The nitrogen isotope composition of groundwater nitrates from the East Midlands Triassic Sandstone aquifer, England

Wilson, George; Andrews, John N.; Bath, Adrian

doi:10.1016/0022-1694(94)90097-3

Cited by 39 publications

(18 citation statements)

References 10 publications

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“…Many of the UK studies have used change factor / delta methods, which will produce very different understanding of impacts to that which will be gained by the probabilistic UKCP09 scenarios. There are as yet few published studies on this, although Fowler et al (2007) (Wilson et al, 1994). Predictions using the NEAP-N model, which estimates current losses from the base of the soil zone from agricultural land, show that concentrations range up to 180 mg L -1 NO 3 (Silgram et al, 2001).…”

Section: Figurementioning

confidence: 99%

A review of the impact of climate change on future nitrate concentrations in groundwater of the UK

Stuart

Gooddy

Bloomfield

et al. 2011

Science of The Total Environment

142

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This paper reviews the potential impacts of climate change on nitrate concentrations in groundwater of the UK using a Source-Pathway-Receptor framework. Changes in temperature, precipitation quantity and distribution, and atmospheric carbon dioxide concentrations will affect the agricultural nitrate source term through changes in both soil processes and agricultural productivity. Non-agricultural source terms, such as urban areas and atmospheric deposition, are also expected to be affected. The implications for the rate of nitrate leaching to groundwater as a result of these changes are not yet fully understood but predictions suggest that leaching rate may increase under future climate scenarios. Climate change will affect the hydrological cycle with changes to recharge, groundwater levels and resources and flow processes. These changes will impact on concentrations of nitrate in abstracted water and other receptors, such as surface water and groundwater-fed wetlands.The implications for nitrate leaching to groundwater as a result of climate changes are not yet well enough understood to be able to make useful predictions without more site-specific data.The few studies which address the whole cycle show likely changes in nitrate leaching ranging from limited increases to a possible doubling of aquifer concentrations by 2100.These changes may be masked by nitrate reductions from improved agricultural practices, but a range of adaption measures need to be identified. Future impact may also be driven by economic responses to climate change. The study draws on extensive literature mainly from the UK and so presents a UK-based perspective, although literature for other temperate climates is included to augment that from Keywordsthe UK and to demonstrate that the proposed framework and general conclusions have a wider applicability.The principal N input to UK groundwater is derived from manures, fertilisers, sewage sludges and crop residues in agricultural areas (DEFRA, 2006). There are also smaller inputs from urban point sources and aerial deposition (Wakida and Lerner, 2005). N fertiliser can be applied as urea or ammonia, as well as nitrate, but the non-nitrate forms are generally converted rapidly to nitrate in the soils of the UK (MAFF, 1999). A small percentage of applied N is lost to the atmosphere as NH 3 , NO or N 2 O (Destouni and Darracq, 2009;Skiba et al., 1997;Sommer and Hutchings, 1995). A proportion of soil N is leached as nitrate from the base of the soil. This is either stored in, or transmitted through, the unsaturated zone to groundwater. groundwater. They found that although an ensemble average suggests there will be about a 5% reduction in annual potential groundwater recharge across the study area, this was not statistically significant at the 95% confidence level and more importantly observed that the spread of results for simulated changes in annual potential groundwater recharge range from a 26% decrease to a 31% increase by the 2080s, with ten GCMs predicting a decrease and three a...

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Section: Figurementioning

confidence: 99%

A review of the impact of climate change on future nitrate concentrations in groundwater of the UK

Stuart

Gooddy

Bloomfield

et al. 2011

Science of The Total Environment

142

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“…However, in some cases denitrification has been positively identified using N2/Ar and/or isotope data and/or bacterial data (Wilson et al 1994, in only two of 23 samples ;Parker et al 1988;Spence et al 2001a, b;Williams et al 2001;Fukada et aL 2004;Buss et al 2005). In some cases -especially where the nitrate source is also organic-richthere will be enough organic matter to facilitate NO3 reduction, but elsewhere there may be other, as yet uninvestigated, processes occurring involving Fe II or Mn, for example (e.g.…”

Section: R E D U C T I O N -O X I D a T I O N Reactionsmentioning

confidence: 99%

Towards prediction of saturated-zone pollutant movement in groundwaters in fractured permeable-matrix aquifers: the case of the UK Permo-Triassic sandstones

