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MMOM *AECOM is not responsible for locating buried utilities and assumes no responsibility for damages caused to buried utilities as a result of inaccurate information received from the 811 utility locator service. 2.2 Task 2—Geophysical Investigation A geophysical investigation, consisting of a ground penetrating radar(GPR) and electromagnetic (EM) survey will be conducted in the location of the proposed borings for utility clearance. The EM survey identifies magnetic responses to mild electrical current induced to metallic substances from in a hand-held array. Magnetic responses are recorded for both subsurface and subsurface metallic substances, hence nearby fencing, rail, reinforced concrete or similar materials can interfere, or mask buried drums, tanks or similar. Under ideal conditions, 250 MHz GPR unit can penetrate soil at depths of up to eight meters(24'), but this depth may be greatly reduced due to site-specific conditions that attenuate the signal. GPR surveys do not rely on metallic substances but look for anomalies in radar wave signals bouncing off subsurface soil layers. Signal penetration decreases with increased soil conductivity. Thus, penetration is greatest in unsaturated sands and fine gravels. Clayey, highly saline and moist soils as well as areas covered by steel reinforced concrete and foundry slag cause reduced GPR penetration. 2.3 Task 3—Soil and Groundwater Investigation AECOM proposes to install up to six soil borings via Geoprobe® drilling technology on the Subject Property in the vicinity of the 10,000-gallon UST up to a depth of approximately 14 feet below ground surface (bgs). The concrete or asphalt surface will be cored and the first five feet of each boring will be hand augured to assist in utility clearance. All borings will be advanced via a track-mounted or truck- mounted probe until groundwater is encountered or refusal up to a depth of 14 feet bgs. The borings will be advanced in the following locations: • One boring on the northern boundary of the UST; • Two borings along the eastern boundary of the UST; • One boring along the southern boundary of the UST; and • Two borings on the western/pump side of the UST. Each boring will be field screened (visual/olfactory/photo-ionization detector) for evidence of impact. If evidence of impact is encountered, a soil sample will be collected from the interval showing the greatest evidence of impact. If no evidence of impact is encountered, one soil sample will be collected directly above the soil groundwater interface. If groundwater is encountered, a one-inch temporary monitoring well will be installed in one downgradient boring and one upgradient boring for the collection of a grab groundwater sample. AECOM will collect depth to water readings utilizing a water level indicator prior to collecting samples. The construction of the temporary wells will include the removal of the drill rods and installation of temporary one-inch polyvinyl chloride (PVC) casing with five feet of screen in the open boring. The temporary well will be developed prior to sample collection. A Teflon bailer