Nitrate sources and watershed denitrification inferred from nitrate dual isotopes in the Beijiang River, south China

Chen, Fajin; Jia, Guodong; Chen, Jianyao

doi:10.1007/s10533-009-9316-x

Cited by 164 publications

(118 citation statements)

References 52 publications

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“…When compared with the TN concentrations of rivers and lakes in the Beijing metropolitan area in 2003, at which point they were all below 2 mg $L -1 [17], TN concentrations showed an increasing trend. The TN concentrations reported in this study are higher than those in the Taihu lake region [26], in the Haicheng river basin [27]and in the Beijiang river in south China [28], but close to the TN level of the Thames river in the UK [29], and of stream water in Pennsylvania, USA [30]. These increasing TN concentrations may be due to intensification of human activities caused by urbanization, and agrees with other studies which have shown that urbanization results in elevated TN and NO -3 -N concentrations in watersheds in developing areas [31,32], and that urbanization soon takes over as the major source of nitrogen in urban freshwater ecosystems [27].…”

Section: Characteristics Of Nitrogen Pollutioncontrasting

confidence: 53%

Nitrogen pollution and source identification of urban ecosystem surface water in Beijing

Ren

Zhang

et al. 2013

Front. Environ. Sci. Eng.

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Nitrogen contamination of surface water is a worldwide environmental problem with intensive agriculture and high population densities. We assessed the spatial and seasonal variation in concentrations of total nitrogen and different nitrogen species present in surface-water in Beijing, China. Also, chemical (NO , and total nitrogen from 2.4 to 17.0 mg$L -1 . Inorganic nitrogen accounted for between 60 and 100% of total nitrogen at the ten monitoring sites. Nitrate nitrogen, ammonium nitrogen, and total nitrogen concentrations at the 2 downstream monitoring sites in south-eastern Beijing were significantly higher than those at the other eight upstream monitoring sites (P < 0.01). Examination of seasonal variation showed that there was a significant inverse relationship between nitrate nitrogen concentrations and precipitation, and that nitrate nitrogen concentrations peaked in the dry seasons. The information given by the δ 15 N nitrate values and nitrate nitrogen concentrations, combined with the NO - -N=C1ratio distribution, showed that domestic sewage was the major source of nitrate in Beijing. Methods to control and reduce sewage pollution are urgently needed to help manage surface water quality in Beijing.

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Section: Characteristics Of Nitrogen Pollutioncontrasting

confidence: 53%

Nitrogen pollution and source identification of urban ecosystem surface water in Beijing

Ren

Zhang

et al. 2013

Front. Environ. Sci. Eng.

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“…Concentrations sharply increased from low values to values well over 15 mg·L −1 , after which the concentration decreased in a downstream direction until it almost zero downstream. The fact that this decline was accompanied by a consistent increase in the 15 N isotope abundance in the pool NO 3 -N identifies that nitrate loss is due to denitrification to nitrogen gas, rather than from dilution [7,35,37,45]. In the model, the decline of nitrate was reproduced with a first-order nitrate consumption rate of 1 kg day −1 , again comparable to parameters often used in sediment models (e.g., 0.2-3.5 kg·day −1 ) [46].…”

Section: Inorganic N In Surface Watersmentioning

confidence: 96%

“…Finally, the ∂ r values are transformed to percentages (%) to obtain the degree of denitrification for each sampling point [37]. To calculate the degree of denitrification from our data, the initial isotopic composition (∂ r0 ) was chosen to be the lowest 15 N value during the samplings.…”

Section: Stable Isotope Calculationsmentioning

confidence: 99%

“…The nitrate may be removed by denitrification resulting in the enrichment of N and oxygen isotopic in the residual NO 3 -N. Estimates of oxygen isotope fractionation during denitrification are rare [36]. However there are some studies of oxygen and nitrogen isotope enrichment factors for microbial nitrate reduction in aquatic environments [35][36][37][38][39][40][41][42][43][44][45][46][47]. It is reported that the ratios of 15 N/ 18 O range from −1.3 to −2.1 [48].…”

Section: Nitrate Sources Through Isotopic Composition In Stream Watermentioning

confidence: 99%

“…While most of the samples do not correspond to the ranges for sewage and manure, there are some values within this range. The lower NO 3 -N/Cl − ratios in sewage and livestock waste was partly due to the fact that they contain nitrogen that has not yet been converted to nitrate [37].…”

