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r <br /> 14 November 1995 <br /> AGE-NC Protect No 95-0121 <br /> � y <br /> s <br /> ,t Page 2 of 20 r ' <br /> 23 SITE ASSESSMENT <br /> A total of ten soil borings and rine monitoring wells were installed at the site between May 1989 and ` <br /> m December '1994 Nine soil borings (B-1 through B-9) were drilled and sampled in May 1989 by <br /> Kleinfelder Hydrocarbons were detected in soil samples from seven of the nine borings In February <br /> 1991, Klennfelder drilled and installed monitoring wells MW-1 through MW-3 at the site Total <br /> petroleum hydrocarbons quantified as gasoline (TPH-g) were detected in water samples collected <br /> from each well during the initial sampling event In June 1991, 15 feet of free product was measured <br /> in MW-1 <br /> In May 1992, three additional morutonng wells were installed at the site (MW-4 through MW-6)by <br /> Artesian Environmental Consultants(AEC) Petroleum hydrocarbons(TPH-g)were detected in MW- + <br /> 4 and MW-6 at concentrations as great as 15,000 parts per billion (ppb) No hydrocarbons,were <br /> detected in the sample from MW-5 <br /> 'In December 1994, three monitoring wells (MW-7 to MW-9) and one boring were installed for the <br /> continuing investigation Two wells were installed off-site and one well was installed on-site (see <br /> Figure 2)by Geological Audit Services, Inc (GeoAudnt) Petroleum hydrocarbons were detected in <br /> 4 of 11 soil samples analyzed from the wells and boring No petroleum hydrocarbons'were detected <br /> in either soil or ground water samples from MW-8 or MW-9 " <br /> t 2 4 GROUND WATER DEPTH AND FLOW DIRECTION n <br />■ t, <br /> Depth to ground water at the site has,fluctuated from approximately 25 feet bsg to approximately 33 <br /> feet bsg,between 1991 grid 1995 Ground water flow direction at-the site has fluctuated from <br /> northwest to southeast Dominant ground water flow direction is north-northeast r ' � <br /> r <br /> 3.0. QUARTERLY GROUND WATER MONITORING, JULY 1995 _ <br /> +Y , 3 1 MONITORING WELL PURGE PROCEDURES <br /> On 14 July 1995, the depth to ground waterandproduct thickness in the nine monitoring wells were „ <br /> measured relative to the,top of the well casing using a Sohnst water level meter or an Ullage interface <br /> probe The ground water elevations in each well and hydraulic gradient were calculated by subtracting ' <br /> the depth to ground water from the surveyed casing elevation (Table 1) The casing water in each <br /> well was then purged using a,2-stage submersible purge pump Approximately 8 to' 14'gallons (a <br /> minimum of 3 well'volumes)of water were removed from each well to stabilize temperature, pH and <br /> I <br /> + <br /> Y t k <br /> I <br /> 1 t <br />