Behavior of heavy metals in model three-component soil systems

Model three-component soil systems including goethite (a mineral component) and a suspension of microorganisms (a biological component) have been used to study the interaction of Pb and Zn with the mineral surface. The results show that live microorganisms markedly reduced the adsorption of these metals, especially Pb, on the goethite shell surface. In the case of Pb, this is due to a decrease in the content of its nonexchangeable form; in the case of Zn, to a decrease in the content of its exchangeably bound compounds. An organic matter preparation obtained by autoclave treatment of microorganisms has a markedly weaker effect on metal adsorption, compared to the suspension of live microbial cells.