An isotope study of the sources of nitrate in Malta’s groundwater

Heaton, T.H.E.; Stuart, Marianne; Sapiano, Manuel; Sultana, M. Micallef

doi:10.1016/j.jhydrol.2011.10.037

Cited by 65 publications

(26 citation statements)

References 35 publications

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“…Many detailed studies have documented the sources and transformation of nitrate in groundwater and rivers, using dual isotope analyses (Mayer et al , ; Silva e t al. , ; Pardo et al , ; Liu et al , ; Panno et al , ; Wexler et al , ; Heaton et al , ).…”

Section: Introductionmentioning

confidence: 99%

Sources and transport of nitrate constrained by the isotopic technique in a karst catchment: an example from Southwest China

Yue

Lang

et al. 2014

Hydrological Processes

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The concentration and isotopic composition of nitrate were analyzed to improve an understanding of nitrate sources and transformation processes in a typical karstic agricultural field in the Houzhai catchment, Guizhou Province, Southwest China. The results revealed that no distinct spatial pattern of content and isotopic composition of nitrate exists in this karst catchment. Nitrate in surface stream (SFS) had slightly lighter isotopic composition and lower concentration compared with nitrate in subterranean stream (STS) during the dry season. Concentrations of SFS nitrate increased to concentrations similar to those of STS during the wet season. The isotopic values indicated that nitrate were mainly impacted by manure sources during the dry season and influenced by a mix of chemical fertilizer and manure during the wet season. The denitrification rates were roughly estimated based on the isotopic compositions of nitrate after considering volatilization and ignoring assimilation. The calculated result showed that approximately one fifth of nitrate load was removed by denitrification in the catchment. Annual nitrate flux from the outlets accounted for 14.2% of applied total fertilizers used in the catchment, approximately 85% of total transported flux from the catchment in the wet season. Furthermore, chemical weathering processes were enhanced by using nitrogen fertilizer because liberated protons and enhanced HCO3− flux were produced through by nitrification. Copyright © 2014 John Wiley & Sons, Ltd.

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Section: Introductionmentioning

confidence: 99%

Sources and transport of nitrate constrained by the isotopic technique in a karst catchment: an example from Southwest China

Yue

Lang

et al. 2014

Hydrological Processes

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“…NO 3 − -N, NO 2 − -N, NH 4 + -N, and TN were analyzed by a flow-injection analyzer (HACH Quick chem 8500S2, Hach Company, Loveland, CO, USA). The solid samples were centrifugal oscillated and filtered (0.3 µm) before hydrochemical analysis [34]. The analytical precision was less than ±3%.…”

Section: Laboratory Analysesmentioning

confidence: 99%

Evaluating Temporal and Spatial Variation in Nitrogen Sources along the Lower Reach of Fenhe River (Shanxi Province, China) Using Stable Isotope and Hydrochemical Tracers

Meng

Yang

Qin

et al. 2018

Water

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Abstract:Nitrate is one of the most common pollutants in river systems. This study takes the lower reach of Fenhe River as a case study, combined with a multi-isotope and hydrochemical as the tracers to identify nitrate sources in river system. The results show that all samples in the industrial region (IR) and urban region (UR) and 68.8% of the samples in the agriculture region (AR) suffer from nitrate pollution. NO 3 − -N is the main existing form of dissolved inorganic nitrogen (DIN), followed by NH 4 + -N, which account for 57.9% and 41.9% of the DIN, respectively. The temporal variation in nitrogenous species concentration is clear over the whole hydrological year. The spatial variation is smaller among different sampling sites in the same region but greater among different regions. The main source of nitrogenous species is from anthropogenic rather than natural effects. Multi-isotope analysis shows that denitrification is found in some water samples. Combined with the apportionment of nitrate sources by the IsoSource model and the analysis of the Cl − content, the main source of nitrate in the IR, UR and AR are industrial sewage and manure, domestic sewage and manure, and chemical fertilizers, respectively. Atmospheric nitrogen deposition is also a source of nitrate in the study area.

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“…In the European Union (EU), a study has shown that the nitrogen leaching to groundwater derived from agricultural activities results in a general surplus in EU-27 member-states [30]. Groundwater pollution due to agriculture-derived pollutant loads has been studied around the world [31][32][33][34], and high nitrogen loads may result both from the application of fertilizers and from the leaching of grazed pasturelands [35,36].…”

Section: Introductionmentioning

confidence: 99%

Nitrates in Groundwater Discharges from the Azores Archipelago: Occurrence and Fluxes to Coastal Waters

Cruz

Andrade

Pacheco³

et al. 2017

Water

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Abstract:Groundwater discharge is an important vector of chemical fluxes to the ocean environment, and as the concentration of nutrients is often higher in discharging groundwater, the deterioration of water quality in the receiving environment can be the result. The main objective of the present paper is to estimate the total NO 3 flux to coastal water bodies due to groundwater discharge in the volcanic Azores archipelago (Portugal). Therefore, 78 springs discharging from perched-water bodies have been monitored since 2003, corresponding to cold (mean = 14.9 • C) and low mineralized (47.2-583 µS/cm) groundwater from the sodium-bicarbonate to sodium-chloride water types. A set of 36 wells was also monitored, presenting groundwater with a higher mineralization. The nitrate content in springs range between 0.02 and 37.4 mg/L, and the most enriched samples are associated to the impact of agricultural activities. The total groundwater NO 3 flux to the ocean is estimated in the range of 5.23 × 10 3 to 190.6 × 10 3 mol/km 2 /a (∑ =~523 × 10 3 mol/km 2 /a), exceeding the total flux associated to surface runoff (∑ =~281 × 10 3 mol/km 2 /a). In the majority of the islands, the estimated fluxes are higher than runoff fluxes, with the exception of Pico (47.2%), Corvo (46%) and Faial (7.2%). The total N-NO 3 flux estimated in the Azores (~118.9 × 10 3 mol/km 2 /a) is in the lower range of estimates made in other volcanic islands.

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An isotope study of the sources of nitrate in Malta’s groundwater

Abstract: SUMMARY, respectively, and even higher in the younger groundwaters of the perched aquifers on Malta (37 mg NO 3 -N L -1

Cited by 65 publications

References 35 publications

Sources and transport of nitrate constrained by the isotopic technique in a karst catchment: an example from Southwest China

Sources and transport of nitrate constrained by the isotopic technique in a karst catchment: an example from Southwest China

Evaluating Temporal and Spatial Variation in Nitrogen Sources along the Lower Reach of Fenhe River (Shanxi Province, China) Using Stable Isotope and Hydrochemical Tracers

Nitrates in Groundwater Discharges from the Azores Archipelago: Occurrence and Fluxes to Coastal Waters

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