• Korean Journal of Ecology and Environment
• /
• v.46 no.4
• /
• pp.524-540
• /
• 2013

After the construction of the Geum River estuary dam, we investigated the ecological property of phytoplankton community with physicochemical property in 9 stations of Geum River estuary 4 times seasonally in 2010 about the environmental changes through the change of phytoplankton. Physicochemical property seems to show eutrophication which developed from the tendency of accruing of the nutrients (those involved in intermittency of freshwater which flows from the dike and the surrounding cities), caused by the changing of tidal flow, the decreasing of the inflow of seawater after the construction of the Geum River estuary dam (dike). A total of 233 species of species composition of phytoplankton emerged, showing a highly increased result compared to that of the former research. The reason for the increase in number is considered as a phenomenon resulting from the mix of blackish and freshwater marine species in the flow of intermittency of freshwater discharge. Also, the standing crops of phytoplankton considerably increased compared to when the dike had not yet been built. Highly affected by the discharge of occasional freshwater, the diatoms of blackish water zone dominated in spring and winter, while freshwater species appeared to dominate in summer and autumn. The species diversity showed over 2.0 except in winter season. After a cluster analysis, the result showed that the Geum River estuary was influenced by runoff from cities like Gunsan, the sewage which flows from Gyeongpo River, and the intermittency of freshwater discharge from the Geum River estuary dam.

• Geophysics and Geophysical Exploration
• /
• v.10 no.1
• /
• pp.98-109
• /
• 2007

Over the last twenty years, farmers in Western Australia have begun to change land management practices to minimise the effects of salinity to agricultural land. A farm plan is often used as a guide to implement changes. Most plans are based on minimal data and an understanding of only surface water flow. Thus farm plans do not effectively address the processes that lead to land salinisation. A project at Broomehill in the south-west of Western Australia applied an approach using a large suite of geospatial data that measured surface and subsurface characteristics of the regolith. In addition, other data were acquired, such as information about the climate and the agricultural history. Fundamental to the approach was the collection of airborne geophysical data over the study area. This included radiometric data reflecting soils, magnetic data reflecting bedrock geology, and SALTMAP electromagnetic data reflecting regolith thickness and conductivity. When interpreted, these datasets added paddock-scale information of geology and hydrogeology to the other datasets, in order to make on-farm and in-paddock decisions relating directly to the mechanisms driving the salinising process. The location and design of surface-water management structures such as grade banks and seepage interceptor banks was significantly influenced by the information derived from the airborne geophysical data. To evaluate the effectiveness ofthis planning., one whole-farm plan has been monitored by the Department of Agriculture and the farmer since 1996. The implemented plan shows a positive cost-benefit ratio, and the farm is now in the top 5% of farms in its regional productivity benchmarking group. The main influence of the airborne geophysical data on the farm plan was on the location of earthworks and revegetation proposals. There had to be a hydrological or hydrogeological justification, based on the site-specific data, for any infrastructure proposal. This approach reduced the spatial density of proposed works compared to other farm plans not guided by site-specific hydrogeological information.

• Korean Journal of Ecology and Environment
• /
• v.43 no.1
• /
• pp.55-68
• /
• 2010

The seasonal variation of microbial community, based on the bacteria, heterotrophic nanoflagellates (HNF), phytoplankton and ciliates, was investigated at three sites in the eutrophic brackish water of Lake Shihwa and its adjacent areas from May 2007 through May 2008. At the upstream-region site St. 1, compared to the other two sites, significantly lower salinities and higher concentrations of nutrients and chlorophyll $\alpha$ (Chl. $\alpha$) were recorded. The annual average abundances of bacteria at St. 1, St. 2 and St. 3 were $6.8{\times}10^6$, $7.4{\times}10^6$ and $4.6{\times}10^6\;cells\;mL^{-1}$, respectively. As for the annual average concentrations of HNF, $19{\times}10^2$, $6.7{\times}10^2$ and $5.9{\times}10^2\;cells\;mL^{-1}$, were recorded in St. 1, St. 2 and St. 3 respectively. The highest ciliate abundance appeared at St. 1 on 29 April, 2008 and in which, 99% were autotrophic ciliate Mesodinium rubrum (Myrionecta rubra). Significant linear correlations between the biomass of bacteria and Chl. $\alpha$ were found, however, no significant relationships between ciliates abudance/biomass and their prey organisms were detected in all three sites, implying relatively low energy transfer efficiencies between them. These results indicated that the trophic relationship between ciliates and their prey organisms in the microbial community might be influenced by indirect route since higher trophic level organisms did not directly correlate to those of lower trophic level, although high primary productions were detected in the eutrophic brackish water of Lake Shihwa and its adjacent areas.

