• Journal of Korean Society of Environmental Engineers
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• v.31 no.4
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• pp.241-248
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• 2009

A farming area located near an abandoned copper mine in GuPo-ri, Choongchung province is heavily contaminated with heavy metals such as As, Pb, Cd, Cu and Zn of which concentrations are higher than the values typically detected in Korean soil environment. In this work, laboratory and field studies were conducted to examine feasibility of using Ca-citrate-phosphate solution in stabilizing heavy metals in the polluted soils. In laboratory batch experiments with field soil, the addition of Ca-citrate-phosphate solution resulted in decrease of aqueous phase concentration of phosphate and improvement of heavy metal stabilization, compared to those for sterilized soil samples. This indicates that microbial uptake of phosphate may have provided positive effects on availability of phosphate toward heavy metal stabilization. According to microbial community analysis for the field experiment, the use of Ca-citrate-phosphate led to increased diversity of microbial populations, and strict anaerobic microorganisms such as Anaerofilum and Treponema became the most dominant populations in the solution-amended field experiments. These findings suggest that, when Ca-citrate-phosphate is used for heavy metal stabilization in soils, microbial processes may have important roles in improving the stabilization of heavy metals by providing reducing conditions to the treatment locations or/and by making phosphate available to heavy metal stabilization.

• Journal of the Korean earth science society
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• v.26 no.8
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• pp.759-770
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• 2005

The purpose of this study is to examine the Earth science content relevance of the 7th national science curriculum. For this purpose, we (1) analyzed science curriculum or content standards of Korea, California, England and Japan, (2) compared science textbooks of Korea and Japan, (3) conducted a nationwide survey to gather opinions from students, teachers, professors and textbook authors about the relevance of the science curriculum and textbooks. According to the results, the Earth science contents of the 7th national science curriculum were not appropriate in terms of the objectives of science curriculum and the needs of students and society. The main reasons include the equal division among physics, chemistry, biology and earth science, iack of connection due to fractionation of units, overly strict application of spiral curriculum, and redundant amount of activities and concepts to cover in the textbook. Major suggestions fir securing the relevance of Earth science contents are as follows: First, the science contents and the size of units at each grade level should be determined according to the students' characteristics, not by equal portion rule. Second, the excessive overlapping and repetition of contents due to the spiral curriculum should be avoided. In addition, the number of activities should be reduced and the quality of required science activities should be improved. Third, to raise students' interest in Earth science, real-life applications and real-world Earth science contents should be emphasized including natural disasters, safety, universe and space exploration, and natural resources. Lastly, considering one of the relevance criteria is feasibility, supports for schools and science teachers are needed to realize the goal of the intended science curriculum.

• Environmental and Resource Economics Review
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• v.27 no.3
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• pp.569-611
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• 2018

Rapid economic growth, urbanization, and industrialization of China have tremendously degraded the overall quality of living environments, especially the air quality, not only negatively affecting Chinese people but also impacting citizens of neighboring countries, namely Korea. The Chinese government has invested much effort to regulate the air pollution due to burning coal through introducing strict environmental monitoring policies and aggressive implementation. This paper presents an overview of Chinese air pollution prevention policy due to burning coal, and the associated trends and specifics of institutional arrangements regarding air pollutant emission regulations. It turns out that the policies have become stricter than before; some polices are geared towards enforcing extra regulation at the regional level. It is expected that the regulation will become stricter in the future. However, the actual contribution and feasibility of such policies must be analyzed based on sound science. The policies seem to care little about influencing the air quality of Korea, and this has to be improved. In order to do so, it is important to strengthen environmental cooperation between Korea and China, and better yet to research on not only the air quality but also the associated fields, such as energy, industrial technology, and global environmental governance.

• Journal of Chest Surgery
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• v.41 no.5
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• pp.610-618
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• 2008

Background: There are various treatment modalities for atherosclerotic arterial obstructive disease at the lower limbs, for example, conservative physical therapy, medication, operation etc. Yet it has been established that an arterial bypass operation is the most effective treatment. The aim of this study is to evaluate the effect of arterial bypass operation within our experience and to determine the indicators of treatment. Material and Method: Ninety six patients received arterial bypass operation for atherosclerotic arterial obstructive disease from June 2002 to April 2006. We evaluated the feasibility of arterial bypass operation based on the improvement of symptoms and the ankle-brachial index (ABI) and the surgical outcomes, as based on the complications, the amputation rates and the patency rates. We also assessed the possible risk factors such as gender, age, a smoking history, co-morbidities, the anastomotic sites, the graft size and the graft type. We retrospectively reviewed the medical records of the patients. The total mean follow-up period was $29.4{\pm}13.1$ months. Result: The mean age was $65.95{\pm}9.61$ and there were 88 male patients. The most common clinical manifestation was ischemic resting pain in the lower extremities. The underlying combined diseases were hypertension (61%), diabetes (43%), cardiac problems (35%) and smoking (91.7%). The most frequent site of arterial obstruction was the superficial femoral artery (44 cases, 40%). A femoropopliteal artery bypass operation with a Polytetrafluoroethylene(PTFE) synthetic graft was done in 44 cases (40%) and the great saphenous vein graft was used in 11 cases. The postoperative ABI increased significantly from $0.30{\pm}0.11$ preoperatively to $0.63{\pm}0.11$ (p<0.001) postoperatively. In 8 cases, amputations above the ankle level were necessary. The graft patency rates were 86.4% and 68.0% after 1 and 3 years, respectively. There were 29 cases (30.21%) of patency failure; the male gender, smokers and hypertension were significantly more frequent in the failure group. Of these, hypertension was the most powerful risk factor (p=0.042). Conclusion: The arterial bypass operation is an effective treatment modality for controlling the symptoms such as pain and claudication, and for preventing major amputations for the patients with atherosclerotic arterial obstructive disease. This study suggests quitting smoking, strict blood pressure control, selection of an appropriate graft, regular outpatient follow up and proper medication would offer higher patency rates and more favorable outcomes.