Laserfiche WebLink
Mr. M. Scott Mansholt—CEMC <br /> First Quarter 2006 Groundwater Monitoring and Sampling Report April 18,2006 <br /> US Can-Welty Road Page 5 of <br /> CONCLUSIONS AND RECOMMENDATIONS <br /> Groundwater elevations from the site wells indicate that groundwater flow was to the east at an <br /> approximate gradient of 0.001 ft/ft during first quarter 2006. No dissolved-phase TPHg or BTEX <br /> appear to be present at the site. Dissolved-phase TPHd were detected in two of the wells (MW-3 <br /> and WFSMW-1) during first quarter 2006 at concentrations of 1,000 and 66 µg/L, respectively. <br /> SPO has been observed in wells MW-1 and MW-2 since 1999. TPHg and TPHd appear to be <br /> present in the SPO in the vicinity of wells MW-1 and MW-2. Low concentrations of PAHs were <br /> detected in wells MW-3 and WFSMW-1, below the respective PRGs for direct exposure to <br /> residential tap water. <br /> SAIC recommends continued quarterly groundwater monitoring and sampling of wells MW-1 <br /> through MW-5 and WFSMW-1. SAIC is preparing a work plan to properly destroy and replace <br /> wells MW-3 and MW-4 because the water volumes in these wells are insufficient for adequate <br /> sample collection. The work plan will be submitted in the second quarter of 2006. Oleophilic <br /> socks in wells MW-1 and MW-2 will be monitored quarterly and replaced as necessary. When <br /> the petroleum sheen has been removed, SAIC recommends that wells MW-1 and MW-2 be <br /> incorporated into the quarterly monitoring and sampling program. <br /> CLOSING <br /> If you have any questions regarding this report, please call Chris Dennis at (916) 979-3866. <br /> Sincerely, <br /> SCIENCE APPLICATIONS INTERNATIONAL CORPORATION <br /> %l C' <br /> Suzette Villanueva Christopher B. Dennis, P.G. <br /> Staff Scientist Senior Geologist <br /> Enclosures: �Z <br /> k O <br /> Figure 1: Site Vicinity Map 0 CHRISTOPHER <br /> Figure 2: Site Map a B. <br /> Figure 3: Potentiometric Surface Map—First Quarter 2006 * DENNIS <br /> Figure 4: Petroleum Distribution in Groundwater—First Quarter 2006 Tj No.7184 <br /> Table 1: Groundwater Elevation Data and SPO Thickness Measurements <br /> Table 2: Groundwater Chemical Analytical Results—TPH, MTBE, and BTEX OP CA►-�F <br /> Table 3: Groundwater Chemical Analytical Results—PAHs Expires August 31 ;tc -_1 <br /> Attachment A: Field Data Sheets <br /> Attachment B: Laboratory Chemical Analytical Report <br />