• Korean Journal of Environmental Agriculture
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• v.20 no.2
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• pp.116-121
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• 2001

To observe the stimulating effects of low dose ${\gamma}$ - radiation on the dormancy breaking and physiological activity, potato (Solanum tuberosum L. cv. Dejima) were irradiated at the dose of $0.5{\sim}30$ Gy. Low dose ${\gamma}$ - radiation exhibited promoting effects on the sprouting rate within the range of optimum dose of 1 Gy and 2 Gy and on the sprout length within the range of optimum dose of 2 Gy and 4 Gy. Regardless of storage duration and irradiation doses, the number of sprouts was enhanced. The number of sprouts, which were reserved for 15 days after production (DAP), were significantly increased under 4, 8 and 16 Gy irradiation. The growth of 45 DAP sprouts was extremely stimulated under 4 Gy irradiation accompanying the increase of peroxidase activity in the plantlet. In this study, it was also suggested that the activities of antioxidative enzymes of potato plantlets were not related to the irradiation dose during the plantlet development with the exception of decrease in catalase activity.

• Korean Journal of Environmental Agriculture
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• v.35 no.1
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• pp.6-14
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• 2016

BACKGROUND: Residual organochlorine pesticides (OCPs) are chemical substances that persist in the environment, bioaccumulate through the food web, and pose a risk of causing adverse effect to human health and the environment. They were designated as persistent organic pollutants (POPs) by Stockholm Convention. Greenhouse strawberry is economic crop in agriculture, and its cultivation area and yield has been increased. Therefore, we tried to investigate the POPs residue in greenhouse soil and strawberry.METHODS AND RESULTS: Extraction and clean-up method for the quantitative analysis of OCPs was developed and validated by gas chromatography (GC) with electron capture detector (ECD). The clean-up method was established using the modified quick, easy, cheap, effective, rugged, and safe(QuEChERS) method for OCPs in soil and strawberry. Limit of quantitation (LOQ) and recovery rates of OCPs in greenhouse soil and strawberry were 0.9-6.0 and 0.6-0.9 μg/kg, 74.4-115.6 and 75.6-88.4%, respectively. The precision was reliable sincerelative standard deviation (RSD) percentage (0.5-3.7 and 2.9-5.2%) was below 20, which was the normal percent value. The residue of OCPs in greenhouse soil was analyzed by the developed method, and dieldrin, β-endosulfan and endosulfan sulfate were detected at 1.6-23, 2.2-28.4 and 1.8-118.6 μg/kg, respectively. Those in strawberry were not detected in all samples.CONCLUSION: Dieldrin, β-endosulfan and endosulfan sulfate in a part of investigated greenhouse soil were detected. But those were not detected in investigated greenhouse strawberry. These results showed that the residue in greenhouse soil were lower level than bioaccumulation occurring.

• Journal of the Korea Organic Resources Recycling Association
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• v.9 no.1
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• pp.73-78
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• 2001

The biological carbon dioxide fixation using microalgae and photo-bioreactor has been known as an effective carbon dioxide reduction technology. As algae has many other environmental factor for its growth, the desirable cultivation factors were investigated using a green alga, Euglena gracilis Z. In this study, Euglena gracilis Z showed good $CO_2$ fixation ability in high $CO_2$ concentration of 10-20% and it contained the high protein and vitamin E enough to be used as fodder. For the mass cultivation, the continuous and semi-continuous cultivation methods were employed. The optimum hydraulic retention time (HRT) for the continuous cultivation was 4 days at carbon dioxide concentration of 10%. In this condition, the final cell number was $3.57{\times}10^6/m{\ell}$. The growth of Euglena gracilis Z increased according to the light intensity.

• Journal of the Korea Organic Resources Recycling Association
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• v.20 no.1
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• pp.78-86
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• 2012

In this study, dark fermentative hydrogen production (DFHP) from acid pretreated microalgal biomass was optimized with via statistical experimental design. Acid concentration and reaction time were varied from 0.1 to 3% (v/w) and 10 to 60 min with substrate concentration of 76 g dry cell weight (dcw)/L and initial pH of 7.4, respectively. During the fermentation, pH was not controlled. The optimal condition was found that at $H_{2}$ yield reached to 37.3 mL $H_{2}/g$ dcw at 1.2% HCl and 48 min. Through regression analysis, it was found that $H_{2}$ yield was well fitted by a quadratic polynomial equation ($R^{2}$=0.95). HCl concentration was the most significant factor influencing DFHP. The results of ANOVA verify that HCl concentration was the most significant factor influencing DFHP.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.26 no.3
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• pp.277-285
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• 2016

