Page 304 - gas transport in porous media

CHAPTER 18

MEASUREMENT OF VAPOR CONCENTRATIONS

CLIFFORD K. HO, MICHAEL KELLY, AND MICHAEL T. ITAMURA
Sandia National Laboratories, P.O. Box 5800, Albuquerque, NM 87185, USA

18.1 INTRODUCTION

The measurement of vapor-phase concentrations is important in environmental appli-
cations ranging from preliminary site characterization to long-term environmental
monitoring and stewardship. Characterizing the extent and potential migration of sub-
surface volatile organic compounds and other vapor-phase contaminants is needed
to address regulatory metrics and to ensure public safety. Current methods of con-
taminant characterization rely on manual soil and groundwater sampling, which is
costly and time consuming. This chapter reviews several technologies that are used to
measure vapor-phase concentrations of volatile organic compounds, as well as their
potential to be used for continuous in-situ applications.

18.1.1 Background and Scope
Numerous sites containing toxic chemical spills, leaking underground storage tanks,
and chemical waste dumps require accurate characterization and long-term moni-
toring to reduce health risks and ensure public safety. In addition, over two million
underground storage tanks containing hazardous (and often volatile) contaminants are
being regulated by the United States Environmental Protection Agency (U.S. EPA,
1992), and the tanks require some form of monitoring to detect leaks from the tanks
and pipe network. However, current methods are costly and time-intensive, and lim-
itations in sampling and analytical techniques exist. Looney and Falta (2000, Ch. 4)
report that the Department of Energy (DOE) Savannah River Site requires manual
collection of nearly 40,000 groundwater samples per year, which can cost between
$100 to $1,000 per sample for off-site analysis. Wilson et al. (1995, Ch. 36) report
that as much as 80% of the costs associated with site characterization and cleanup of
a Superfund site can be attributed to laboratory analyses. In addition, the integrity of
the analyses can be compromised during sample collection, transport, and storage.
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C. Ho and S. Webb (eds.), Gas Transport in Porous Media, 303–318.
© 2006 Springer.