nitrate, arsenic and selenium concentrations in the pecos valley aquifer, west texas,usa

Fate of Arsenic in the Mahomet Aquifer: The Influence of Added Sulfate and Nitrate

Material from the Mahomet aquifer, known to have pockets of high arsenic concentration, was evaluated for different microbiological activities that could influence the mobility of arsenic in groundwater. Project activities included a thorough assessment of core material collected in a region of the aquifer known for high arsenic concentration and flow-through column experiments evaluating the p...

Nitrate and Pesticide Penetration into a Northern Mississippi Valley Loess Hills Aquifer

Distribution and variability of redox zones controlling spatial variability of arsenic in the Mississippi River Valley alluvial aquifer, southeastern Arkansas.

Twenty one of 118 irrigation water wells in the shallow (25-30 m thick) Mississippi River Valley alluvial aquifer in the Bayou Bartholomew watershed, southeastern Arkansas had arsenic (As) concentrations (<0.5 to 77 microg/L) exceeding 10 microg/L. Sediment and groundwater samples were collected and analyzed from the sites of the highest, median, and lowest concentrations of As in groundwater i...

Modeling of Arsenic and Selenium in Soils

Inorganic Chemistry of As and Se in Soil Solution .......................................... 66 Methylation and Volatilization Reactions ......................................................... 66 Precipitation-Dissolution Reactions .................................................................. 68 Oxidation-Reduction Reactions ..................................................................

Arsenic and selenium in microbial metabolism.

Arsenic and selenium are readily metabolized by prokaryotes, participating in a full range of metabolic functions including assimilation, methylation, detoxification, and anaerobic respiration. Arsenic speciation and mobility is affected by microbes through oxidation/reduction reactions as part of resistance and respiratory processes. A robust arsenic cycle has been demonstrated in diverse envi...

Inverse geochemical modeling of groundwater evolution with emphasis on arsenic in the Mississippi River Valley alluvial aquifer, Arkansas (USA)

r a 200 .027 sent add gmail.c Summary Inverse geochemical modeling (PHREEQC) was used to identify the evolution of groundwater with emphasis on arsenic (As) release under reducing conditions in the shallow (25–30 m) Mississippi River Valley Alluvial aquifer, Arkansas, USA. The modeling was based on flow paths defined by high-precision (±2 cm) water level contour map; X-ray diffraction (XRD), sc...