Basic concepts on heavy metal soil bioremediation

The utilization of organisms, primarily microbes, to clean up contaminated soils, aquifers, sludges, residues, and air, known as “bioremediation”, is a rapidly changing and expanding area of environmental biotechnology, that offers a potentially more effective and economical clean-up technique than conventional physicochemical methods. Although it is certain that up to now the technologies employed are not technically complex, considerable experience and expertise is required to design and implement a successful bioremediation program. As a matter of fact, and since bioremediation frequently addresses multiphasic, heterogenous environments (i.e., soils), successful bioremediation is dependent on an interdisciplinary approach involving such disciplines as microbiology, engineering, ecology, geology, and chemistry. The bio-enthusiasm of the early years that followed the initial promising research results and inspired the creation of many remediation companies has ended in a more realistic and sometimes even sceptical view of bioremediation since it has now become clear that results obtained in the laboratory do not necessarily indicate what may happen actually in the field, since it is not possible to simulate all the changing conditions of a real situation. Most traditional remediation methods do not provide acceptable solutions for the removal of metals from soils. Microorganisms that use metals as terminal electron acceptors, or reduce metals as a detoxification mechanism can be used for the removal of metals from contaminated environments. In some cases, phytoextraction of metals is a cost-effective approach that uses metal-accumulating plants to clean up metal polluted soils. © 2003 SDU. All rights reserved.