In the same way dishwashing detergents clean greasy dishes, scientists studying groundwater contamination are using detergent-like surfactants to clean contaminated regions underground. Surfactants aid in soil and groundwater clean up by dissolving contaminants, such as oil or dry cleaning fluids. Surfactants make the removal of contaminants easier and faster.
The beneficial effects of surfactants on soil and groundwater clean-up efforts come at the cost of complicating our ability to use computer models to predict the behavior of contaminant and water flow. That is especially true in soil and rocks in the vadose zone, which is a lower water content zone above the water table.
Scientists Eric Henry, University of North Carolina at Wilmington, and James Smith, McMaster University, authored an article in the May issue of Vadose Zone Journal, published by the Soil Science Society of America, that summarizes the current state of knowledge on the effects of surfactants on water flow in the vadose zone.
Among the findings that Henry and Smith discuss are data from their research that shows surfactants can cause contaminants to move more rapidly through the vadose zone and reach the water table more quickly than if no surfactant was present. This behavior needs to be considered when deciding how, when, and where to use soil-washing systems. Despite this seemingly adverse effect caused by surfactant use in the vadose zone, the authors are not discouraged.
"This type of information advances our knowledge of unsaturated flow processes and will allow us to
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Contact: Sara Uttech
suttech@agronomy.org
608-273-8080
American Society of Agronomy
19-May-2003