GRA 1997 Seminar: Innovative Soil Gas Monitoring and Remediation Applications The GRA along with the Cal/EPA/Department of Toxic Substances Control cosponsored two, one day seminars on Innovative Soil Gas Monitoring and Remediation Applications this past September as part of their 1997 Seminar Series. Course instructors for the seminar were Dr. Donn L. Marrin, Consulting and Research Scientist; Dr. Harold W. Bentley, President of Hydro Geo Chem Inc.; and Mr. Craig Cooper, Superfund Project Manager for United States Environmental Protection Agency (USEPA). Topics covered by the course instructors included the following: Overview of Soil Gas Sampling and Analysis Applicability of Soil Gas vs. Soil Analyses Estimating Site Volatile Organic Compound (VOC) Mass Distribution Cleanup Objectives and Site Closure Criteria Monitoring Intrinsic Biodegradation and Vapor Flux for Site Closure Soil Gas Techniques to Support RI Process Monitoring of In-Situ Remediation Specific points presented during the seminar consisted of the following items. The instructors encouraged the use of soil gas sampling alone or in combination with soil matrix sampling. Soil gas sampling for VOCs at depths 5 feet or less was not recommended, because the majority of the VOCs would have volatilized. Deeper sample depths were recommended. For coarse-grained soils, soil gas samples were preferred over soil matrix samples. The rationale provided was that contaminants did not readily sorb to the coarse grained soil matrix and an area would be construed as not impacted if solely based on soil matrix samples. Soil gas samples would be able to detect these contaminants in coarse grained samples and would permit the investigator to better assess if contaminants had reached groundwater. Soil gas techniques are an under used tool that should be considered beyond the site characterization phase of a field program. Soil gas techniques can be used for monitoring the effectiveness of remediation and assess natural biodegradation at a site. Soil gas monitoring techniques should be considered when developing operation and maintenance programs for sites being remediated. These are just some of the items discussed during the seminar. We still have some extra Seminar Manuals available. Individuals interested in a copy can purchase it for $40 from GRA. Please send your requests, along with your name, mailing address and payment to: GRA Soil Gas Seminar Manual P.O. Box 1446 Sacramento, CA 95812 Please make checks payable to Groundwater Resources Association. Orders will not be processed without payment. Funds acquired from the sale of these manuals will be used to help offset costs for future seminars so that we may provide you with high quality seminars at the most economical prices. GRA greatly appreciates the presentations provided by Dr. Marrin, Dr. Bentley, and Mr. Cooper. We thank them for making time in their busy schedules to prepare course handouts and give their presentations. We thank McClellan Air Force Base Environmental Management Directorate for letting us use their facilities in northern California. We thank InterPhase Environmental, Inc. for handling registration and for sponsoring travel and lodging for seminar instructors. Lastly, we thank those individuals behind the scenes who undertook the necessary effort to assure these seminars were a success. Keep your eyes open for our 1998 Seminar Series. We are always receptive for suggestions on future seminars.