• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.27 no.1
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• pp.1-16
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• 2022

Nitrate (NO₃^-) plays an important role in aquaculture and ecosystems in the Korea Strait. Observational data propose that ocean currents are crucial to NO₃^- budget in the Korea Strait. However, assessment of budget by currents and biogeochemical processes has not yet been investigated. This study examines seasonal and spatial variations in NO₃^- budget by currents and biological processes in the Korea Strait from 2011 to 2019 using a physical-biogeochemical coupled model. Model results suggest that current-driven net supply of NO₃^- is consumed by uptake of phytoplankton in the Korea Strait. Advective influx is driven by the Tsushima warm current and the influx by the Jeju warm current is approximately one third of it. All of the influxes are transported out to the East Sea through the Korea Strait, of which two third passes through the western channel and the rest through the eastern channel. Annual mean NO₃^- net transport show that currents supply NO₃^- year round except for January, but the budget by biogeochemical processes consumes it every season except for winter.

• Economic and Environmental Geology
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• v.57 no.2
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• pp.271-280
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• 2024

This study examines the European Union (EU)'s policies on managing nitrate contamination in groundwater and provides implications for the future groundwater management in South Korea. Initiated by the 1991 Nitrate Directive, the EU has pursued a multifaceted approach to reduce agricultural nitrate pollution through sustainable ('good') farming practices, regular nitrate level monitoring, and designating Nitrate Vulnerable Zones. Further policy integrations, like the Water Framework Directive and Groundwater Directive, have established comprehensive protection strategies, including the use of pollutant threshold values. Recently, the 2019 Green Deal escalated efforts against nitrates, aligning with broader environmental and climate objectives. This review aims to explore these developments, highlighting key mitigation strategies against nitrate pollution, and providing valuable insights for the future sustainable groundwater nitrate management in South Korea, emphasizing the importance of preventive measures and collaborative efforts to restore and improve groundwater quality.

• Journal of Radiation Protection and Research
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• v.12 no.2
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• pp.9-18
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• 1987

The present study has determined BUN, createinine, c-AMP and $PGE_2$ activities as a clinical signs of radiation toxicity caused by uranylnitrate in rats. The significant increasing of $PGE_2$ concentration in plasma between the administration of uranylnitrate and lead nitrate were shown radiotoxic in nature on the effect of radiation energy. The reduction of PGE activities in plasma in uranylnitrate treated rats after furosemide, aldosterone and glucagone I.P. administration have observed the stimulating effect of uranium excretion into cells.

• Asian Journal of Turfgrass Science
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• v.5 no.1
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• pp.41-45
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• 1991

서양잔디중 난지형 잔디에 속하는 세인트 어거스틴그래스에서 암모늄태 질소와 질산태 질소질 비료의 시비가 브라운팻치 병 발생에 미치는 영향을 알아보고자 본 실험이 수행되었다. 포장에서 재배되고 있는 세인트 어거스틴그래스를 작경 10cm의 플러그를 굴취하여 플라스틱 포트에 이식한 후 뿌리의 활착을 위하여 온실내에서 한달간 재배하였고, 50kg N/ha의 성분비율에 맞추어서 균의 접종 1일전에 시비를 하였다. 잔디포장에서 분리한 Rhizoctonia solani균을 agar위에서 배양시킨 후 균이 배양되어 있는 agar block 을 떼어서 태운 perennial ryegrass에 접종시켰다. 감염된 perennial ryegrass를 다시금 세인트 어거스틴그래스위에다 치상시켜서 잔디로의 접종을 꾀하였다. 그 결과 암모늄태 질소비료나 질산태 질소비료 그리고 무시비상태의 잔디에서의 병발생간에는 유의차가 인정되지 않았으나 질산화 억제제를 처리하여 암모늄상태의 질소 성분이 질산태로 전환되는 것을 억제시킨 구에서는 타처리구에 비하여 6~9배의 발생율을 보였다. 따라서 잔디의 시비와 병발생을 연관시켜 볼 때 암모늄태 질소비료 와 질산태 질소비료 공히 큰 차이는 없으나, 다만 질산태로 변한 후의 질소양분의 토양용탈로 인한 소모를 억제시키기 위하여 사용되는 질산화 억제제는 상당량의 암모늄태 질소성분을 상당 기간동안 유지시키기 때문에 브라운팻치 병발생에 영향을 주므로 그 사용시기에 있어서 신중을 기하여야 하겠다.

• Current Research on Agriculture and Life Sciences
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• v.6
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• pp.113-120
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• 1988

Concern was forcused to investigate the relationship between nitrite and ascorbic acid contents in spinach during processing and storage in this experiment. Contents of nitrate and nitrite in fresh spinach were 3,000ppm and 0.25ppm, respectively. Nitrite contents were decreased by branching and storaging, while the nitrite contents were increased. The tendency was accelerated by seasoning. When spinach was stored at $4^{\circ}C$ and $25^{\circ}C$, Changes of nitrate and contents were rapid at $25^{\circ}C$, but slow at $4^{\circ}C$. In the relationship among the contents of nitrite, nitrate, and ascorbic acid during storage, nitrate contents were decreasing, whereas nitrite and ascorbic acid contents were increasing.

