• Korean Journal of Soil Science and Fertilizer
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• v.42 no.1
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• pp.14-20
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• 2009

Classification of land uses and analysis of nitrogen isotope fractionation in groundwater nitrate were carried out to examine its contamination sources in Jeju province. ${\delta}^{15}N$ values of urea (hydrolyzed with urease), ammonium sulfate, compost, water from septic tank were -1.7, -5.8, +14.1, and +24.0‰, respectively. Urea, when it was directly distillated, showed -16.5‰. Based on these ${\delta}^{15}N$ values, sources of nitrate could be classified as originated from chemical fertilizers with ${\delta}^{15}N$ values below +5‰ and as from animal manure or municipal waste with ${\delta}^{15}N$ values over +10‰. Results of ${\delta}^{15}N$ analysis of 33 wells showed that most wells had the chemical fertilizers as their dominant contamination source. However, some wells were contaminated by other sources: animal wastes or municipal wastes. Some wells were also contaminated by the combined sources of nitrate. It was also demonstrated that ${\delta}^{15}N$ analysis could be a useful tool even in the case where no apparent contamination source is found.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2003.04a
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• pp.459-462
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• 2003

충청북도 증평에 위치한 문화마을 인근의 19개 지하수 관측정에서 시료를 채취하여 질산성질소 농도와 $\delta$$^{15}$ N 값, 암모니아성질소 농도와 $\delta$$^{15}$ N 값을 정량하였다. 그 결과 질산성질소에 의한 심각한 오염은 관찰되지 않으며, 질산성질소내 $\delta$$^{15}$ N이 +9.4~+36.8%0의 범위를 갖는 것으로 보아 계분이나 생활하수 혹은 두 가지 이상의 오염원이 동시에 작용함을 나타낸다. 연구지역의 $^{15}$ N 부화지수($\varepsilon$)은 -6.697%0로 탈질에 의한 범위를 만족한다. 암모늄의 질산화가 주요한 반응기작일 경우에 나타나는 암모늄 농도 감소에 따른 $^{15}$ N의 부화는 관찰할 수 없다.

• Korean Journal of Soil Science and Fertilizer
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• v.32 no.1
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• pp.47-56
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• 1999

$^{15}N$-Isotope concentrations of groundwater from l4 wells with different land-use types in Kyonggi Province were measured to investigate the nitrate contamination sources. Water samples were collected monthly from January to December 1997 and analyzed for pH. PC, anions (fluoride, chloride, nitrate, sulfate, inorganic phosphate, and bicarbonate), and canons (calcium, magnesium, potassium, and sodium). For the analysis of the $^{15}N/^{14}N$ ratio as ${\delta}^{15}N$, $N_2$ samples were prepared through Kjeldahl-Rittenberg method and were analyzed using an isotope ratio mass spectrometer (VG Optima IRMS). Reproducibility of the method and precision of the IRMS were below 1.0‰ and 0.1‰, respectively. The ionic composition of each groundwater sample was only slightly different according to the land-use type. The nitrate concentrations of groundwater in cropland or livestock farming areas were higher than those in the residential area. The percentages of nitrate to total anions of groundwater samples from the livestock farming area were higher than those of other areas. The ${\delta}^{15}N$ values of ammonium sulfate, urea, groundwater sample in the non-contaminated area, and water from the animal manure septic tank were -2.7, 1.4, 5.5, and 27.2‰, respectively. Based on the ${\delta}^{15}N$ values, the sources of nitrate could be classified as originated from chemical fertilizers with ${\delta}^{15}N$ values below 5% and as from animal manure or municipal waste with ${\delta}^{15}N$ values over 10‰. In most cases, contamination sources investigated from ${\delta}^{15}N$ values of groundwater samples were correlated with the specific sources according to the land-use types. However, some ${\delta}^{15}N$ values did not matched the apparent land-use types, and there were seasonal variations of ${\delta}^{15}N$ values within the same well. These results suggest that the groundwater quality was affected by two or more contamination sources and the contribution of each source to the groundwater quality varied depending on the sampling season.