Objectives: This study was performed in order to evaluate whether 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) could be detected among residents living near Camp Caroll in Waegwan and whether serum concentrations of dioxins, including 2,3,7,8-TCDD, and organochlorine pesticides (OCPs) are associated with length of residence. Methods: Study subjects totaled 113 (for dioxins) and 190 (for OCPs) adults who were selected from participants in a medical investigation. Serum concentrations of dioxins and OCPs were measured using HRGC/HRMS. Information on length of residence was obtained through questionnaires. Results: 2,3,7,8-TCDD was not detected in serum among all subjects. When length of residence was classified as a categorical variable, after adjusting for confounding variables, only residents living in Waegwan for 40 years or longer tended to have high total TEQ values and 2,3,4,7,8-PeCDF with marginal significances. There was no dose-response relation between length of residence and serum concentrations of these chemicals. In multiple regression models with continuous values of the length of residence, total TEQ value and 1,2,3,4,6,7,8-HpCDF were positively associated with length of residence. However, they explained about 3-5% of total variations of serum concentrations of these compounds, while age, consumption of fatty fish, body mass index, alcohol drinking, and cigarette smoking were main variables affecting serum concentrations of dioxins or OCPs. Conclusions: In the current study, high concentrations of certain compounds were mainly observed among persons who lived in Waegwan for at least for 40 years without a dose-response relation. Therefore, it seems difficult to conclude that length of residence meaningfully contributed to the current serum concentrations of dioxins or OCPs among residents in Waegwan. However, considering the half-life of 2,3,7,8-TCDD and indirect exposure routes, the limitations of the current study design should be considered in the interpretation of the study findings.

• Journal of the Korean Wood Science and Technology
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• v.27 no.2
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• pp.53-61
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• 1999

Effects of culture conditions and Mn(II) addition were investigated for production of extracellular manganese peroxidase by lignin-degrading fungus LSK-27, Nitrogen source was shown to more influence the production of extracellular manganese peroxidase by LSK-27 than carbon source. When peptone or yeast extract as nitrogen source was added, high MnP activity was obtained. Especially, nitrogen-sufficient culture condition was effective in MnP activity, showing significantly increase up to 1.0% peptone concentration, but carbon-sufficient was not. Mn(II) was shown to strongly induce the MnP production in culture fluids of LSK-27. Increase of MnP actiyity was obeserved up to addition of 100ppm Mn(II), and over this Mn(II) concentration appeared to be inhibitory. The highest level of MnP activity was attained when Mn(II) was added after 2 day incubation.

• Korean Journal of Ecology and Environment
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• v.42 no.3
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• pp.271-279
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• 2009

Vinyl chloride (VC) is a known human carcinogen, and it is released to multi-environmental media via several exposure routes. VC was potentially evaluated as a water quality pollutant based on human health risk assessment in Korean water environments. In this study, we investigated physicochemical and toxicological properties of VC, human health and ecological risk assessment, and the regulation of VC as a water quality pollutant in developed countries. Currently there are no standard or guideline values of VC in Korean legal system for the protection of human health and aquatic ecosystem, except that it is designated as a specific toxic substance and a water quality pollutant. Human health risk assessment of VC was previously performed based on the limited water quality monitoring data. The monitoring level of VC in Korean water system is more higher than other countries'. VC was assessed as potential hazardous chemical based on the US EPA's cancer risk assessment. There were a few ecotoxicity data of VC available using very limited kinds of aquatic organisms, and the toxicity results obtained seem to be overestimated without considering the losses of VC in open exposure system. Therefore it is needed to monitor the VC in various areas and to carry out the ecotoxicity research using multi-level organisms. We expect that these results can be useful information for implementing VC as a water quality pollutant in legal system for the protection of human health and aquatic ecosystem in near future.

• Membrane Journal
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• v.23 no.2
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• pp.159-169
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• 2013

The effect of humic acid (HA), and the roles of microfiltration (MF), PES (polyethersulfone) beads adsorption, and photo-oxidation were investigated in hybrid process of ceramic MF and PES beads loaded with titanium dioxide ($TiO_2$) photocatalyst for advanced drinking water treatment. The results of water and nitrogen back-flushing were compared in viewpoints of membrane fouling resistance ($R_f$), permeate flux (J), and total permeate volume ($V_T$). Because membrane fouling increased dramatically as increasing HA, Rf increased and J decreased, and finally $V_T$ was the highest at 2 mg/L HA. Average turbidity treatment efficiencies were almost same independent of HA concentration. Average organic matter treatment efficiency was the minimum 71.4% at 10 mg/L HA in water back-flushing, but those were almost constant in nitrogen back-flushing. The hybrid process of MF, PES beads, and UV (MF + $TiO_2$ + UV) have the lowest $R_f$, and the highest J and $V_T$ in both water and nitrogen back-flushing. The turbidity and organic matter treatment efficiencies were the maximum at MF + $TiO_2$ + UV independent of water and nitrogen back-flushing, and decreased sequently as simplifying the process to MF. However, adsorption performed the more important role than photo-oxidation in water back-flushing, and photo- oxidation was the more than adsorption in nitrogen back-flushing.

