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California "-gional Water Quality Control Board
<br /> Central Valley Region J
<br /> Linda S.Adams Arnold
<br /> Secreran,.for Sacramento Main Office Schwarzenegger
<br /> Envirwvnental 11020 Sun Center Drive#200,Rancho Cordova.California 95670-6114 Governor
<br /> Prorecoon Phone(916)464-3291 •FAX(916)464-4645
<br /> http://wwM-.waterboards.ca.gov/centralvalley
<br /> ul
<br /> 17 January 2007
<br /> ENVI,�UNf�?E;�JT E-1c
<br /> Ms. Anne Conner PERMlr t t HEALTH
<br /> Pacific Gas and Electric Company
<br /> 375 North Wiget Lane, Suite 200
<br /> Walnut Creek, Ca 94598
<br /> REVIEW OF ANNUAL 2005 GROUNDWATER MONITORING REPORT AND 1 ST SEMI-
<br /> ANNUAL 2006 GROUNDWATER MONITORING REPORT FOR THE FORMER CLASS /l
<br /> SURFACE IMPOUNDMENTS, MCDONALD ISLAND GAS STORAGE FACILITY
<br /> The Regional Water Quality Control Board (Regional Water Board) staff has reviewed the
<br /> Annual 2005 and 1St Semi-annual Groundwater Monitoring Reports for the Former Class II
<br /> Surface Impoundments at McDonald Island Gas Storage Facility. The reports were prepared
<br /> in accordance with Waste Discharge Requirements (WDRs) Order No. 96-176. The Annual
<br /> 2005 report stated that statistically significant increases of constituents of concern (CDCs)
<br /> were observed in wells MW-1 RD (SO4), MW-2 (Na), MW-3 (Na), MW-5 (Cl, Na), MW-7 (EC,
<br /> TDS, Na, SO4), MW-9 (Ba), and MW-11 (Na). The 1 st Semester Report reported
<br /> concentration limit exceedences in wells MW-4 (Na); MW-7 (Na, SO4, Ba); MW-1 RD (Cl, Na,
<br /> Ba, TDS, EC); MW-2 (Cl, Na, SO4, TDS, EC); MW-3 (Cl, Na, SO4, TDS, EC); MW-5 (Cl, Na,
<br /> Ba, TDS, EC); MW-6 (Cl, Na, Ba, TDS, EC); MW-9 (Cl, Na, Ba, TDS, EC); MW-10 (Ba);
<br /> MW-11 (Cl, Na, Ba, TDS, EC).
<br /> Based on reports, staff is concerned the current corrective action is ineffective at remediating
<br /> the groundwater pollution. Please submit by 16 February 2007 an explanation for the
<br /> increasing COCs and a plan that discusses how the site will be brought into compliance with
<br /> WDRs Order No. 96-176.
<br /> The request that monitoring be decreased to annual sampling does not seem appropriate
<br /> based on the monitoring data.
<br /> If you ha a any questions please call me at (916) 464-4737.
<br /> Todd A. DekTrate
<br /> Engineering Geologist
<br /> Lower San Joaquin River Watershed
<br /> Discharge to Land Unit
<br /> California Environmental Protection Agency
<br /> C17 Recycled Paper
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