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Ms. Lori Duncan March 31, 2008 Page 4 of 7 was removed from the well by hand bailing, through the use of a passive oil skimmer, and by the automated belt skimmer. The product thickness was reduced from a high of 1.47 feet in September 2001 to not measurable by the end of June 2006. The waste was stored and disposed of in accordance with 49 CFR part 172 and 40 CFR part 262. Table 5 summarizes free product monitoring and removal in well MW3. PROPOSED SCOPE OF WORK Pursuant to 12/28/07 EHD's request for additional investigation, Ground Zero proposes the following scope of work: • An investigation of the vertical extent of groundwater contamination. • A soil gas investigation and vapor intrusion/risk evaluation. • A review of the construction details and potential for vertical transport of contaminants in monitoring well MW3. Proposed field and analytical methods are presented below. Groundwater Investigation As directed by EHD, we will investigate the vertical extent of groundwater contamination beneath the former UST. In order to avoid cross-contamination from penetrating known impacted soil intervals, Ground Zero proposes advancing a direct push boring at a 10° angle approximately ten feet east of the former UST (Figure 3). Previous soil investigation activities suggest that there is soil contamination up to five feet from the former UST at 20 feet bgs (Figure 4). As shown on Figure 5, contact with soil contamination at 20 feet and 31 feet bgs can be avoided using a 10' angle. A shallow drilling angle also minimizes the risk of refusal when using direct push technology. The rods will be advanced to a measured depth of 51 feet bgs (true vertical depth of 50 feet) and pulled back one-foot to expose a stainless steel screen. Groundwater samples will be collected via check valve and dedicated tubing, placed in the appropriate containers, checked for headspace, uniquely labeled, and placed in an ice chest chilled to approximately 4oC for shipment to a State Certified Laboratory. The groundwater samples will be analyzed for following constituents: • Total Petroleum Hydrocarbons as gasoline (TPHg) by EPA method 8015M • Total Recoverable Petroleum hydrocarbons with Silica Gel Clean-up by IR Spectrometry (TRPH) by EPA method 418.1 • Volatile Organic Compounds including fuel oxygenates by EPA method 8260B G:\GROUNDZE\GABBARD\warkple \wp_0308.doa