• Journal of Environmental Impact Assessment
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• v.21 no.3
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• pp.483-501
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• 2012

The purpose of this study was to apply a multi-metric model of Lentic Ecosystem Health Assessments(LEHA) for environmental impact assessments of Cheongpyung Reservoir during 2005 - 2006 and assessed the ecological model values. The ecosystem model of LEHA was composed of eleven metrics such as biological parameters($B_p$), physical parameters($P_p$), and chemical parameters($C_p$), and determined the rank of ecological health by the criteria. The variables of $B_p$ were metrics of % sensitive species($M_2$, NMS) and insectivore species($M_5$, % $I_n$), which decrease as the water quality degradates, and these metric values were low as 1.5% and 32.4%, respectively. In contrast, the proportions of tolerant species and omnivore species as the other $B_p$ parameters were 43% and 62%, respectively, which indicate a degradation and disturbance of the ecosystem. Riparian vegetation coverage($M_9$, % $V_c$) as a variable of $P_p$, were higher in the 2nd than 1st survey, and decreased toward the dam site from the headwaters. This was due to a habitat simplification(modifications) by frequent bottom dredging of sand and rocks. The variables of $C_p$ were two metrics of specific conductivity($M_{10}$, $C_I$) as an indicator of ionic contents(cations and anions) and the Trophic State Index(TSI) based on chlorophyll-a($M_{11}$, $TSI_{CHL}$) as an indicator of trophic state. These metric values of $C_p$ had high temporal variations, but low spatial variations on the main axis of the reservoir along with the ecological health of a good condition. The environmental impact assessments using the LEHA multi-metric model indicated that the model values of LEHA averaged 30.7 in 1st survey(fair - poor condition) vs. 28 in 2nd survey(poor condition), indicating a temporal variation of the ecological health. The model values of LEHA showed a minimum(28) in the lacustrine zone(S5) and ranged from 29 to 30 in the other locations sampled, indicating a low longitudinal variation. Overall, environmental impact assessments, based on LEHA model, suggest that chemical water quality conditions were in good, but biological conditions were disturbed due to habitat modifications by frequent dredgings in the system.

• Economic and Environmental Geology
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• v.40 no.3 s.184
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• pp.277-293
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• 2007

Seasonal and spatial variations in the concentrations of trace elements, pH and Eh were found in a creek watershed affected by mine drainage and leachate from several waste rock dumps within the As-Pb-rich Indae mine site. Because of mining activity dating back to about 40 years ago and rupture of the waste rock dumps, this creek was heavily contaminated. Due to the influx of leachate and mine drainage, the water quality of upstream reach in this creek was characterized by largest seasonal and spatial variations in concentrations of Zn(up to $5.830 mg/{\ell}$), Cu(up to $1.333 mg/{\ell}$), Cd(up to $0.031 mg/{\ell}$) and $SO_4^{2-}$(up to $173 mg/{\ell}$), relatively acidic pH values (3.8-5.1) and highly oxidized condition. The most abundant metals in the leachate samples were in order of Zn($0.045-13.909 mg/{\ell}$), Fe($0.017-8.730mg/{\ell}$), Cu($0.010-4.154mg/{\ell}$) and Cd($n.d.-0.077mg/{\ell}$), with low pH(3.1-6.1), and high $SO_4^{2-}$(up to $310 mg/{\ell}$). The mine drainage also contained high concentrations of Zn, Cu, Cd and $SO_4^{2-}$ and remained constantly near-neutral pH values(6.5-7.0) in all the year. While the leachate and mine drainage might not affect short-term fluctuations in flow, it may significantly influence the concentrations of chemicals in the stream. The abundance and chemistry of Fe-(oxy)hydroxide within this creek indicated that the Fe-(oxy)hydroxide formation could be responsible for some removal of trace elements from the creek waters. Spatial and seasonal variations along down-stream reach of this creek were caused largely by the influx of water from uncontaminated tributaries. In addition, the trace metal concentrations in this creek have been decreased nearly down to the background level at a short distance from the discharge points without any artificial treatments after hydrologic mixing in a tributary. The nonconservative(i.e. precipitation, adsorption, oxidation, dissolution etc.) and conservative(hydrologic mixing) reactions constituted an efficient mechanism of natural attenuation which reduces considerably the transference of trace elements to rivers.

