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Topic:  Advanced Methods for Mass Flux Characterization in NAPL Zones

Speaker:  Michael Gefell, PG, CPG, Principal Scientist, Anchor QEA, LLC

Time: Tuesday, January 8, 11:30am-1pm

Location: PLEASE note the change of location for this meeting.  CEMS will be meeting at Davis Graham & Stubbs LLP, 1550 17th Street, Suite 500 (5th Floor), Denver, CO 80202. When entering the building, please proceed to the fifth floor to register with the CEMS representative.

CEMS has received one (1) CLE for this presentation  

At nonaqueous phase liquid (NAPL) sites, including petroleum facilities, manufactured gas plants, and wood-treating sites, NAPL mobility and aqueous-phase concentrations emanating from NAPL zones directly affect mass flux, risk and remedial design. These considerations are particularly important when NAPL is present in sensitive ecological settings such as sub-aqueous sediment and shoreline areas, but they also apply to NAPL zones farther upland. NAPL effective hydraulic conductivity (Kn) strongly affects NAPL mobility and can be estimated based on laboratory NAPL mobility tests. These tests impose hydraulic gradients orders of magnitude stronger than those that exist in situ. If NAPL in a given test sample is immobile under these test conditions, that NAPL is also immobile in the field. If NAPL is mobilized during laboratory tests, multiple lines of evidence should be used to interpret whether the NAPL is above or below the residual saturation under field conditions. NAPL movement during a laboratory test can be used to quantify Kn and significantly improve the conceptual site model. Kn values at some sites are so low that the NAPL is functionally immobile even if it is above the residual saturation. If NAPL is immobile or can be contained by an engineered remedy, aqueous chemical concentrations and fluxes drive risk and remedial needs. However, measuring dissolved chemical concentrations in a NAPL zone is challenging. Any NAPL mass included in a water sample or adhered to a passive hydrophobic sampler is included in the reported aqueous concentration, thereby overstating actual aqueous concentrations. Porous, hydrophilic, ceramic capillary barriers can be used to exclude NAPL and collect representative porewater and groundwater samples by diffusion or pumping, even in direct contact with NAPL. In combination, the methods presented herein significantly advance our ability to quantify mass flux associated with NAPL zones.

Michael Gefell, PG, CPG, is a principal scientist at Anchor QEA, LLC. He holds a BA in geological sciences from Cornell University and an MS in geology from the University of California–Davis. Mr. Gefell has more than 29 years of experience in environmental site assessment and remediation. His primary areas of interest include quantitative hydrogeology, NAPL mobility assessment, groundwater/surface water interaction, fractured bedrock, innovative site characterization methods, modeling, and remedial design. He is the Technology Spotlight editor and an associate editor of Groundwater journal and received the 2013 Technology Award from the National Ground Water Association.

CEMS January 2019 presentation notes

CEMS January 2019 Presentation notes with note space

Location: PLEASE note the change of location for this January meeting.  CEMS will be meeting at Davis Graham & Stubbs LLP, 1550 17th Street, Suite 500 (5th Floor), Denver, CO 80202. When entering the building, please proceed to the fifth floor to register with the CEMS representative.

MEETING FORMAT: Members may either bring their own lunch and attend the meeting for no charge, or they may request that CEMS order a box lunch for them. The cost of the box lunch for members is $16.00; for non-members, $19.00.

RESERVATIONS: PLEASE give your name, company name and phone number via email to admin@coems.org. PLEASE INDICATE IF YOU ARE RESERVING A BOX LUNCH OR BRINGING YOUR OWN. Reservations must be received BEFORE Friday, January 4, 2019 at 5:00PM. No reservations will be taken after this date! Payment of $16.00 for members, $19.00 for non-members will be accepted at the door with prior reservation. Please cancel your reservation by Friday, January 4, 2019 if you are unable to attend. It is the policy of the Society to bill for meals reserved but unclaimed. You may also pay with credit card via PAYPAL below:

Box Lunch