USGS Scientific Investigations Report 2008-5088
Prepared in cooperation with the U.S. Environmental Protection Agency
Measurement and Monitoring for the 21st Century Initiative
By Don A. Vroblesky
U.S. Geological Survey Scientific Investigations Report 2008-5088, 59 pages (Published online, July 2008)
This report is available online in PDF format:
SIR 2008-5088 (
) (2.6 MB)
Analysis of the volatile organic compound content of tree
cores is an inexpensive, rapid, simple approach to examining
the distribution of subsurface volatile organic compound
contaminants. The method has been shown to detect several
volatile petroleum hydrocarbons and chlorinated aliphatic
compounds associated with vapor intrusion and ground-water
contamination. Tree cores, which are approximately 3 inches
long, are obtained by using an increment borer. The cores
are placed in vials and sealed. After a period of equilibration,
the cores can be analyzed by headspace analysis gas chromatography.
Because the roots are exposed to volatile organic
compound contamination in the unsaturated zone or shallow
ground water, the volatile organic compound concentrations in
the tree cores are an indication of the presence of subsurface
volatile organic compound contamination. Thus, tree coring
can be used to detect and map subsurface volatile organic
compound contamination. For comparison of tree-core data at
a particular site, it is important to maintain consistent methods
for all aspects of tree-core collection, handling, and analysis.
Factors affecting the volatile organic compound concentrations
in tree cores include the type of volatile organic compound,
the tree species, the rooting depth, ground-water chemistry,
the depth to the contaminated horizon, concentration differences
around the trunk related to variations in the distribution
of subsurface volatile organic compounds, concentration
differences with depth of coring related to volatilization loss
through the bark and possibly other unknown factors, dilution
by rain, seasonal influences, sorption, vapor-exchange rates,
and within-tree volatile organic compound degradation.
Abstract
Introduction
Advantages of Tree Coring as a Tool to Examine Subsurface Volatile Organic Compound Concentrations
Limitations of Tree Coring as a Tool to Examine Subsurface Volatile Organic Compound Concentrations
Acknowledgments
Part 1. Methodology for Collection and Analysis of Tree Cores
Tree-Core Collection
Tree-Core Analysis
Quality Control and Assurance
Part 2. Historical Perspectives and Technical Considerations
Historical Perspectives
Technical Rationale for Methodology
Factors Influencing Volatile Organic Compound Concentrations in Tree Cores
Summary
References Cited
Appendix 1. Case Studies
Appendix 2. Air Sample Analysis for Volatile Organic Compounds
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Suggested citation: Vroblesky, D.A., 2008, User’s guide to the collection and analysis of tree cores to assess the distribution of subsurface volatile organic compounds: U.S. Geological Survey Scientific Investigations Report 2008–5088, 59 p. (available online at http://pubs.water.usgs.gov/sir2008-5088)
For more information, please contact Don A. Vroblesky.
U.S. Department of the Interior |
U.S. Geological Survey
Persistent URL: http://pubs.water.usgs.gov/sir2008-5088
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