The objective of this research is to evaluate the chemical and biochemical processes that result in the binding of select contaminants to soils and sediments. Such binding reactions can affect the fate and transport of pollutants by their in-situ humification with a significant impact on the chemicals' environmental mobility and ecotoxicity. Research will focus on studying the environmental fate of phenols and anilines in soils and sediments. Oxides of transition metals and enzymes can catalyze oxidative coupling reactions that polymerize select chemicals or bind them covalently to humic-acid type macromolecules. The proposed research will investigate the possibility of engineering similar humification processes in natural soils and sediments to permanently "trap" and detoxify phenols, anilines and hydroxylated polynuclear aromatic hydrocarbons. Ecotoxicology of the sequestered contaminants will be assessed by evaluating their leachability, bioavailablilty and toxicity. The overall results of this investigation will comprise the basis for a scientific understanding of the factors controlling enzyme and metal oxide mediated sequestration of aromatic acids and bases in soils and sediments, and provide information on the applicability of engineered humification processes to achieve health-risk based alternative remediation endpoints.
