HGL Geology CoP Presents: Passive Soil Gas Sampling with James Landmeyer, USGS

Sponsoring Organization

HydroGeoLogic, Inc. Geology Community of Practice

Sponsor Website

https://www.hgl.com/hgl-endeavors/blog-5-1-2026-cultivating-communities-of-practice

Activity Date

August 27, 2026

Activity Availability

not-repeated

Delivery Type

online-live

Hours Approved

1.0

Course Description

James will be presenting on the following: A unique, passive sampler containing multiple adsorbent traps to target a broad range of compounds with high sensitivity was developed for use in trees. The sampler comprises a series of sorbent cartridges that are inserted in a particular tree for a specified length of time to collect a time-integrated measurement over days or weeks. These passive samplers were tested for proof-of-concept at two field sites. One site is located near Pensacola, FL, and is characterized by TCE-contaminated groundwater. Mature live oaks grow above the plume of TCE. The second site is located near Charleston, SC, and is characterized by BTEXand PAH-contaminated groundwater. A grove of hybrid poplar trees was planted over the contamination in 1998. At each site, a small-diameter hole was drilled in 10 representative trees, a passive sampler was installed, and the hole was plugged. Installation of the samplers required basic hand tools and was accomplished within minutes at each tree. The samplers were retrieved within 14 days and retrieval was rapid. The samples were then sent to the laboratory for analyses by thermal desorption-GC/MS following EPA Method 8260C. No ice or preservatives are required during transport and the samplers have a 30-day hold time requirement, which makes the method well suited for international applications, as well. Results are reported in nanograms of specific compounds or compound groups per sample.