ESTCP Technology Demonstration Final Report: Field Demonstration of Rhizosphere-Enhanced Treatment of Organics-Contaminated Soils on Native American Lands With Application to Northern FUD Sites

摘要

The problem that these ESTCP demonstrations addressed is surface soil contaminated with petroleum, located at remote sites, covering large areas, and in cold climates. There are many such Department of Defense (DoD) sites in Alaska. These sites are generally not easily accessible, thus increasing the costs of mobilization and demobilization, have limited infrastructure to support traditional cleanup, are subject to harsh winters, causing equipment failures. Conventional cleanup strategies are sufficiently costly to limit their use, yet there are few alternatives. These results are the first cold- regions data, and some of the few field data available, that use scientifically defensible techniques to confirm that plants have a positive effect on petroleum depletion relative to either nutrients alone or control treatments. The data all show that plant associated effects do occur, but not uniformly for all petroleum fractions, and that the effects are greatest for more recalcitrant petroleum fractions. Rhizosphere-enhanced treatment of surface soils is a long-term strategy, and using standard analysis techniques to monitor sites may lead users to conclude that rhizosphere treatment is not working. Significantly, these field data support both theory and laboratory data. We evaluated rhizosphere-enhanced remediation as a possible effective solution. Rhizosphere enhanced remediation is a subset of phytoremediation, which includes techniques for many contaminants and many remediation mechanisms. These demonstrations were specific for petroleum in surface soils. The mechanisms active in rhizosphere-enhanced remediation are based on enhanced microbial activity at the root-soil interface. For petroleum remediation, plant uptake is not thought to be significant.