ESTCP Project #1011, Rhizosphere
3.7 Selection of Analytical/Testing Laboratory
Chemical analytical capabilities are important. The most useful data for describing the treatment
effects were TPH, summed PAHs, and fraction specific hydrocarbons (FSH) normalized to a
recalcitrant biomarker and to growing degree days (GDD). Few laboratories have the capabilities
or expertise to do this, although the instrumentation is fairly common. For this project, useful
analyses were conducted by Battelle, Duxbury Operations, Battelle Environmental Forensics
Group, 397 Washington Street, Duxbury, MA 02332.
The analytical laboratory used for the regulatory samples was approved by the appropriate
regulatory body, in this case the Alaska Department of Environmental Conservation (ADEC).
These samples are insufficient for monitoring this type of remediation process. The architect-
engineering firm (AE) provided chemical analysis of all quality assurance (QA) samples. All QA
laboratory services were performed in accordance with the Quality Assurance Plan (see Section
9 of the Demonstration Plan) and conformed to ER 1110-1-263 (1 April 96). The AE used only
those QA laboratories that are validated by the Corps of Engineers Missouri River Division
(CEMRD) for the required analyses and had ADEC approval.
The certified analytical laboratory analyzed just the regulatory grab samples. Additional samples
were analyzed by ERDC-CRREL soil microbiology laboratory.
4. Performance Assessment
4.1 Performance Criteria
We used two approaches to analyze the data. Because the demonstration at each site is a factorial
experiment and designed as a balanced replicated, randomized complete block, we conducted
factorial analysis of variance (ANOVA) to test for significance of the main effects (plants or
nutrients) and (plant x nutrient) interactions on selected dependent variables. Additionally, we
used 1-way ANOVA to compare each treatment. The latter approach loses sensitivity relative to
the factorial approach because there are fewer replications of main factor, but this approach is
also more likely to be used in by many in future demonstration where full factorial experiments
are cost prohibitive. These two approaches to hypothesis testing were chosen to provide evidence
for enhanced remediation at these sites, and also may provide new understanding that would
suggest other tests, other monitoring approaches, or both.
A challenge in using rhizosphere-enhanced remediation is that successful treatment may be
occurring at an enhanced rate relative to natural attenuation (controls), yet the treatment may still
require a number of years before cleanup goals, or even chemically measurable treatment effects,
can be observed. This is exacerbated in cold regions, where low temperatures and variable
conditions slow surface biological processes. This lack of uncertainty may not be acceptable to
stakeholders or regulatory communities. Multiple lines of evidence that rely on alternative
protocols may lead to new monitoring strategies that convincingly demonstrate that remediation