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<br /> R.°.. n. Former Apache Plastics -2- 19 May 2017
<br /> ° 2D50Stockton.
<br /> East Fremont Street
<br /> wx ew emu Stockton,San Joaquin County
<br /> Water Boards
<br /> Central Valley Regional Water Quality Control Board 2, The Site does not meet LTCP's Direct Contact and Outdoor Air Exposure media specific
<br /> criteria. Shallow soil data has not been collected from the source area so there is no
<br /> data available to compare to LTCP screening criteria. Collection of shallow soil data is
<br /> 19 May 2017 needed to allow for comparison to LTCP dermal contact criteria and to allow for
<br /> determination of the presence of a bio-attenuation zone for evaluation of vapor intrusion
<br /> to indoor air
<br /> Mr.Bill Stoermer 3. The Site does not meet LTCP's Petroleum Vapor Intrusion to Indoor Air media specific
<br /> Fremont Plaza Investments,LP criteria due to benzene concentrations in groundwater greater than 1,000 ug/L and no
<br /> 7015 Morton Court shallow soil data. Due to the lack of shallow soil data the concentration of total
<br /> Stockton,CA 95209 petroleum hydrocarbons in shallow soil and the bio-attenuation zone thickness are
<br /> unknown. A comparison of Site conditions to LTCP media specific vapor intrusion
<br /> criteria is presented in the table below:
<br /> Project Status,former Apache Plastics,2050 East Fremont Street,Stockton,
<br /> San Joaquin County i Scenario TPH in soil Bio-attenuation Foundation to NAPL Benzene in 02>4
<br /> (mg/kg) zone(TPH NAPL/GW Allowed Groundwater
<br /> Central Valley Regional Water Quality Control Board(Central Valley Water Board)staff zone)thickness (feet) (ug/L)
<br /> (2302)
<br /> reviewed the Groundwater Monitoring Report-Second Quarter 2016(2Q2016 Report)dated 1 <100 30 30 Yes No
<br /> 24 August 2016,submitted on your behalf by Advanced GeoEnvironmental,Inc.(AGE). The 2 <100 30 30 Yes — No
<br /> former Apache Plastic is located at 2050 East Fremont Street in Stockton(Site). I 3a <100 5 5 No <100 No
<br /> 3b '100 10 10 No >/=1DO& No
<br /> During the second quarter 2016,AGE detected benzene at a maximum concentration of '1,000
<br /> 12,400 micrograms per liter(ug/L). A new Notice of Applicability to operate under General 3c <1 DO 5 5 No '1,000 Yes
<br /> Order No.R5-2015-0012 was issued on 9 May 2017,and the Site was assigned Order No.
<br /> R5-2015-0012-028. The General Order allows for injection of hydrogen peroxide to remediate unknown unknown 45 Not 12,400 unknown
<br /> petroleum hydrocarbons. ( SITE measured
<br /> Central Valley Water Board staff compared the Site to low risk closure criteria,as outlined in the
<br /> State Water Resources Control Board's Low Threat Underground Storage Tank Case Closure Therefore,by 30 June 2017,please submit a work plan to assess risk to human health due to
<br /> Policy(LTCP). Staff determined the Site does not meet low risk closure criteria as follows: f dermal contact and vapor intrusion to indoor air. It may be appropriate to postpone
<br /> implementation of field work pending completion of active remediation.
<br /> 1. The Site does not meet groundwater media specific criteria due to benzene
<br /> concentrations,plume length,and the distance to the nearest water supply well. A ! As required by Monitoring and Report Order No.R5-2015-0012-028,the First 2017 Semi-
<br /> comparison of Site conditions to LTCP media specific groundwater criteria is presented i Annual Groundwater Monitoring Report is due 1 August 2017.
<br /> in the table below:
<br /> If you have any questions,please contact me by phone at(916)464-4792 or by email at
<br /> Scenario Plume Distance to Closest Well and Maximum Maximum Free Product Plume Stable I vera.fischer@waterboards.ca.gov.
<br /> Length Surface Water(feet) Benzene MTBE Allowed to Decreasing i
<br /> feet u (u )
<br /> 1 100 250 n/a n/a No Yes
<br /> 2 250 1,000 3,000 1,000 No Yes
<br /> 3 250 . 1,000 no/ n/a Yes Yes for>/=5 N.
<br /> Vera Fischer,P.G.
<br /> ears 1 Engineering Geologist Br-
<br /> 4 1,000 1,000 1,000 1,000 No Yes
<br /> Site >100 300 ft west-southwest— 12,400 ug/L Not detected Not unknown i OF
<br /> '1,000 Industrial well measured
<br /> 450 to 500 ft east-well cc: Nuel Henderson,San Joaquin County Environmental Management,Stockton
<br /> Surface water>I Daniel Villanueva,Advanced GeoEnvironmental,Inc.,Stockton
<br /> Ken,C-.Lo..o SCD,P.E.,CH-I P—L.C.Ceee P.E.,SCEE,execvrne orecen l
<br /> I t UO gun C-1.1 Dr 0200,Ruch.Cw0ov0.CA MB7n www.wetunougece.q°v/cantnlre,iey
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