• Journal of Korean Society for Atmospheric Environment
• /
• v.26 no.3
• /
• pp.265-275
• /
• 2010

Mass and ion concentrations of $PM_{10}$ and $PM_{2.5}$ were measured in Yongin, downwind of the Seoul metropolitan area. Twenty-four hour average samples were collected daily for a month or so in spring and fall of both 2007 and 2008. Asian dust occurred twice in each period except in the fall of 2007. During the Asian dust period, nitrate in fine particles decreased since large amount of cations in coarse particles of Asian dust absorbed it. In spring 2008, sulfate as well as ammonium also increased in coarse particles. In spite of occasional Asian dust events, the influence of secondary formation was dominant over the period. Excessive ammonium over sulfate was enough to neutralize nitrate as well. High correlation coefficients between $K^+$ and sulfate, nitrate, and ammonium indicate a close relationship between secondary formation and biomass burning. Biomass burning and open burning are considered to be important sources of chloride.

• Journal of Environmental Health Sciences
• /
• v.16 no.2
• /
• pp.11-20
• /
• 1990

To investigate ionic characteristics of acid rain by the succeeding rainfall. bulk precipitation was collected every each 5mm rainfall from march to october 1990 at Dae Jeon area. pH, sulfate nitrate, chloride, ammonium ion was measured and analyzed. The result was as follows: 1. The weighted average pH of rain was 5.1$\pm$ 0.72(4.15~7.6) and rain pH less than 5.5 was appeared 51.3% 2. Average ion concentrations of sulfate, nitrate, chloride and ammonium ion was 125.12 $\mu$eq/l, 62.38 $\mu$eq/l, 31.95 $\mu$eq/l, 66.6 $\mu$eq/l and rates of each anions was 57%, 28.4%, 14.6% and rate of sulfate by nitrate was 2 times. 3. There is no correlations time interval of rainfall and Ion concentration change. 4. From initial to 15mm rainfall, each ion concentrations were decreased. and average concentration of pH, SO$^{-2}_{4}$, Cl ion concentration was increased in the succeeding rainfall 5. Only sulfate ion was correlated by the simple regression analysis with pH except NO$^{-}_{3}$, Cl$^{-}$ and NH$_{4}^{+}$ Cl$^{-}$ correlation coefficient was very high at the multiple regression analysis with pH. 6. Simple & multiple correlation coefficient among anions and NH$^{+}_{4}$ was very high especially N$^{+}_{4}$ and SO$^{2-}_{4}$ at simple regression analysis and SO$^{-2}_{4}$ and NO$_{3}^{-}$, Cl$^{-}$, NH$_{4}^{-}$ at multiple regression analysis.

• ALGAE
• /
• v.34 no.2
• /
• pp.111-126
• /
• 2019

The phototrophic dinoflagellate Biecheleriopsis adriatica is a small suessioid species characterized by a fragile thin wall. Although the morphology of this dinoflagellate is well established, there is currently little information available on its distribution and the environmental factors that influence this distribution. Thus, to investigate the spatial and seasonal distributions of the vegetative cells of B. adriatica in Korean waters, surface water samples were collected on a seasonal basis from 28 stations in the East, West, and South Sea of Korea and Jeju Island from April 2015 to October 2018, and abundances of the vegetative cells of B. adriatica were quantified using quantitative real-time polymerase chain reactions, for which we developed the species-specific primer and probe set. Simultaneously, major environmental parameters, including temperature, salinity, nutrient concentrations, and dissolved oxygen concentrations were measured. The vegetative cells of B. adriatica were detected at 20 of the 28 sampling stations: 19 stations in summer and 6 in autumn, although from no stations in either spring or winter. The ranges of water temperature and salinity at sites where this species was detected were $17.7-26.4^{\circ}C$ and 9.9-34.3, respectively, whereas those of nitrate and phosphate concentrations were not detectable-96.2 and $0.18-2.66{\mu}M$, respectively. Thus, the sites at which this species is found are characterized by a narrow range of temperature, but wide ranges of salinity and concentrations of nitrate and phosphate. The highest abundance of the vegetative cells of B. adriatica was $41.7cells\;mL^{-1}$, which was recorded in Jinhae Bay in July 2018. In Jinhae Bay, the abundance of vegetative cells was significantly positively correlated with the concentration of nitrate, but was negatively correlated with salinity. On the basis of these findings, it appears that the abundance of B. adriatica vegetative cells shows strong seasonality, and in Jinhae Bay, could be affected by the concentrations of nitrate.

• Ocean and Polar Research
• /
• v.27 no.3
• /
• pp.341-349
• /
• 2005

Temporal variation of the natural planktonic community in the Southern Sea of Korea was investigated by using low floating enclosed bags (3.2m deep and 2,500 liter) in order to understand the effect of enriched nitrate on the planktonic community in the spring (March-April) of 2002. Prior to beginning the incubation, the bags were placed in two different concentrations of nitrate, which consisted of control (ambient water) and experimental mesocosms (final concentration of $12{\mu}M$). The nitrate concentration in the experimental mesocosms remained significantly higher than those in control mesocosms throughout the study period (ANOYA, p<0.001). Following the addition of nitrate, abundance and chi-a concentration of phytoplankton peaked on Day 1, when diatoms established the peak in the experimental mesocosms. Diatoms consisted mainly of Thalasxiosira decipiens, Pseudo-nitzschia pungem, Leptocylindrus danicu, Thalassionema nitzschioides, Chaetoceros pseudocrinitus and Actinoptychus senariu. However, the peak did not lead to the difference in abundance and composition of phytoplankton between control and experimental mesocosms during the study period. The dinoflagellates began to increase soon after the diatoms decreased in all mesocosms. Copepods, as a dominant group in the rnosozooplankton community, showed no immediate peak in relation to the nitrate addition, but only their own developmental process from the eggs to adult stage during the study period. The bottom-up control from enriched nitrate via phytoplankton to adult copepods was not distinguished in terms of the abundance of the planktonic community. This might stem from the relatively low nitrate availability of phytoplankton at no N-limited seawater and the weak coupling between rapidly sunken diatoms and copepods through the water column.

