Isotopic constraints on water source mixing, network leakage and contamination in an urban groundwater system
| Autor: | Nadine Goeppert, Jochen Klinger, Felix Grimmeisen, Moritz F. Lehmann, Nico Goldscheider, Jakob Zopfi, Tanja Liesch |
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| Rok vydání: | 2016 |
| Předmět: |
Hydrology
Pollution Environmental Engineering media_common.quotation_subject 0208 environmental biotechnology Environmental engineering 02 engineering and technology Groundwater recharge 010501 environmental sciences 01 natural sciences 020801 environmental engineering chemistry.chemical_compound Wastewater Nitrate chemistry Environmental Chemistry Environmental science Waste Management and Disposal Effluent Surface water Groundwater 0105 earth and related environmental sciences media_common Isotope analysis |
| Zdroj: | The Science of the total environment. 583 |
| ISSN: | 1879-1026 |
| Popis: | Water supply in developing countries is prone to large water losses due to leaky distribution networks and defective sewers, which may affect groundwater quality and quantity in urban areas and result in complex subsurface mixing dynamics. In this study, a multi-stable isotope approach was used to investigate spatiotemporal fluctuations of surface and sub-surface water source partitioning and mixing, and to assess nitrogen (N) contamination in the urban water cycle of As-Salt, Jordan. Water import from the King Abdullah Canal (KAC), mains waters from the network, and wastewater are characterized by distinct isotopic signatures, which allowed us to quantify city effluents into the groundwater. Temporal variations in isotopic signatures of polluted groundwater are explained by seasonally fluctuating inflow, and dilution by water that originates from Lake Tiberias and enters the urban water cycle via the KAC. Isotopic analysis (N and O) and comparison between groundwater nitrate and nitrate from mains water, water imports and wastewater confirmed that septic waste from leaky sewers is the main contributor of nitrate contamination. The nitrate of strongly contaminated groundwater was characterized by highest δ15NNO3 values (13.3 ± 1.8‰), whereas lowest δ15NNO3 values were measured in unpolluted groundwater (6.9‰). Analogously, nitrate concentration and isotopic ratios were used for source partitioning and qualitatively confirmed δDH2O and δ18OH2O-based estimates. Dual water isotope endmember mixing calculations suggest that city effluents from leaky networks and sewers contribute 30–64% to the heavily polluted groundwater. Ternary mixing calculations including also chloride revealed that 5–18% of the polluted groundwater is wastewater. Up to two thirds of the groundwater originates from mains, indicating excessive water loss from the network, and calling for improved water supply management. |
| Databáze: | OpenAIRE |
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