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Memorandum • <br /> May 6, 04 <br /> David Jenkins - <br /> Environmental Protection Agency <br /> California Regional Water Quality Control Board <br /> Central Valley Region _ <br /> 3443 Routier Road, Suite A - <br /> Sacramento, California 95827-3098 <br /> r` <br /> Upcoming Activities <br /> at the Alden Park Site <br /> Tracy, California <br /> This letter is a follow up to our meeting on April 20th. In that meeting you <br /> asked for a final copy of the results from our as round of ground water <br /> sampling at Alden Park, and a schedule for the upcoming events at the site. <br /> Ground Water Analytical Results <br /> Attached is a complete copy of the ground water sampling results, including a <br /> letter report from Dames and Moore describing their field procedures. All of <br /> the samples were analyzed for Aromatic Volatile Organics (EPA 602/SW <br /> 8020A), Semi-Volatile Organics (EPA 8270), and TPH-Waste Oil (EPA 8015 <br /> Modified). There was some question at our meeting about whether they had run <br /> Oil and Grease instead of TPH. The EPA 8015 Modified method that the lab ran <br /> is a full GC-FID scan, as opposed to a simple test for oil and grease. It reports <br /> TPH in the waste oil range, instead of the gasoline or diesel range that is more <br /> commonly reported for Underground Storage Tank sites. Based on past sampling <br /> work, we knew that the hydrocarbons at the Alden Park site fall in the "waste <br /> oil" range of the TPH chromatogram, rather than in the lighter end of GC run. <br /> We therefore felt that TPH-waste oil was the most appropriate method for <br /> Alden Park. <br /> Table A summarizes the results of the lab analysis. All samples were non <br /> detect for both BTEX components and for TPH-w. The only semi-volatile <br /> detected was Bis(2-ethylhexyl)phthalate. It appeared in several samples at <br /> levels close to the detection limit. Bis(2-ethylhexyl)phthalate has not been <br /> detected at Alden Park in the past, and is a common lab contaminant (see the <br /> comments' section on the lab data sheets). <br /> Free Product Recovery <br /> Also attached is a memo from our field technician, outlining the results of our <br /> program to remove hydrocarbons from MW-1, MW-3, MW-15, and MW-16. As you <br /> may recall, the results of an earlier test by Dames and Moore indicated that the <br /> sustained recovery rate of hydrocarbons by pumping the wells would be less ° " ~ <br /> than .003 gpm. At the meeting, we proposed continuing to handbaonths.the free <br /> ix <br /> product from these four wells, on a weekly basis, for the next sm <br /> Based on the data gathered during that period, we will reevaluate the success <br /> of the bailing program, discuss the results with you, and determine if a full <br /> time pumping system is warranted. We realize that, regardless of the results <br />