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April 23, 2019

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Todd McAlary's Report Entitled "Demonstration/Validation of More Cost-Effective Methods for Mitigating Radon and VOC Subsurface Vapor Intrusion to Indoor Air" Published by SERDP/ESTCP

Todd McAlary, Ph.D., P.Eng., P.G. (Ontario) authored a report entitled "Demonstration/Validation of More Cost-Effective Methods for Mitigating Radon and Volatile Organic Compounds (VOC) Subsurface Vapor Intrusion to Indoor Air" published by the Strategic Environmental Research and Development Program (SERDP)/ Environmental Security Technology Certification Program (ESTCP) in March 2019.

Todd is a Senior Principal Engineer with more than 30 years of international consulting experience focused on the evaluation of contaminant fate and transport in soil and groundwater. He has been the Practice Leader for Vapor Intrusion services at Geosyntec since 1998. Todd co-authored the first technical publication demonstrating the potential for enhanced groundwater contamination attributable to vapor diffusion in 1989 and co-authored the U.S. EPA's first vapor intrusion (VI) guidance document in 2001 and has since conducted site-specific assessments of VI at hundreds of sites throughout the world.  He is an Adjunct Professor at the University of Toronto and has taught undergraduates part-time for 16 years.

This applied research project demonstrated several new lines of evidence for monitoring the performance of subslab venting systems, including: vacuum vs. time, vacuum vs. distance, inter-well tracer testing, tracer floods, mass flux monitoring, and mathematical modeling using a modified Hantush-Jacob Leaky Aquifer Model. The objectives of the project were to demonstrate and validate a more technically advanced process for the design and optimization of subslab venting systems for protecting indoor air from radon and volatile organic compounds in the subsurface. The study found that for large buildings, these approaches can provide net present value savings approximately ten times higher than the incremental costs of the additional lines of evidence. This work was directed by Todd of Geosyntec. Key team members include William Wertz, Darius Mali and Paul Nicholson.

ESTCP is U.S. Department of Defense's environmental technology demonstration and validation program. The Program was established in 1995 to promote the transfer of innovative technologies that have successfully established proof of concept to field or production use. ESTCP demonstrations collect cost and performance data to overcome the barriers to employ an innovative technology because of concerns regarding technical or programmatic risk, the so-called "Valley of Death."  ESTCP has funded three vapor intrusion research projects by Geosyntec: ER200830, ER201322 and ER201503.

More Information

Learn more about the article: https://www.serdp-estcp.org/Program-Areas/Environmental-Restoration/Contaminated-Groundwater/Emerging-Issues/ER-201322/ER-201322
For consultation regarding cost-effective methods for mitigating radon and VOC subsurface vapor intrusion, contact Todd McAlary at This email address is being protected from spambots. You need JavaScript enabled to view it..
Learn more about Todd at: https://www.geosyntec.com/people/todd-mcalary