Microbial induced carbonate precipitation for immobilizing Pb contaminants: Toxic effects on bacterial activity and immobilization efficiency

Microbial induced carbonate precipitation (MICP) is a natural bio-mediated process, which has been explored for soil stabilization and heavy metals immobilization in soil and groundwater. Previous studies have shown that MICP is capable of immobilizing various heavy metals including lead (Pb). However, most studies focus merely on the immobilization of heavy metals with relatively low concentration. This study: (1) presents results of an investigation into the toxic effects of Pb on bacterial activity and immobilization efficiency within a wide range of Pb concentrations; and (2) identifies controlling biotic and abiotic factors of Pb immobilization by MICP. In the first series of tests, bacterial strains (Sporosarcina pasteurii) are inoculated into nutrient solutions containing 0-50 mM Pb(NO3)2 and incubated at 30 °C.…