Laserfiche WebLink
Geological Technics/"." Page 4 <br /> Groundwater Monitoring Report <br /> Project No. 662.2 <br /> March 31,2003 <br /> detection for this event. The concentration of MTBE appears to be stable within a range <br /> of values. <br /> { • Deep screened well MW-104 contained 66 ug/l MTBE. This the second event in which <br /> this well has tested positive for MTBE. <br /> • Figure 4: MTBE vs. Groundwater Elevation - MW-3 illustrates a fairly direct <br /> �= relationship between the concentration of MTBE in groundwater and the elevation of <br /> groundwater in well MW-3. <br /> • Neither BTEX nor TPH-G was present in any of the groundwater samples above the <br /> laboratory reporting limits. <br /> • Oxidation-Reduction Potential measurements (Table 3) show.that the values for all four <br /> wells are positive, suggesting that there is a limited amount of biodegradation of the <br /> contaminant plume occurring. This is,to be expected, since the primary contaminant is <br /> MTBE, which is resistant to biodegradation. <br /> The lateral extent of the groundwater contamination plume is only defined upgradient to the <br /> { northwest by MW-2. The well MW-104 may be near 'the vertical limit of MTBE <br /> contamination on site.. <br />+a <br /> GTI makes the following recommendations: <br /> • Perform plume definition by performing CPT testing and an extraction well installation <br /> as approved by SJC PHS/EHD on February 14, 2003. Additional wells will be installed <br /> after this work is completed and pending concurrence from the SJC PHS/EHD. <br /> f 3.0 LIMITATIONS <br /> This report was prepared in accordance with the generally accepted standard of care and <br /> practice in effect at the time Services were rendered. It should be recognized that definition <br /> and evaluation of environmental conditions is an inexact science and that the state or <br /> practice of environmental geology/hydrology is changing and evolving and that standards <br /> L existing at the present time may change as knowledge increases and the state of the practice <br /> continues to improve. Further, that differing subsurface soil characteristics can be <br /> experienced within a small distance and therefore cannot be known in an absolute sense. <br /> All conclusions and recommendations are based on the available data and information. <br /> The tasks proposed and completed during this project were reviewed and approved by the <br /> local regulatory agency for compliance with the Iaw. No warranty, expressed or implied, is <br /> made. <br /> i <br />