Soil contamination and the feasibility of biological remediation

The prevention of soil pollution and cleanup of contaminated soils have become a worldwide environmental priority. Interdisciplinary cooperation is required to solve many of the complex problems involved in biologically remediating contaminated soils. This chapter examines the degree of contamination that exists in the soils of the USA and discusses bioremediation techniques that can be used to detoxify polluting chemicals. Bioremediation is the use of microorganisms or plants to detoxify an environment, mostly by transforming or degrading pollutants. Four basic techniques may be used: stimulation of the activity of indigenous microorganisms by the addition of nutrients, regulation of redox conditions, optimizing pH conditions, etc.; inoculation of the sites with microorganisms of specific biotransforming abilities; application of immobilized enzymes; and use of plants (phytoremediation) to remove, contain, or transform pollutants. Advantages and disadvantages of these techniques are addressed and potential technologies and improvements for the future are examined.