• 한국농공학회:학술대회논문집
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• 한국농공학회 2001년도 학술발표회 발표논문집
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• pp.479-483
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• 2001

This Study was carried out to know the soil properties and the quality of shallow groundwater in the plastic film house fields around mid-Korea. This study was conducted at 11 sites in Suweon, Pyungtaek, Yongin, and Chunchen on May, June, July and August in 1999. The the average concentration of nitrate-nitrogen was 19.1 mg/L, it reached almost to the limiting level, 20 mg/L. Moreover about 36.4% of survey sites exceeded limiting level to agricultural groundwater quality. And Sulfur concentrations also at some sites exceeded to agricultural groundwater quality limit level (50 mg/L), which could make damage to the crop. Nitrate-nitrogen, which is one of the most important factors in the groundwater quality, It has highly positive correlation with any other ion in groundwater. This result showed that groundwater quality management practices should be taken for the agricultural production as well as for environment at the plastic film house areas.

• 한국대기환경학회지
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• 제10권2호
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• pp.124-129
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• 1994

Aerosol size distribution was determined using Anderson sampler for the anions( sulfate nitrate and chloride ) and TSP. Ionic species concentration and size distribution have been investigated in the daytime and nightime individually. Size classified samples were extracted with distilled water and analyzed for C $l^{[-10]}$ , N $O_3$$^{[-10]}$ and S $O_4$$^{2-}$, by ion chromatography. The size distribution of these ions and TSP was analyzed to investigate the seasonal and diurnal variation of concentrations as follows: (1)Size distribution of TSP showed bi- modal type in the daytime, but indicated tri-mode distribution in the nightime without any seasonal variation. (2)Sulfate concentrations were higher in fine- mode both in the daytime and nightime but fraction of sulfate was higher in coarse-mode during the Yellow Sand Period. (3)Nitrate and Chloride ions are dominant in fine-mode in winter while dominant in coarse-mode in the summer.

• 한국지하수토양환경학회지:지하수토양환경
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• 제20권7호
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• pp.80-89
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• 2015

Nitrate is on the most seriou pollutant encountered in shallow groundwater aquifer in agricultural area. There are various remediation technologies such as ion exchange, reverse osmosis, and biological denitrification to recover from nitrate contamination. Biological denitrification by indigenous microorganism of the technologies has been reviewed and applied on nitrate contaminated groundwater. In this work, we selected the site where the annual nitrate (NO₃⁻) concentration is over 105 mg/L and evaluated denitrification process with sampled soil and groundwater from 3 monitoring wells (MW4, 5, 6). In the results, the nitrate degradation rate in each well (MW 4, 5, and 6) was 25 NO₃⁻ mg/L/day, 6 NO₃⁻ mg/L/day, and 3.4 NO₃⁻ mg/L/day, respectively. Nitrate degradation rate was higher in batch system treated with 2 times higher fumarate as carbon source than control batch system (0.42M fumrate/1M NO₃⁻), comparing with batch system with soil sample. This result indicates that increase of carbon source is more efficient to enhance denitrification rate than addition of soil sample to increase microbial dynamics. In this work, we also confirmed that monitoring method of functional genes (nirK and nosZ) involved in denitrification process can be applied to evaluated denitrifcation process possibility before application of field process such as in-situ denitrification by push-pull test.

• 한국물환경학회지
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• 제24권6호
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• pp.718-724
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• 2008

The ion selective microelectrode (ISME) has been used for measuring the ion profile of DO, $NH_4{^+}-N$, $NO_2{^-}-N$ and $NO_3{^-}-N$ in biofilm. In this study we evaluated the detection limit and validity of ISME and applied ISME for the continuous measurement of $NH_4{^+}-N$ and $NO_3{^-}-N$ concentration in the modified Ludzack-Ettinger (MLE) process. Average detection limits of $NH_4{^+}-N$ and $NO_3{^-}-N$ ISME were $10^{-4.44}M$ and $10^{-4.62}M$, respectively. Since the ISME with $5{\sim}10{\mu}m$ of tip diameter showed a faster response time than that of $1{\sim}5{\mu}m$, the ISME with a tip diameter of $5{\sim}10{\mu}m$ was fabricated and used to make real-time ion detections. Direct monitoring of $NH_4{^+}-N$ and $NO_3{^-}-N$ concentrations in the aerobic (2) tank causes the instability of the electromotive force (EMF) for the initial 5~8 hours and also causes remarkable error values of $NH_4{^+}-N$ and $NO_3{^-}-N$ concentration. This phenomenon is caused by aeration and mixing in the reactor. Thus, the measuring chamber was newly designed for the aerobic (2) tank and then the EMF of the ISME were stabilized in less than 1 hour. Errors of $NH_4{^+}-N$ and $NO_3{^-}-N$ concentration were decreased after stabilization of the EMF. The ISME analysis were well corresponded to the results of auto analyzer and ion chromatography. Consequently, the concentration of $NH_4{^+}-N$ and $NO_3{^-}-N$ could be continuously measured for 178 hours by the ISME.

