SITE INFORMATION AND CORRESPONDENCE

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517 West Fremont Street y Page l of 2 ( Nuel Henderson [EH] From : bill [wlittle@advgeoenv.com] Sent: Friday, September 28, 2007 12:34 PM To : Frank Girardi [EH] Cc: Nuel Henderson [EH] i Subject: 517 West Fremont Street Attachments: Guardino Well Design 0907.pdf; Guardino SITE PLAN FIGURE 2 0907.pdf Mr. Frank Girardi: AGE has reviewed the letter sent to the Responsible Party the Guardinos for the property at 517 West Fremont Street and provides the following comments. AGE reviewed the underground storage tank report from your office and determine the release occurred at the former fuel dispensing island at the eastern edge of the building (EHD letter dated 27 March 1996 and 27 June 2006). AGE has performed assessment at the location and surrounding the area utilizing geoprobe borings . The values of PID, field screening observations, analytic data and soil type indicated the release did occurred at the fuel dispensing island : The pipe line #3 sample (dispenser) contained 700 mg/kg of TPH and UST sample contained 68 mg/kg of TPH ; associated BTEX values were also greatest the former fuel dispenser; PID values from the soil samples were most consistently greater at the former fuel dispenser island boring P3 (5 feet - 922, 10 feet - 425, 20 feet 355) as compared to boring MW-1 (5 feet - 293 , 10 feet - 560 , 15 feet - 679 and 20 feet - 1 .6). The lack of sampling at boring P3 at a depth of 15 feet was due to sand and 15 feet represents the ground water table level ; a ground water sample collected from boring P8 contained the second greatest TPH and BTEX values detected on the site (second to boring P6 to be discussed later). The highest mass is concentrated at the former fuel dispenser located near boring P3 and P8 . Secondary impacted soil is present under the current water table at depth greater than 15 feet or greater, located east and northeast of boring P3 or at well MW-1 . AGE assert the location of a proposed soil vapor extraction well for extraction testing should be located at the dispenser island area. The location and construction of feasibility testing observation wells should be at boring P6 (OBW-1 ), representing a distance of 15 feet from the proposed extraction points . Further a second observation well location should be installed at the location adjacent to boring P5 (OBW-2). The wells should be 20 feet in depth to allow for static water level monitoring, thus producing adequate monitoring of the upper water table level to evaluated the performance of the ground water extraction pilot test, using a well screen which intersection the water bearing coarse grained soil at the site . A single well, screened from a depth of 5 feet to 20 feet (See Figure Attached), serves the two proposed feasibility tests and their location supplies a completion of two data gaps currently on the site (P5 and P6). The distance from the ground water extraction well are the following: MW-1 5 feet, MW-7 25 feet, OBW-1 15 feet, OBW-2 30 feet, MW-2 25 feet. The distance from the soil vapor well VW-1 should be OBW-1 15 feet and OBW-2 30 feet, with monitoring wells MW-2, 32 4 and MW-7 at their associated distances from the soil vapor extraction well. The proposed well reduces costs for a site with multiple wells already installed and provides the best benefit for site assessment (including feasibility tests). The distance of observation points for soil vapor extraction feasibility testing should be no closer than 15 feet bsg as proposed , based on a minimum radius of influence for the soil type at present at the site (See attached Map 2). The needed assessment and feasibility testing of the site should not be delayed further and approval for the proposed pilot tests is urged, based on the time delay of the EHD review of the work plan and minimal work plan modifications proposed . Please respond as soon as possible. If questions arise, a site inspection is urged to complete the approval process . William R Little 9/28/2007