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C A
<br />077
<br />O P N I A
<br />Water Boards
<br />Central Valley Regional Water Quality Control Board
<br />28 June 2019
<br />Michael and Sharon Olivarez
<br />540 Scotts Avenue
<br />Stockton, CA 95203
<br />RESPONSE TO WORK PLAN ADDENDUM, FORMER SKIPS SERVICE STATION,
<br />AKA: OLIVAREZ PROPERTY, 300 SOUTH CALIFORNIA STREET, STOCKTON,
<br />SAN JOAQUIN COUNTY
<br />Central Valley Regional Water Quality Control Board (Central Valley Water Board) staff
<br />reviewed the Report Second Quarter 2019 Groundwater Monitoring (2Q2019 Report)
<br />dated 1 May 2019, and the Addendum: Path to Closure Impediment Discussion & Site
<br />Investigation Work Plan (Work Plan Addendum) dated 30 April 2019, both submitted on
<br />your behalf by Ground Zero Analysis, Inc. (Ground Zero). The Former Skips Station,
<br />also known as the Olivarez Property, is located at 300 South California Street in
<br />Stockton (Site).
<br />Site wells are screened in three zones, A zone wells are screened between 18 and 35
<br />feet below ground surface (ft bgs), B zone wells are screened between 40 and 65 ft bgs,
<br />and C zone wells are screened between 90 and 115 ft bgs. During the second quarter
<br />2019, Ground Zero detected:
<br />290 micrograms per liter (ug/L) total petroleum hydrocarbons as gasoline
<br />(TPH-G) and 0.64 ug/L naphthalene in the A zone;
<br />up to 36,000 ug/L TPH-G, 2,700 ug/L benzene, 1.6 ug/L methyl tent butyl ether
<br />(MTBE), 6.4 ug/L 1,2-dichloroethane (1,2 -DCA), and 140 ug/L naphthalene in the
<br />B zone; and
<br />up to 150 ug/L TPH-G, 35 ug/L benzene, and 1.4 ug/L 1,2 -DCA in the C zone.
<br />Ground Zero calculated a downward vertical gradient, and groundwater flow directions
<br />towards the north-northeast in the A, B, and C zones.
<br />In the Work Plan Addendum, Ground Zero proposed the following:
<br />KARL E. LONGLEV ScD, P.E., CHAIR I PATRICK PULUPA, ESO., EXECUTIVE OFFICER
<br />11020 Sun Center Drive #200, Rancho Cordova, CA 95670 1 wwwwaterboards. ca. gov/centraly alley
<br />4i RECIC1150 PAPER
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<br />RESPONSE TO WORK PLAN ADDENDUM, FORMER SKIPS SERVICE STATION,
<br />AKA: OLIVAREZ PROPERTY, 300 SOUTH CALIFORNIA STREET, STOCKTON,
<br />SAN JOAQUIN COUNTY
<br />Central Valley Regional Water Quality Control Board (Central Valley Water Board) staff
<br />reviewed the Report Second Quarter 2019 Groundwater Monitoring (2Q2019 Report)
<br />dated 1 May 2019, and the Addendum: Path to Closure Impediment Discussion & Site
<br />Investigation Work Plan (Work Plan Addendum) dated 30 April 2019, both submitted on
<br />your behalf by Ground Zero Analysis, Inc. (Ground Zero). The Former Skips Station,
<br />also known as the Olivarez Property, is located at 300 South California Street in
<br />Stockton (Site).
<br />Site wells are screened in three zones, A zone wells are screened between 18 and 35
<br />feet below ground surface (ft bgs), B zone wells are screened between 40 and 65 ft bgs,
<br />and C zone wells are screened between 90 and 115 ft bgs. During the second quarter
<br />2019, Ground Zero detected:
<br />290 micrograms per liter (ug/L) total petroleum hydrocarbons as gasoline
<br />(TPH-G) and 0.64 ug/L naphthalene in the A zone;
<br />up to 36,000 ug/L TPH-G, 2,700 ug/L benzene, 1.6 ug/L methyl tent butyl ether
<br />(MTBE), 6.4 ug/L 1,2-dichloroethane (1,2 -DCA), and 140 ug/L naphthalene in the
<br />B zone; and
<br />up to 150 ug/L TPH-G, 35 ug/L benzene, and 1.4 ug/L 1,2 -DCA in the C zone.
<br />Ground Zero calculated a downward vertical gradient, and groundwater flow directions
<br />towards the north-northeast in the A, B, and C zones.
<br />In the Work Plan Addendum, Ground Zero proposed the following:
<br />KARL E. LONGLEV ScD, P.E., CHAIR I PATRICK PULUPA, ESO., EXECUTIVE OFFICER
<br />11020 Sun Center Drive #200, Rancho Cordova, CA 95670 1 wwwwaterboards. ca. gov/centraly alley
<br />4i RECIC1150 PAPER
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