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�} TABLE 1 - CHECKLIST OF REQUIRED DVA
<br /> FOR NO FURTHER ACTION REQUESTS AT UNDERGROUND TANK SITES
<br /> I
<br /> i' Site Name and Location: AT&T Communications,90 West Turner Road, Lodi, San Joaquin County
<br /> 1. Distance to production wells for municipal, domestic,agriculture, Eight wells were identified within 2,000 feet of the
<br /> industry and other uses within 2000 feet of the site; former UST. The closest well was sampled and found
<br /> to be non-detect for constituents of concern.
<br /> 2. Site maps, to scale, of area impacted showing locations of former and existing tank systems, One 15,000-gallon diesel
<br /> 1 Y� UST was removed in,3/99.
<br /> excavation contours and sample locations, boring and monitoring well elevation contours,. Site maps are available in
<br /> gradients, and nearby surface waters, buildings, streets, and subsurface utilities; the various reports.
<br /> i
<br /> I 3. Figures depicting lithology(cross section), treatment system diagrams; Site lithology consists of silt,silty sand,',and
<br /> sand to 38 feet, the total depth investigated.
<br /> >I 4. Stockpiled soil disposed off-site(quantity); Approximately 371 tons of excavated soils were disposed off-site at BFl
<br /> p p (q y)' Landfill in Livermore.
<br /> 5. Monitoring wells remaining on-site, fate;
<br /> Three monitoring wells remain on-site. The wells will be properly destroyed
<br /> fylpending site closure.
<br /> '- — "'- �"-`_ "� �' A"` `The deptia to wa er varies from`281 30 fee"t,�an
<br /> Qd'
<br /> Y . Tabulated results of all groundwater elevations and depths to water,'
<br /> _6� the groundwater flow ranges from South to SW.
<br /> I; is
<br /> The maximum soil contamination shows TPHd at 4,900 mg/kg at
<br /> 0 7. Tabulated results of all sampling and analyses: f
<br /> 17 feet, which attenuates to 490 mg/kg at 25 feet. The maximum i
<br /> Detectionlimits for confirmation sampling groundwater contamination shows TPHd at 150 pg/l. TPHg,benzene,
<br /> j HLead analyses and MtBE were non-detect at acceptable detection limits.
<br /> 8. Concentration contours of contaminants found and those remaining in soil The extent of soil and groundwater
<br /> j 0 and groundwater, both on-site and off-site: contamination has been defined.
<br /> i# Y❑ Lateral and Y❑ Vertical extent of soil contamination
<br /> Latera!and Vertical extent of groundwater contamination
<br /> I` Based on no detected contaminants in site
<br /> L: 9. Zone of influence calculated and assumptions used for subsurface I
<br /> 0 remediation system and the zone of capture attained for the soil and monitoring wells,site remediation beyond
<br /> groundwater remediation system; :UST and impacted soil removal was not
<br /> required.
<br /> Y1 10.Reports/information yl� Unauthorized Release Form T] QMRs(December 2000 to October 200 1)
<br /> Y� Boring logs N� PAR FRP Y❑ Closure Report,July 2002.
<br /> Y� 11.Best Available Technology(BAT)used or an explanation for.not using BAT'. The UST and visually impacted soils were
<br /> removed.
<br /> fI
<br /> _0 12.Reasons why background wasps - Yarea o_
<br /> Soil and groundwater contamination in the f the former US -
<br /> unattainable-usingBAT,..- _ _._ ._ ina;.on remains _ T.
<br /> ._.. J
<br /> Y 13.Mass balance calculation of substance The consultant estimates that based on two soil samples, 1528 pounds or
<br /> treated versus that remaining; 248 gallons of petroleum hydrocarbons as diesel remain in site soils.
<br /> tBased on the limited soil contamination, a risk
<br /> 0 14.Assumptions,parameters, calculations and model used in risk
<br /> assessments, and fate and transport modeling; assessment was not required.
<br /> 15. Rationale why conditions remaining at site will not adversely Soil contaminated with diesel is limited in extent,and it
<br /> impact water quality, health, or other beneficial uses;and will continue to degrade.
<br /> By: Comments: The site is an active AT&T telecommunications facility. One 15,000-gallon diesel UST was removed from the
<br /> MH site in March 1999. Soil contamination was identified during the tank removal activities, and multiple soil borings were
<br /> completed to define the extent of soil and groundwater contamination. Three groundwater monitoring wells were installed
<br /> I in 12/00, and groundwater was monitored quarterly from 12/00 to 10/01. The maximum concentration of diesel identified
<br /> Date:
<br /> in groundwater is at 150 ygf!in MW-3, which is approximately 30 feet downgradient of the former UST area. Currently, all i
<br /> three monitoring wells are non-detect for all constituents of concern. Eight wafer supply wells were identified within 2,000
<br /> feet of the former UST area. Two of the wells are located at the AT&T facility at 130 feet north and 160 feet east of the
<br /> I 1011/02 former UST area, respectively. The closest well was sampled in August 1999 and found to be non-detect for all
<br /> j constituents of concern. Based on the limited extent of contamination and the current non-detect concentrations of diesel
<br /> in groundwater, Board staff concur with San Joaquin County's Closure Recommendation.
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