|
TABLe1 - CHECKLIST OF REQUIRED 641A
<br /> FOR NO FURTHER ACTION REQUESTS AT UNDERGROUND TANK SITES
<br /> Site Name and Location: Franklin High School,300 N.Gertrude Avenue,Stockton,San Joaquin County
<br /> Y 1.Distance to production wells for municipal, domestic,agriculture, A well survey in 2000 showed thhtaen private supply
<br /> industry and other uses within 2000 feet of the site; wells located between 800 feet and 2000 feet of the
<br /> site. The nearest downgradlent private supply well Is
<br /> located 1,560 feet from the site.
<br /> Y� 2. Site maps, to scale, of area impacted showing locations of former and existing tank One 500-gallon gasoline UST
<br /> was removed in December
<br /> systems,excavation contours and sample locations,boring and monitoring well elevation 1989. One 1,000-gallon and one
<br /> contours,gradients,and nearby surface waters,buildings, streets, and subsurface utilities, 6,600-gallon diesel USTs were
<br /> removed in October 1990.
<br /> 0 Y
<br /> 3. Figures depicting lithology(cross section), treatment system diagrams; Site lithology consists of sand,slit and clay,with discontinuous lenses of sandy slit at 62
<br /> and 110 feet The total depth investigated was
<br /> 120 feet
<br /> Fate of the excavated soil is unknown,although the tank removal report
<br /> Q 6 SiYedsoddi8poaedoff• i( rrit' ,
<br /> L'ta sslbhr s s -
<br /> 5. Monitoring wells remaining on-site, fate; One monitoring well has been Installed for this Investigation. The well(MW-
<br /> 1))will be properly destroyed pending site closure. Two ons Marley
<br /> Cooling Towers monitoring wells(MW-208 and MW-320)were also sampled
<br /> once in the investigation and revealed no petroleum hydrocarbons.
<br /> FY 6. Tabulated results of all groundwater elevations and depths to water, The depth to water varied from 52 to 60 feet. The
<br /> regional groundwater flow direction Is to the east
<br /> 07.Tabulated results of all sampling and analyses: In 1990 and 1991,soil analysis showed TPHd(84 mg/kg), TPHg(4,400
<br /> Y mg/kg),benzene(0.020 mg/kg),and MtBE(0.00752 mg/kg).
<br /> Yn Detection limits for confirmation sampling Groundwater monitoring results in 12102 were<50 Ng/L for TPHg,<0.5
<br /> Lead analyses pg/L for benzene,and<2 Ng/L for MtBE. Lead was not analyzed.
<br /> Q8. Concentration contours of contaminants found and those remaining in soil The extent of contamination Is defined by
<br /> and groundwater,both on-site and off-site: on-site soil borings and monitoring wells.
<br /> e
<br /> Lateral and Vertical extent of soil contamination
<br /> 8
<br /> Lateral and Vertical extent of groundwater contamination
<br /> Q9.Zone of influence calculated and assumptions used for subsurface Based n the limited extent of soil
<br /> remediation system and the zone of capture attained for the soil and contamination,an engineered remediation
<br /> groundwater remediation system; system was not required at this site.
<br /> 0-1
<br /> Q 10.Reports/information © Unauthorized Release Form nine QMRs(2199 to 12102)
<br /> 0 Boring logs N❑ PAR FRP Other (Additional Site Assessment Reports, 6/99 and 5/02)
<br /> a11.Best Available Technology(BAT)used or an explanation for not using BA T, Remove USTs,natural attenuation.
<br /> �Y d?acrga�itry corrcertrattara t ttrrr been a#�aiRest st efl mcrxFter: +rcfis. Minor;�-
<br /> -12 Awsone why background wsW& coil conbtmins ion r aces or lie:
<br /> unattainable using BAT,
<br /> Q 13.Mass balance calculation of substance The consultant estimates 35 gallons of TPHg and 0.0025 gallons of benzene
<br /> treated versus that remaining; remain in soil,and 0.00022 gallons of TPHg remain In groundwater.
<br /> 14.Assumptions,parameters,calculations and model used in risk A risk assessment was not required.
<br /> assessments,and fate and transport modeling;and
<br /> Ya15.Rationale why conditions remaining at site will not adversely Son contamination Is limited in extent,and based on
<br /> impact water quality,health, or other beneficial uses. nine sampling events,contamination Is not continuing to
<br /> leach to groundwater. Groundwater monitoring shows a
<br /> decreasing trend In concentrations.
<br /> By. Comments: One 500-gallon gasoline UST was removed from the subject site in December 1989. One 1,000-gallon and
<br /> 1LB one 6,600-gallon diesel USTs were removed from the subject site in October 1990. Multiple borings and one monitoring
<br /> well were completed in 1999 to delineate and monitor contamination at this site. Two onsite Marley Cooling Towers
<br /> Date: monitoring wells(MW-208 and MW-320)were also sampled once in the investigation and revealed no petroleum
<br /> hydrocarbons. Additional borings and grab sampling were completed in 1999 and 2002. Monitoring well maximum
<br /> 7/21/03 groundwater concentrations declined from 210 pg/L to<50 pg4.for TPHg, 2.3 p9l to<0.5 pg/L for benzene, and 51.4
<br /> pg/L to<2 pg/L for WE. Lead was not analyzed. Based on the limited extent of soil contamination and decreasing
<br /> contaminante w n
<br />
|