간행물
한국환경과학회지 KCI 등재 Journal of Environmental Science International
- 발행기관 한국환경과학회
- 자료유형 학술지
- 간기 월간
- ISSN 1225-4517 (Print)2287-3503 (Online)
- 수록기간 1992 ~ 2023
- 주제분류 자연과학 > 자연과학일반 자연과학 분류의 다른 간행물
- 십진분류KDC 539DDC 628
권호리스트/논문검색
제17권 제3호 (2008년 3월) 10건
1.
2008.03
서비스 종료(열람 제한)
The objective of this study was to evaluate the relationship between nutrients and phytoplankton. This study was done by the comparison to two costal areas Mokpo, which inflow fresh water, and Wando. In August, salinity of the sea water decreased by 3.5-4.5‰ in Mokpo coastal area, but was not nearly decreased in Wando coastal area. This suggests a lot of fresh water inflow in Mokpo coastal area. DIN and DIP were decreased by water temperature increasing in Wando. However, in Mokpo, DIN and DIP were increased greatly during the summer season. Nitrogen was limited to a 10 N/P ratio especially during the summer season in Wando coastal area while phosphorus in Mokpo coastal area was limited with over 28 N/P ratio in all the seasons. Coefficient of determination(r2) between DIP and Chl.-a was 0.91 in Mokpo coastal area. On the other hand, Coefficient of determination(r2) between Chl.-a and DIN, DIP were 0.93 and 0.89, respectively, in Wando coastal area. These results suggest DIP in Mokpo and DIN and DIP in Wando might be limited at the increase of phytoplankton.
2.
2008.03
서비스 종료(열람 제한)
The floc formation, breakage and reformation of humic acid by inorganic (alum and PAC) and organic coagulants (cationic polyelectrolytes) at several conditions (pH, ionic strength and floc breakage time) were examined and compared among the coagulants at different conditions using a continuous optical monitoring method, with controlled mixing and stirring conditions. For alum, the shapes of formation, breakage and reformation curves at different pH (5 and 7) were different, but the shapes and the sizes of initial floc and reformed floc were nearly the same in the absence and presence of electrolytes at pH 7. For PAC, similar shapes of the curves were obtained at different pH and ionic strength, but the sizes were different, except for those of reformed flocs at different pH. However, for these coagulants, reformed flocs after floc breakage, occurred irreversibly for all the conditions used in this study. For organic coagulants, the time to attain the initial plateau floc size, the extent of floc strength at high shear rate and reversibility of reformed flocs were different, depending floc formation mechanism. Especially, for the cationic polyelectrolyte forming humic flocs by charge neutralization or electrostatic patch effect mechanism, reformed flocs occurred reversibly, regardless of pH and floc breakage time, but occurred irreversibly in the presence of electrolytes.
3.
2008.03
서비스 종료(열람 제한)
A comprehensive quality survey for heavy metals, organophosphorous and organochlorine residual pesticides, and coplanar PCBs in samples such as water, sediments and soils as well as spiders has been implemented. The samples were undertaken at nine stream sites and their vicinity in August 2006, representing different surrounding environments. The levels of PCBs were expressed as concentrations and WHO-TEFs. Among 12 coplanar PCBs as target compounds in this study, 2,3',4,4',5-PentaCB (IUPAC # 118) was the congener with the highest concentration. The total concentrations and TEF values of coplanar PCBs in Siheung stream sediment (heavy industrial complex site located in Ansan city) were 3915.50 pg/g and 0.8366 pg-TEQ/g on a dry weight basis, respectively. Such levels were around 40 times higher compared to sediment from Gapyung stream (green site located in the upper of Myunggi mountain). It is probably due to the direct input of PCBs from PCBs treatment materials. Organophosphorous (EPN, dementon-s-methyl, diazinon, parathion, and phenthoate) and organochlorine (alpha-BHC, aldrin, 4,4'-DDT, 4,4'-DDE, endosulfan alpha and etc.) pesticides were not detected above 5 ppb of detection limits. The concentrations of Cu and Cd in water and sediment samples from Siheung stream were 44.11 and 0.17 ug/㎖ and 713.42 ㎍/g and 3.73 ㎍/g, respectively, which contained 20～40 times higher concentrations than those from Gapyung stream. In addition to the water and sediment samples, the levels of heavy metals in spider from designated sampling sites were also determined. Heavy metals in spider collected near Siheung stream was appeared to be equivalent and/or a little higher levels with respect to other spiders. Furthermore, the ratio of relative heavy metals (Cu, Cd, and Pb) in spider from each stream site showed a correlation as similar as that of heavy metals in soil samples.