• 한국환경과학회지
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• 제2권4호
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• pp.337-346
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• 1993

The amount of inorganic ions such as $Na^+$, $K^+$, $Ca^{2+}$, $Mg^{2+}$, $NH_4^+$, $Cl^-$, $NO_3^-$, and $SO_4^{2-}$ in the precipitation at hongwon area were analyzed during the period of February 1991 - June 1993. Ammonium ion was analyzed using Messier and indophenol methods. Cations were determined by atomic absorption spectroscopy, and ion chromatography was used for anions. For the entire period of study, there was no particular ion which has significant]y high correlation coefficient with hydrogen ion. The correlation between $NO_3^-$, and $SO_4^{2-}$ was 0.6, which suggests that these ions may be from the same source. Most cations have high correlation with each other. In the seasonal analysis, the nitrate and sulfate ions have high correlations with the acidity in the fall and winter. The rain waters of Taeahn area showed usually high concentrations of the ions, even though the pH was much higher than that of Chongwon area. It is considered that the ions came as neutral salt in Taeahn, while $NO_x$ and $SO_x$ contributes largely to the acidity of rains in Chongwon.

• Journal of Microbiology and Biotechnology
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• 제10권1호
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• pp.35-42
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• 2000

Reaction characteristics of 4-methylcatechol 2,3-dioxygenase (4MC230) purified from Pseudomonas putida SU10 with a higher activity toward 4-methylcatechol than catechol or 3-cethylcatechol were studied by altering their physical and chemical properties. The enzyme exhibited a maximum activity at pH 7.5 and approximately 40% at pH 6.0 for 4-methylcatechol hydrolysis. The optimum temperature for the enzyme was around $35^{\circ}C$, since the enzyme was unstable at higher temperature. Acetone(10%) stabilized the 4MC230. The effects of solvent and other chemicals (inactivator or reactivator) for the reactivation of the 4MC230 were also investigated. Silver nitrate and hydrogen peroxid severely deactivated the enzyme and the deactivation by hydrogen peroxide severely deactivated the enzyme and the deactivation by hydrogen peroxide was mainly due to the oxidation of ferrous ion to ferric ion. Some solvents acted as an activator and protector for the enzyme from deactivation by hydrogen peroxide. Ascorbate, cysteine, or ferrous ion reactivated the deactivated enzyme by hydrogen peroxide. The addition of ferrous ion together with a reducing agent fully recovered the enzyme activity and increased its activity abut 2 times.

• 한국환경보건학회지
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• 제29권3호
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• pp.91-96
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• 2003

This study was intended as an investigation of characteristics of background site atmospheric respirable particulate matters(RPM), and fine particles(<2.5 ${\mu}{\textrm}{m}$). The particle size distributions during the phenomenon of Yellow Sand(YS) occurs from April, 2001. Atmospheric aerosol particulate matter was directly collected on the Jeju island between 1 to 30, April, 2001 using an eight-stage cascade impacter(particle size range: 0.43-11 ${\mu}{\textrm}{m}$), and cyclone separator(cut size: 2.5, 10 ${\mu}{\textrm}{m}$). The episode of YS observed in background monitoring site, Kosan and appeared 2 times at sampling period. The mass concentrations of fine and coarse particles for YS episode were 34.2 and 59.6 $\mu\textrm{g}$/㎥, respectively, which were significantly increased amounts compared to 13.3 and 13.0 $\mu\textrm{g}$/㎥ for NonYS(NYS). Most size distributions had two peaks, one at 0.43∼.65 ${\mu}{\textrm}{m}$ and the other at 3.3${\mu}{\textrm}{m}$4.7 ${\mu}{\textrm}{m}$. The result of analysis of water-soluble ion component indicated that sulfate was mainly ion component, but nitrate and calcium ion was significantly increased at the YS episode.