• Economic and Environmental Geology
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• v.40 no.4
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• pp.347-360
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• 2007

In order to evaluate the degree and extent of heavy metal pollution and the environmental impacts of abandoned Cu mines in Goseong-gun, soils and paddies were collected from the mine area and have been analysed for heavy metal contents. The heavy metal contents were much higher in mountain soils than in paddy soils. Total content of heavy metals decreased in order of Cu>Zn>Pb>As>Cr>Cd in mountain soils whereas Zn>Pb>Cu>Cr>As>Cd in paddy soils. The extractable amount of heavy metals by 0.1/1N HCl decreased in order of Cu>Pb>Zn>As>Cd>Cr in mountain soils whereas Pb>Cu>Zn>As>Cd>Cr in paddy soils. Although the extraction ratios were highly various depending on the sampling site, their average values were in order of Cd(16%)>Pb(10%)>Cu(9%)>As(4.5%)>Zn-Cr(${\le}2.5%$). The soils investigated were enriched in heavy metals relative to the averages of earth crust as In order of $As{\ge}Cd$>Pb>Zn>Cu>Cr. Pollution index calculated from total or extractable heavy metals of soils indicated that the heavy metal pollution was restricted to mountain soils around abandoned Cu mines, especially the Samsan I mine. The metal contents of brown rice showed no significantly contaminated level as follows; As $nd{\sim}0.87mg/kg,\;Cd\;0.02{\sim}0.34mg/kg,\;Cu\;1.01{\sim}6.25mg/kg,\;Mn\;13.4{\sim}43.2mg/kg,\;Pb\;0.09{\sim}2.83mg/kg,\;and\;Zn\;16.5{\sim}79.1mg/kg$. From the extraction and dispersion properties of heavy metal with the soil pH ($4.5{\sim}7.8$), it can be deduced the conclusion that the heavy metal pollution is spreading in the study area mainly by the detrital migration of waste ore and gangue minerals rather than the dissolution and circulation of heavy metal.

• Korean Journal of Ecology and Environment
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• v.45 no.4
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• pp.444-452
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• 2012

We conducted a comprehensive monitoring for freshwater food web in a wetland system (Jangcheok Lake), from May to October, 2011. Monthly sampling for zooplankton, fish as well as organic matters, was implemented. In order to understand the food web structure and energy flow, we applied stable isotope analysis to the collected samples, based on ${\delta}^{13}C$ and ${\delta}^{15}N$ values of epiphytic particulate organic matter(EPOM) and particulate organic matter (POM), epiphytic and planktonic zooplankton, fish (Lepomis macrochirus). In the study site, epiphytic and planktonic zooplankton was 24 and 30 species, respectively, and coincidence species between epiphytic and planktonic zooplankton were 20 species. Epiphytic zooplankton were more abundant during the spring and early summer (May to July); however, planktonic zooplankton were more abundant during the autumn (September to October) season. Stable isotope analysis revealed that fish and epiphytic zooplankton had seasonal variations on their food sources. EPOM largely contributed epiphytic zooplankton in spring (May), but increasing contribution of POM in autumn (September) was detected. However, planktonic zooplankton depended on only POM in both seasons. Fish utilized both epiphytic and planktonic zooplankton, but small sized (1~3 cm), fish preferred epiphytic zooplankton, where as larger sized (4~7 cm) fish tended to consume planktonic zooplankton, and epiphytic zooplankton had important role in energy transfer. This pattern was clear when results of spring and autumn stable isotope analysis were compared. From the results of this study, we confirmed that wetlands ecosystem supported various epiphytic and planktonic zooplankton species, they depend on other food items, respectively. L. macrochirus also showed a difference of food source according to the body size, they depend on seasonal density change of zooplankton. In particular, epiphytic zooplankton was very important for growth and development of young fish in the spring.

• Korean Journal of Ecology and Environment
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• v.43 no.3
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• pp.428-436
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• 2010

