Laserfiche WebLink
Mr Harlin Knoll <br /> Page 3 of 3 <br /> • SUMMARY AND CONCLUSIONS <br /> Groundwater flowed in an easterly direction, and the potentiometric surface at the site rose <br /> approximately three feet between November 2001 and February 2002 The water level lies above <br /> the screened interval in all site wells except for well MW3 TPHg and BTEX in well MW3 <br /> remains at non-detectable levels Benzene was detected in well MW4 for the first time since <br /> February 1998, but remained below the Maximum Contaminant Level (MCL) of 1 0 ppb in that <br /> well Concentrations of dissolved TPHg and BTEX in well MW5 increased somewhat in well <br /> MW5 since last sampled in November 2001, but decreased in well MW1 over the same period <br /> Contaminant concentrations have generally been gradually declining since their recorded historical <br /> highs The most recent results (February 2002) represent decreases of approximately 79-93% in <br /> well MW5 and 97-99% in well MW 1 <br /> RECOMMENDATIONS <br /> EHD previously requested that Ground Zero evaluate ozone injection as a remediation alternative <br /> for groundwater contamination Pursuant to this request Ground Zero reviewed specific files at <br /> the offices of EHD for sites which have used or tested ozone infection Unfortunately, the files <br /> were incomplete and contained no information regarding the method or results of ozone infection <br /> Ground Zero is continuing to work with EHD to review the complete files EHD had also <br /> requested that a replacement well for recently destroyed well MW8 be installed to continue to <br /> monitor groundwater quality downgradient of well MW5 Ground Zero is currently preparing a <br /> work plan for installation of the replacement well <br /> The next groundwater monitoring and sampling event is scheduled for May 2002 Ground Zero <br /> will provide EHD with at least 48 hours notice prior to conducting any site activities <br /> Please contact John Lane at (209) 838-9888 if you have any questions or comments regarding this <br /> report ` <br /> D GF��p <br /> Respectfully, <br /> Ground Zero Analysis, Inc JOHN P <br /> LANCE <br /> No 6795 <br /> Jo P Lane cn� <br /> CA Registered Geologist 6795 �F Op <br /> C kL <br /> Attachments <br /> cc Mr Carl Knowles <br /> Mr Patrick D Riddle, Attorney at Law <br /> Mr Marty Hartzell, CRWQCB Sacramento <br /> G\Data\GRouNDZEIKNOWLES HAM\REP0RTS\QMR\1QM2002 doc <br />