August 29, 2016

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Geosyntec Assigned Patent for Passive Soil Vapor Sampling Device and Method of Sampling and Analysis

Todd McAlary (Ontario) and his co-inventors from the University of Waterloo, Dr. Tadeusz Górecki and Dr. Suresh Seethapathy, were recently named inventors of a passive sampling device and method of sampling and analysis by the United States Patent and Trademark office.

The invention provides a device, named the Waterloo Membrane SamplerTM (WMSTM), and a method to quantitatively measure concentrations of volatile organic compound vapors below the ground surface using a passive device that is placed in a drilled or bored hole for a specified period of time, wherein the sampler constrains the uptake rate to match values that minimize or eliminate the starvation effect and provide acceptable sensitivity for most soil types as calculated via mathematical models.

The theory supporting the invention was proven with transient and steady-state mathematical models, controlled laboratory experiments and field testing. In addition to this patent, the work resulted in five publications in peer-reviewed journals, and a Ph.D. for Dr. McAlary.

Until recently, regulatory guidance documents had said that passive soil gas sampling can only be used to measure relative proportions between compounds and locations, and not for quantitative concentration measurements, so this represents a significant breakthrough.

More Information

For more information regarding the WMSTM patent, visit the full text in the USPTO Patent Full Text and Image.
For more information about SiREM:
For more information on the Waterloo Membrane SamplerTM, contact Todd McAlary at This email address is being protected from spambots. You need JavaScript enabled to view it. or Hester Groenevelt at This email address is being protected from spambots. You need JavaScript enabled to view it..