|
Stantec
<br /> L & M OPERABLE UNIT- FOURTH QUARTER AND ANNUAL 2010 SITE STATUS,
<br /> REMEDIAL SUMMARY, AND GROUNDWATER MONITORING REPORT
<br /> Summary of 2010 Annual Monitoring and Sampling
<br /> January 31, 2011
<br /> SPH removal activities were conducted on shallow zone wells 2AMW-13 and MW-19 during all
<br /> four quarters of 2010. SPH thickness appears to be stable in each of these wells following
<br /> removal activities.
<br /> During 2010, groundwater elevation and SPH elevations over time was analyzed in wells DPE-1
<br /> through DPE-4, DPE-6 through DPE-8, DPE-10, and DPE-12 and are presented in Appendix J.
<br /> Well DPE-1 through DPE-5 and DPE-7 through DPE-13 have had a decreasing trend since
<br /> monitoring began in 2002 through 2003. Measurable SPH has not been observed in wells
<br /> DPE-1 through DPE-4, DPE-7, and DPE-10 through DPE-13 in the last five consecutive
<br /> quarters. Well DPE-5 had decreased since August 2006 from SPH to mostly sheen, but
<br /> reappeared in small quantities (up to 0.01 ft) during three consecutive quarters (4Q09, 1Q10,
<br /> and 2Q10). Well DPE-6 had decreased significantly since February 2004 from SPH to mostly
<br /> sheen, but reappeared in 2009 with a historical presence of 7.74 ft (2Q09). Well DPE-8 had
<br /> decreased significantly since April 2008 from SPH to mostly sheen, but reappeared during three
<br /> consecutive quarters, during third and fourth quarters 2009 and 1Q10. Measurable SPH has
<br /> not been observed in well DPE-9 since monitoring began in June 2004; however, during the
<br /> fourth quarter 2009 and 1010, small amounts (up to 0.01 ft) of SPH were observed.
<br /> 5.5.2 Deep Zone Trends
<br /> During 2010, sheen or measurable SPH was observed in wells MW-17, MW-43, MW-46 through
<br /> MW-50, and MW-52. In the deep zone wells, sheen and SPH product was mainly observed on
<br /> the northern section of the L&M OU and south of the Water Front Towers' parking lot. In the off
<br /> Site deep zone wells, sheen has been observed in the Delta View Apartments in well MW-46
<br /> only.
<br /> Wells MW-17 and MW-46 contained sheen during all four quarters of 2010. Wells MW-47 and
<br /> MW-48 contained sheen during the 1Q10, and contained SPH during the 2Q10, 3Q10, and
<br /> 4Q10. Wells MW-43, MW-49, MW-50, and MW-52 contained SPH during all four quarters of
<br /> 2010. The highest observed SPH thickness for 2010 was in MW-50 (30.66 ft) during 2Q10.
<br /> Wells MW-17, MW-43, MW-46 through MW-49, and MW-52 have had a decreasing trend since
<br /> monitoring began, in 2005, or since sheen has been observed, in 2008. Well MW-50 has had a
<br /> stable trend. Measurable SPH has not been observed in wells MW-17 and MW-46 since 2008.
<br /> Measurable SPH has not been observed in well MW-47 since November 2006; however, during
<br /> the recent three quarters 2010 (2Q10 through 4Q10), small amounts (up to 0.03 ft) of SPH were
<br /> observed. Measurable SPH in wells MW-43, MW-48, MW-49, MW-50, and MW-52 ranged
<br /> between 0.01 foot (MW-52) and 30.66 foot (MW-50) during 2010.
<br /> SPH removal activities were conducted on B-Zone wells MW-17, MW-43, MW-46 through
<br /> MW-50, and MW-52 during all four quarters 2010. During SPH removal events in 2010,
<br /> approximately 15.25, 0.5, 1.5, 39.0, and 62.0 gallons of product were removed from wells
<br /> MW-43, and MW-47 through MW-50, respectively. Each of these wells is located in the
<br /> Waterfront Towers Parking facility north of the L&M OU.
<br /> Iffidewater7W Stockton(Parcel 2A-0415)\Reports\QMR\2010\4010-Annual\4Q10 and Annual QSSRQRSRQMR Stockton_FINAL.doc 5.3
<br />
|