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Anthropogenic impacts on the nitrate pollution in an urban river: Insights from a combination of natural-abundance and paired isotopes.
- Source :
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Journal of environmental management [J Environ Manage] 2023 May 01; Vol. 333, pp. 117458. Date of Electronic Publication: 2023 Feb 07. - Publication Year :
- 2023
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Abstract
- Urban rivers are often characterized by high nitrate (NO <subscript>3</subscript> <superscript>-</superscript> ) loadings. High NO <subscript>3</subscript> <superscript>-</superscript> loadings cause water quality and ecological damages, which undermines the sustainable development of cities. To date, the drivers of these high NO <subscript>3</subscript> <superscript>-</superscript> loadings remain unclear. This study, for the first time, integrated natural-abundance isotopes (δ <superscript>15</superscript>  N/δ <superscript>18</superscript> O-NO <subscript>3</subscript> <superscript>-</superscript> and δD/δ <superscript>18</superscript> O-H <subscript>2</subscript> O) and <superscript>15</superscript> N-pairing techniques to comprehensively reveal the anthropogenic impacts on the NO <subscript>3</subscript> <superscript>-</superscript> pollution in an urban river. Natural-abundance isotopes suggested that in both the wet and dry seasons, the NO <subscript>3</subscript> <superscript>-</superscript> was predominantly from the conservative mixing of different sources, and biological NO <subscript>3</subscript> <superscript>-</superscript> removal was minor. The <superscript>15</superscript> N-pairing experiments supported the natural-abundance isotope data, quantitatively showing that in-soil nitrification was prevailing, while NO <subscript>3</subscript> <superscript>-</superscript> removal processes (denitrification, anammox, and dissimilatory NO <subscript>3</subscript> <superscript>-</superscript> reduction to ammonium) were weak. A Bayesian isotope-mixing model showed that soil sources (soil organic nitrogen and chemical fertilizer) dominated the NO <subscript>3</subscript> <superscript>-</superscript> in the upper reaches, while in the lower reaches, the impermeable riparian zone short-circuited the access of soils to the river. Here, the wastewater treatment plants became a significant source of NO <subscript>3</subscript> <superscript>-</superscript> . This study quantitatively revealed the drivers of high NO <subscript>3</subscript> <superscript>-</superscript> loadings in an urban river, and generated important clues for effective NO <subscript>3</subscript> <superscript>-</superscript> pollution control and remediation in urban rivers.<br />Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.<br /> (Copyright © 2023 Elsevier Ltd. All rights reserved.)
Details
- Language :
- English
- ISSN :
- 1095-8630
- Volume :
- 333
- Database :
- MEDLINE
- Journal :
- Journal of environmental management
- Publication Type :
- Academic Journal
- Accession number :
- 36758410
- Full Text :
- https://doi.org/10.1016/j.jenvman.2023.117458