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(ABLE 1 -CHECKLIST OF REQUIRED DATE-,
<br /> FOR NO FURTHER ACTI[ON REQUESTS AT UNDERGROUND TANK SITES
<br /> Site Name and Location: Spreckels Sugar Co., Inc. (Former Holly Sugar), 20500 Holly Dr., Tracy, San Joaquin County
<br /> (RB#390132)
<br /> 7Y 1. Distance to production wells for municipal, domestic, Three inactive process supply wells are located 400'to
<br /> agriculture, industry and other uses within 2000 feet of the site, the southwest, 550'to the west, and 800'to the north. The
<br /> facility is closed and the wells were not impacted or
<br /> threatened.
<br /> Y, 2. Site maps, to scale, of area impacted showing locations of Two 1,000-gallon gasoline USTs were removed 10185
<br /> any former and existing tank systems, excavation contours and (Sites A and B), and one 10,000-gallon fuel oil
<br /> sample locations, boring and monitoring well elevation underground bunker UST was removed 1/11 during site
<br /> contours, gradients, and nearby surface waters, buildings, demolition,
<br /> streets, and subsurface utilities;
<br /> :YD 3. Figures depicting lithology(cross section), treatment system Site lithology consists of clay to 17', the total depth of the
<br /> diagrams; investigation. The nearby City wastewater treatment
<br /> ponds (WWTP) investigated to 100 bgs and reported
<br /> clay, silt,sand, and gravel,
<br /> Y 4. Stockpiled soil remaining on-site or off-site disposal (quantity), 1,700 yF of over-excavated soil was transported to
<br /> Forward Landfill in Manteca
<br /> Two remaining monitoring wells(MW-Al and MW-B1R)installed for the USTs
<br /> Y b Monitoring wells remaining on-site, fate; investigation will be properly abandoned. The City WWTP monitoring wells,
<br /> also used for the USTs investigation, remain for WDRs monitoring.
<br /> 6. Tabulated results of all groundwater Depth to groundwater varied from 4' to 10'bgs. Groundwater flow
<br /> elevations and depths to water; I direction was towards the northeast.
<br /> 7. Tabulated results of all sampling All data adequately tabularized in various reports, including closure report.
<br /> and analyses:
<br /> Y❑ Detection limits for confirmation
<br /> sampling
<br /> ❑Y Lead analyses
<br /> 8, Concentration contours of contaminants found and those remaining in soil and The extent of the identified
<br /> groundwater, and both on-site and off-site: contamination is described in the
<br /> reports.
<br /> ElLateral and El Vertical extent of soil contamination
<br /> Lateral and FY Vertical extent of groundwater contamination
<br /> 9. Zone of influence calculated and assumptions used for subsurface remediation An engineered remediation was not
<br /> system and the zone of capture attained for the soil and groundwater remediation required by the lead agency.
<br /> system;
<br /> 10.Reports/information ❑Y Unauthorized Release Form ❑Y QMRS 9/98 to 6/09
<br /> FYI Well and boring logs El PAR n FRP R Other Closure Report(12194)
<br /> Y 11 Best Available Technology (BAT) used or an explanation for not using USTs removal, soil over-excavation and
<br /> BAT; natural attenuation.
<br /> 12. Reasons why background was/is Minor residual soil and groundwater(MW-B1) contamination remain on-
<br /> ttairrahle using BAT; site.
<br /> N 13.Mass balance calculation of substance Mass was not calculated by the consultant.
<br /> treated versus that remaining;
<br /> 14. Assumptions, parameters, calculations RP's consultant(Ground Zero)states that based on soil and GW sampling
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<br /> and model used in risk assessments, and fate minimal threat by contact or vapor migration exists from residual impacts.
<br /> and transport modeling; WQGs(TPH) will be reached in 30 years.
<br /> Y 15. Rationale why conditions remaining at site Soil contamination reportedly is limited in extent. Water quality is
<br /> will not adversely impact water quality, health, seriously degraded due to WWTP salinity. All buildings have been
<br /> or other beneficial uses;and demolished and the site is vacant land next to a wastewater treatment
<br /> plant under WDRs. Land use(commercial)is not expected to change in
<br /> the foreseeable future.
<br /> By: JLB Comments Two 1,000-gallon gasoline USTs were removed 10/85, and one 10,000-gallon fuel oil UST was
<br /> removed 1/11 during site demolition at the subject site. Minor residual soil and groundwater contamination
<br /> Date: remains on-site. Based upon 17 monitoring events showing declining gasoline concentrations, the limited
<br /> 7/11/2011 extent of contamination reported in soil, groundwater reaching WQGs in 30 years, no foreseeable changes in
<br /> land use, and minimal risks from soil, soil vapor, and groundwater, Regional Board staff concur with San
<br /> Joaquin County's Closure Recommendation.
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