|
'-,�rABLE 1 -CHECKLIST OF REQUIRED DATk-,-
<br /> FOR NO FURTHER ACTION REQUESTS AT UNDERGROUND TANK SITES
<br /> Site Name and Location: Manteca Unified School District Grounds/Shop, 660 Mikesell Avenue, Manteca,
<br /> San Joaquin County(Lustis Case#391037)
<br /> Y 1. Distance to production wells for municipal, domestic, agriculture, A well survey in 2006 reported no wells located
<br /> industry and other uses within 2000 feet of the site. within 2,000'of the site.
<br /> Y 2. Site maps, to scale, of area impacted showing locations of any former One 1,000-gallon diesel,and one 1,000-gallon
<br /> and existing tank systems, excavation contours and sample locations, gasoline USTs were removed 11/98.
<br /> boring and monitoring well elevation contours, gradients, and nearby
<br /> surface waters, buildings, streets, and subsurface utilities;
<br /> Y 3. Figures depicting lithology(cross section), treatment system diagrams; Site lithology consists of clay,silt,and sand
<br /> to 36 feet, the total depth investigated.
<br /> N 4. Stockpiled soil remaining on-site or off-site disposal(quantity); The consultant did not report the amount and fate of the
<br /> soil removed from the tanks removal.
<br /> :ND 5. Monitoring wells remaining on-site, fate; Monitoring or remediation wells were not required by the lead agency.
<br /> 6. Tabulated results of all groundwater Depth to groundwater varied from 15 to 25 feet below ground surface.
<br /> elevations and depths to water, I The regional groundwater flow direction is to the North.
<br /> 7. Tabulated results of all sampling In 11/98, the maximum confirmation soil concentration was TPHd, 1,100 mg/kg. In
<br /> and analyses: 13100,fhe maximum soil'concenfrat/on was TPHd;68 mg/kg. Maximum gra
<br /> groundwater concentration in 12/00 was TPHd, 540 ug/L. In 6/07,all grab
<br /> Detection limits for confirmation groundwater results were non-detect.
<br /> sampling
<br /> QN Lead analyses
<br /> 8. Concentration contours of contaminants found and those remaining in soil The extent of contamination is adequately
<br /> and groundwater, and both on-site and off-site: defined by soil borings and grab
<br /> groundwater samples.
<br /> Y❑Lateral and El Vertical extent of soil contamination
<br /> FY
<br /> Lateral and M Vertical extent of groundwater contamination
<br /> 9. Zone of influence calculated and assumptions used for subsurface An engineered remediation was not required
<br /> remediation system and the zone of capture attained for the soil and by the lead agency.
<br /> groundwater remediation system;
<br /> 10.Reports/information ❑Y Unauthorized Release Form QN QMRs
<br /> FEWell and boring logsY PAR � FRP Y Other; Sensitive Receptor Survey
<br /> Y 1 11.Best Available Technology(BAT) used or an explanation for not using BAT, TRemoval of USTs and natural attenuation.
<br /> Y1 12.Reasons why background wads unattainable using BAT, Limited soil contamination and no groundwater pollution
<br /> remain on-site.
<br /> NJ 13.Mass balance calculation of substance treated versus that The consultant did not estimate remaining TPHd mass in
<br /> remaining;
<br /> soil.
<br /> N . 14_Assumptions-parameters, calculations and model-used _.. SoiL ESLs or Water Quality Go_aIs are not currently exceeded
<br /> in risk assessments, and fate and transport modeling;
<br /> Y 15. Rationale why conditions remaining at site will not Soil contamination is limited in extent and is not leaching
<br /> adversely impact water quality, health, or other beneficial into groundwater. Results of two investigations for
<br /> uses;and groundwater show a decreasing trend in concentrations to
<br /> non-detect.
<br /> By: J Comments: One 1,000-gallon diesel, and one 1,000-gallon gasoline USTs were removed 11/98 from the subject
<br /> �, site. In 11/98, the maximum confirmation soil concentration was TPHd, 1,100 mg/kg. In 12/00, the maximum soil
<br /> Date: concentration was TPHd, 68 mg/kg. Maximum grab groundwater concentration in 12/00 was TPHd, 540 ug/L. In
<br /> 8/28/2007 6/07, all grab groundwater results were non-detect. Soil contamination is limited in extent and is not leaching into
<br /> groundwater. Results of two investigations for groundwater show a decreasing trend in concentrations to non-detect.
<br /> Based upon the limited extent of contamination present in soil, and no exceedance of Region 2 Soil ESLs or Region
<br /> 5 Water Quality Goals, Regional Board staff concur with San Joaquin County's Closure Recommendation.
<br />
|