1. Executive Summary
This document is a cost and performance report for ESTCP project #1011, "Field Demonstration
of Rhizosphere-Enhanced Treatment of Organics-Contaminated Soils on Native American Lands
with Application to Northern formerly used defense (FUD) Sites." The accompanying Final
Report provides additional details on the methods used, data from the field demonstration sites, a
statement of knowledge gaps, and suggestions on how these data and approaches can be used in
other situations dealing with surface soil contamination.
This project included field demonstrations of rhizosphere-enhanced bioremediation of petroleum,
oils, and lubricants (POLs) at three cold sites in Alaska. The demonstrations evaluated the use of
rhizosphere-enhanced remediation in northern regions where low temperatures, site
inaccessibility, permafrost, and freeze-thaw cycles limit or, in many cases, prevent cost-effective
application of both traditional technologies and a number of emerging innovative technologies.
1.1 Background
Petroleum, oils, and lubricants (POLs) are widespread contaminants at many northern facilities
owned, formerly owned, or formerly used by the Department of Defense (DoD). In cold regions,
POLs and especially the polynuclear aromatic hydrocarbon fraction (PAHs) are persistent in
soils due to the low mean annual soil temperatures and the brevity of the summer season. Some
constituents in POLs are known human carcinogens.
Cleanup problems are compounded for sites that are in remote, inaccessible areas. The DoD has
numerous sites in Alaska that were constructed during World War II and expanded in the
ensuing cold-war era. During these times, fuel was often transported and stored in 55-gallon
drums, resulting in accidental POL releases. At many of these sites, mobilization and
demobilization costs are excessive. In some cases, ground transportation is possible only in
winter when the soil is frozen. During the summer, when biotreatment would be feasible, air
transportation must be used, but landing sites cannot support larger aircraft. Construction
supplies at many facilities were delivered by air during the winter using packed-snow runways.
Low-cost, effective, and applicable treatment technologies are needed for all of these situations.
Rhizosphere-enhanced remediation is a developing technology. It is a subset of
phytoremediation--a term that is often used in a broad sense, and sometimes used
inappropriately or too generally because phytoremediation encompasses a wide range of
processes. The operative process in phytoremediation depends largely on the contaminant and
can include plant uptake coupled with accumulation, biological transformations in the plant, or
transpiration into the atmosphere. For the situation that we addressed--petroleum compounds in
near-surface soils--the generally accepted mechanism is microbial degradation that is enhanced
in the rhizosphere--the soil immediately adjacent to and affected by plant roots.
We demonstrated the ability of cold-tolerant plants, nutrient additions, and their combination to
remediate POL-contaminated soils at three geographically diverse sites in Alaska: Annette Island
(southern), Galena-Campion (interior), and Barrow (north slope). We used soil-sock sampling
techniques along with both grab and composite samples and analyzed changes in both petroleum
concentrations and composition.
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