Using a gas-phase tracer test to characterize the impact of landfill gas generation on advective-dispersive transport of VOCs in the vadose zone

Gregg R. Monger, Candice Morrison Duncan, Mark L. Brusseau

Research output: Contribution to journalArticle

1 Scopus citations


A gas-phase tracer test (GTT) was conducted at a landfill in Tucson, AZ, to help elucidate the impact of landfill gas generation on the transport and fate of chlorinated aliphatic volatile organic contaminants (VOCs). Sulfur hexafluoride (SF6) was used as the nonreactive gas tracer. Gas samples were collected from a multiport monitoring well located 15.2 m from the injection well and analyzed for SF6, CH4, CO2, and VOCs. The travel times determined for SF6 from the tracer test are approximately two to ten times smaller than estimated travel times that incorporate transport by only gas-phase diffusion. In addition, significant concentrations of CH4 and CO2 were measured, indicating production of landfill gas. Based on these results, it is hypothesized that the enhanced rates of transport observed for SF6 are caused by advective transport associated with landfill gas generation. The rates of transport varied vertically, which is attributed to multiple factors including spatial variability of water content, refuse mass, refuse permeability, and gas generation.

Original languageEnglish (US)
Article number2226
JournalWater, Air, and Soil Pollution
Issue number12
StatePublished - Dec 2014



  • Gas tracer test
  • Gas-phase transport
  • Landfill gas generation
  • VOCs

ASJC Scopus subject areas

  • Environmental Engineering
  • Environmental Chemistry
  • Ecological Modeling
  • Water Science and Technology
  • Pollution

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