• 환경영향평가
• /
• 제20권6호
• /
• pp.815-821
• /
• 2011

This study aims to estimate the biological decomposition capacity of MPC(Microorganism Porous-Concrete). MPC has specific surface area formed by inside pores, and bio compound was added to those pores to reduce pollutants loading. To evaluate the water purification capacity of MPC, we carried out the comparative studies using different media types [GPC(General Porous-concrete), CPC(Compound porous-concrete), LPC(Lightweight aggregate porous-concrete)] under the condition of CFSTR, and different retention times (30, 60 and 120 min). We also estimated the purification capacity of MPC under different concentrations of pollutant loadings. The MPC showed higher efficiency in water purification function than other conventional porous concretes with efficient decrease rates of SS, BOD, COD, and nutrient concentrations. In the comparison experiment for different retention times, MPC showed the highest removal efficiency for all tested pollutants in the longest retention time(120 min). In the long period test, the removal efficiencies of MPC concrete were high until 100 days after the set up of the operation, but began to decrease. Outflow flux was invariable compared with inflow flux so that extra detention time for media fouling such as back washing is not needed. But the results suggested that appropriate management is necessary for long-term operation of MPC. As the final outcome, MPC using bio organisms is considered to be efficient for stream water purification when they used as substrates for artificial river structure.

• Journal of Plant Biotechnology
• /
• 제44권2호
• /
• pp.164-170
• /
• 2017

A rapid and efficient in vitro regeneration system was established for Hibiscus syriacus L. The successful regeneration protocol employs induction of shoot organogenesis on leaf, petiole, and root explants. Among the various plant growth regulators evaluated, thidiazuron (TDZ) was the most effective for inducing rapid shoot formation. Most efficient shoot regeneration frequency was obtained from Murashige and Skoog (MS) media containing 0.01 mg/L TDZ. Regeneration efficiency was highest in the roots, and lowest in the leaves. A combination of 0.01 mg/L TDZ with benzyladenine (BAP) markedly improved the frequency of shoot differentiation from the root (up to 98%) and petiole (up to 88%) explants. Furthermore, leaf and petiole explants showed the highest frequency of shoot induction in half-strength MS media containing 0.01 mg/L TDZ and 1.0 mg/L BAP, while root explants formed the greatest number of shoots when 0.01 mg/L TDZ and 0.1 mg/L BAP were added to half-strength MS media. Although the frequency of shoot differentiation from leaf explants was only 50%, the leaf is considered the most efficient plant organ for use in tissue culture because leaves are easier to obtain than roots and petioles. Our findings show that various organs of H. syriacus can be used for plant regeneration, and the protocol developed in this study may be applicable in the horticulture industry.

• The Plant Pathology Journal
• /
• 제20권4호
• /
• pp.244-246
• /
• 2004

Sectors of rice blast fungus, Pyricularia grisea, frequently appeared on potato dextrose agar amended with edifenphos and iprobenfos. Thus, we assessed the sector-forming frequency of isolates of P. grisea and compared the fungicide sensitivity between wild types and sectors against the fungicides. The 905 isolates of the fungus were obtained from rice-growing locations in Korea from 1997-1998. When the isolates were grown on potato dextrose agar amended with minimal inhibitory concentrations of edifenphos (20 ${\mu}$g a.i./ml)and iprobenfos (55 ${\mu}$g a.i./ml), they produced sectors that overcame the effect of the fungicides. Among the 905 isolates tested, 9.0% produced sectors against edifenphos and 5.6%, against iprobenfos. Different sector-forming frequencies were also observed among the 11 locations of Korea. Sectors obtained from the fungicide-amended media generally grew more than their counterpart wild types grown on the media with either edifenphos or iprobenfos, regardless of their origins. In this study, greater relative growth of sectors over wild types of tested isolates can support the resistant characteristic of the fungus to survive against the fungicides. Therefore, the results indicate that the sectoring in rice blast fungus, P. grisea, may play a role in the occurrence of fungicide resistance.

