A large number of defense-related sites are contaminated with elevated levels of secondary explosives. Levels of contamination range from barely detectable to levels above 10% that need special handling due to the detonation potential. Characterization of explosives-contaminated sites is particularly difficult due to the very heterogeneous distribution of contamkdion in the environment and within samples. To improve site characterization, several options exist including collecting more samples, providing on-site analytical data to help direct the investigation, compositing samples, improving homogenization of samples, and extracting larger samples. On-site analytical methods are essential to more economical and improved characterization. On-site methods might suffer in terms of precision and accuracy, but this is more than ' TheU.S. Environmental Protection Agency @PA), through its Office of Research and Development, funded this research and approved the abstrad as a basis for an oral presentation. The actual presentation has not been peer reviewed by EPA. Mention of trade names or commercial products does not constitute endorsement or recommendation for use. P DISCLAIMER Portions of this document may be illegible in electronic image products. Images are produced from the best available original document. DISCLAIMER This report was prepared as an account of work sponsored by an agency of the United States Government. Neither the United States Government nor any agency thereof, nor any of their employees, makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. Reference herein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise does not necessarily constitute or imply its endorsement, mommendation, or favoring by the United States Government or any agency thereof. The views and opinions of authors exptessed herein do not necessarily state or reflect those of the United States Government or any agency thereof. I Moditications to on-site methods may be able to improve method performance. In most cases, a larger soil sample can be extracted to improve the representativeness of the analytical sample. Also, with heavy soils or soils with high organic matter contenf it may be useful to conduct a short-term kinetic study to determine whether a 3-minute extraction period is adequate. It is recommended that the shakinglextraction phase of all methods last at least 3 minutes. In all cases, it is recommended that a portion of the on-site analytical results be cmfirmed using a standard laboratory method.