• The Journal of Engineering Geology
• /
• v.10 no.1
• /
• pp.27-38
• /
• 2000

We hydrogeologically studied a mountainous area and its vulnerability to groundwater contamination. Groundwater flow and recharge occur mainly through a network of fractures in this areaTransmissivity and storativity obtained from slug, slug interference, and pumping tests range from 3.2$\times$10$^{-3}$ to 2.0$\times$10$^{-2}$$m^2$/min and 1.3$\times$10$^{-7}$ to 9.15$\times$10$^{-4}$, respectively. The groundwater was contaminated bylivestock activities in the upgradient. The groundwater in the downgradient residential area wasthreatened by the upgradient livestock activities.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
• /
• 2004.09a
• /
• pp.290-292
• /
• 2004

Heavy metal contamination has been increased in aqueous environments near many industrial facilities, such as metal plating facilities, mining operations, and tanneries. The soils in the vicinity of many military bases are also reported to be contaminated and pose a risk of groundwater and surface water contamination with heavy metals. The biological removal of metals through bioaccumulation has distinct advantages over conventional methods; the process rarely produces undesirable or deleterious chemical byproducts, it is highly efficient, easy to operate and cost-effective in the treatment of large volumes of wastewater containing toxic heavy metals. In addition, a recent development of molecular biology shed light on the enhancing the microorganism's natural remediation capability as well as improving the current biological treatment. In this study, characteristics of the cell growth and heavy metal accumulation by Saccharomyces cerevisiae strains expressing phytochelatin syntahse (PCS) gene were studied in batch cultures. The AtCRFI gene was demonstrated to confer substantial increases in metal tolerance in yeast. PCS-expressing cells tolerated more Cd$^{2＋}$ than controls.

• Journal of Periodontal and Implant Science
• /
• v.26 no.1
• /
• pp.133-142
• /
• 1996

Ten intrabony defects in 10 patients were treated by flap surgery including root surface debridement and placement of an expanded polytetrafluoroethylene(ePTFE) membrane. The membranes were removed after 4-6 weeks. This study was performed to examine the retrived ePTFE membrane by scanning electron microscopy(SEM) for bacterial contamination and adherent connective tissue elements, and to compare it with clinical conditions. The cervical portion of the membrane, which in most cases had become partially exposed to the oral cavity, had a bacterial deposit. Small bacterial colonies and a scatter of single cells in some instances extended into the apical portion of the membrane. Fibroblast-like cells, erythrocytes and fibrous structures were seen in the apical portion of the membrane. Outer surface of membrane tends to more bacterial contamination than inner surface(p<0.01), and upper portions more than lower portions(P<0.01). Comparison of ultrastructural findings and clinical conditions revealed that extent of bacterial contamination of the membrane correlated with gingival inflammation and extent of membrane exposure, but it was not significant statistically. The results suggested that gingival inflammation and membrane exposure affect periodontal regeneration by the use of ePTFE membrane.

• Journal of The Korean Association For Science Education
• /
• v.19 no.4
• /
• pp.585-594
• /
• 1999

The purpose of this study is to examine the concept of Greenhouse Effect as understood by middle school high school university students using a closed-form questionnaire. Based on results of the questionnaire which was administered to 619, the extent to which alternative concepts were held was quantified and compared the difference of various group based on grade level. gender, text and major. Also, subjects were divided into two groups, one is middle school students and the other is high school university students and common themes within conceptual framework of each group were identified by factor analysis. The result showed that students confused Greenhouse Effect with ozone layer depletion in stratosphere and linked familiar contamination around everyday life. acid rain. radioactive contamination, nuclear arsenal to Greenhouse Effect. These trends were more appreciable in female than male, biology major than any other major and text did not make any significant difference. In addition, the result of factor analysis showed that two groups linked familiar contamination around everyday life to Greenhouse Effect and high school university students understand the consequences of an increase in the Greenhouse Effect more systematically than middle school student, perceived the relation between the origin of an increase in the Greenhouse Effect and human activity but confused Greenhouse Effect with ozone layer depletion in stratosphere.

• Fisheries and Aquatic Sciences
• /
• v.13 no.3
• /
• pp.244-253
• /
• 2010

The quality of marine sediments from the industrialized coastal areas of Korea (Ulsan Bay, Masan Bay, and artificial Lake Shihwa) was investigated using a bacterial bioluminescence toxicity test. Sediment toxicity results were compared with the levels of chemical contamination (trace metals, organic wastewater markers, acid volatile sulfides, total organic carbon). Effective concentration 50% (EC50) of sediments ranged from 0.014 to 1.126 mg/mL, which is comparable to or lower than values in contaminated lakes, rivers, and marine sediments of other countries. Sediment reference index (SRI) ranged from 13 to 1044, based on the EC50 of the negative control sample. Mean average SRI values in Masan Bay and Lake Shihwa were approximately 8 and 9 times as high as that in Ulsan Bay, indicating higher sediment toxicity and greater contamination in the two former regions. Sediment toxicity were strongly associated with the concentrations of some chemicals, suggesting that this test may be useful for determining potential chemical contamination in sediments.