• Journal of the Mineralogical Society of Korea
• /
• v.26 no.2
• /
• pp.101-110
• /
• 2013

Due to the large specific surface area and great reactivity toward environmental contaminants, nanocrystalline mackinawite (FeS) has been widely applied for the remediation of contaminated groundwater and soil. Furthermore, nanocrystalline FeS is rather thermodynamically stable against anoxic corrosion, and its reactivity can be regenerated continuously by the activity of sulfate-reducing bacteria. However, nanocrystalline mackinawite is prone to either spread out along the groundwater flow or cause pore clogging in aquifers by particle aggregation. Accordingly, this mineral should be modified for the application of permeable reactive barriers (PRBs). In this study, coating methods were investigated by which mackinawite nanoparticles were deposited on the surface of alumina or activated alumina. The amount of FeS coating was found to significantly vary with pH, with the highest amount occurring at pH ~6.9 for both minerals. At this pH, the surfaces of mackinawite and alumina (or activated alumina) were oppositely charged, with the resultant electrostatic attraction making the coating highly effective. At this pH, the coating amounts by alumina and activated alumina were 0.038 and 0.114 $mmol{\cdot}FeS/g$, respectively. Under anoxic conditions, arsenite sorption experiments were conducted with uncoated alumina, uncoated activated alumina, and both minerals coated with FeS at the optimal pH for comparison of their reactivity. Uncoated activated alumina showed the higher arsenite removal compared to uncoated alumina. Notably, the arsenite sorption capacity of activated alumina was little changed by the coating with FeS. This might be attributed to the abundance of highly reactive hydroxyl functional groups (${\equiv}$AlOH) on the surface of activated alumina, making the arsenite sorption by the coated FeS unnoticeable. In contrast, the arsenite sorption capacity of alumina was found to increase substantially by the FeS coating. This was due to the consumption of the surface hydroxyl functional groups on the alumina surface and the subsequent occurrence of As(III) sorption by the coated FeS. Alumina, on the surface area basis, has about 8 times higher FeS coating amount and higher As(III) sorption capacity than silica. This study indicates that alumina is a better candidate than silica for the coating of nanocrystalline mackinawite.

• Journal of Preventive Medicine and Public Health
• /
• v.25 no.1 s.37
• /
• pp.88-100
• /
• 1992

This study was conducted to assess the effects of implementation of the patient referral system started July 1st, 1989. A comparison on the pattern of outpatient services of the Departments of Internal Medicine, General Surgery, and Pediatrics at the Yeungnam University Hospital was conducted for each one year period before and after implementation of the patient referral system. The pre-implementation period was from July 1, 1988 to June 30, 1989 and the post-implementation period was from July 1, 1989 to June 30, 1990. The information used for this study was obtained from official forms, prepared by the Yeungnam University Hospital, and submitted to the Korean Medical Insurance Cooperatives. After implementation of the patient referral system, the number of outpatient cases in the Department of Internal Medicine decreased 36.1% from 9,669 cases to 6,181 cases a year. Cases in the Department of General Surgery decreased 23.7% from 1,864 cases to 1,422 cases a year. The number of cases in the Department of Pediatrics decreased 36.9% from 3,372 cases to 2,128 cases a year. After implementation of the patient referral system, the average age of cases in the Departments of Internal Medicine and General Surgery was 52.5 and 49.7 years old, respectively. This was a significant increase in comparison with the pre-implementation period. After implementation of patient referral system, the proportion of new outpatients in the Department of Internal Medicine decreased from 24.1% to 14.6%, the Department of General Surgery from 36.0% to 23.4%, and the Department of Pediatrics from 15.5% to 8.3%. The number of visits per case decreased significantly in the Department of Internal Medicine(from 1.74 to 1.61), but there was no significant change in the Departments of General Surgery and Pediatrics. The length of treatment per case increased significantly in all three departments(from 16.1 days to 19.3 days in the Department of Internal Medicine, from 12.0 days to 15.2 days in the Department General Surgery, and 8.9 days to 11.2 days in the Department of Pediatrics). The number of clinical tests per case increased significantly in the Department of Internal Medicine (from 2.2 to 2.5), in the Department of Pediatrics(from 0.8 to 1.1) and increased in the Department of General Surgery(from 6.4 to 6.6). The average medical cost per case decreased from 43,900 Won to 42,500 Won in the Department of Internal Medicine, while the cost increased from 75,900 Won to 78,500 Won in the Department of General Surgery and from 12,700 Won to 13,500 Won in the Department of Pediatrics. In case-mix, the chronic degenerative disease(i. e. hypertension, diabetes mellitus, angina pectoris, malignant neoplasm, and pulmonary tuberculosis) ranked higher and acute infectious diseases and simple cases(i. e. gastritis and duodenitis, haemorrhoids, anal fissure, carbuncle, acute URI, and bronchitis) ranked lower after implementation of the patient referral system compared to before implementation.