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epi
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<br /> Pacific Pride-South El Dorado Street Page 2
<br /> 3147 South El Dorado Street March 18, 2008
<br /> Stockton, California 95206
<br /> depths as great as 100 feet bsg. Please submit a work plan to the EHD by June 19, 2008, that will
<br /> address the lateral extent of the dissolved petroleum hydrocarbon plume southeast of MW-9A in the
<br /> shallow zone (approximately 35 to 45 feet bsg).
<br /> Although the SCM provided much information about your site, there was no mention concerning the
<br /> high concentrations of total petroleum hydrocarbons quantified as kerosene (TPH-k) detected in
<br /> groundwater collected from MW- 1 and MW-7 and the abrupt disappearance of this chemical of
<br /> concern. In addition to detecting TPH-k at low concentrations in groundwater samples collected from
<br /> MW-2, MW-3, MW-4, and MW-5, TPH-k was also detected in soil samples collected from MW- 1 ,
<br /> MW-5, and MW-8 . Please provide the EHD an explanation why TPH-k is no longer being detected in
<br /> groundwater collected at your site.
<br /> AGE has recommended that a soil vapor extraction pilot study be performed to determine if this
<br /> remedial method may decrease the concentrations of petroleum hydrocarbons present in soil and
<br /> groundwater. The EHD approves this pilot test. Please submit a work plan to the EHD by June 19,
<br /> 2008, that will address performing a soil vapor extraction pilot test at your site.
<br /> Continue to collect groundwater samples quarterly from MW-1 , MW-7, MW-8A, MW-9A, and
<br /> MW-10A, MW- lOB, and MW- 10C; and continue to analyze for total petroleum hydrocarbons
<br /> quantified as diesel (TPH-d) in groundwater samples collected quarterly from MW- 1 and MW-7.
<br /> Semi-annually collect groundwater samples from MW-5 and MW-8B . Annually, during the first quarter
<br /> of each year, collect groundwater samples from MW- 1 , MW-2, and MW-4 through MW- 12 and include
<br /> TPH-d and TPH-k in the analytical list at this time. Ethyl tertiary-butyl ether (ETBE), di-isopropyl
<br /> ether (DIPE), 1 ,2-dibromoethane (EDB), and tertiary-butyl alcohol may be removed from the analytical
<br /> list since these compounds have not been detected in groundwater samples collected quarterly since
<br /> 2004. If any analytes are detected in samples collected on a non-quarterly basis, the well should be
<br /> sampled the following quarter(s) until concentrations return to non-detect (i.e. MW-6). Collect
<br /> groundwater samples from MW-6 during the next monitoring event and analyze the groundwater for
<br /> MTBE and TAME.
<br /> If you have any questions, please contact Vicki McCartney, Senior Registered Environmental Health
<br /> Specialist, at (209) 468-9852 or by email at vmccartney@sjcehd.com.
<br /> Sincerely,
<br /> Victoria L. McCartney, REHS Nuel C. Henderson, Jr., PG
<br /> Senior Registered Environmental Health Specialist Engineering Geologist
<br /> c : Mr. Timothy J. Cuellar, Advanced GeoEnvironmental, Inc., 837 Shaw Road, Stockton,
<br /> California 95215
<br /> Mr. James L.L. Barton, PG, California Regional Water Quality Control Board Central Valley
<br /> Region, 11020 Sun Center Drive, Suite 200, Rancho Cordova, California 95670
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