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Y <br /> Herding Lawson Associates <br /> June 17, 1988 <br /> 4167,218-02 <br /> Mr, James M. Kerr, Jr., P.G. <br /> Exxon Company, USA <br /> Page 2 <br /> the present owner regarding the tests or an application for the repair <br /> work. The County then informed FLA that due to the unauthorized work <br /> being performed, the drilling permits would not be authorized until a <br /> detailed work plan addressing the failed tank test was sutmitted. <br /> On May 27, 1988, an FLA representative visited the site. At that time, <br /> the asphalt concrete and backfill material was removed above the regular <br /> gasoline tank. According to station personnel, several sections of the <br /> vapor return lines had been replaced. Pb obvious signs of contamination <br /> was observed in the excavation or backfill material removed from the exca- <br /> vation. <br /> Based on conversations with Walton Engineering, it is our understanding <br /> that all repair work has been completed, the excavation backfilled, and <br /> the site repaved. <br /> DISCUSSION <br /> At the present time, FLA is unable to evaluate if a release of petroleum <br /> hydrocarbons has occurred at the site. It is recommended that due to the <br /> recent repairs performed at the site, the age of the tanks, and the sen- <br /> sitive nature of the local ground-water aquifers, an investigation be <br /> performed at the site to evaluate if the soil and ground-water quality <br /> has been impacted. If contamination is discovered during this investiga- <br /> tion, then state regulations require that further site work be conducted <br /> to evaluate the extent and magnitude of petroleum contamination. Depend- <br /> ing on actual site conditions, up to three phases could be implemented. <br /> A description of these phases and a cost range for each is detailed below. <br /> Phase <br /> - Evaluate surrounding area for other potential contamination sources <br /> - Drill three to five soil borings to a maximum depth of 45 feet and <br /> collect soil samples <br /> - If ground water is encountered above 45 feet, convert three of the <br /> borings to monitoring wells <br /> - Calculate hydraulic gradient <br /> - Drill and install a fourth monitoring well if required <br />