This study was to evaluate water quality characteristics and ecological health using a mulimetric fish model in Taehwa-River watershed during May~September 2009. The ecological health assessments were based on the Index of Biological Integrity (IBI) using fish community and the multimetric model of Qualitative Habitat Evaluation Index (QHEI). For the study, the models of IBI and QHEI were modified as 8 and 11 metric attributes, respectively. We also analyzed spatial patterns of chemical water quality over the period of 2000~2009, using the water chemistry dataset, obtained from the Ministry of Environment, Korea. Values of BOD and COD averaged $1.7\;mg\;L^{-1}$ (scope: $0.1{\sim}31.8\;mg\;L^{-1}$) and $3.6\;mg\;L^{-1}$ (scope: $0.4{\sim}33\;mg\;L^{-1}$), respectively during the study. Total nitrogen (TN) and total phosphorus (TP) averaged $2.8\;mg\;L^{-1}$ and $96.8\;{\mu}g\;L^{-1}$, respectively, indicating an eutrophic-hypertrophic state. Also, TN and TP showed longitudinal increases toward the downriver reach. In the watershed, QHEI values varied from 67.5 (fair condition) to 164.5 (good condition) by the criteria of US EPA (1993). There was a abruptly decreasing tendency from T9 site in the QHEI values. According to 1st and 2nd surveys of Taewha River, multimetric model values of IBI was averaged 26.1 (n=14) with "good" condition (B) and the spatial variation was evident. Our results suggest that the mainstream sites was getting worse health condition along the river gradient due to inputs of the point and non-point sources from the urban (Ulsan city). Overall, dataset of IBI, QHEI, and water chemistry indicated that the ecological river health showed a downriver decline and the pattern was closely associated with habitat degradations and chemical pollutions as the waters pass through the urban region.

• Korean Journal of Ecology and Environment
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• v.40 no.2
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• pp.254-263
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• 2007

The objective of this study was to evaluate biological water quality using fish assemblages in Nakdong River watershed. We selected 6 sites along the main axis of the river and evaluated the Index of Biological Integrity (IBI), Qualitative Habitat Evaluation Index (QHEI) and chemical water quality during July 2004${\sim}$March 2006. For the study, we applied the 10 metric IBI model, which was developed for national biological water quality criteria. Nakdong River's IBI value averaged 20.8 (n=14) during the study which means poor biological water quality. Physical habitat health at all sites, based on QHEI model, was measured as 110, indicating fair${\sim}$good condition. The habitat health varied depending on the locations sampled. Habitat health in sites 1 and 6 was judged as good, while the health in sites 3 and 4 was $poor{\sim}fair$. Especially, we found the metric values of $M1{\sim}M5$, M7, M10 were low in sites 3 and 4 compared to other sites. In these sites, thus, habitat restoration of substrate composition, riffles, and bank vegetation may be necessary. In the mean time, chemical water quality, based on BOD, COD, TSS, and nutrients, had no large spatial and temporal variations. Overall data analysis indicated that site 3 was largely impacted by the polluted-tributary, Keumho River and the downstreams showed better water quality due to the dilution of the polluted river water by Nam River and Hwang River.

• Journal of Embryo Transfer
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• v.16 no.3
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• pp.213-221
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• 2001

This study was conducted to examine in vitro developmental ability of porcine embryos after somatic cell nuclear transfer. The porcine ear fell was cultured in vitro for confluency in serum-starvation condition(TCM-199 + 0.5% FBS) far 3~6 days of cell confluency. The zona pellucida of IVM oocytes were partially drilled using laser system. Single somatic cell was individually transferred into enucleated oocytes. And the reconstructed embryos were electrically fused(single DC 1.9kv/cm, 30$\mu$ sec) with 0.3M mannitol. After electrofusion, embryos were activated(single AC 5v/mm, 5sec) and cultured in HCSU-23 medium containing 10% FBS at 39$^{\circ}C$, 5% $CO_2$ in air for 6 to 8 days. The fusion rate of donor cells was 45.6, 36.8 and 46.1% in 3~4, 5~6 days of serum starvation and non serum starvation(N-S), and were 52.7. 53.0 and 51.7% in 1~2. 5~6 and 13~14 passages of donor cell culture, respectively. No significant difference was found in the fusion rate of donor cells by the duration of serum starvation treatment or the number of donor cell passages. By the size of donor cells, however, the fusion rate was significantly higher(P<0.05) for reconstructed embryos derived from 25r $\mu$m $\geq$ site of donor cells (65.3%) than that of 25~30$\mu$ m(42.5%) or 30$\mu$ m(45.5%)$\leq$ cells. The cleavage rate was significantly (P<0.05) higher in 3~4 darts of serum starvation treatment(67.1%) than that in N-S (50.7%) or 5~6 days of starvation(57.1%). The activation rate by the size of donor cells in fused oocytes was 56.5, 68.8 and 58.5%, respectively, and was not significant.

