|
n TAB 1 - CHECKLIST OFjREQUIRED WTA
<br /> FOR NO FURTHER ACTION REQUESTS AT UNDERGROUND TANK SITES
<br /> Site Name and Location: Stockton Municipal Utilities Dept., 1465 S. Lincoln Street, Stockton,San Joaquin County
<br /> ETI 1. Distance to production wells for municipal, domestic, agriculture, As shown in GeoTracker, the closest municipal well is
<br /> industry and other uses within 2000 feet of the site, approximately 2,300 feet northeast of the site. Multiple
<br /> LUST sites are located in close proximity to this site.
<br /> r
<br /> 0 2. Site maps, to scale, of area impacted showing locations of former and existing tank systems, Three oil USTs were
<br /> excavation contours and sample locations, boring and monitoring well elevation contours, removed in September 1993,
<br /> gradients, and nearby surface waters, buildings, streets, and subsurface utilities, and three fuel USTs were
<br /> removed in April 1995.
<br /> 3. Figures depicting lithology(cross section), treatment system diagrams; Site lithology consists of silty clay with minor
<br /> sandy.silt to 30 feet, the total depth investigated.
<br /> FE
<br /> 4. Stockpiled soil disposed off-site (quantity); -Approximately 125 cubic yards of soil was disposed off-site at the
<br /> French Camp Landfill in August 1996.
<br /> 5. Monitoring wells remaining on-site, fate; Monitoring wells were not installed during this investigation.
<br /> 6. Tabulated results of a!1 groundwater elevations and depths to water; Monitoring wells were not installed during this
<br /> investigation. Estimated flow is to the SE.
<br /> 7.Tabulated results of all sampling and analyses:
<br /> The maximum soil concentrations in;mg/kg show TPHd at 100, TPHg
<br /> at 6.0, total STEX at 0.48,lead at 20,and PCE at 0.048. Maximum
<br /> Detection limits for confirmation sampling concentrations in groundwater show,'TPHd at 89 pg/l,and PCE at
<br /> 0 Lead analyses 1.61rg/L All other constituents including MfBE were non-detect at
<br /> acceptable detection limits.
<br /> 8. Concentration contours of contaminants found and those remaining in soil The extent of soil contamination has been
<br /> 0 and groundwater,both on-site and off-site: defined. 'Based on the low concentrations
<br /> Y❑ Lateral and � Vertical extent of sotl contamination
<br /> in soil, the full extent of groundwater
<br /> ❑ Latera!and ❑ Ver[ical extent of groundwater contamination contamination was not required. Threegroundwater grab samples were collected.
<br /> 9. Zone of influence calculated and assumptions used for subsurface
<br /> 0 remediation system and the zone of capture attained for the soil and Based on the limited soil contamination,
<br /> groundwater remediation system; site rem6.dlatfon beyond UST and impacted
<br /> soil removal was not required.
<br /> y� 10.Reports/information y� Unauthorized Release Form QMRs
<br /> d
<br /> Y❑ Boring logs Hl PAR ❑ FRP ❑ Groundwater Investigation Report, February 2002 `
<br /> Y� 11.Best Available Technology(BAT)used or an explanation for not using BAT,• The.USTiand contaminated soils were I'
<br /> removed.
<br /> r. :�12.Reasons-wh- background wasfis"'
<br /> unattainable using BAT, Soil contamination remains in the former tank pit and piping areas.
<br /> TI 13.Mass balance calculation of substance
<br /> treated versus that remaining; Based on the limited soil contamination, a mass balance was not required.
<br /> a
<br /> 14.Assumptions,parameters, calculations and model used in risk Based on the limited soil contamination, a risk
<br /> assessment was not required.
<br /> assessments, and fate and transport modeling;
<br /> 15. Rationale why conditions remaining at site will not adversely .The US Ts and vlsually,,impacted soils were removed
<br /> 0 impact wafer quality, health,.or other beneficial uses;and from the tank pit areas: Diesel in groundwater is less
<br /> than the 100 Ng/1 SNARL level, and PGE in groundwater
<br /> is less than the 5 pg1l P,rimary MCL.
<br /> By: Comments: The site is a City of Stockton Municipal Utilities yard located in the industrial area of south Stockton. Three
<br /> MH 1000-gallon o!!USTs(one waste oil, one motor oil, and one hydraulic oil) were removed in September 1993, and three
<br /> 12,000-gallon fuel USTs(one diesel and two gasoline) were removed in April 1995. A waste oil piping line was closed in l
<br /> Date: place, and soil samples were collected at two feet below the piping. Soil contamination was identified during the tank and h
<br /> piping removal activities, and three soil borings and groundwater grab samples were collected for analysis. As presented
<br /> 5/6/02 above, low concentrations of petroleum hydrocarbons and PCE were identified in soil, and TPHd and PCE were identified
<br /> in groundwater below drinking water standards. Based on the!ow concentrations of contaminants at the site, and the
<br /> predominantly fine-grained site lithology, Board staff concur with San Joaquin County's Closure Recommendation.
<br />
|