• KCID journal
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• v.12 no.1
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• pp.84-90
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• 2005

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 2000.10a
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• pp.513-518
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• 2000

It has been acknowledged that fertilizer, natural soil nitrogen and animal waste, municipal waste have different mass ratio of nitrogen which is presented as a symbol of $\delta^{15}$N. and that the values of $\delta^{15}$N for fertilizer and natural soil nitrogen and animal waste are placed less than +5$\textperthousand$ and higher than +10$\textperthousand$, respectively. thus, Nitrogen pollution sources and contribution can be interpreted in watershed through $\delta^{15}$N analysis and then, analysis is performed with Kjeldhl-Dumas method. In this study, The values of $\delta^{15}$N are between +1.46$\textperthousand$ and +8.97$\textperthousand$, and the nitrate concentration is placed less than 3.31mg/L and higher than 0.19mg/L, respectively. Thus, this watershed is noncontamination area at the present time. But as a result of $\delta^{15}$N, contribution of natural soil nitrogen be discovered in this watershed, presently.

• Analytical Science and Technology
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• v.32 no.1
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• pp.17-23
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• 2019

Sources of NOx are both anthropogenic (e.g. fossil fuel combustion, vehicles, and other industrial processes) and natural (e.g. lightning, biogenic soil processes, and wildfires). The nitrogen stable isotope ratio of NOx has been proposed as an indicator for NOx source partitioning, which would help identify the contributions of various NOx sources. In this study, the ${\delta}^{15}N-NO_2$ values of vehicle emissions were measured in an urban region, to understand the sources and processes that influence the isotopic composition of NOx emissions. The Ogawa passive air sampler was used to determine the isotopic composition of $NO_2$(g). In urban tunnels, the observed $NO_2$ concentration and ${\delta}^{15}N-NO_2$ values averaged $3809{\pm}2656ppbv$ and $7.7{\pm}1.8$‰, respectively. The observed ${\delta}^{15}N-NO_2$ values are associated with slight regional variations in the vehicular $NO_2$ source. Both $NO_2$ concentration and ${\delta}^{15}N-NO_2$ values were significantly higher near the expressway ($965{\pm}125ppbv$ and $5.9{\pm}1.4$‰) than at 1.1 km from the expressway ($372{\pm}96ppbv$ and $-11.5{\pm}2.9$‰), indicating a high proportion of vehicle emissions. Ambient ${\delta}^{15}N-NO_2$ values were used in a binary mixing model to estimate the percentage of the ${\delta}^{15}N-NO_2$ value contributed by vehicular NOx emissions. The calculated percentage of the ${\delta}^{15}N-NO_2$ contribution by vehicles was significantly higher close to the highway, as observed for the $NO_2$ concentration and ${\delta}^{15}N-NO_2$.

• Journal of the Korean Society of Groundwater Environment
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• v.4 no.1
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• pp.1-4
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• 1997

This study was carried out to find out the source of nitrate-nitrogen (NO$_3$-N) contamination in the groundwater in Cheju Island. Among the sites which have exceeded or may exceed the criterion level (10 mg/L) of NO$_3$-N in drinking water, seven sampling sites including two reference sites were chosen. The former regions are mainly agricultural ones (A-1 to A-6) and residential (R). The latter regions are forest (F-1 and F-2). The predicted major source and its contribution to NO$_3$-N concentration at each site, using $\delta$$\^$15/N and NO$_3$-N concentration, were as follow; Those at A-1, R and F-1 was 61.1%, 50.0% and 20.0% to manure or domestic sewage, 27.8%, 45.7% and 40.0% to chemical fertilizers and 11.1%, 4.3% and 40.0% to natural soil, respectively. Those at A-2 to A-6 were 37.8%, 25.0%, 40.9%, 26.2% and 35.7% to manure or domestic sewage, 59.6%, 71.7%, 53.0%, 71.5% and 60.2% to chemical fertilizers and 2.6%, 3.3%, 6.1%, 2.3% and 4.1% to natural soil, respectively.

