Microbial remediation of contaminated soils.

Abstract

Our environment is threatened by thousands of contaminants, mainly as a result of human activities and industrialization. These include both inorganic (e.g. heavy metals) and organic compounds (e.g. polycyclic aromatic hydrocarbons, chlorinated hydrocarbons and herbicides). It has been shown that many of these hazardous chemicals cause health problem such as cancer in living organisms. Therefore, removing them from environments and soils represents a key challenge from both ecosystem and human health perspectives. Among the approaches used to remove these pollutants, microbial remediation or bioremediation represents a promising technology that is cost-effective, environmentally friendly and less disruptive than alternative technologies. Bioremediation involves microbes that are present in or added to the contaminated environment which are capable of degrading contaminants, or reducing them to less toxic forms. There are a number of bioremediation techniques, including natural attenuation, bioaugmentation, biostimulation, phytoremediation/rhizoremediation and necrophytoremediation Many factors, such as soil texture, pH, temperature, levels of oxygen, nutrients and the microbial status of the soils, influence the rate and extent of bioremediation along with the type and bioavailability of the contaminants. In this chapter, we highlight the current status of bioremediation, examining the development of techniques used to assess and optimize the degradation of the contaminants.