Biosensors for ecotoxicity of xenobiotics: a focus on soil and risk assessment.

In this chapter we discuss the potential application of biosensors for the ecotoxicologal risk assessment of xenobiotics in soil environments. In the first part we introduce basic concepts of ecotoxicological risk assessment, ecotoxicology, environmental fate of xenobiotics, with particular focus on bioavailability processes and their importance in exposure and ecotoxicity of xenobiotics in soils. Specifically, all the main processes controlling the environmental fate of xenobiotics in soils are explained. In the second part we introduce some principles of the functioning of different classes of whole cell biosensors and chemical sensors for xenobiotics of ecotoxicological interests and present some applications and their contribution to improve the ecoxicological risk assessment of xenobiotics in soils. We show how biosensors can be applied together with chemical assessment of bioavailability of xenobiotics in soil to assess ecotoxicological risk. The application of biosensors to improve the classical risk assessment paradigm is presented, in order to show how this technology can be used to assess the ecotoxicological risk of xenobiotics in soils. Examples of biosensors with potential application for ecotoxicological risk assessment are also presented and discussed. The relevance of these studies of environmental health is also acknowledged. We conclude that biosensors technology holds relevant potential for ecotoxicological risk assessment of xenobiotics in soils.