• Korean Journal of Environmental Agriculture
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• v.15 no.3
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• pp.383-390
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• 1996

This experiment was conducted to investigate the influence of nitrogen fertilizer forms, fertilizer and herbicide application rates on growth of radish. The nitrate content and nitrate reductase activity of radish were analyzed along with the growing stage. Nitrate nitrogen was more efficient than ammonium nitrogen for radish. With increasing the fertilizer application rate, accumulated of nitrate content was increased. The amount of nitrate nitrogen was highest at 25days after seeding in petioles, and $32{\sim}39days$ after seeding in root. Nitrate content was decreased as sampling date was delayed, whereas the content increased in the root at early growing stage and then decreased. The nitrate cotent increased in the order of petioles, roots, and leaf blades and nitrate reductase activity increased petioles, leaf blades, and roots. The higher nitrogen fertilizer and herbicide application increased nitrate nitrogen accumulation in radish as compaired with control treatment and nitrate reductase activity showed similar trend.

• KSBB Journal
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• v.24 no.3
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• pp.296-302
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• 2009

This paper was investigated the research regarding the effects of several factors such as initial ammonium nitrogen concentration, aeration rate. biomass amount and C/N ratio on nitrification process using synthetic wastewater and activated sludge obtained from wastewater treatment facility. As a result, in high ammonium nitrogen concentration above 100 mg/L, the pH of wastewater was dropped to pH 6.8. The increases of initial ammonium nitrogen concentration, aeration rate and initial biomass amount were linearly enhanced the removal rate of ammonium nitrogen. In the condition of C/N ratio of 0 to 3, high ammonium nitrogen removal rate was obtained.

• Korean Journal of Soil Science and Fertilizer
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• v.25 no.1
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• pp.57-61
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• 1992

For testing salts effect on seed germination, nitrogen solutions($(NH_4)_2SO_4$, $NH_4NO_3$, $KNO_3$, $Mg(NO_3)_2$, $Ca(NO_3)_2$, $(NH_2)_2CO$) were treated to chinese cabbage(Brassica rape L.) and lettuce(Lactuca sativa L.) seeding on the quartz sand bed given a tilt to wet by dripping. Electrical conductivities (mS/cm) increased with direct proportion by equivalent gram-molecular weight at $(NH_4)_2SO_4$ and $KNO_3$, $NH_4NO_3$, but those of Mg and Ca salt remained 1 1/2 times higher. And urea solution never showed EC at all. $(NH_4)_2SO_4$ solution appeared to have value of EC with 1.37 times as high as that of $KNO_3$ and it was in order of $(NH_4)_2SO_4>NH_4NO_3>KNO_3>Ca(NO_3)_2>Mg(NO_3)_2$ comparing with same percentage solution. Application of $Mg(NO_3)_2$ and $(NH_4)_2SO_4$ among 6 salts resulted in a severe decreas in germination of both crops, and $NH_4NO_3$ showed light inhibition in comparison to $KNO_3$. Urea showed little effect on germination as the same as $Ca(NO_3)_2$ and $KNO_3$ solution at low concentrations, but the latter two salts reduced germination remarkably at high concentrations. It is likely to show that germination inhibition is not affected by salt salanity but by the sort of salts.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.30 no.5
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• pp.782-793
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• 1997

To study the physiological adaptation (shift-up) of phytoplankton under the simulated upwelling conditions, nitrate uptake capacity of Dunaliella tertiolecta batch culture was measured in the laboratory using the stable isotope $^{15}N-KNO_3$. Contrary to the expected, there was no significant relationship between the maximum $V_{NO3}$ (nitrogen specific nitrate uptake rate) and the initial nitrate concentration. However, there was a strong relationship between the maximum $\rho_{NO3}$ (nitrate transport rate) and the initial nitrate concentration of $<25\;{\mu}M$, which was also influenced by the physiological status of the culture. The increase in $V_{NO3}$ was mainly due to the increase in PON (particulate organic nitrogen) concentration and partly due to the increase in $V_{NO3}$. When the phytoplankton population was severely shifted-down, the physiological adaptation of nitrate uptake was significantly inhibited at high initial nitrate concentrations. The timing of the maximum $V_{NO3}$ or $\rho_{NO3}$ was related to the initial nitrate concentration. At higher initial nitrate concentrations, maxima in $V_{NO3}$ and $\rho_{NO3}$ occurred 1 or 2 days later than at lower nitrate concentrations. This relationship was the opposite to the prediction from the shift-up model of Zimmerman et al. (1987), The shift-up process is apparently controlled by an internal time sequence and the initial nitrate concentration, but the magnitude of $V_{NO3}$ was affected little by changes in nitrate concentration.

• Resources Recycling
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• v.26 no.1
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• pp.51-58
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• 2017

The present study to develop a process for extracting nitric acid and gold from aqua regia leach solution using TBP(tributyl phosphate) was conducted. The pure aqua regia was used to investigate the extractive behavior of nitric acid depending on the concentration of extractant, concentration ratio of nitric and hydrochloric acid. The extraction rate of nitric acid and gold from the gold bearing aqua regia was also examined. The theoretical extraction number was verified by counter current using the number of operations and the phase ratio obtained from McCabe-Thiele diagram. Stripping experiments were carried out for continuous recovery of nitric acid and gold in loaded organic. Considering the effect of extraction acid and gold, the simulation showed that greater than 99.9% extraction of $103.0mg{\cdot}L^{-1}$ gold and 98.0% of $151.2g{\cdot}L^{-1}$ nitric acid could be attained in a two and three-stage counter-current extraction at an O/A phase ratio of 1:0.85. Distilled water and sodium thiosulfate were used as the nitric acid and gold stripping solution. The stripping rates were 99.5% and 92.0%, respectively. The study revealed that the recovery of nitric acid and gold from gold bearing aqua regia was a plausible approach through simultaneous extraction and continuous stripping of nitric acid and gold.