ABSTRACT
This chapter elucidates the importance of bioavailability compared with other factors also involved in soil bioremediation, and discusses constraints and alternatives to increase bioavailability of recalcitrant compounds found in contaminated soils. A number of constraints that could influence bioavailability must be identified before planing a bioremediation strategy. These include the nature of microorganisms, the composition and properties of pollutants and the nature of soils. Three general strategies to increase bioavailability have been developed: use of biosurfactants, addition of organic solvents and addition of synthetic surfactants. Addition of organic solvents changes the polarity of the soil-water environment, influencing partition and consequently bioavailability of non-ionic pollutants. The uses of synthetic surfactants to promote bioavailability of contaminant molecules attached to soil have recently gained attention, in particular, when insoluble persistent contaminants such as polycyclic aromatic hydrocarbons and polychlorinated biphenyls in soils and sediments are present.
