|
ABLE 1 -CHECKLIST OF REQUIRED DATA
<br /> FOR NO FURTHER ACTION REQUESTS AT UNDERGROUND TANK SITES
<br /> Site Name and Location: BP#11192/ConocoPhillips, 1403 Country Club Blvd.,Stockton, San Joaquin County
<br /> (RB#390424)
<br /> Y 1. Distance to production wells for municipal, A 2001 sensitive receptor survey reported three water supply wells
<br /> domestic,agriculture, industry and other uses located within 2,000'of the Site. The nearest well is 1,000'to the
<br /> within 2000 feet of the site. northwest.None of the wells are threatened by the release.
<br /> Y 2. Site maps, to scale, of area impacted showing locations of In 2/91, three 10,000-gallon gasoline, three 2,500-gallon
<br /> any former and existing tank systems,excavation contours motor oil and one 2,500-gallon waste oil USTs were
<br /> and sample locations,boring and monitoring well elevation removed. Site maps and figures showing tank
<br /> contours,gradients,and nearby surface waters,buildings, locations, excavations,building and residual
<br /> streets,and subsurface utilities; pollutants were provided in investigation reports.
<br /> Y 3.Figures depicting lithology(cross Site lithology consists of clay,silt,sand,and gravel to 140', the total depth
<br /> section), treatment system diagrams; investigated An ozone injection treatment system was constructed with a
<br /> designed 25 radius of influence.
<br /> Y 4.Stockpiled soil remaining on-site Approximately 1,750 y of excavated soil was removed and transported to an
<br /> or off-site disposal(quantity); unknown Class Ill landfill. Mass estimates for soil were not reported by the
<br /> consultant.
<br /> Y 5.Monitoring wells remaining on-site, Twelve(12)monitoring wells(MW--1,and MW-3 through MW-8)and twelve(12)
<br /> ate; remediation wells(SP-A through SP-H,SP-J,SP-K, VW-1 and VW-2)will be
<br /> properly destroyed prior to closure.
<br /> YJ 6. Tabulated results of all groundwater Tabulated data was provided in reports indicating depth to groundwater from
<br /> elevations and depths to water; 10'bgs to 32'bgs. Groundwater flow direction from northwest to northeast.
<br /> Groundwater gradient varied from 0.001 ft/ft to 0.002 ft/ft.
<br /> 7. Tabulated results of all sampling All data adequately tabularized in various reports,except the report for USTs
<br /> and analyses: removal was missing from the Regional Board and County files. The County USTs
<br /> Y removal permit and IT workplan showed all analyses,including waste oil analytes,
<br /> ❑ Detection limits for were reported from confirmation soil samples.
<br /> confirmation sampling
<br /> ❑Y Lead analyses
<br /> LyJ 8. Concentration contours of contaminants found and those remaining in The horizontal and vertical extent of the
<br /> soil and groundwater,and both on-site and off-site: petroleum pollution is confined to the
<br /> property limits.
<br /> 0 Lateral and 0 Vertical extent of soil contamination
<br /> Lateral and Vertical extent of groundwater contamination
<br /> 9.Zone of influence calculated and assumptions used for subsurface Multiple technologies were pilot tested but
<br /> remediation system and the zone of capture attained for the soil and failed until ozone injection remediation was
<br /> groundwater remediation system; implemented.
<br /> 10.Reports/informationFY] Unauthorized Release Form ❑Y QMRs(76)5-90 to 1-13
<br /> ❑Y Well and boring logs❑5 PAR ❑Y FRP ❑Y Other No Further Action Report, 6-13
<br /> YJ 11.Best Available Technology(BAT)used or Leak was stopped by removing tank and piping,over-excavation
<br /> an explanation for not using BAT; removed additional soil pollution. Use of additional cleanup technology
<br /> was attempted but proved unsuccessful after pilot testing for soil vapor
<br /> extraction,groundwater extraction,and dual phase extraction. Ozone
<br /> injection was chosen as the BAT and operated from 2002 to 2012.
<br /> M12. Reasons why background was/is not Soil pollution presents a minimal threat to human health and
<br /> finable using BAT; groundwater pollution is predicted to be restored in 18 years.
<br /> Y1 13.Mass balance calculation of substance Consultant estimated residual TPH mass as 7.32 lbs. (1.1 gallon)in
<br /> treated versus that remaining; groundwater. No estimate reported for mass removed by over-
<br /> excavation or other remediation was provided
<br /> Y 14. Assumptions, parameters,calculations Site meets the criteria in the LTCP for commercial use(active service
<br /> 7
<br /> and model used in risk assessments,and fate station). Consultant states site does not represent a significant
<br /> and transport modeling; environmental or health risk.
<br /> -y] 15. Rationale why conditions remaining at Soil and groundwater pollution is reportedly confined to the property
<br /> site will not adversely impact water quality, limits.Land use(commercial)is not expected to change in the
<br /> health,or other beneficial uses;and foreseeable future. WQGs will be reached by 2031. Groundwater plume
<br /> is stable and slowly decreasing in concentration.
<br /> By: JLB Comments:In 2/91,multiple USTs were removed at the subject site. Based on the stable and declining
<br /> concentrations in groundwater,no foreseeable changes in future land use(commercial),and no risks from
<br /> Date: soil vapor and soil,Regional Board staff concur with San Joaquin County's Closure Recommendation.
<br /> 8/26/2013
<br />
|