Measurement & Monitoring: 23rd Quarterly Literature Update

Advancement of Nucleic Acid-Based Tools for Monitoring In Situ Reductive Dechlorination Vangelas, K., E. Edwards, F. Loeffler, B.B. Looney. Paper No: WSRC-STI-2006-00332, 23 pp, Nov 2006 Regulatory protocols generally recognize that destructive processes are the most effective mechanisms that support natural attenuation of chlorinated solvents. In many cases, these destructive processes will be biological processes and, for chlorinated compounds, will often be reductive processes that occur under anaerobic conditions. The existing EPA guidance (EPA, 1998) provides a list of parameters that provide indirect evidence of reductive dechlorination processes. In an effort to gather direct evidence of these processes, scientists have identified key microorganisms and are currently developing tools to measure the abundance and activity of these organisms in subsurface systems. The research presented in this paper continues the development efforts to provide a suite of tools to enable direct measures of biological processes related to the reductive dechlorination of TCE and PCE. The study investigated the strengths and weaknesses of the 16S rRNA gene-based approach to characterizing natural attenuation capabilities in samples. The results suggest that an approach based solely on 16S rRNA may not provide sufficient information to document the natural attenuation capabilities in a system because it does not distinguish between strains of organisms that have different biodegradation capabilities. The results of the investigations provided evidence that tools focusing on relevant enzymes for functionally desired characteristics may be useful adjuncts to the 16SrRNA methods. http://www.osti.gov/bridge/product.biblio.jsp?query_id=8&page=0&osti_id=898370