The nitrate time bomb: a numerical way to investigate nitrate storage and lag time in the unsaturated zone

Wang, L.; Butcher, Andrew S.; Stuart, Marianne; Gooddy, Daren C.; Bloomfield, John P.

doi:10.1007/s10653-013-9550-y

Cited by 97 publications

(42 citation statements)

References 26 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Wang et al . () have estimated historical peak nitrate loading from the Penrith Sandstone has arrived in most parts of the River Eden catchment, north‐west England. Several areas including parts of the River Leith sub‐catchment will experience peak nitrate loading in the next 30–40 years highlighting the need to resolve spatial and temporal patterns in environmental risk associated with groundwater nitrate fluxes.…”

Section: Introductionmentioning

confidence: 99%

Diffusive equilibrium in thin films provides evidence of suppression of hyporheic exchange and large‐scale nitrate transformation in a groundwater‐fed river

Byrne

Zhang

Ullah

et al. 2014

Hydrological Processes

View full text Add to dashboard Cite

Abstract:The hyporheic zone of riverbed sediments has the potential to attenuate nitrate from upwelling, polluted groundwater. However, the coarse-scale (5-10 cm) measurement of nitrogen biogeochemistry in the hyporheic zone can often mask fine-scale (<1 cm) biogeochemical patterns, especially in near-surface sediments, leading to incomplete or inaccurate representation of the capacity of the hyporheic zone to transform upwelling NO 3 À . In this study, we utilised diffusive equilibrium in thin-films samplers to capture high resolution (cm-scale) vertical concentration profiles of NO 3 À , SO 4 2À , Fe and Mn in the upper 15 cm of armoured and permeable riverbed sediments. The goal was to test whether nitrate attenuation was occurring in a sub-reach characterised by strong vertical (upwelling) water fluxes. The vertical concentration profiles obtained from diffusive equilibrium in thin-films samplers indicate considerable cmscale variability in NO 3 À (4.4 ± 2.9 mg N/L), SO 4 2À (9.9 ± 3.1 mg/l) and dissolved Fe (1.6 ± 2.1 mg/l) and Mn (0.2 ± 0.2 mg/l). However, the overall trend suggests the absence of substantial net chemical transformations and surface-subsurface water mixing in the shallow sediments of our sub-reach under baseflow conditions. The significance of this is that upwelling NO 3 À -rich groundwater does not appear to be attenuated in the riverbed sediments at <15 cm depth as might occur where hyporheic exchange flows deliver organic matter to the sediments for metabolic processes. It would appear that the chemical patterns observed in the shallow sediments of our sub-reach are not controlled exclusively by redox processes and/or hyporheic exchange flows. Deeper-seated groundwater fluxes and hydro-stratigraphy may be additional important drivers of chemical patterns in the shallow sediments of our study sub-reach.

show abstract

Section: Introductionmentioning

confidence: 99%

Diffusive equilibrium in thin films provides evidence of suppression of hyporheic exchange and large‐scale nitrate transformation in a groundwater‐fed river

Byrne

Zhang

Ullah

et al. 2014

Hydrological Processes

View full text Add to dashboard Cite

show abstract

“…Nevertheless, we are confident that decrease in the cropland area and the promotion and implementation of agricultural best practices are the primary reasons for nitrate decline in Korean groundwater. Considering the time lag between nitrate loading from agricultural area and changes of nitrate concentration in groundwater (Wang & Burke, 2017;Wang, Butcher, Stuart, Gooddy, & Bloomfield, 2013), the result of this study highlights the importance of long-term efforts to reduce nitrate contamination at the source as opposed to active remediation.…”

