Record Display for the EPA National Library Catalog


Main Title Remobilization of Toxic Heavy Metals Adsorbed to Bacterial Wall-Clay Composites.
Author Flemming, C. A. ; Ferris, F. G. ; Beveridge, T. J. ; Bailey, G. W. ;
CORP Author Guelph Univ. (Ontario). Dept. of Microbiology.;Environmental Research Lab., Athens, GA.
Publisher c1990
Year Published 1990
Report Number EPA-R-813605; EPA/600/J-90/454;
Stock Number PB91-183350
Additional Subjects Heavy metals ; Environmental transport ; Bacteria ; Waste disposal ; Earth fills ; Soil science ; Desorption ; Adsorption ; Organic matter ; Clays ; Microbiology ; pH ; Leaching ; Toxic substances ; Sediments ; Vadose water ; Water pollution ; Land pollution ; Reprints ;
Library Call Number Additional Info Location Last
NTIS  PB91-183350 Some EPA libraries have a fiche copy filed under the call number shown. 07/26/2022
Collation 15p
Significant quantities of Ag(I), Cu(II), and Cr(III) were bound to isolated Bacillus subtilis 168 walls, Escherichia coli K-12 envelopes, kaolinite and smectite clays, and the corresponding organic material-clay aggregates (1:1, wt/wt). These sorbed metals were leached with HNO3, Ca(NO3)2, EDTA, fulvic acid, and lysozyme at several concentrations over 48 h at room temperature. The remobilization of the sorbed metals depended on the physical properties of the organic and clay surfaces and on the character and concentration of the leaching agents. Cr was very stable in the wall, clay, and composite systems; pH 3.0, 500 microM EDTA, 120-ppm (mg/liter) fulvic acid, and 160-ppm Ca remobilized less than 32% (wt/wt) of sorbed Cr. Ag (45 to 87%) and Cu (up to 100%) were readily removed by these agents. Although each leaching agent was effective at mobilizing certain metals, elevated Ca or acidic pH produced the greatest overall mobility. The organic chelators were less effective. Lysozyme digestion of Bacillus walls remobilized Cu from walls and Cu-wall-kaolinite composites, but Ag, Cr, and smectite partially inhibited enzyme activity, and the metals remained insoluble. The extent of metal remobilization was not always dependent on increasing concentrations of leaching agents; for example, Ag mobility decreased with some clays and some composites treated with high fulvic acid, EDTA, and lysozyme concentrations. It is apparent that remobilization of toxic heavy metals in sediments, soils, and the vadose zone is a complicated issue.