Role of the biotic compartment in the transfer of zinc through the vadose zone - application to an infiltration system

摘要

Relatively little is known about the influence of microorganisms which develop in urban stormwater infiltration basins on the transfer of heavy metals, whereas many reports have emphasized their importance in the mechanisms of retention or solubilization of these elements. We therefore examined the transfer of zinc solutions (2-20 ppm) at different pH (4-7) by columns of sterile sand or sand colonized with Pseudomonas putida. The shape of the elution curves shows that the biofilm adsorbed zinc, causing its elution to be retarded. Adsorption seemed to be reversible, except at pH 6 and 7, and non-instantaneous. Consequently, the stormwater infiltration speed may be of considerable importance.