Little is known about the importance of drainage/irrigation channels and biogeochemical processes in arsenic distribution of shallow groundwaters from the Hetao basin. This investigation shows that although As concentrations are primarily dependent on reducing conditions, evaporation increases As concentration in the centre of palaeo-lake sedimentation. Near drainage channels, groundwater As co...

The Yaoba Oasis is an irrigated cropland entirely dependent on groundwater; previous investigations (1980–2015) revealed over-abstraction of groundwater and deteriorating quality. For further exploring the hydrodynamic behaviors geochemical processes during irrigation season, samples were collected analyzed using different techniques including classical statistics, correlation analysis, Piper d...

Groundwater from unconfined chalk aquifers constitutes a major water resource in the UK. The unsaturated zone in such systems plays a crucial role in the hydrological cycle, determining the timing and magnitude of recharge, and the transport and fate of nutrients. However, despite more than three decades of study, our physical understanding of this system is incomplete. In this research, state ...

Hydrogeochemical investigations had been carried out at the Amol-Babol Plain in the north of Iran. Geochemical processes and factors controlling the groundwater chemistry are identified based on the combination of classic geochemical methods with geographic information system (GIS) and geostatistical techniques. The results of the ionic ratios and Gibbs plots show that water rock interaction me...

Estimates of groundwater recharge are often needed for a variety of groundwater resource evaluation purposes. A method for estimating long-term groundwater recharge and actual évapotranspiration not known in the English literature is presented. The method uses long-term average annual precipitation, runoff, potential evaporation, and crop-yield information, and uses empirical parameter curves t...

A geochemical study was conducted to obtain a comprehensive understanding of fluoride concentration increase in groundwater from a crystalline (hard-rock) aquifer in a small Indian agricultural watershed, where groundwater is intensively abstracted for paddy irrigation. A reactive1-D geochemical model using PHREEQC was used to reproduce fluoride concentrations under rice paddies taking into acc...

Monthly evapotranspiration (ET) rates (2000 to 2009) across Nebraska at about 1-km resolution were obtained by linear transformations of the MODIS (MODerate resolution Imaging Spectroradiometer) daytime surface temperature values with the help of the Priestley-Taylor equation and the complementary relationship of evaporation. For positive values of the mean annual precipitation and ET differenc...

Is the recently found seepage groundwater on Mars pure H2O, or mixed with salts and other antifreeze compounds? Given the surface conditions of Mars, it is unlikely that pure water could either exist in its liquid state or have shaped Mars’ fluid erosional landforms (gullies, channels, and valley networks). More likely is that Mars’ seepage groundwater contains antifreeze and salt compounds tha...

By employing chemical and isotopic tracers ((15)N and (18)O in NO(3)(-)), we investigated the main processes controlling nitrate distribution in the unsaturated zone and aquifer. Soil water was extracted from two soil cores drilled in a typical agricultural cropping area of the North China Plain (NCP), where groundwater was also sampled. The results indicate that evaporation and denitrification...