Phil Dennis, (Ontario) will present “Combining Molecular Tools and Compound-Specific Isotope Analysis for Natural Attenuation Assessment” at SMART Remediation Conference at the Ottawa Conference and Event Centre in Ottawa, Ontario, on April 7, 2022.

Phil’s co-presenters are Silvia Mancini, Ph.D., Julie Konzuk, Ph.D., & Carol Cheyne (Geosyntec Consultants, ON); and Anko Fischer, Ph.D., & Kevin Kuntze, Ph.D. (Isodetect GmbH, Germany).

Phil is a Principal Molecular Biologist with more than 20 years of experience focused environmental microbiology, molecular genetic testing, enhanced bioremediation and technology commercialization. He currently directs the molecular testing services, next generation sequencing and is the innovation lead for SiREM’s research and development program. He has also played a leading role in developing relationships with many universities and serves on the Board for University of Waterloo Center for Microbial Research.

SiREM once again is proud to sponsor this event.

Smart Methods in Advanced Remediation Technologies (SMART) is a series of technical learning seminars for environmental professionals where our goal is to bring the North American environmental community together to enhance our collective understanding of cutting-edge characterization and remediation technologies. This year a series of four webinars to be held on each Thursday in February: 4th, 11th, 18th and 25th, 2021. Each webinar will be approximately 2 hours long and will be followed by an optional virtual networking/Q&A opportunity for attendees.

SMART is a series of technical learning seminars for environmental professionals and designed with the following in mind:

  • To provide information and an opportunity to learn about advanced technologies and approaches for effective delineation and remediation of contaminated soil and groundwater
  • To facilitate discussion between professionals regarding these technologies and approaches
  • To network with other professionals in the industry

The goal is to bring the North American environmental community together to enhance the collective understanding of cutting-edge characterization and remediation technologies.

With ongoing changes in regulations and requirements, all environmental professionals need to be up to date on the latest strides in SMART Remediation.

The founder of SMART, Vertex Environmental has grown to become one of the largest environmental remediation firms in Canada. They have successfully completed hundreds of remediation projects across Canada and internationally. Specializing in solving soil and water contamination issues, we offer a wide range of services, including site evaluations, along with designing and implementing various remedial solutions. They not only have the experience to resolve environmental concerns, but also the commitment to provide great service.


Assessing natural attenuation potential, progress and degradation rates is critical for decision making regarding the feasibility of monitored natural attenuation (MNA) remedies for sites with chlorinated solvents, petroleum hydrocarbons, 1,4-dioxane, and other contaminants. While numerous tests are employed in evaluating natural attenuation, the combination of compound-specific isotope analysis (CSIA) and molecular tools can be particularly useful. CSIA indicates the extent of degradation and quantifies bond breaking processes over non-degradative losses such as sorption. CSIA also has the potential for estimating long-term degradation rates. Molecular tools, including quantitative polymerase chain reaction (qPCR) tests and next generation sequencing (NGS) that quantify key biodegradative microorganisms, functional genes and whole microbial communities, provide insight into whether observed degradation can be explained by biotic processes. CSIA and molecular tools are tertiary lines of evidence in MNA protocols, and provide compelling data to answer the questions (1) Has degradation occurred and to what extent? and (2) Which microbes are responsible for any observed biodegradation?

This presentation will provide examples of where CSIA and molecular genetic data were collected from several sites undergoing MNA assessments. The CSIA data (mainly for carbon: 13C/12C as δ13C, was used to determine if contaminant degradation processes were evident, or absent, based on enrichment of the heavy isotope in the remaining undegraded contaminant fraction. Corresponding molecular genetic data, including qPCR was used to determine if biodegradative microbes were present, and at quantities able to meaningfully impact contaminant degradation.  In several cases, CSIA and molecular genetic testing data indicated natural attenuation processes were occurring and clarified complex biotic and abiotic remediation processes. At a site in Alaska, trichloroethene to cis-1,2-dichloroethene (cDCE) degradation was conclusively confirmed by CSIA but further cDCE degradation by reductive or oxidative processes was inconclusive. By correlating the extent of 13C-enrichment in cDCE with the proportion of dechlorinators as determined by molecular tools the case for natural attenuation of cDCE was more compelling. At and industrial site, downgradient detections of 1,2-DCA and PCE were attributed to production of these compounds, from breakdown of 1,1,2-TCA and pentachloroethane respectively, and not transport of 1,2-DCA and PCE from the source zone. At a site in Denmark a complex combination of reductive dechlorination abiotic degradation by iron sulfides and aerobic bioremediation was indicated by CSIA and molecular data.

Overall, the combination of CSIA and molecular tools allows conclusions to be drawn on natural attenuation processes that are not easily arrived at by using other analytical methods.

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About the event: SMART Remediation
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