• Journal of Soil and Groundwater Environment
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• v.11 no.6
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• pp.18-27
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• 2006

Air Sparging (IAS, AS) is a ground-water remediation technique, in which organic contaminants are volatilized into air as they rise from saturated to vadose soil zone. This study was conducted to investigate the variation characteristics of TPH, VOCs and $CO_2$ for air sparging of diesel contaminated saturated soil. Initial TPH concentration was 10,000 mg/kg for saturated soil phase and 1,001 mg/L for soil aquifer phase. After 36 days of air sparging, the equilibrium temperature of 2-Dimension experiment system was $24.9{\pm}1.5^{\circ}C$. The saturated soil TPH concentration (in the C10 port close to air diffuser) was reduced to 66.0% of the initial value. The mass amount of $CO_2$ was 3,800 mg and 3,200 mg in air space (C70 port) and in unsaturated soil zone (C50 port), respectively. The VOCs production kinetic parameter was 0.164/day in the air space (C70 port) and 0.182/day in the unsaturated soils (C50 port).

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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• 2001.04a
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• pp.80-80
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• 2001

제지 공정의 효율적인 운영을 위한 수단으로 보류 및 탈수성의 분석은 매우 중요한 작 업 이 다. 보류 및 탈수 특성 을 평 가하기 위 하여 SR(Shopper-Riegler), CSF(Canadian S Standard Freeness tester) 그리고 원형 수초지기 등의 비난류 상태의 자연탈수 특성 평가 장치와 동적 조건의 감압식 탈수성 분석기 등이 사용되고 있다. 하지만 이것들은 제지 공정 에 보다 더 근접한 탈수 및 보류 특성을 평가하기에는 부족한 점이 있다. 특히 wet-end 첨 가제들의 효능을 보다 정확히 분석하는 것이 불가능하다. 이런 이유로 난류 발생과 감압 탈 수 둥을 유도한 탈수 특성 평가 장치 개발의 필요성이 커지고 있다. R RDA - HSF(Retention Drainage Analyzer- Handsheet Former)는 지료조성, 감압탈수 및 습지의 성형이 자동화되어 보류도와 탈수성, 종이지합 및 강도를 종합 평가 할 수 있는 새 로운 실험실용 초지기이다. 보다 현장에 가까운 초지 조건을 구현하기 위해서 지료의 농도 를 높이고 진공 탈수를 실시함에 따라 기존의 탈수성 분석기나 보류도 측정기의 단점을 보 완하게 되 었다. 본 연 구에 서 는 Canadian Standard Freeness test와 Dynamic Drainage Jar test 및 원 형 수초지기를 활용한 기존의 탈수성, 보류도 분석 결과와 RDA-HSF를 비교하여, 자연 탈수를 이용하는 기존의 탈수 및 보류 설비에 비해 현장 공정을 보다 현실적으로 재현할 수 있는 감압 탈수 초지 설비로서 RDA-HSF의 활용 가능성을 분석하였다. RDA-HSF를 활용한 실험실적 분석을 통해 현장의 상황올 유사하게 재현함에 따라 공정 운영 인자의 변화에 따른 제품의 품질 및 생산효율을 예측할 수 있게 된 바, 보다 효율적 인 공정 관리가 가능할 것으로 기대된다. 안료 입자의 경우 피인쇄체의 표면 공극을 채우고, 비히클의 경우 미세한 공극속으로 침투되어 경화됨으로써 피인쇄체가 지니고 있는 공극량을 감소시커 게 될 것이다. 그리고 피인쇄체의 각종 형태의 공극으로 침투된 잉크의 양에 반비례적으로 피인쇄체의 표변에 잉크가 잔류하게 될 것이다. 따라서 본 연구에서는 여러가지 안료를 사용하여 각각 다른 공극 특성을 지니는 도공지를 제조한 후 이들이 가지는 공극 특성과 잉크의 잔류 거동에 대해 고찰해 보고자 하였다.여 표면 유효층 일부만 오버레이시키며I 주조 및 단조가 불가능한 재료까지도 표면부에 오버레이 시킴으로 서 부품 및 설비의 제조에 있어 재료비의 절감과 제품의 수명이 획기적으로 개선될 수 있다. 그리고 최근에는 도금 빛 용사 둥과 같은 표면처리를 할 경우임의 소재 표면에 도금 및 용 사에 용이한 재료를 오버레이용접시킨 후 표면처리를 함으로써 보다 고품질의 표면층을 얻기위한 시도가 이루어지고 있다. 따라서 국내, 외의 오버레이 용접기술의 적용현황 및 대표적인 적용사례, 오버레이 용접기술 및 용접재료의 개발현황 둥을 중심으로 살펴봄으로서 아직 국내에서는 널리 알려지지 않은 본 기 술의 활용을 넓이고자 한다. within minimum time from beginning of the shutdown.및 12.36%, $101{\sim}200$일의 경우 12.78% 및 12.44%, 201일 이상의 경우 13.17% 및 11.30%로 201일 이상의 유기의 경우에만 대조구와 삭제 구간에 유의적인(p<0.05) 차이를 나타내었다.는 담수(淡水)에서 10%o의 해수(海水)로 이주된지 14일(日) 이후에 신장(腎臟)에서 수축된 것으로 나타났다. 30%o의 해수(海水)에 적응(適應)된 틸라피아의 평균 신사구체(腎絲球體)의 면적은 담수(淡水)에 적응된 개체의 면적보다 유의성있게 나타났다. 해수(海水)에 적응(適應