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<br /> `MILE 1 -CHECKLIST OF REQUIRED DATA
<br /> FOR NO FURTHER ACTION REQUESTS AT UNDERGROUND TANK SITES
<br /> Site Name and Location: H&H Engineering and Construction Facility, 212 Industrial Drive,Stockton, San Joaquin County
<br /> (Lustis Case#391003)
<br /> A well survey in 2000 reported 6 municipal or
<br /> y 1. Distance to production wells for municipal, domestic, agriculture, irrigation wells within 2000 feet of the site: 1000 ft
<br /> industry and other uses within 2000 feet of the site. west, 1600 ft southwest;1800 ft east, 1800 ft
<br /> northeast,and 1300 and 9400 ft northwest. !
<br /> 2. Site maps, to scale, of area impacted showing locations of any former One 1,000-gallon gasoline UST was removed
<br /> Y and existing tank systems, excavation contours and sample locations, without a permit in 1987. A groundwater
<br /> boring and monitoring well elevation contours, gradients, and nearby investigation for an unrelated SLIC case
<br /> surface waters, buildings, streets, and subsurface utilities; I discovered the UST pollution in 3/98.
<br /> Site lithology consists of clay,silt,and sand F
<br /> Y 3. Figures depicting lithology(cross section), treatment system diagrams; to 53 feet, the Iotal depth investigated.
<br /> N. 4. Stockpiled soil remaining on-site or off-site disposal(quantity);
<br /> The fate and amount of soil removed was not specified.
<br /> YD 5. Monitoring wells remaining on-site, fate; Three monitoring wells(MW-1 through MW-3)remaining on-site will be
<br /> ro erly abandoned.
<br />! Depth to groundwater varied from 26 to 38 feet below ground surface.
<br /> 6. Tabulated results of all groundwater The groundwater gradient was 0.01 ft/ft,and the downgradient direction
<br /> elevations and depths to water,
<br />` 7..Tabulated results of all sampling In 2198, maximum soil concentrations were TPHg, 260 mg/kg;benzene, 6.8 mg/kg;
<br />` and analyses: toluene;21 mg/kg;ethylbenzene, 15 mg/kg;and xylenes, 34 mg/kg. In 3/05,all soil
<br /> concentrations were ND. Maximum grab groundwater concentrations in 3/98&
<br /> E 0 Detection limits for confirmation 8/98 were TPHg, 11,000 ug/L;benzene, 10,000 ug/L;toluene, 250 ug/L;
<br /> ethylbenzene, 290 ug/L;and xylenes, 970 ug/L. In 3/07, all groundwater monitoring
<br /> sampling well concentrations were ND.
<br /> ❑_- Lead analyses
<br /> 8. Concentration contoursof 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,grab groundwater
<br /> samples, and monitoring wells.
<br /> Lateral and 0 Vertical extent of soil contamination
<br /> Lateral and Vertical extent of groundwater contamination.
<br /> 9. Zone of influence calculated and assumptions used for subsurface An engineered remediation system was not
<br /> remediation system and the zone of capture attained for the soil and required by the lead agency.
<br /> groundwater remediation system;
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<br /> 10.Reportsl. information QY Unauthorized Release FormFYJQMRS(18 from 10198 to 3107)
<br /> Welland boring logs PAR ❑N FRP ❑y Other,"Sensitive Receptor Survey, Human Health Risk
<br /> Screening Evaluation;Request for'Closure
<br /> Y 11.Best Available Technology(BAT)used or an explanation for not using BAT, Removal of UST and natural attenuation. "
<br /> Limited soil contamination and minimal groundwater
<br /> y 12.Reasons why background wads unattainable using BAT, pollution remain on-site.
<br /> 13:Mass balance'calculation of substance.treated versus drat` -in-2005-the consultant,estimated 30-gallons-of-TPPPg1remain- "
<br /> in soil,and 0.7 lbs of TPHg remain in groundwater.
<br /> remaining, !
<br /> Y 14. Assumptions,parameters, calculations and model used Residual soil contamination does not exceed ESLs. The
<br /> in risk assessments, and fate and transport modeling; Water Quality Goals(WQGs) have been reached. In 8/06 a
<br /> risk assessment did not find a significant risk from residual
<br /> soil contamination and groundwater pollution.
<br /> 7Y 15. Rationale why conditions remaining at site will not Soil contamination is limited in extent. Results of 18
<br /> adversely impact water quality, health, or other beneficial quarters of groundwater monitoring show a decreasing
<br /> uses;and trend in concentrations to ND.
<br /> By: JLB I Comments:One 1,000-gallon gasoline UST was removed without a permit in 1987 from the subject site. A
<br /> groundwater investigation for an unrelated SLIC case discovered the UST pollution in 3/98. Twenty borin s
<br /> Date: were advanced and three monitoring wells(MW-1 through MW-3) were installed for the investigation.
<br /> 9/12/2007 Residual soil contamination does not exceed ESLs. The Water Quality Goals(WQGs)have been reached.
<br /> ` Soil contamination is limited in extent. Results of 18 quarters of groundwater monitoring show a decreas ng
<br /> trend in concentrations to ND. Regional Board staff concur with San Joaquin County's Closure
<br /> Recommendation.
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