• 한국지하수토양환경학회지:지하수토양환경
• /
• 제16권2호
• /
• pp.12-29
• /
• 2011

Risk-based screening levels (RBSLs) of some pollutants for residential adults were derived with risk assessment tools developed by United States Environmental Protection Agency (USEPA), American Society for Testing and Materials (ASTM), and Korea Ministry of Environment (KMOE) and compared each other. To make the comparison simple, ingestion of soil, dermal contact with soil, outdoor inhalation of vapors, indoor inhalation of vapors, and inhalation of soil particulates were chosen as exposure pathways. The results showed that the derived RBSLs varied for every exposure pathway. For direct exposure pathways (i.e., ingestion of soil and dermal contact with soil), the derived RBSLs varied mainly due to the different default values for exposure factors and toxicity data. When identical default values for the parameters were used, the same RBSLs could be derived regardless of the assessment tools used. For inhalation of vapors and inhalation of soil particulates, however, different analysis methods for cross-media transfer rates were used and different assumptions were established for each tool, identical RBSLs could not be obtained even if the same default values for exposure factors were used. Especially for inhalation of soil particulates pathway, screening level derived using KMOE approach (most conservative) was approximately 5000~10000 times lower than the screening level derived using ASTM approach (least conservative). Our results suggest that, when deriving RBSL using a specific tool, it is a prerequisite to technically review the analysis methods for cross-media transfer rates as well as to understand how the assessment tool derives the default values for exposure factors.

• 한국버섯학회지
• /
• 제17권4호
• /
• pp.179-184
• /
• 2019

본 연구는 표고 재배방식의 변화와 함께 톱밥재배가 증가됨에 따라 재배과정에서 발생 가능한 다양한 진균류를분리, 동정하고 이들에 대한 다양성 분석하고자 시험을 수행하였다. 경남지역 5개 농가로부터 수집된 시료에서 405균주를 분리하고 이들에 ITS 염기서열 분석을 통해 24속 42종을 확인하였다. 분리된 진균들에 대한 동정결과 Penicillium 속이 11종, Trichoderma속 4종이 확인되어 높은 다양성을 보여주었다. T. harzianum 의 경우 5개 농가에서 수집된 모든 시료에서 확인되었으며, Penicillium brevicompactum의 경우 3개 농가에 확인되었다. 2개 농가에서 확인되어진 Scytalidium cuboideum의 경우 표고 톱밥배지 조기부후 및 버섯 발생 저해 등의 피해증상이 확인됨에 따라 주의가 필요할 것으로 사료되었다. 또한 표고 톱밥재배의 경우 다양한 진균류이 존재가능하기 때문에 재배사 내부의 환경관리 및 예방이 필요할 것으로 판단되었다.

• Environmental Engineering Research
• /
• 제18권3호
• /
• pp.163-168
• /
• 2013

In this study, an innovative media, iron mixed ceramic pellet (IMCP) has been developed for arsenic (As) removal from groundwater. A porous, solid-phase IMCP (2-3 mm) was manufactured by combining clay soil, rice bran, and Fe(0) powder at $600^{\circ}C$. Both the As(III) and As(V) adsorption characteristics of IMCP were studied in several batch experiments. Structural analysis of the IMCP was conducted using X-ray absorption fine structure (XAFS) analysis to understand the mechanism of As removal. The adsorption of As was found to be dependent on pH, and exhibited strong adsorption of both As(III) and As(V) at pH 5-7. The adsorption process was described to follow a pseudo-second-order reaction, and the adsorption rate of As(V) was greater than that of As(III). The adsorption data were fit well with both Freundlich and Langmuir isotherm models. The maximum adsorption capacities of As(III) and As(V) from the Langmuir isotherm were found to be 4.0 and 4.5 mg/g, respectively. Phosphorus in the water had an adverse effect on both As(III) and As(V) adsorption. Scanning electron microscopy results revealed that iron(III) oxides/hydroxides are aggregated on the surface of IMCP. XAFS analysis showed a partial oxidation of As(III) and adsorption of As(V) onto the iron oxide in the IMCP.

