Environmental Molecular Diagnostics
The Environmental Molecular Diagnostics (EMD) Team, formed in 2010, is collecting and summarizing fundamental background information on, and current status of, available EMDs, as well as assessing the future of EMDs. In 2011, the team produced a series of fact sheets, “Environmental Molecular Diagnostics Fact Sheets (EMD-1)”, describing compound specific isotope analysis (CSIA) and molecular biology–based methods which may be commonly encountered by project managers. The team continued its work through the following tasks:
- providing objective guidance on the best practices for using EMDs for contaminated sites management
- determining appropriate uses of EMDs, including their strengths and limitations
- providing information to support evaluating, applying, and interpreting the results of EMDs
- developing a technical and regulatory guidance document called “EMD-New Site Characterization and Remediation Enhancement Tools (EMD-2)”
- developing an Internet-based training course to foster greater use and confidence in the EMD methods
“Environmental molecular diagnostics” is a collective term that describes a group of advanced and emerging techniques used to analyze biological and chemical characteristics of soils, sediments, groundwater, and surface water. Many of the tools were originally developed for applications in medicine, defense, and industry. However, over the last decade, great advances have been made in adapting and applying EMDs for environmental remediation.
CSIA measures the amounts of stable isotopes (typically carbon, hydrogen, or chlorine) in contaminants to determine the extent of specific chemical and biochemical reactions impacting the contaminant. As a contaminant degrades through natural or engineered processes, the relative amount of each stable isotope in the contaminant can change. In contrast, the isotopic composition of contaminants is largely unaffected by processes such as dilution that do not result in degradation of the contaminant. Questions pertaining to a chemical’s source, degradation mechanism, and rate of degradation can be answered, supported, and resolved through CSIA.
Molecular biology–based EMDs are used to determine the biochemical capabilities of microorganisms present in the environment. In many cases, particular microorganisms are responsible for the degradation of specific contaminants. Some molecular biology–based EMDs can be used to detect and quantify these known microorganisms. Other molecular biology–based EMDs can be used determine whether microorganisms are actively degrading specific contaminants and can also identify currently unknown microorganisms involved in these processes. Questions pertaining to biochemical capabilities and activities of microorganisms and changes in microbial population sizes in natural and engineered environments can be answered, supported, and resolved through these types of analyses.
EMDs have application to the phases of typical project management, including site characterization, remediation, monitoring, and closure activities. EMDs are expected to provide additional lines of evidence for decision making during contaminated sites management.
There is clearly a growing need for technical information and training on EMDs. EMDs are becoming increasingly powerful, and standardized methods are being developed. As a result, their use is increasing rapidly. Using these tools provides the following benefits:
- improve the management of contaminated sites
- determine whether biotic or abiotic degradation is occurring at a site
- reveal whether multiple sources of contamination are present
- help decide what remediation strategy will work
- help determine when enhancements such as chemical amendments or bioaugmentation are necessary
- aid in reducing or optimizing a monitoring program
- provide complementary data to support site closure
ITRC’s EMD technical and regulatory guidance and Internet-based training will foster the appropriate uses of EMDs and help regulators, consultants, and site owners to better understand a site and to make decisions based on the results of EMD analyses.
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