4.
2008.03
서비스 종료(열람 제한)
For last couple of years many apartments, roads and bridges are constructed along the Kok-kyo stream which is penetrating Asan city, Chung-Nam Province. The effect of construction on stream environment was investigated in this study. Various kinds of water qualities of the Kok-kyo stream were monitored for 5 months. As it passed through the construction sites, CODcr concentration increased abruptly whereas the increment of the BOD5 was not so great, indicating that non-biodegradable organics were flowed from the construction sites to the stream. Particularly, 0.2 mg/L of N-hexane was measured, which is believed to be mainly responsible for the organic pollution from construction sites. In spite of short periods of water quality monitoring, it could be concluded that there was a good correlation between construction sites and stream pollution. Therefore, legislative activity or enforced management by local government to the construction sites are needed for keeping the small stream environment better.
5.
2008.03
서비스 종료(열람 제한)
As forest land takes up 65% of the Korean peninsula, there have been continuing conflicts between the development and conservation of forest land. As the income level has changed over time, the usage of forest land in society has changed. There has been increasing demands for forest land for urban development and recreational use. On the other hand, a large proportion of the land is required to be preserved for the forest and the natural ecosystem in it. The existing management system for the forest land has been designed focusing on the management of the trees on the land, and not the land itself. Due to this limitation, the current management system of forest land has failed to protect the forest land from being developed indiscreetly, making it difficult to conserve and develop the forest land in an efficient way. A major question in forest land management is how to integrate economic use activities with the supporting ecosystems to maximize performance of the ecological-economic system. In order to promote sustainable use of forest resources, and to achieve efficient forest land management, it is prerequisite to evaluation on forest resources of natural ecosystems. Quantitative measures are needed that signify how necessary the services and products of forested ecosystems are to human endeavors. In this study, the natural wealth provided by forest land was quantified based on emergy synthesis. Emergy is a universal measure of real wealth of the work of nature and society made on a common basis. Thus, Calculations of emergy provide a basis for making choices about environment and economy following the general public policy to maximize real wealth. The goals of forest land management to achieve balance between the ecology and economy of its integrated system and to foster equity among the diverse outcomes of the forest land were assessed with emergy. Emergy was demonstrated to holistically integrated and quantify the interconnections of a coupled nature-human system allowing the goals of ecological balance and outcome equity to be measured quantitatively. Doing so will provide a better understanding of the basis of forest land wealth and the consequences of management decisions.
6.
2008.03
서비스 종료(열람 제한)
Based on the result of extraction of common factors executed in order to elucidate the visual attributes of street scenery by types through the rotation of 23 adjective variables by Varimax, the visual attributes expressed after the construction of the facilities using street scenery were anylized to be 4 factors including factor 1 through factor 4. The explanation of the 4 factor groups to explain the entire distribution was 65.3% and these factor groups are the psychological attributes felt when using facilities are constructed by securing the street spaces in downtowns and the factors were named as naturalness(factor 1), locality(factor 2), identity(factor 3) and clarity(factor 4) respectively. Based on the result of one-way layout distribution analysis, the preferences for street scenery by types were found out to show considerable differences at 1% significance level. Based on the result of multiple regression analysis, all of the factors explaining preferences including factor 1 through factor 4 were significant at 1 % significance level. In case other conditions are constant, if the values of the adjective variables related to locality(factor 2) increase by 1 unit, the preferences which are the values of dependent variables will increase by 0.709. The variable with the largest relative contribution among the 4 factor groups was the locality(factor 2) factor group and on the contrary, it was found that the independent variable with least influences was the clarity(factor 4) factor group.