• Proceedings of the Korea Air Pollution Research Association Conference
• /
• 2003.11a
• /
• pp.151-152
• /
• 2003

대기중에는 토양입자나 해양입자와 같이 직접적으로 방출되는 입자상 물질 이외에 자연적으로 생성되거나 인간의 활동에 의하여 배출되는 유황, 질소산화물 및 유기물의 가스상 물질이 대기 화학 반응에 의하여 입자상 물질로 변환된 이차입자가 혼재되어 있다. 이러한 입자상물질은 $K^{＋}$, $Na^{＋}$, $Mg^{2+}$, NH$_4$$^{+}$, $Ca^{2+}$ 등의 양이온과 Cl$^{-}$, NO$_3$$^{-}$, SO$_4$$^{2-}$ 등의 음이온 성분으로 구성되어 있다. (중략)

• Journal of Korean Society for Atmospheric Environment
• /
• v.10 no.2
• /
• pp.124-129
• /
• 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.

• Journal of Soil and Groundwater Environment
• /
• v.24 no.6
• /
• pp.26-32
• /
• 2019

An analysis of groundwater quality is significant for monitoring and managing water contamination and groundwater system. For the purpose of those, the geochemical characteristics of groundwater were studied over the concern for water quality, water type and origin of nitrate nitrogen. Total colony counts were detected in 11 out of 20 samples, and the average value was 31.73 CFU/ml. Range and average of NO₃-N concentrations were 0.9~24.0 mg/L and 8.3 mg/L. All groundwater types were found to be Ca²⁺-HCO₃^-. The range and average of NO₃-N were 0.2~17.4 mg/L and 8.7 mg/L, and those of δ¹⁵N were 1.7~8.9‰, and 5.0‰. Careful consideration is required for evaluating the origin of nitrogen when NO₃-N concentration is low. In general, noticeable difference between rockbed and alluvial water was not found. The ranges of nitrate origins by chemical fertilizer, livestock manure and domestic sewage, and natural soil were 29.6~76.4%, 14.2~58.9% and 2.6~7.0%, and the average values of those were 57.4%, 37.4%, and 5.3%, respectively. Origin of nitrate was affected by more chemical fertilizer than the other parameters. Rockbed water was more affected by chemical fertilizer than alluvial water.

• Proceedings of the Korean Society of Crop Science Conference
• /
• 2000.11a
• /
• pp.135-136
• /
• 2000

• Journal of Bio-Environment Control
• /
• v.8 no.3
• /
• pp.216-221
• /
• 1999

To reduce leaf nitrate content, lettuce plants(Lactuca sativa var. capitata) were grown in deep flow culture. Nitrogen concentrations were controlled to 1 (6.Sme/$\ell$), 3/4 (4.9me/$\ell$), 2/4 (3.3me/$\ell$), and 1/4 strength(1.6me/$\ell$) of Yamaziki's nutrient solution from 7 days before harvest. The pH of nutrient solution was maintained at high level between 7.2 and 8.4. The values of pH and EC were increased with the nitrogen concentration in the nutrient solution. The nitrate contents were lowest at the treatment of 1/4 strength, but not significantly different among other treatments. The nitrate content was lower in outer leaves than in head leaves. The weight and diameter of head and shoot weight were lowest at the treatment of 1/4 strength.

• Journal of Biosystems Engineering
• /
• v.41 no.2
• /
• pp.75-84
• /
• 2016

Purpose: In-situ water quality monitoring based on ion-selective electrodes (ISEs) is a promising technique because ISEs can be used directly in the medium to be tested, have a compact size, and are inexpensive. However, signal drift can be a major concern with on-line management systems because continuous immersion of the ISEs in water causes electrode degradation, affecting the stability, repeatability, and selectivity over time. In this study, a computer-based nitrate monitoring system including automatic electrode rinsing and calibration was developed to measure the nitrate concentration in water samples in real-time. Methods: The capabilities of two different types of poly(vinyl chloride) membrane-based ISEs, an electrode with a liquid filling and a carbon paste-based solid state electrode, were used in the monitoring system and evaluated on their sensitivities, selectivities, and durabilities. A feasibility test for the continuous detection of nitrate ions in water using the developed system was conducted using water samples obtained from various water sources. Results: Both prepared ISEs were capable of detecting low concentrations of nitrate in solution, i.e., 0.7 mg/L $NO_3-N$. Furthermore, the electrodes have the same order of selectivity for nitrate: $NO_3{^-}{\gg}HCO_3{^-}$ > $Cl^-$ > $H_2PO_4{^-}$ > $SO{_4}^{2-}$, and maintain their sensitivity by > 40 mV/decade over a period of 90 days. Conclusions: The use of an automated ISE-based nitrate measurement system that includes automatic electrode rinsing and two-point normalization proved to be feasible in measuring $NO_3-N$ in water samples obtained from different water sources. A one-to-one relationship between the levels of $NO_3-N$ measured with the ISEs and standard analytical instruments was obtained.