant using activated-sluge process is developed in order to increase the efficiency of management of the wastewater treatment plant. This software is based on the expert system and the visualized user interface including the diagnosis of quantitative and qualitative data. For the generalization of this software, the initialization of each unit process and updating the files can be possible.
This study was carried out to obtain the optimal operating parameter on organic matters and nutrient removal of mixed wastewater which was composed of sewage and stable wastewater using SBR. A laboratory scale SBR was operated with An/Ae(Anaerobic/ Aerobic) ratio of 3/3, 2/4 and 4/2(3.5/2.5) at organic loading rate of 0.14 to 0.27 ㎏BOD/㎥/d. TCOD/SCOD ratio of mixed wastewater was 3, so the important operating factor depended upon the resolving the particulate parts of wastewater.
Conclusions of this study were as follows:
1) For mixed wastewater, BOD and COD removal efficiencies were 93-96% and 85-89%, respectively. It was not related to each organic loading rate, whereas depended on An/Ae ratio. During Anaerobic period, the amount of SCOD consumption was very little, because ICOD in influent was converted to SCOD by hydrolysis of insoluble matter.
2) T-N removal efficiencies of mixed wastewater were 55-62% for Exp. 1, 66-76% for Exp. 2, and 67-81% for Exp. 3, respectively. It was found that nitrification rate was increased according to organic concentration in influent increased. Therefore, the nitrification rate seemed to be achieved by heterotrophs. During anoxic period, denitrification rate depended on SCOD concentration in aerobic period and thus, was not resulted by endogenous denitrification. However, the amount of denitrification during anaerobic period were 3.5-14.1㎎/cycle, and that of BOD consumed were 10-40㎎/cycle.
3) For P removal of mixed wastewater, EBPR appeared only Mode 3(3*). It was found that the time in which ICOD was converted to VFA should be sufficient. For mode 3 in each Exp., P removal efficiencies were 74, 87, and 81%, respectively. But for 45-48 of COD/TP ratio in influent, P concentration in effluent was over 1 ㎎/L. It was caused to a large amount of ICOD in influent. However, as P concentration in influent was increased, the amounts of P release and uptake were increased linearly.
This study was performed to determine the optimum coagulant dosing for effective treatment of raw water in Chinyang lake. Removal rates of algae and characteristics of the water according to coagulants dosage were investigated by treatment with Microcystis aeruginosa, which is a kind of blue-green algae, to the raw water below 5NTU. The coagulants dosage for maximum removal rate of algae were 30 ㎎/ℓ of Alum, 30 ㎎/ℓ of PAC and 10 ㎎/ℓ of PACS, respectively. The removal rate of algae in 30 ㎎/ℓ of PAC was highest as 85% compared with the other treatments. At the point of maximum removal rate of algae, the removal rates of turbidity were 34%, 66% and 22% in Alum, PAC and PACS, respectively. Residual Al was decreased depend upon decreasing turbidity in water by treatment of Alum or PAC, but decreased depend upon increasing turbidity in water by treatment of PACS. The removal rate of Mn2+ in water was high in the order of Alum, PAC and PACS treatment. And Fe2+ in water was not changed by treatment of these coagulants. Particle numbers distributions according to the particle size of suspended solids that were not precipitated at 8 min. of settling time after treatment of coagulants dosage for the maximum removal rate of algae were investigated. Most of the particle sizes were below 30 ㎛ and particle numbers distributions below 10 ㎛ were 64%, 56% and 66% by treatment of Alum, PAC and PACS, respectively. Zeta potential was in the range of -6.1∼-9.7 mV at optimum coagulants dosage for algae removal.
A series of meteorological observation using automation weather station(AWS) carried out to investigate characteristics of nocturnal meteorological parameters for 16∼17 June 1998 at Buljeongdong mountain slope, Kyungbuk. Dry temperature at valley was lower than mountain because of high lapse rate at valley, so the strong inversion layer occurrenced at mountain slope for nighttime. Contrary of dry temperature, relative humidity of valley was higher than mountain for nighttime. Wind speed at valley from sunset to next day morning was lower than mountain, but that of valley after sunrise was higher than mountain. Wind direction at valley for all observation time were southeasterlies(SE), that of mountain for nighttime were northeasterlies(NE) or northnorthwesterlies(NNW), and that of mountain after sunrise were irregular. Vapor pressure at valley for all observation time was higher mountain, particularly the difference was high for nighttime.