ABSTRACT
Bioremediation of organically contaminated soils is currently regarded as one of the most successful techniques for remediating some contaminated soils. The technique is based on optimization of biological processes to remediate or to minimize the concentrations of hazardous pollutants at contaminated sites. The underlying basis of bioremediation of organic pollutants is the detoxification or mineralization of the contaminating species to https://www.w3.org/1998/Math/MathML"> C O 2 https://s3-euw1-ap-pe-df-pch-content-public-p.s3.eu-west-1.amazonaws.com/9780429080050/6559e41b-64b9-4256-96a3-5980cbb6d757/content/eq885.tif" xmlns:xlink="https://www.w3.org/1999/xlink"/> and https://www.w3.org/1998/Math/MathML"> H 2 O https://s3-euw1-ap-pe-df-pch-content-public-p.s3.eu-west-1.amazonaws.com/9780429080050/6559e41b-64b9-4256-96a3-5980cbb6d757/content/eq886.tif" xmlns:xlink="https://www.w3.org/1999/xlink"/> . Therefore, it makes an attractive, environmentally friendly, and relatively cost-effective alternative to conventional physicochemical techniques, which rely mainly on incineration, volatilization, or immobilization of the contaminant. However, the success of bioremediation is determined by the metabolic potential of microorganisms to detoxify or utilize the contaminant, provided the contaminant is accessible for microbial attack and other environmental factors are optimal. The process is therefore dependent on both accessibility and bioavailability of the contaminants to microbes. There is, however, considerable controversy in the literature as to what constitutes the bioavailable fraction, including the definition itself and the methods of its measurements. For instance, while microbiologists often regard the concentration that causes ecotoxicity to microorganisms as the bioavailable fraction, plant scientists regard the plant-available fraction as the bioavailable fraction. Consequently, terms such as "bioavailable," "phytoavailable," and "available" are in use. The concept of bioavailability is applicable to all organisms regardless of their nature, including microorganisms, plants, animals, and humans.