Section: Nitrate Sources Through Isotopic Composition In Stream Watermentioning

confidence: 99%

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Tracing Nitrate-Nitrogen Sources and Modifications in a Stream Impacted by Various Land Uses, South Portugal

Yevenes

Soetaert

Mannaerts

2016

Water

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Abstract:The identification of nitrate-nitrogen (NO 3 -N) origin is important in the control of surface and ground water quality. These are the main sources of available drinking water. Stable isotopes ( 15 N and 18 O) for NO 3 -N and along with a 1-D reactive transport model were used to study the origin and processes that lead to nitrogen transformation and loss in a major stream that flows into a reservoir within an intensively cultivated catchment area (352 km 18 O values in surface water samples from the stream and wells indicated that the dominant NO 3 -N sources were derived mainly from the soil and fertilizers. There was also significant nitrification in surface water at the head of the stream. Sediment pore waters showed high NO 3 -N values near the sediment-water interface (reaching 25 mg·N·L −1 ) and NO 3 -N concentrations sharply decreasing with sediment depth, suggesting significant NO 3 -N consumption. Denitrification was also detected using the 15 N signature in upstream waters, but not downstream where very low NO 3 -N levels were measured. In the stream, the calculated isotopic enrichment factor for NO 3 -N was −2.9‰ for 15 N and −1.78 for 18 O, this indicates that denitrification accounts for 7.8% to 48% of nitrate removal.

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Coupled hydrological and biogeochemical processes controlling variability of nitrogen species in streamflow during autumn in an upland forest

et al. 2014

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Autumn is a season of dynamic change in forest streams of the northeastern United States due to effects of leaf fall on both hydrology and biogeochemistry. Few studies have explored how interactions of biogeochemical transformations, various nitrogen sources, and catchment flow paths affect stream nitrogen variation during autumn. To provide more information on this critical period, we studied (1) the timing, duration, and magnitude of changes to stream nitrate, dissolved organic nitrogen (DON), and ammonium concentrations; (2) changes in nitrate sources and cycling; and (3) source areas of the landscape that most influence stream nitrogen. We collected samples at higher temporal resolution for a longer duration than typical studies of stream nitrogen during autumn. This sampling scheme encompassed the patterns and extremes that occurred during base flow and stormflow events of autumn. Base flow nitrate concentrations decreased by an order of magnitude from 5.4 to 0.7 mmol L 21 during the week when most leaves fell from deciduous trees. Changes to rates of biogeochemical transformations during autumn base flow explained the low nitrate concentrations; in-stream transformations retained up to 72% of the nitrate that entered a stream reach. A decrease of in-stream nitrification coupled with heterotrophic nitrate cycling were primary factors in the seasonal nitrate decline. The period of low nitrate concentrations ended with a storm event in which stream nitrate concentrations increased by 25-fold. In the ensuing weeks, peak stormflow nitrate concentrations progressively decreased over closely spaced, yet similarly sized events. Most stormflow nitrate originated from nitrification in near-stream areas with occasional, large inputs of unprocessed atmospheric nitrate, which has rarely been reported for nonsnowmelt events. A maximum input of 33% unprocessed atmospheric nitrate to the stream occurred during one event. Large inputs of unprocessed atmospheric nitrate show direct and rapid effects on forest streams that may be widespread, although undocumented, throughout nitrogen-polluted temperate forests. In contrast to a week-long nitrate decline during peak autumn litterfall, base flow DON concentrations increased after leaf fall and remained high for 2 months. Dissolved organic nitrogen was hydrologically flushed to the stream from riparian soils during stormflow. In contrast to distinct seasonal changes in base flow nitrate and DON concentrations, ammonium concentrations were typically at or below the detection limit, similar to the rest of the year. Our findings reveal couplings among catchment flow paths, nutrient sources, and transformations that control seasonal extremes of stream nitrogen in forested landscapes.

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Nitrate sources and watershed denitrification inferred from nitrate dual isotopes in the Beijiang River, south China

Cited by 164 publications

References 52 publications

Nitrogen pollution and source identification of urban ecosystem surface water in Beijing

Nitrogen pollution and source identification of urban ecosystem surface water in Beijing

Tracing Nitrate-Nitrogen Sources and Modifications in a Stream Impacted by Various Land Uses, South Portugal

Coupled hydrological and biogeochemical processes controlling variability of nitrogen species in streamflow during autumn in an upland forest

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