AMPHIPHIL


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The influence of amphiphilic substances on water repellency of effluent irrigated soils

AMPHIPHIL


Project Outline

The phenomenon of soil water repellency (SWR) has been observed in soils around the world. Its consequences include poor plant growth, reduced seed germination, accelerated surface runoff and soil erosion, and enhanced preferential flow in the vadose zone of soils, which can lead to accelerated leaching of nutrients and agrichemicals [DeBano, 2000; Doerr et al., 2000b]. SWR is affected by a vast number of different factors (e.g., fire, vegetation type, soil organic matter, water content, pH). Recently, it was found that long-term irrigation with secondary effluent can cause the development of SWR [Wallach et al., 2005].

The objective of this study to evaluate whether amphiphilic substances (particularly surfactants) contained in the effluent, can cause SWR. In order to analyze surfactants in the effluent and in aqueous soil extracts, the development and establishment of a suitable analysis method was necessary. This was successfully done for anionic surfactants, which we spectrophotometrically determined as methylene blue active substances (MBAS).
Mandy Görnitz

References

Doerr, S. H., Shakesby, S. H. and Walsh, R. P. D. (2000b). "Soil water repellency: its causes, characteristics and hydro-geomorphological significance." Earth-Science Reviews 51(1-4): 33-65.

DeBano, L. F. (2000). "Water repellency in soils: a historical overview." Journal of Hydrology 231-232: 4-32.

Wallach, R., Ben-Arie, O. and Graber, E. R. (2005). "Soil Water Repellency Induced By Long-Term Irrigation with Treated Sewage Sludge Effluent." Journal of Environmental Quality: DOI: 10.2134/jeq2005.0073.