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3 0 CONCLUSIONS, RECOMMENDATIONS AND PROJECT STATUS <br />' Between June 29, and September 21, 2005, the groundwater surface dropped an average of 1 09 <br /> p <br /> feet, the groundwater gradient increased from 0 0020 to 0 0024 footlfoot, and the direction of <br /> groundwater flow remained toward the east-southeast The groundwater surface configuration <br /> appears to be consistent with historical and seasonal trends <br /> Between June 29, and September 21, 2005, the concentrations of gasoline compounds in <br /> groundwater remained relatively stable, except for a significant increase in the concentration of <br /> MTBE in MW-2 from 720 to 4,670 micrograms per liter (pg/1) Gasoline hydrocarbons are <br /> concentrated as free product near former UST#3, and concentrations of gasoline compounds <br /> decrease with distance from the source area As shown on the isoconcentration maps, the lateral <br /> extent of TPH-as-gasoline and benzene are defined (Figures 5 and 6), and the lateral extent of <br /> MTBE in groundwater is mostly defined (Figure 7) The vertical extent of impacted groundwater <br /> has not been investigated <br /> During the third quarter of 2005, approximately 1 55 ounces of free product were removed from <br /> MW-1 in three monthly site visits <br /> On November 1, 2005, EHD met with representatives of the San Joaquin County Facilities <br /> Management Department In a letter summarizing the meeting dated November 17, 2005, EHD <br />' states that <br /> Soil and groundwater contamination by MTBE as well as by petroleum hydrocarbon <br /> contaminants has been confirmed at the site Currently, seven monitoring wells have been <br /> installed on-site The lateral extent of the shallow groundwater contamination is basically <br />' defined, but the vertical extent has not been investigated Air sparge and vapor extraction <br /> wells have been installed and feasibility test are to be conducted Cross sections should <br /> be prepared by your consultant to identify potential or likely contaminant migration <br /> pathways EDB should be added to the suite of analytes being tested for in the <br /> groundwater samples <br /> Ramage Environmental recommends that upon the availability of funding, the previously-approved <br /> remedial feasibility testing and vertical investigation tasks be completed In the meantime, <br /> monthly free product removal and quarterly groundwater monitoring should continue The <br /> groundwater samples collected during the fourth quarter of 2005 will include EDB, and an updated <br /> cross-section will be included in the fourth quarter 2005 report <br /> 7 <br />