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H <br />11 <br />i <br />MW k%j KLEINFELDER <br />6 DISCUSSION OF FINDINGS <br />6.1 EXCAVATION O 3SERVATIONS <br />Approximately 5,000 cubic yards of sots and debris was excavated from Site B and about 10,000 <br />cubic yards from site C. Groundwater was encountered in both borings at about 6 to 9 feet bgs. <br />Site B and C excavation had an estimated average depth of twelve feet and ten feet, respectively. <br />An estimated l percent of debris material was excavated from Site B consisting of plastic, wood <br />wire, concrete and railroad ties. Approximately 25 percent of the material at Site B was slaked <br />lime and lime material. Discolored soil and an organic odor was noted in the vicinity of the <br />slaked lime. A soil and two groundwater samples were collected in the vicinity of this material. <br />An estimated 25 percent of material was estimated to be debris from Site C consisting of sheet <br />metal, concrete, culvert piping. bricks. wire, and wood. No soil discoloration or odor was noted <br />from the soil or groundwater from the excavation at Site C. Two soil samples were analyzed <br />from within this excavation were collected at depths ranging from 9 to 12 feet bgs. <br />1 6.2 MONITORING WELL ABANDONMENT OBSERVATIONS <br />Kleinfelder observed the abandonment of three of six wells (MW -7, MW -9 and MW -11) used for <br />monitoring groundwater in the vicinity of the two disposal sites (B and C). Monitoring wells MW - <br />8, MW -10 and MW -12 were not able to be located and were presumed destroyed during grading <br />operations on site. Well abandonment was conducted by drilling out well casing and well materials <br />from surface to the respective total depths of each of the three wells and subsequently tremmie- <br />grouted with a neat cement/bentonite slurry to surface grade in accordance with the approved <br />PHS/EHD permit. <br />1 6.3 ANALYTICAL RESULTS <br />The analytical results of the three soil samples collected from the two excavation sites and <br />submitted for analyses were reviewed and compared to the 1998 United States Environmental <br />Protection Agency (EPA) Region IX Preliminary Remediation Goals (PRGs) for soil for <br />residential and industrial sites. Residential PRGs were selected for comparison because they are <br />the most conservative. However.. the site is zoned and proposed for industrial site use. PRGs are <br />contaminant concentrations in environmental media (i.e. soil, air, water), calculated by the U.S. <br />20-3978-03. W36/2019766 Page 15 of 20 <br />© 1999. Kleinfelder. Inc. September 9. 1999 <br />