Department of Earth Science |Northeastern Illinois University
Aqueous Geochemistry
Earth Science 406
Fall 2002

Conference Presentation Abstract

Journal Article: Redox Patterns and Trace-Elements Behavior in the East Midlands Triassic Behavior in the East Midlands Triassic Sandstone Aquifer, U.K. by Pauline L. Smedley and W. Mike Edmunds.  Ground Water Volume 40 Number 1, 2002

Abstract written by Yvette Shiu

Redox processes are an important control measure in the Sherwood Sandstone ground water, especially when a distinct redox reaction occurs. The Triassic Sherwood Sandstone Aquifer (300 m wide to the North and 120 m wide in the South) in the English East Midlands is an aquifer where there is a distinct redox boundary with an important influence on trace-element distribution and mobilization. The complete reaction of oxygen is accompanied by a decrease in redox potential (Eh). This boundary marks a geochemical line that controls elemental movement. This polluted aquifer contains high nitrate concentrations and organic compounds due to confined conditions.

Different ions have different concentrations in this type of environment. For example, Fe, Mn and Mo have high concentrations in a reducing environment and on the opposite end of that As, Sb, Se, and U have low concentrations in this same reducing environment. This study presents the redox elements in the ground water collected from the same sampling process both studied previously and current.  With increased residence time, minerals have undergone more extensive mineral reaction (gypsum and anhydrite). Ground water tends to represent and older generation of saline water in this aquifer.
 

Last updated December 2, 2002