Superfund Research Program
Anaerobic Mobilization Technology for Remediation of Low Availability Hydrophobic Organic Contaminants
Project Leader: Frederic K. Pfaender
Grant Number: R41ES011890
Funding Period: Phase I: 2002-2004
A major contaminant at over 8,000 sites in the United States are polynuclear aromatic hydrocarbons (PAHs) - a class of organic compounds containing two or more fused aromatic rings of carbon and hydrogen atoms. Many of these compounds are both toxic and carcinogenic. This contamination results from almost all combustion processes, the creosote treatment of wood, and the use of organic pesticides, among others. It has been observed that these highly hydrophobic compounds bind tightly to soil by a number of possible interactions between the soil mineral matrix, the organic fraction of soil, and the compounds. Microbes in the soil appear to mediate these processes in some circumstances. Most of the PAH are biodegraded by microorganism, at least partially, but data suggests that a major fraction of the compound associated with the soil is not biologically available to be toxic or to be biodegraded by microorganisms, thereby impeding cleanup of the many PAH contaminated sites.
Research conducted by the grantee has revealed that the incubation of soil in microcosms under anaerobic conditions leads to a change in the soil organic matter such that the PAH previously unavailable are made available to microbes capable of degrading the compound. This microbially based process may also have the potential to mobilize other hydrophobic chemicals from the soil.
This project seeks to expand these findings by testing soils with a variety of properties to determine how broadly applicable the technology may be for site remediation. Further, it will examine a number of approaches for efficiently and cheaply establishing highly reducing conditions in soil so the PAH will be released. Finally, the project will develop and test several potential methods for biodegrading the released PAH.
A subsequent phase of this project will involve conducting a field test of the method at an actual PAH site.