Naturally-high nitrate in unsaturated zone sand dunes above the Stampriet Basin, Namibia

Stone, Abi; Edmunds, W.M.

doi:10.1016/j.jaridenv.2014.02.015

Cited by 20 publications

(6 citation statements)

References 39 publications

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“…High NO 3 concentrations in the USZ are found widely in other arid and semi-arid areas including western United States (Walvoord et al, 2003), the Sahel in northern Africa (Edmunds and Gaye, 1997;Deans et al, 2005), the Kalahari desert in southern Africa (Heaton et al, 1983;Stone and Edmunds, 2014), Australia (Barnes et al, 1992) as well as China (Gates et al, 2008c). In these areas, as in the present study, aerobic conditions permit the inert behaviour and preservation of biogenically produced NO 3 .…”

Section: Source Of Dissolved Nitratesupporting

confidence: 69%

Geochemistry of sediment moisture in the Badain Jaran desert: Implications of recent environmental changes and water-rock interaction

Jin

Edmunds

et al. 2015

Applied Geochemistry

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Section: Source Of Dissolved Nitratesupporting

confidence: 69%

Geochemistry of sediment moisture in the Badain Jaran desert: Implications of recent environmental changes and water-rock interaction

Jin

Edmunds

et al. 2015

Applied Geochemistry

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“…Though safe levels of NO 3 − for humans in drinking water are still debated (Schullehner et al 2018), it is clear that this is a critical and widespread pollutant. Elevated concentrations of NO 3 − have been found in arid environments, including the Kalahari Desert, where it is believed to be the product of the decomposition of ancient vegetation deposits (Heaton et al 1983;Stadler et al 2012;Stone and Edmunds 2014). Stadler et al (2012) differentiated between naturally occurring and anthropogenic NO 3 − in groundwater in the Kalahari using stable isotopes: NO 3 − in the deeper groundwater was older in age and tended to be naturally occurring, while NO 3 − in the shallower, younger groundwater tended to come from human and cattle sources.…”

Section: Introductionmentioning

confidence: 99%

Complex interactions between climate change, sanitation, and groundwater quality: a case study from Ramotswa, Botswana

et al. 2019

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Groundwater quantity and quality may be affected by climate change through intricate direct and indirect mechanisms. At the same time, population growth and rapid urbanization have made groundwater an increasingly important source of water for multiple uses around the world, including southern Africa. The present study investigates the coupled human and natural system (CHANS) linking climate, sanitation, and groundwater quality in Ramotswa, a rapidly growing peri-urban area in the semi-arid southeastern Botswana, which relies on the transboundary Ramotswa aquifer for water supply. Analysis of long-term rainfall records indicated that droughts like the one in 2013-2016 are increasing in likelihood in the area due to climate change. Key informant interviews showed that due to the drought, people increasingly used pit latrines rather than flush toilets. Nitrate, fecal coliforms, and caffeine analyses of Ramotswa groundwater revealed that human waste leaching from pit latrines is the likely source of nitrate pollution. The results in conjunction indicate critical indirect linkages between climate change, sanitation, groundwater quality, and water security in the area. Improved sanitation, groundwater protection and remediation, and local water treatment would enhance reliable access to water, de-couple the community from reliance on surface water and associated water shortage risks, and help prevent transboundary tension over the shared aquifer.

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“…Numerical simulation of groundwater flow is an essential tool to synthesize hydrogeological information and reveal groundwater flow patterns (Bredehoeft and Konikow, 2012;Anderson et al, 2015;Tóth et al, 2016). The combination of these approaches is robust to reveal groundwater origin, flow regimes, renewability, hydrochemical evolution and interaquifer mixing, as well as surface water and groundwater interactions, etc., in basins with complex hydrogeology or sparse monitoring data, and has been successfully applied in many basins such as the Great Artesian Basin and Murray Basin in Australia, Michigan Basin in US, Minqin Basin and Ordos Plateau in China, Stampriet Basin in Africa (Edmunds et al, 2006;Banks et al, 2010;Love et al, 2013Love et al, , 2017Stone and Edmunds, 2014;Su et al, 2016;Cartwright and Morgenstern, 2017;Petts et al, 2017;Priestley et al, 2017b).…”

mentioning

confidence: 99%

Groundwater origin, flow regime and geochemical evolution in arid endorheic watersheds: a case study from the Qaidam Basin, northwestern China

Xiao

Shao

Frape

et al. 2018

Hydrol. Earth Syst. Sci.

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Groundwater origin, flow and geochemical evolution in the Golmud River watershed of the Qaidam Basin was assessed using hydrogeochemical, isotopic and numerical approaches. The stable isotopic results show groundwater in the basin originates from precipitation and meltwater in the mountainous areas of the Tibetan Plateau. Modern water was found in the alluvial fan and shallow aquifers of the loess plain. Deep confined groundwater was recharged by paleowater during the late Pleistocene and Holocene under a cold climate. Groundwater in the low-lying depression of the central basin is composed of paleobrines migrated from the western part of the basin due to tectonic uplift in the geological past. Groundwater chemistry is controlled by mineral dissolution (halite, gypsum, anhydrite, mirabilite), silicate weathering, cation exchange, evaporation and mineral precipitation (halite, gypsum, anhydrite, aragonite, calcite, dolomite) and varies from fresh to brine with the water types evolving from HCO 3 · Cl-Ca · Mg · Na to Cl-Na, Cl-K-Na and Cl-Mg type along the flow path. Groundwater flow patterns are closely related to stratigraphic control and lithological distribution. Three hierarchical groundwater flow systems, namely local, intermediate and regional, were identified using numerical modeling. The quantity of water discharge from these three systems accounts for approximately 83 %, 14 % and 3 %, respectively, of the total groundwater quantity of the watershed. This study can enhance the understanding of groundwater origin, circulation and evolution in the Qaidam Basin as well as other arid endorheic watersheds in northwestern China and elsewhere worldwide.

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Naturally-high nitrate in unsaturated zone sand dunes above the Stampriet Basin, Namibia

Cited by 20 publications

References 39 publications

Geochemistry of sediment moisture in the Badain Jaran desert: Implications of recent environmental changes and water-rock interaction

Geochemistry of sediment moisture in the Badain Jaran desert: Implications of recent environmental changes and water-rock interaction

Complex interactions between climate change, sanitation, and groundwater quality: a case study from Ramotswa, Botswana

Groundwater origin, flow regime and geochemical evolution in arid endorheic watersheds: a case study from the Qaidam Basin, northwestern China

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