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T'A16LE 1 -CHECKLIST OF REQUIRED DATA N-.011
<br /> FOR NO FURTHER ACTION REQUESTS AT UNDERGROUND TANK SITES
<br /> Site Name and Location 77 Eleven No. 19976, 1399 N.Main St., Manteca, San Joaquin County(RB#390928)
<br /> Y 1. Distance to production wells for municipal,domestic, A 1999 sensitive receptor survey reported 16 water supply
<br /> agriculture, industry and other uses within 2000 feet of wells within 2,000'of the Site. The nearest well is 200 south.
<br /> the site. The supply wells are not threatened by the petroleum
<br /> h drocarbons release.
<br /> Y 1 2.Site maps,to scale,of area impacted showing In 9/96, two 10,000-gallon and one 6,000-gallon gasoline
<br /> locations of any former and existing tank systems, USTs were removed.In 6/03, three 10,000-gallon gasoline
<br /> excavation contours and sample locations,boring and USTs were removed.Site maps and figures showing tank
<br /> monitoring well elevation contours, gradients,and locations,area of excavations,buildings and residual
<br /> nearby surface waters, buildings,streets,and pollutants were provided in investigation reports.
<br /> subsurface utilities;
<br /> Y1 3. Figures depicting lithology(cross Site lithology consists of clay,silt,and sand to 55, the total depth investigated.
<br /> section),treatments stem diagrams; All figures were provided in the investigation reports.
<br /> Y 4.Stockpiled soil remaining on-site Approximately 650 tons of soil was excavated and transported to Forward
<br /> or off-site disposal (quantity); Landfill in Manteca. Consultant estimated 16.1 lbs. (2.44 gal.)of TPH removed by
<br /> excavation.
<br /> Y 5. Monitoring wells remaining on-site, Sixteen(16)monitoring(MW--1 through MW-8, MW-1A, MW-4A and MW-5A, SG-
<br /> ate; 12 through SG-16)and four(4)remediation(SP-1 through SP-3, SP-1A) wells will
<br /> be properly destroyed prior to closure.
<br /> YJ 6.Tabulated results of all groundwater Tabulated data was provided in reports indicating depth to groundwater ranged
<br /> elevations and depths to water; from 13'bgs to 27'bgs. Groundwater flow varied from northwest to west-
<br /> northwest. Groundwater gradient varied from 0.001 ft/ft to 0.002 ft/ft.
<br /> 7.Tabulated results of all sampling All data was adequately tabulated in various reports.
<br /> and analyses:
<br /> Y❑ Detection limits for
<br /> confirmation sampling
<br /> QY Lead analyses
<br /> 8. Concentration contours of contaminants found and those remaining in The horizontal extent of the petroleum
<br /> soil and groundwater, and both on-site and off-site: pollution remains onsite. Vertical extent
<br /> was delineated by non-detect results at
<br /> Y❑Lateral and Y❑Vertical extent of soil contamination MW-1A
<br /> Lateral and Vertical extent of groundwater contamination
<br /> 9.Zone of influence calculated and assumptions used for subsurface Pilot study for 02 Injection demonstrated a
<br /> remediation system and the zone of capture attained for the soil and radius of influence at 55'.A full scale
<br /> groundwater remediation system; treatments stem ran from 3-03 to 9-12.
<br /> 10.Reports/information ❑Y Unauthorized Release Form ❑Y QMRs(60)9-98 to 1-13
<br /> DY Well and boring logs�Y PAR �Y FRP �y Other Soil Vapor Survey&Human Health Risk
<br /> Assessment,3-12;Site Closure Request, 11-13
<br /> Y 11.1.Best Available Technology(BAT)-used or Leak was stopped by removing tanks. Oxygen injection and natural
<br /> an explanation for not using BAT; attenuation were implemented as the BAT.
<br /> 12. Reasons why background was/is not Contaminant concentrations declined naturally and groundwater has
<br /> �,
<br /> enable usin BAT; been restored to Water Quality Objectives.
<br /> YJ 13.Mass balance calculation of substance Consultant estimates initial mass as 33.8 lbs. (5.12 gal.)in soil and
<br /> treated versus that remaining; negligible residual mass remains in soil and groundwater.
<br /> 7I, 14. Assumptions, parameters, calculations Site passed LTCP levels in soil and soil vapor,and is an active service
<br /> and model used in risk assessments, and fate station that is exempt from LTCP vapor intrusion limits. Consultant
<br /> and transport modeling; states site does not represent a significant environmental or health risk.
<br /> I, 15. Rationale why conditions remaining at Groundwater pollution was reportedly confined to the property limits.
<br /> site will not adversely impact water quality, Land use(commercial)is not expected to change in the foreseeable
<br /> health,or other beneficial uses; and future. WQOs were reached. Groundwater is no longer impacted.
<br /> By: JLB Comments: Multiple UST were removed at the subject site.Residual soil pollution presents a minimal threat
<br /> to human health and groundwater pollution is no longer present.Based on the lack of measurable pollution
<br /> Date: in groundwater, no foreseeable changes in future land use(commercial), and minimal risks from soil vapor
<br /> 4/22/2014 and soil, Regional Board-staff concur with San Joaquin County's Closure Recommendation.
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