• Korean Journal of Ecology and Environment
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• v.50 no.4
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• pp.452-458
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• 2017

The nitrogen isotope value in both ammonium and nitrate ion were determined at 9 stations during both June and August 2016, in order to understand the origin of DIN at the Han river. ${\delta}^{15}N-NO_3$ and ${\delta}^{15}N-NH_4$ values in 8 stations (CP, SB, MHC, P4, SJ, SBC, P2, SC) were no significant variation. However ${\delta}^{15}N-NO_3$ and ${\delta}^{15}N-NH_4$ values in KK (Kyeongan stream) showed significant different in comparison with 8 stations, with an apparent increase of nitrogen isotope values. These results indicate that antropogenic nitrogen source influence on KK station. Also the ${\delta}^{13}C$ and ${\delta}^{15}N$ isotope ratio of phytoplankton (Diatom and Cyanobacteria) in KK (Kyeongan stream) showed heavier values, compared to other study stations. These results indicate that nitrogen isotope value in phytoplankton effects by different nitrogen source in study sites. These results suggest that the analysis of stable isotope ratios is a simple but useful tool for the identification of dissolved inorganic nitrogen origin in aquatic environments.

• Korean Journal of Ecology and Environment
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• v.50 no.4
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• pp.459-469
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• 2017

Nitrogen (N) loading from domestic, agricultural and industrial sources can lead to excessive growth of macrophytes or phytoplankton in aquatic environment. Many studies have used stable isotope ratios to identify anthropogenic nitrogen in aquatic systems as a useful method for studying nitrogen cycle. In this study to evaluate the precision and accuracy of denitrification bacteria method (Pseudomonas chlororaphis ssp. Aureofaciens ($ATCC^{(R)}$ 13985)), three reference (IAEA-NO-3 (Potassium nitrate $KNO_3$), USGS34 (Potassium nitrate $KNO_3$), USGS35 (Sodium nitrate $KNO_3$)) were analyzed 5 times repeatedly. Measured the ${\delta}^{15}N-NO_3$ and ${\delta}^{18}O-NO_3$ values of IAEA-NO-3, USGS 34 and USGS35 were ${\delta}^{15}N:4.7{\pm}0.1$‰ ${\delta}^{18}O:25.6{\pm}0.5$‰, ${\delta}^{15}N:-1.8{\pm}0.1$‰ ${\delta}^{18}O:-27.8{\pm}0.4$‰, and ${\delta}^{15}N:2.7{\pm}0.2$‰ ${\delta}^{18}O:57.5{\pm}0.7$‰, respectively, which are within recommended values of analytical uncertainties. Also, we investigated isotope values of potential nitrogen source (soil, synthetic fertilizer and organic-animal manures) and temporal patterns of ${\delta}^{15}N-NO_3$ and ${\delta}^{18}O-NO_3$ values in river samples during from May to December. ${\delta}^{15}N-NO_3$ and ${\delta}^{18}O-NO_3$ values are enriched in December suggesting that organic-animal manures should be one of the main N sources in those areas. The current study clarifies the reliability of denitrification bacteria method and the usefulness of stable isotopic techniques to trace the anthropogenic nitrogen source in freshwater ecosystem.

• Korean Journal of Environmental Agriculture
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• v.14 no.1
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• pp.97-108
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• 1995

Nitrate concentration and ${\delta}^{15}N$ value in the groundwater in Miyakojima Island, Okinawa, were measured during 1992-1993. Water from the shallow and the deep wells at the ten separate sites were sampled. Mineral contents and natural nitrogen isotope abundance(${\delta}^{15}N$) were analyzed using a liquid chromatography and a mass spectrometry (Finnigan MAT 252). Except for waters which were directly influenced by sea water invasion, most of the groundwater showed small variations among their mineral contents and ${\delta}^{15}N$ values. The average nitrate nitrogen concentrations were $1.4{\sim}11.5mgL^{-1}$ and average ${\delta}^{15}N$ values were +4.3${\sim}$+9.7$%_o$. From the nitrate concentration and ${\delta}^{15}N$ value observed, the types of the groundwater could be categorized into four groups, such as high ${\delta}^{15}N$ and high nitrate, high ${\delta}^{15}N$ and medium nitrate, low ${\delta}^{15}N$ and medium nitrate, and low ${\delta}^{15}N$ and low nitrate, reflecting the main source of nitrate contamination, such as animal and domestic waste, animal waste and soil organic matter, soil organic matter and chemical fertilizer, and chemical fertilizer, respectively. It was discussed that the lowest ${\delta}^{15}N$ value was higher than the ${\delta}^{15}N$ value of the chemical fertilizers used in this island(-3.9${\sim}$-1.4$%_o$), then considerable amounts of nitrogen must be lost by ammonium evaporation or denitrification after fertilization.