Waterloo Membrane Sampler: Ongoing Research of Passive Air Sampling at Refineries & Comparison to Continuous Monitoring Results



Passive sampling has been growing in popularity for the measurement of volatile organic compounds (VOCs) in ambient air due to lower costs, simpler sampling protocols and ease of deployment; with applications ranging from indoor/outdoor air quality and soil vapor intrusion assessments. Many passive sampling devices have been developed including polyurethane foam disks, permeation devices, solid phase micro-extraction (SPME) fibers and thermal desorption (TD) tubes packed with sorbent materials. The Waterloo Membrane SamplerTM (WMSTM) is a passive permeation sampler which use a thin layer of polydimethylsiloxane across the face of a vial filled with sorbent medium, which provides additional advantages such as a high resistance to water vapor and the ability to predict uptake rates for virtually any VOC, thus making it a good candidate for long term urban air sampling campaigns. Modifications to the traditional WMSTM design incorporating either a thermally-desorbable (TD) sorbent packet or thin-film SPME sorbent for ease of detection/quantitation by TD-gas chromatography-mass spectrometry (TD-GC-MS) provide potential benefits compared to traditional TD tubes (EPA Method TO-17) or Summa canisters (EPA Method TO-15). SiREM has recently been conducting applied research in collaboration with the Ontario Ministry of Environment, Conservation and Parks (MECP) at their road-side research station adjacent to Highway 401 in Toronto, Canada for VOCs. Preliminary resuls will be discussed and directly compared to TD-tubes and continuous monitoring results.

The Presenters:

Todd McAlary

Dr. Todd McAlary 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. Todd specializes in assessing and mitigating the migration of volatile organic compound (VOC) vapor from the sub-surface environment into buildings and in the assessment of human health risks associated with inhalation exposure. He co-authored the first U.S. EPA guidance document on Vapor Intrusion (VI) in 2001 and has been a leading researcher in the field ever since. He has developed several technologies to avoid common challenges with conventional VI assessments (spatial and temporal variability and background sources of VOCs), including Passive Sampling, High Volume Sampling, Building Pressure Cycling, Tracer Testing, Mathematical Modeling and Isotope Analysis. Todd provides technical consultation to clients in support of litigation involving several VI challenges and is a technical specialist in regulatory negotiations involving groundwater contamination and VI issues where his expertise and communication skills have been critical to stakeholder understanding of the complex nature of the topics. He is also an Adjunct Professor a the University of Toronto, where he has taught over 3,800 undergraduate students in Chemical Engineering.

Brent Pautler

Dr. Brent Pautler is the Customer Service Coordinator at SiREM and an environmental analytical chemist with advanced technical experience in passive sampling, spectroscopy, chromatography, mass spectrometry and chemistry informatics. Throughout his career he has been dedicated to working with scientists, engineers and consultants, applying his chemistry and information technology expertise to help them solve unique problems both in the laboratory and the field. He is the lead contact at SiREM for passive sampling products and services for sediment pore and surface waters (SP3TM, SPeepersTM), the Waterloo Membrane Sampler (WMS)TM and the KB-1® bioaugmentation cultures.