Tellam

Barker

2006

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Abstract:The UK on-shore Permo-Triassic sandstones are fluvial and aeolian red beds showing a nested cyclic architecture on scales from millimetres to 100s of metres. They are typical of many continental sandstone sequences throughout the world. Groundwater flows through both matrix and fractures, with natural flow rates generally of less than 200 m year -1. At less than 30 m horizontal distances, below important minimum representative volumes for both matrix and fracture network permeability, breakthroughs are likely to be multimodal, especially close to wells, with proportionately large apparent dispersivities. 'Antifractures' -discontinuities with permeability much less than that of the host rockmay have a dominating effect. Where present, low-permeability matrix (e.g. mudstones) will significantly affect vertical flow, but will rarely prevent eventual breakthrough. Quantitative prediction of breakthrough is associated with large uncertainty. At scales of 30 to a few 100s of metres, multimodal breakthroughs from a single source become less common, although very rapid fracture flow has been recorded. At distances of hundreds of metres to a few kilometres, there is evidence that breakthroughs are unimodal, and may be more immediately amenable to quantitative prediction, even in some cases for reacting solutes. At this and greater scales, regional fault structures (both slip surfaces and granulation seams) can have major effects on sub-horizontal solute movement, and mudstones and cemented units will discourage vertical penetration. The aquifer has limited oxidizing capacity despite the almost ubiquitous presence of oxides, limited reductive capacity and limited organic sorption capacity. It has a moderate cation-exchange capacity, and frequently contains carbonate. Mn oxides are important for sorption and oxidation, but are present in limited quantity. Relationships between hydraulic and chemical properties are largely unknown. 'Hard' evidence for the solute transport conceptual model presented above is relatively limited. To be able to predict to a reasonably estimated degree of uncertainty requires knowledge of: the geological, and thence the hydraulic and geo-chemical, structure of the complex sandstone architecture (including the correlations between these properties); the development of suitable investigation techniques (especially geophysical) for mapping the structures; and the development of modelling tools incorporating matrix, fractures, 'antimatrix' and antifracture elements, each with associated hydraulic and possibly geochemical properties. In common with solute movement studies in most aquifer types, much more geological characterization needs to be undertaken. Although new investigation and modelling tools are being developed specifically for (shallow) hydrogeological applications with some considerable success, much greater advantage could be taken of importing techniques from other disciplines, and in particular from oil exploration and development.

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“…The distinct differences in δ 15 N of NO 3 − originating from animal waste (generally >10‰) versus mineral N fertilizers (typically close to or <0‰) means that NO 3 − in waters originating from a combination of these sources should lie within the range of these samples if NO 3 − behaves in a conservative manner during transport (Heaton, 1986). This has been the basis for the identification of NO 3 − sources using natural abundances of 15 N, a technique that has been applied primarily to studies of groundwater NO 3 − contamination (Kreitler and Browning, 1983;Wells et al, 1989;Wilson et al, 1994;Komor and Anderson, 1993;Aravena et al, 1993). The use of this technique to identify surface water NO 3 − contamination sources is virtually untested with the exception of a study by Kohl et al (1971) and the inclusion of data from the Melarchez River Basin by Mariotti (1984).…”

Section: Introductionmentioning

confidence: 99%

Evaluation of nitrogen isotopes as indicators of nitrate contamination sources in an agricultural watershed

Kellman

Hillaire‐Marcel

2003

Agriculture, Ecosystems & Environment

122

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Determining the relative contributions of nitrate contamination in agricultural watersheds characterized by applications of both mineral and animal waste nitrogen to fields is important in evaluating the environmental consequences of these practices. Here, the use of nitrate-nitrogen (NO 3 − -N) stable isotopes to identify contaminant sources was examined in surface waters of an agricultural watershed to investigate whether NO 3 − -δ 15 N fractionation processes obscure source signatures. This study was conducted in a 500 ha headwater agricultural watershed within the St. Lawrence lowlands where fertilization with mineral N and hog manure is a common practice. Sampling within the watershed was designed to monitor NO 3 − concentrations and δ 15 N temporal trends at a series of locations that allowed evaluation of water flowing in watershed streams and entering these streams via different hydrological pathways. This required analysis of stream water, tile drain water, and streamside water transported through the soil matrix. These data demonstrated that NO 3 − -δ 15 N values often exceeded the maximum δ 15 N source of approximately +12.5‰ that was associated with hog manure in the watershed. The δ 15 N values and NO 3 − concentrations during such periods were consistent with a pattern of denitrification between precipitation events within the watershed, with values repeatedly exceeding +15‰ in tile drain and stream samples during extended periods with little rainfall. Tile drain NO 3 − concentrations were consistently elevated (4-38 mg l −1 N) relative to streamside soil and shallow groundwater exiting the same field (0.013-0.812 mg l −1 N). These data suggest that NO 3 − -N stable isotopes cannot be used as contaminant source indicators in the surface waters of this watershed between precipitation events, and that further evaluation of their use during storm events is required.

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The nitrogen isotope composition of groundwater nitrates from the East Midlands Triassic Sandstone aquifer, England

Cited by 39 publications

References 10 publications

A review of the impact of climate change on future nitrate concentrations in groundwater of the UK

A review of the impact of climate change on future nitrate concentrations in groundwater of the UK

Towards prediction of saturated-zone pollutant movement in groundwaters in fractured permeable-matrix aquifers: the case of the UK Permo-Triassic sandstones

Evaluation of nitrogen isotopes as indicators of nitrate contamination sources in an agricultural watershed

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