7.
2008.03
서비스 종료(열람 제한)
The feasibility of the automation of upper-air sounding is examined by using recent 3-year(2002~2004) observation data from Autosonde at Haenam, Korea. The Autosonde has been successfully operated since 2002 in order to produce an intensive observation data at high-impact weather events for research purpose. It is found from the analysis of recent 3 years' operation data of the system that the system could be capable of making a stable observation when strong wind greater than 20 m/s was recorded under the influence of typhoons Rusa in 2002 and Maemi in 2003. It might be concluded that there is some possibility in automating upper-air sounding for operational purpose through the reduction of operator's payment and operating cost for upper-air sounding.
8.
2008.03
서비스 종료(열람 제한)
This study based on electro-coagulation & oxidation reaction is applied to wastewater treatment. Electro-oxidation reaction is used to remove cyanide(CN) which is contained in plating wastewater. Cyanide is transferred by gases such as NH3, NOx, CO2. Analysis result and removal efficiency of Cyanide which is contained in heavy metal wastewater of plating plant, are shown as following paragraph. In electrode arrangement experiment, removal efficiency of carbon electrode(-)/STS316L electrode(+) arrangement method is superior to carbon electrode(-)/carbon electrode(+) arrangement method. Removal efficiencies of cyanide in different HRT such as 30 min, 45 min, 60 min, 75 min and 90 min are 85.5%, 93.1%, 98.0%, 98.7% and 99.4% respectively in carbon electrode(-)/STS316L electrode(+) arrangement method. Finally we can estimate the critical point at HRT of 60 min which the variation of removal efficiency is decreased and HRT to obtain removal efficiency of less than 1 ㎎/LCN is minimum 90 min.
9.
2008.03
서비스 종료(열람 제한)
The fate of two cyclic ethers, THF(Tetrahydrofuran) and 1,4-Dioxane, in conventional biological wastewater treatment plants was investigated using sequential activated sludge process. Removal efficiency of THF were about 86% in average, which was greater than that of 1,4-Dioxane, 30%. However, it was not clear whether the removal of cyclic ethers in biological system was caused by microbial activity or not. Thus treatability tests were conducted by batch experiments. The effects of mixing, aeration and the addition of activated sludge on the removal of cyclic ethers were investigated in batch experiments. THF was totally removed by mixing and aeration in 24 hours while removal ratio of 1,4-Dioxane was at most 30% for the same period. This results could be ascribed to the differences in Henry's law constants between the two chemicals. In addition, biological degradation including biosorption was not obviously observed in these batch tests.
10.
2008.03
서비스 종료(열람 제한)
In order to develope an efficient way for the synthesis of highly pure 1,4-sorbitan solution from sorbitol, some experimental studies were performed. The reaction showed first order reaction with activation energy of 118.3 KJ/mol. Color of the product solutions changed to brown with reaction temperature and reaction time. The equilibrium contents of 1,4-sorbitan increased with decrease in reaction pressure, but the content of major impurity, sorbide, showed maximum about 550 torr vacuum with H3PO4 catalyst. The reasonable catalyst configuration was 0.26 wt% PTSA and 1 wt% H3PO2 and optimum reaction temperature and pressure range was 110～120℃ and 700～720 torr vacuum, respectively. At optimum reaction conditions, we could obtain white product solutions of highly pure 1,4-sorbitan with sorbide less than 10 wt%. This white product solution is advantageous for preparation of high quality span, anti-fogging agent.
