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<br /> Raymond Investment Corporation- Page 2
<br /> 730 Channel Street November 8, 2010
<br /> Stockton, California 95202
<br /> • Replace the leak detection compound 1,1-difluoroethane with helium when collecting
<br /> soil gas samples from SV4 through SV6;
<br /> • Install no additional monitoring wells in the sidewalk or parking lane at the southwest
<br /> corner of Channel and Grant Streets.
<br /> The EHD concurs, based on the soil and groundwater analytical results, that no additional site
<br /> investigation is needed in the area of monitoring well MW=6, and soil borings SB-12 through
<br /> SB-14; however, based on the analytical data collected from MW-5, where high concentrations
<br /> of total petroleum hydrocarbons as diesel (TPH-D) were detected at. 4,100 milligrams .per
<br /> kilogram (mg/kg), and 1,100 mg1kg in soil samples collected at 35 and 40 feet below surface
<br /> grade, respectively, and groundwater,samples at 12,000.micrograms per, liter (pg/L), the EHD
<br /> believes at least one of the three previously-approved monitoring wells should be installed in the
<br /> sidewalk or parking lane at the southwest corner of Channel and Grant Streets to delineate the
<br /> petroleum hydrocarbon plume down gradient of the source area.
<br /> Submit an encroachment permit issued by the City of Stockton, along with a Master File Record
<br /> Information Form (MFR), well and'.boring permit application, and permit/inspection fees to the
<br /> EHD and complete the well installation/s by December 31, 2010. The MFR, revised permit
<br /> application and current fees may be obtained by visiting EHD's website at www.sjgov.org/ehd.
<br /> Notify the EHD at least a week prior to the pending fieldwork.
<br /> Following the installation of the additional monitoring well/s, submit the report of findings to the
<br /> EHD within sixty days of the well installation/s; collect groundwater samples quarterly for one
<br /> hydrological cycle from the newly installed Well/s, and submit a Remediation Feasibility Report,
<br /> based on the current site data, within sixty day of collecting groundwater samples from the
<br /> newly installed monitoring wellls located in the City of Stockton right-of-Way.
<br /> Collect soil gas samples one additional time from soil vapor wells SV4, SV5 and SV6 using
<br /> helium as the leak detection compound.. If the analytical results are similar to the previous soil
<br /> gas results, additional sampling of SV4 through SV6 will not be necessary.
<br /> If you have any questions regarding this letter, please contact Vicki McCartney at (209) 468-
<br /> 9852, or by email at vmccartney@sicehd.com.
<br /> Sincerely,
<br /> Victoria L. McCartney, REHS Nuel C. Henderson, Jr., PG
<br /> Senior Registered Environmental Health Specialist Engineering Geologist
<br /> c: :Mr. Bill A. Cook 111, PG, Condor'Earth Technologies, Incorporated, 188 .Frank West Circle,
<br /> Suite 1, Stockton, California 95206
<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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