• 콘크리트학회논문집
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• 제17권6호
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• pp.931-938
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• 2005

RC 구조물이 해양 환경에 장기간 노출된 콘크리트 안의 철근은 해수에 포함된 염화물 이온의 침투에 의해 부식하게 된다. 염화물 이온에 의한 철근의 부식 피해는 매우 다양하기 때문에, 많은 연구들이 수행되어 왔다. 염화물 이온의 침투깊이를 쉽게 측정할 수 있는 질산은 변색법이 최근 많이 사용되고 있다. 그러나, 질산은 변색법의 특성이 완전히 파악되지 않은 채 사용되고 있는 실정이다. 그러므로 본 연구의 목적은 변색법의 적용성을 조사하는데 있다. 이러한 목적을 가지고 변색법의 메커니즘과 영향인자에 대하여 파악하고자 하였다. 변색법 실험 결과에 따르면, 콘크리트 할렬면에 질산은이 분무될 때, AgCl의 흰색반응과 AgOH의 갈색 반응, 두 반응이 발생한다. 또한, 반응 속도 상수비는 흰색 반응, 즉 AgCl이 3240배 빠르게 반응하는 것으로 나타났다. 변색 법을 콘크리트에 적용할 경우, 0.05N 이상의 질산은 용액을 분무하는 것이 바람직하다. 현장 콘크리트 구조물에 있어 변색법은 염화물을 평가하는데 유용한 방법이다. 변색 구간에서의 평균 염화물량 값은 콘크리트 단위중량 당 $0.9kg/m^3$으로 나타났다.

• 한국약용작물학회지
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• 제23권6호
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• pp.446-453
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• 2015

Background : Excessively high concentration of sodium ion causednutrient deficiency and significantly decrease growth. This study was carried out to determine the limiting concentration range of sodium ion in the soil of ginseng field. Methods and Results : The growth of the ginseng cultivar Chunpoong reduced with increase in salinity, and the rate of growth reduction was higher in shoots than that of roots. Particularly, ginseng plants cultivated at high level of nitrate nitrogen or sodium may suffer delayed development and stunted growth. Chlorophyll damage occurred on the leaves of ginseng planted in relatively high levels (> $0.2cmol^+/kg$) of sodium ion, as determined by the fluorescence reaction. The incidence of physiological disorder in ginseng cultivated at 249 sites was correlated with the concentration of sodium ion in the soils. About 74% of ginseng fields in which physiological disorders occurred had concentrations of sodium ion in soil greater than $0.2cmol^+/kg$. In contrast, the concentration of sodium ions at 51 of 85 sites where no damage occurred was relatively ($0.05cmol^+/kg-0.15cmol^+/kg$). Conclusions : The concentration of sodium ion in soil of ginseng fields can be classified into three levels optimum (${\leq}0.15$), permissible allowance (0.15 - 0.2) and excessive (> 0.2).

• 폴리머
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• 제26권2호
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• pp.153-159
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• 2002

본 연구에서는 지하수 중의 NO$_{3}^{-}$ 이온을 선택적으로 흡착 제거시키기 위하여 E-beam 전조사법에 의해 GMA 단량체를 폴리프로필렌 섬유 기재에 그라프트 반응시켜 PP-g-GMA 공중합체를 제조한 후 아민화 반응을 통하여 강염기성 APP-g-GMA 음이온교환수지를 합성하였다. 공중합체의 그라프트율 및 TMA에 의한 아민화율은 반응온도가 증가할수록 증가하였으며, $60^{\circ}C$일 때 각각 133%, 88% 최대치를 나타내었고, 이때의 팽윤율과 이온교환용량은 각각 86%, 2.5 meq/g으로 IMAC HP555, Amberlite IRA 400와 같은 상용 이온교환수지 보다 높게 나타났다. $NO_3;^-$ 이온흡착의 최적 조건은 pH 5~6이었으며, trimethylammonium 기를 갖는 -Cl형의 APP-g-GMA 이온교환체가 가장 높은 선택 흡착성을 나타냈다.