Gary Wealthall is a Senior Principal Hydrogeologist based in Toronto with more than 20 years of experience focused on contaminant hydrogeology research and practice. He advises regulatory authorities and clients in the chemical, waste disposal, land development, and insurance industries.
Specializing in the development and application of high-resolution site characterization methodologies for dense non-aqueous phase liquids (DNAPLs) in fractured bedrock aquifers and aquitards and in shallow, intergranular aquifers, Gary has been a project manager or project director on numerous DNAPL remediation projects for clients in North America, South America, and Europe. Also, Gary developed a Technology Evaluation Screening Tool to implement guidance from the U.S. Department of Defense's Environmental Security Technology Certification Program to optimize remedial selection at chlorinated solvent DNAPL sites. His experience at a coal tar DNAPL site in New Jersey included the use of state-of-the-art 3D visualization and analysis techniques and demonstrated that the original volume estimate of soils requiring treatment could be halved, saving the client more than $20 million in remediation costs.
As a Principal Researcher with the British Geological Survey in the United Kingdom, Gary led a team that focused on the application of process-based research to advance conceptual understanding of the behavior of DNAPLs in heterogeneous geological systems. He also examined the impacts of dewatering on the management of an unlined landfill site in a faulted mudrock sequence. His research studies during his tenure as a Research Fellow at the University of Sheffield included modeling and a field investigation of the fate and transport of petroleum hydrocarbons in a fractured double-porosity aquifer. As part of this work, he established a revised conceptual model for light non-aqueous phase liquid (LNAPL) migration in fractured bedrock and applied it to a site impacted by MTBE. Gary played a pivotal role in the investigations of the fate and transport of chlorinated solvents in Permo-Triassic sandstones, leading to a new model for DNAPL behavior based on the discovery of extensive sediment fills in fractures.
To advance the state of the practice, Gary continues to publish numerous articles on the fate and transport of DNAPL in aquifers and aquitards. He also is the co-author of a widely cited illustrated handbook on DNAPL fate and transport for the UK Environment Agency and is currently co-authoring a LNAPL guidance document. He has delivered invited, sponsored lectures and professional short courses across five continents and also has served as an external examiner for Ph.D. candidates at the Universities of Cambridge, Edinburgh, and Western Australia. He recently joined the faculty at the University of Guelph as an Adjunct Professor, for the university's fractured bedrock course.