• 한국지반공학회:학술대회논문집
• /
• 한국지반공학회 2010년도 춘계 학술발표회
• /
• pp.448-456
• /
• 2010

The mechanical behavior of granular soils is affected by particle bonding including natural cementation. This study addresses a simple model of small strain stiffness and salt concentration based on wave measurements of salt-cemented particulate media. Published models of artificially cemented soils with different curing methods and several types of cementation agents are reviewed. Glass beads with the median diameter of D50 = 0.5mm are prepared in rectangular cells using the water-pluviated method in salt water with different concentrations. Piezo disk elements and bender elements embedded in the cell are used for the measurements of compressional and shear waves. The relationships between elastic wave velocities and salt concentration show an exponential function. The measured small strain stiffness matches well the predicted small strain stiffness based on micromechanics for simple cubic monosized sphere particles. This study demonstrates that the salt concentration in salt-cemented specimen may be evaluated by using elastic wave velocities.

• 한국물환경학회지
• /
• 제22권1호
• /
• pp.45-50
• /
• 2006

This study was performed to evaluate the air lift reactors (ALR) by variations of HRT and recycling rate. Air lift reactor was composed of bioreactor and clarifier above it. To remove organic matters and nitrogen through the formation of microbic film and filtration, bio-filter reactors were filled with clay, glass, bead, waste plastic, respectively. Influent wastewater was fed to biofilter reactor, and effluent wastewater from bio-filter reactor was injected ALR again, instead of adding external carbon source. Effluent BOD concentration was satisfied with lower than 10 mg/L in recycling rate 100% regardless of the variation of HRT and the kinds of media materials. In HRT 4 hr, recycling rate 100%, BOD removal efficiency rate was from about 85 to 90%, COD removal efficiency rate was higher than 90%. Effluent TN concentration was satisfied with less than 20 mg/L, if HRT was maintained by over than 6 hr regardless of recycling rate and media materials. Over than HRT was 4 hr, microbes concentration in air lift reactor was maintained over than 2,500 mg/L constantly, not sensitive to environmental condition, and organic removal was effective as it was higher.

• Journal of Preventive Medicine and Public Health
• /
• 제45권6호
• /
• pp.335-343
• /
• 2012

Mercury is emitted to the atmosphere from various natural and anthropogenic sources, and degrades with difficulty in the environment. Mercury exists as various species, mainly elemental ($Hg^0$) and divalent ($Hg^{2+}$) mercury depending on its oxidation states in air and water. Mercury emitted to the atmosphere can be deposited into aqueous environments by wet and dry depositions, and some can be re-emitted into the atmosphere. The deposited mercury species, mainly $Hg^{2+}$, can react with various organic compounds in water and sediment by biotic reactions mediated by sulfur-reducing bacteria, and abiotic reactions mediated by sunlight photolysis, resulting in conversion into organic mercury such as methylmercury (MeHg). MeHg can be bioaccumulated through the food web in the ecosystem, finally exposing humans who consume fish. For a better understanding of how humans are exposed to mercury in the environment, this review paper summarizes the mechanisms of emission, fate and transport, speciation chemistry, bioaccumulation, levels of contamination in environmental media, and finally exposure assessment of humans.

• 한국멀티미디어학회논문지
• /
• 제22권8호
• /
• pp.950-959
• /
• 2019

The purpose of this study was to investigate the effect of integrated teaching and learning method using augmented reality for effective promotion of child - friendly attitude and environmental preservation attitude and explored its applicability. For this purpose, based on the augmented reality fairy tale, we designed an experience - oriented integrated teaching and learning method such as reading book, story - telling, drawing, environmental conservation practice activity. The experimental group was divided into two groups: augmented reality reading fairy tales (A) and children's book reading fairy tales (B). First, interest, immersion, and empathy were higher in the application environment of integrated learning teaching method based on Augmented Reality. Second, there was no difference between the two groups in content understanding. Third, in terms of expressiveness, it was verified that various expressions were expressed in the applying environment of the integrated teaching - learning method based on augmented reality through drawing activities. Fourth, in practice activities, more students were practicing in the augmented reality - based integrated teaching - learning method applied environment, and the number of practice activities of individual students was also confirmed. This study suggests that the application of the integrated teaching and learning method can enhance the effect of education when using the smart teaching media using the augmented reality in early childhood education.