Section: Nitrate Levels and Groundwater Usagementioning

confidence: 90%

Unexpected nationwide nitrate declines in groundwater of Korea

Lee

Park

Jeon

2017

Hydrological Processes

View full text Add to dashboard Cite

Elevated levels of nitrate in groundwater are an important concern for health and the environment. The overapplication of nitrogen fertilizer to croplands is one of the major sources of high nitrate content in groundwater. In this study, we analyse the nitrate concentrations in Korean groundwater based on data from groundwater quality monitoring wells (n = 1,022–2,072), which were sampled twice annually over a recent 13‐year analysis period (2001–2013). We report that groundwater nitrate levels are decreasing, despite steadily increasing groundwater use. The maximum nitrate concentration decreased from 168.91 to 48.11 mg/L, whereas the mean values also show a gradual decreasing trend. Non‐parametric Mann–Kendall tests on nitrate concentrations also confirm the decreasing trend. The nitrate decrease is more clearly evident in agricultural groundwater as compared to domestic and drinking groundwaters. This decrease of nitrate in groundwater coincides with a large decline in nitrogen fertilizer application due to reduced cropland areas, more sustainable agricultural practices, and progressive improvement of sewage disposal services. This study proposes that the long‐term adoption of best practices in agriculture has had a positive impact on groundwater nitrate control.

show abstract

“…52 The high nitrate concentrations in drinking waters derived from the Chalk may reect the storage of nitrate in the thick Chalk unsaturated zone and slower ushing of nitrate following changes in agricultural management practices. [53][54][55][56][57] This assessment does not include areas of the Chalk where it is not at outcrop, e.g. the eastern part of East Anglia where some elevated values are shown in Fig.…”

Section: View Article Onlinementioning

confidence: 99%

Provenance of drinking water revealed through compliance sampling

Ascott

Stuart

Gooddy

et al. 2019

Environ. Sci.: Processes Impacts

View full text Add to dashboard Cite

Understanding drinking water hydrochemistry is essential for maintaining safe drinking water supplies.Whilst targeted research surveys have characterised drinking water hydrochemistry, vast compliance datasets are routinely collected but are not interrogated amidst concerns regarding the impact of mixed water sources, treatment, the distribution network and customer pipework. In this paper, we examine whether compliance samples retain hydrochemical signatures of their provenance. We first created and subsequently undertook the first hydrochemical analysis of a novel national database of publically available drinking water compliance analyses (n ¼ 3 873 941) reported for 2015 across England and Wales. k-means cluster analysis revealed three spatially coherent clusters. Cluster 1 is dominated by groundwater sources, with high nitrate concentrations and mineralisation, and lower organic carbon, residual chlorine and THM formation. Cluster 2 was dominated by surface water sources and characterised by low mineralisation (low conductivity and major ion concentrations), low nitrate and high organic carbon concentrations (and hence residual chlorine and THM formation). Cluster 3 shows a mixture of groundwater overlain by confining layers and superficial deposits (resulting in higher trace metal concentrations and mineralisation) and surface water sources. These analyses demonstrate that, despite extensive processing of drinking water, at the national scale signatures of the provenance of drinking water remain. Analysis of compliance samples is therefore likely to be a helpful tool in the characterisation of processes that may affect drinking water chemistry. The methodology used is generic and can be applied in any area where drinking water chemistry samples are taken. Environmental signicanceUnderstanding drinking water hydrochemistry is essential for maintaining safe water supplies. We examined whether routine drinking water samples retain hydrochemical signatures of their provenance. We undertook the rst hydrochemical analysis of a novel national database of routine drinking water samples. Principal component analysis and cluster analysis revealed three spatially coherent clusters reecting groundwater and surface water sources. Despite treatment of drinking water, at the national scale signatures of the provenance remain. Analysis of routine compliance samples is therefore likely to be a helpful tool in the characterisation of environmental processes occurring that may affect drinking water quality.

show abstract

The nitrate time bomb: a numerical way to investigate nitrate storage and lag time in the unsaturated zone

Cited by 97 publications

References 26 publications

Diffusive equilibrium in thin films provides evidence of suppression of hyporheic exchange and large‐scale nitrate transformation in a groundwater‐fed river

Diffusive equilibrium in thin films provides evidence of suppression of hyporheic exchange and large‐scale nitrate transformation in a groundwater‐fed river

Unexpected nationwide nitrate declines in groundwater of Korea

Provenance of drinking water revealed through compliance sampling

Contact Info

Product

Resources

About