The quartz peaks in the control samples might be attributed to thesand sample.
A mixture of heavy metals was found to co-precipitatewith CaCO3as cerussite (lead carbonate, PbCO3) in the bioremedi-ation experiments, while otavite (cadmium carbonate, CdCO3) andcopper carbonate (CuCO3) peaks were also detected
The overallreactions involved in the bioremediation process include: pro-duction of NH4+and HCO3−by urease, desorption of Ca2+and/orheavy metal ions from solid surfaces by the NH4+and HCO3−pro-moted precipitation of CaCO3, and the co-precipitation of heavymetals.