Biosorption of heavy metals onto different eco-friendly substrates

Abstract

Fungi play an important role in biosorption of heavy metals in heavily contaminated soil. Five metals-tolerant fungal species were isolated from two different contaminated soil (soils 1 and 2). The number of fungal colonies isolated from the contaminated soil 2 was higher than that of soil 1. The most resistant fungal species for the toxic studied metals (Pb, Cd, Cu and Zn) was Rhizopus stolonifier followed by Macrophomina phaseolina. It was established that the metal toxicity was related to the contamination levels, the physicochemical properties including pH, conductivity, organic matter and carbonate contents of the soils. This study confirmed the good ability of different chemicals (CaCO3, MO, Zeolite and phosphate) and biological fungal substrates (M. phaseolina and R. stolonifier) in bioremediation of polluted soils and reducing different heavy metals levels as compared to the control, especially for fungi. M. phaseolina amendment was superior in reducing the chemically available heavy metals in the studied soils.   Key words: Heavy metals, fungal adsorption, soil remediation, amendments, sequential extraction technique.