Laserfiche WebLink
26 September 2003 <br /> AGE-NC Project No 95-0128 <br /> Page 8 of 8 <br /> • The highest concentration of MTBE(5 80µg/1)was detected in the ground water sample from <br /> off-site monitoring well MW-11 A Lower or non-detectable MTBE concentrations in down- <br /> gradient and cross gradient wells defined the dissolved MTBE plume toward the north and <br /> west, however, the dissolved MTBE plume has not been defined east of well MW-15 <br /> (Figure 4) <br /> • TBA and 1,2-DCA were detected In samples MW-6 (19 jig/1) and MW-3 (0 91 µg/1), <br /> respectively, these concentrations are above the DHS' Action Level of 12 pg/1 for TBA and <br /> MCL of 0 5 µg/1 for MTBE in drinking water Data from the site and off-site investigation <br /> at 4405 Pacific Avenue, indicates the source of 1,2-DCA Is south of the Pacific Mini Mart <br /> site <br /> • During the quarter, approximately 0 191 lbs of MTBE, 0 0159 lbs of benzene and 1 229 lbs <br /> of TPH-g were removed from the site and treated by the ground water extraction system <br /> 5.0. RECOMMENDATIONS <br /> IBased on the results of this and previous investigations, AGE recommends <br /> • Continued quarterly ground water monitoring of the site, the next monitoring event is <br /> Itentatively scheduled for May 2003 Removal of wells MW-9, MW-10, MW-13, MW-14 <br /> from the sampling schedule <br /> • Continued interim ground water extraction and treatment as a remedial measure, with <br /> incorporation of wells MW-4, MW-5 and VW-1 for ground water extraction <br /> 6.0 LIMITATIONS <br /> Our professional services were performed using that degree of care and skill ordinarily exercised by <br /> environmental consultants practicing In this or similar localities The findings were based mainly <br /> upon analytical results provided by an independent laboratory Evaluations of the hydrogeologic <br /> conditions at the site have been made from a limited number of available data points (I a water <br /> samples and monitoring well samples) and subsurface conditions may vary away from these data <br /> points No other warranty, expressed or implied, is made as to the professional interpretations, <br /> opinions and recommendations contained in this report <br /> I <br /> Advanced GeoEnviron mental Inc <br />