6C(2) Proposal for Supplemental Phase II Assessment

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and GP -4) were established adjacent to the interior floor drains around which pooling of oil had been identified. Field screening, involving the use of a photoionization detector, as well as visual and olfactory observations, did not readily identify the presence of impacted soils within the soil profile of any of the boring locations. However, at least one soil sample was submitted for laboratory analysis of High End Organics and Volatile Organic Compounds (typically the depth interval of between 2 feet to 4 feet was submittal as the most likely to be impacted as a result of surficial and /or drain introduction). In addition, upon encountering the saturated zone (water bearing depth), each of the borings were converted into a temporary well for the collection of a groundwater sample (analysis of Volatile Organic Compounds). Results of the Phase II Environmental Site Assessment (Report dated October 11, 2010, PES Project #10 -044) identified the presence of High End Organics in the soil sample collected in the area of the waste oil drums (2 -feet below land surface) at a level of 75.5 mg /kg. The current RISC Residential criterion for High End Organics is 230 mg /kg. None of the other soil samples submitted from any of the soil borings were reported with either High End Organics or Volatile Organic Compounds above laboratory detection limits. With respect to the groundwater samples collected and submitted for analysis of Volatile Organic Compounds; the presence of Tetrachloroethylene (also known as PCE) was reported for location GP -2 (0.015 mg /L) and GP -3 (0.0116 mg /L). The RISC Residential criterion for Tetrachloroethylene, which is commonly associated with dry cleaning operations, has been established as 0.005 mg /L. We note that the RISC Industrial criterion has been established as 0.55 mg /L; however current RISC guidance stipulates that use of the Industrial Default Closure Values requires the deed attachment of a Restrictive Environmental Covenant that prohibits the use of groundwater. With the exception of Dibromochloromethane reported for the GP -3 groundwater sample (attributed to the presence of a chlorinated municipal water line), no other Volatile Organic Compounds were reported for any of the groundwater samples. Given that 1) Tetrachloroethylene was not detected in any of the soil samples submitted for analysis, 2) that there were no indications of highly impacted zones as would have been noted via the field screening process; and 3) the locations of GP -2 and GP -3 were the easternmost of the four boring locations, with groundwater flow in the area being to the north /northeast; IDES concluded that the likely source of the Tetrachloroethylene was not the commercial garage, but more likely associated with historical off -site sources. Such off -site sources include a former adjacent self - service Laundromat (potential use of coin operated dry cleaning machines) and several historical dry cleaning facilities having been located along Indiana Avenue, to the south of the subject site (up gradient). IDES further concluded that a Supplemental Environmental Site Assessment would be necessary to further delineate the potential source of Tetrachloroethylene in the area. Accordingly, the following sections present our approach toward conducting the Supplemental Environmental Site Assessment, projected costs and a tentative schedule for completion. PROPOSED SCOPE OF SERVICES Soil Sampling via Geoprobe Methodology We note that the City of South Bend currently owns a former residential property located to the southwest of the commercial garage (up gradient), the former residential property to the north of the commercial garage, as well as the former public park, located across Kendall Street from the subject site (side gradient to down gradient). Other publically