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• 13 December 1995 AGE-NC Project No. 95-0109 Page 3 of 8 Selected soil and ground water samples will be analyzed for total petroleum hydrocarbons quantified as gasoline (TPH-g) and volatile aromatics (benzene, toluene, ethyl benzene, and xylene: BTE&X) in accordance with EPA methods 8015/5030 and 8020/602, respectively. Laboratory reports of both soil and ground water analyses, testing methods, laboratory quality assurance/quality control (QA/QC)reports, and sample chain of custody documentation will be presented in a report with the findings and recommendations. Additionally, selected soil and ground water samples will be transmitted to A. Keith Kaufman for physicochemical analysis and microbiological enumeration. 3.2. ADDITION OF NUTRIENTS TO SOIL Laboratory testing of soil samples collected from throughout the site has indicated that certain subsurface areas at the site are now deficient in nitrogen, which is necessary for microbial degradation. Other nutrients, such as phosphate and potassium, appear to be present throughout the site in sufficient concentrations to support microbial growth. The addition of ammonium nitrate will provide a source of nitrogen to supplement naturally-occurring nitrogen at the site. Nutrients will be added to soil only in areas with the greatest benzene concentration. Figures showing benzene concentrations in soil at several depth intervals on-site are included in Attachment B. Based upon past experience and laboratory analysis of soil samples, total nitrogen concentrations (both oxidized and reduced) should be approximately 10% of the average hydrocarbon (TPH) concentration to support maximum microbial growth. Specific areas to be targeted with the addition of nutrient are north of remediation wells VW-5 and VW-6. Nutrients will be injected into the subsurface using temporary, small-diameter wells, drilled to the targeted"zone" of impacted soil. The ammonium nitrate, in a liquid form, will be added directly into the temporary injection. Upon completion of the nutrient addition, the temporary casing will be removed and the borehole grouted to the surface. Soil samples will be collected during the quarter following the addition of the nutrients and analyzed at a microbiological laboratory to evaluate the concentration of total nitrogen. 3.3. ADDITION OF NUTRIENTS OF GROUND WATER Laboratory results from the November ground water sampling event indicate a decrease in organic nutrients in most wells. The decrease includes reduced levels of oxidized and reduced nitrogen,