• Environmental Analysis Health and Toxicology
• /
• v.19 no.1
• /
• pp.1-24
• /
• 2004

Since dioxins became a serious concern in Korea, a significant number of investigations have been conducted to address diverse issues related to dioxins. However, the results have not been organized for ready access and use. The principal purposes of the work were to ⅰ) provide an archive of dioxin researches in Korea and ⅱ) give an overview of dioxin contamination. The focus of this work was placed on the contamination levels and characteristics concerning the waste incinerators emissions, environmental media, and biological samples(fishes/shellfishes, foods, and human body). Principal component analysis was conducted to identify common and/or unique features and the important variables associated with the congener patterns. From a comprehensive search of academic journals, research and monitoring project reports, dissertations, and periodicals of other forms, a total of 115 counts were found that met the purposes of this study. The contamination levels of various samples were summarized and compared to those reported in foreign literatures. The congener patterns varied largely with environmental media and distinguished particularly by OCDD, 1,2,3,4,6,7,8-HpCDF, and OCDF for the samples within the same media. The proximity to emission sources differentiated the congener patterns in air and soil samples by the fraction of OCDD.

• Economic and Environmental Geology
• /
• v.29 no.1
• /
• pp.57-63
• /
• 1996

The Dalsung copper-tungsten mine in the Taegu area, Korea was closed in 1975 and may be the sources of the heavy metal contamination in the tributary system and soil-plant system due to the mine drainage derived from the mine wastes and tailings. To examine the degree and extent of heavy metal contamination in the vicinity of Dalsung mine area, stream water and soil samples were taken and analyzed for heavy metals by ICP-AES and AAS. Highly contaminated soils are found near the Lower Tunnel No.0 ranging up to $1760{\mu}g/g$ As, $2060{\mu}g/g$ Cu, $1120{\mu}g/g$ Pb and 346 ${\mu}g/g$ Zn. From the results of the sequential extraction methods for the metal speciation, the heavy metals in soils may be derived from soil parent materials and acid mine drainage. With the processes for the heavy metal removal, most of the heavy metal ions in the acid mine drainage are removed by being exchanged with Ca ions held by the bentonite, hydroxyapatite and calcium hydoxide.

• Journal of Biosystems Engineering
• /
• v.40 no.1
• /
• pp.67-77
• /
• 2015

Purpose: Fungal secondary metabolite (mycotoxin) contamination in foods can pose a serious threat to humans and animals. Spectroscopic techniques have proven to be potential alternative tools for early detection of mycotoxins. Thus, the aim of this review is to provide an overview of the current developments in nondestructive food safety testing techniques, particularly regarding fungal contamination testing in grains, focusing on the application of spectroscopic techniques to this problem. Methods: This review focuses on the use of spectroscopic techniques for the detection of fungi and mycotoxins in agricultural products as reported in the literature. It provides an overview of the characteristics of the main spectroscopic methods and reviews their applications in grain analysis. Results: It was found that spectroscopy has advantages over conventional methods used for fungal contamination detection, particularly when combined with chemometrics. These advantages include the rapidness and nondestructive nature of this approach. Conclusions: While spectroscopy offers many benefits for the detection of mycotoxins in agricultural products, a number of limitations exist, which must be overcome prior to widespread adoption of these techniques.

• Journal of Environmental Impact Assessment
• /
• v.13 no.3
• /
• pp.115-124
• /
• 2004

To utilize a closed municipal solid waste landfill site in environmentally secure conditions, it is necessary to verify the stabilization level of landfill leachate. To assess leachate stabilization of an open-dumping municipal solid waste landfill (Noeun Landfill) which is located at the upper drainage basin of Namhan River which flows into Lake Paldang utilized for Seoul Metropolitan water supplies, the surrounding characteristics of the landfill site was surveyed. After then, leachate, groundwater and soil samples from this landfill were chemically analyzed, and the analysis results were evaluated by "The Criteria of Landfill Waste Stabilization(CLWS)", "Discharge Criteria of Landfill Leachate", "The Criteria of Domestic Use in Groundwater Quality", and "Soil Contamination Criteria" promulgated by Korean Ministry of Environment. The closed open-dumping landfill was equipped with the final soil cover, 3 groundwater monitoring wells and poor landfill gas extraction devices for the post-closure management of the landfill. BOD/CODcr ratios in leachate were less than or slightly higher than 1/10. This results seemed to imply that the leachate stabilization level of this landfill based on the CLWS was almost completed. Qualities of groundwater sampled from monitoring wells located at outside of landfill were adequate for "The Criteria of Domestic Use in Groundwater Quality". Finally, concentrations of soil contaminants that were likely to be influenced by this landfill site were adequate to "Soil Contamination Criteria".

• Journal of Environmental Impact Assessment
• /
• v.13 no.5
• /
• pp.251-262
• /
• 2004

In order to investigate the geochemical characteristics of surface sediments in lower Yeongsan river system, sediment samples from the main stream of Yeongsan river, Gomakwon and Hampyeong streams were collected and analyzed for grain size and metal and organic carbon contents. The sediment types of the streams widely vary from pebble to mud. The metal contents in the sediments are mainly dependent on grain size of the sediments, geology around the streams and organic matter contents from the domestic sewage. Enrichment factor (EF) representing the degree of metal contamination in the sediments are relatively low in the study area. But, high Zn and Pb values seem to be from the study area, partly.