Laserfiche WebLink
10 CTARWATER <br /> GROUPJNC <br />' migrated to the water table with little lateral migration Upon encountering the <br /> g p g <br /> water table, the contaminants began to spread laterally The current distribution of <br /> soil contamination probably resulted from "smearing" as the water table fluctuates <br /> (historically between 10 and 16 feet below grade) The vertical and lateral extents of <br /> soil contamination are shown graphically on Figure 3 <br /> The mass of TPHg in the vadose zone can be estimated assuming that contaminated <br /> soil has a disc-like, cylindrical shape with the height of 7 feet and a radius of 70 feet <br /> using the following equation <br /> M(TPHg) = n (r)2 (h) p (Max TPHg ppm) 2/3 <br /> where, r = radius = 70 feet , <br /> h = thickness = 7 feet <br /> 1 �o 4',J el p = density = assume 100 lbs /ft3 _ <br /> 5 Max TPHg = 700 ppm or 700 x10-6 lbs /lbs <br /> 111 fs h 611b 0'c;t 2/3 = factor to average maximum contaminant concentration <br /> across impacted area <br /> M(TPHg) = 5,050 lbs <br /> The weight of 5,050 pounds of TPHg is equivalent to approximately 842 gallons of <br /> gasoline, assuming a gasoline density of 0 72 <br /> 4.2 Summary of Shallow Groundwater Contamination <br /> The extent of shallow water contamination was delineated during previous <br /> investigative work by RESNA The extent of water contamination is delineated by <br /> the location of wells MW-3, MW-4, MW-5, MW-6, and MW-7 (see historical water <br /> I sample analytical results on Table 2) The plume is approximately 50 feet in radius <br /> and centered in the vicinity of RW-1, MW-1, and MW-2 SPH have been detected <br /> intermittently in MW-1 and MW-2 <br /> 5 0 FEASIBILITY TESTING <br /> 5.1 Purpose and Scope <br /> From December 19 to December 21, 1995, Clearwater conducted feasibility tests to <br /> evaluate groundwater extraction, soil vapor extraction, and air sparging as potential <br /> remedial alternatives for the site Test data was used to determine the permeability <br /> of sediments beneath the site and potential zones of influence for groundwater and <br /> vapor extraction from individual wells Data collected from these tests were used to <br /> prepare the remedial action plan <br /> D-107, PAR RAP 7 <br /> / February 21, 1996 <br />