• Journal of Chest Surgery
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• v.41 no.5
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• pp.573-579
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• 2008

Background: Composite valve graft replacement is currently the treatment of choice for a wide variety of the lesions of aortic root disease. The purpose of this study was to explore the results of aortic root replacement after using the Cabrol technique over a 13-year period at our institution, and we analyzed the results to help surgeons make better decisions when repairing aortic root disease. Material and Method: Between January 1994 and December 2006, twenty-five patients underwent a Cabrol technique operation at our institution. The mean patient age was $43.7{\pm}14.1$ years old (range: $6{\sim}65$ years) and the male and female ratio was 21:4 (84% : 16%). The patients' follow-up was 100% complete, and the mean follow-up period was $60.7{\pm}50.4$ (range:$1{\sim}162$) months. Annuloaortic ectasia (n=18) was the most frequent cause of aortic disease in this series, followed by aortic dissection (n=7). The mean cardiopulmonary bypass time was $177.2{\pm}44.9$ minutes and the mean aortic cross clamping time was $123.4{\pm}34.1$ minutes. Nine patients were checked with MDCT (Multidetector computed tomography) for evaluating a well functioning secondary graft and the coronary anastomosis site. Result: The early mortality rate was 4% (1 of 25 patients). A significant stenosis, kinking or occlusion of the secondary graft was detected by MDCT in 4 patients. The overall survival rate was 88%. Conclusion: The Cabrol technique demonstrated a significant incidence of long-term complications such as secondary graft stenosis or obstruction. It could be used when the modified Bentall technique is not feasible.

• Economic and Environmental Geology
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• v.36 no.2
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• pp.89-101
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• 2003

River deposits and farmland soils were analyzed to investigate the pollution level of heavy metals in the vicinity of the Goro abandoned Zn-mine. Surface (0-40 cm) and subsurface (40-100 cm) soils were collected around a main river located at the lower part of the Goro mine, and analyzed by ICP-MS for Cd, Cu, Pb, Zn and Cr after 0. 1N HCI extraction and by AAS for As after IN HCI extraction. Concentrations of cadmium and lead at the surface river deposits close to the mine were over the Soil Pollution Warning Limit (SPWL), and 43% of sample sites (6 of 14 samples) were over SPWL for As suggesting that river deposits were broadly contaminated by arsenic. Results from farmland soil analysis showed that surface soils were contaminated by heavy metals, while only arsenic was over SPWL at 50% of sampling sites. Main pollution mechanism around the Goro mine was the discharge of mine tailing and waste rocks from the storage site to the river and to adjacent farmland during flood season. Pollution Grades for sample locations were prescribed by the Law of Soil Environmental Preservation, suggesting that the pollution level of heavy metals around the Goro mine was serious, and the remediation operation fur arsenic and the isolation of mine tailing and waste rocks from river and farmland should be activated to protect further contamination. The area needed to clean up was estimated from pollution distribution data and the remediation methods such as a soil washing method and a soil improvement method were considered as the further remediation operation for arsenic contaminated soils and river deposits around the Goro abandoned mine.

• Journal of Korean Society of Environmental Engineers
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• v.28 no.2
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• pp.158-164
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• 2006

Offensive odor from CAFO(concentrated animal feeding operation) and its control have become a significant issue in Korea. Control of odors from the CAFO requires to identify major odorant and their generation mechanisms. In this study, an easy method to collect gas sample and to quantify its odorants is proposed. The method involves on-site odorant extraction with solid-phase microextraction and quantitation with GC/MSD or GC/FID. Analytes of the current study include: trimethylamine(TMA), carbon disulfide($CS_2$), dimethyl sulfide(DMS), dimethyl disulfide(DMDS), acetic acid(AA), propionic acid(PA) and n-butyric acid(BA). The resulting linearity($R^2$) of calibration curve for each analyte was good over the range from several ppbv to ppmv; 0.984 for TMA(0.056-1.437), 0.996 for $CS_2$(0.039-0.999), 0.994 for DMS(0.029-0.756), 0.995 for DMDS(0.024-0.623), 0.992 for AA(0.068-1.314), 0.955 for PA(0.047-0.940), and 0.976 for BA(0.036-0.712). Method detection limits were 5.67, 6.39, 5.78, 25.2, 0.098, 0.363 and 0.099 ppbv for AA, PA, BA, TMA, DMS, $CS_2$, and DMDS, respectively. With the developed method, odorants from poultry, swine, and cattle barns were analysed. All the compounds but DMDS were detected from the sample collected in the poultry barn, and their levels exceeded the representative published human olfactory threshold.