|
TABL- 1 - CHECKLIST OF REQUIRED D fA
<br /> FOR NO FURTHER ACTION REQUESTS AT UNDERGROUND TANK SITES
<br /> Site Name and Location: Independent Trucking,401 South Lincolni1pproximately
<br /> reet,Stockton, San Joaquin County
<br /> f well receptor survey Identified three watersupply
<br /> 1. Distance to production wells for municipal, domestic, agriculture,
<br /> industry and other uses within 2000 feet of the site; ells within 2,000 feet of the site. The nearest well is
<br /> 1,440 feet southeast of the site.
<br /> 2. Site maps, to scale, of area impacted showing locations of former and existing tank systems, Site maps are provided in
<br /> excavation contours and sample locations, boring and monitoring well elevation contours, the various reports. Two
<br /> gradients,and nearby surface waters, buildings, streets, and subsurface utilities; USTs were removed from
<br /> the site.
<br /> 0 Y 3. Figures depicting lithology(cross section), treatment system diagra s; Boring logs show silty clay and silty sand to
<br /> 30 feet, the total depth completed.
<br /> 4. Stockpiled soil disposed off-site(quantity); The disposition of excavated soil during UST removal was not
<br /> iTJpresented It was likely returned to the tank pit excavation.
<br /> 5. Monitoring wells remaining on-site, fate; Three monitoring well remain on-site. The wells will be properly destroyed
<br /> Y pending site closure.
<br /> ti.VTabulated results of all groundwater elevations and depths to.water Groundwater levels varied from 12 to 15 feet below
<br /> --- ___
<br /> ground surtace,andflow'Is tofhe narfliea3t.='-' �
<br /> 7.Tabulated results of all sampling and analyses: Samples collec din January 2001 show TPHd at 210 Ng/I in only one
<br /> of the three on-site monitoring wells. All other constituents including,
<br /> F-71Detection limits for confirmation sampling MtBE, and other fuel oxygenates are non-detect at acceptable
<br /> ©Lead analyses detection limits. Groundwater samples analyzed in October 2001,
<br /> reported lead at<5 pg/1.
<br /> 8. Concentration contours of contaminants found and those remaining!n soil The highest concentrations of soil
<br /> 0 and groundwater, and both on-site and off-site: contamination were Identified at 25 to 30
<br /> © Lateral andY❑ Vertical extent of soil contamination feet in one boring. The depth to
<br /> Lateral and ❑ g
<br /> Vertical extent of groundwater contami ation groundwater varied from 12 to 15 feet
<br /> below round surface.
<br /> 9. Zone of influencecalculated and assumptions used for subsurface Based on the limited contamination,site
<br /> 0 remediation system and the zone of capture attained for the soil and remediation beyond UST removal was not
<br /> groundwater remediation system; required.
<br /> El 10.Reports/information y❑ Unauthorized Release Form Y❑ Q Rs(12/99, 6/00, 10/00, 1/01, and 10/01)
<br /> 9 Boring logs 0 PAR 0 FRP Y❑ Other(No Further Action Request)
<br /> 11.Best Available Technology(BAT)used or an explanation for not using BAT, Remove the USTs to eliminate the source of
<br /> contamination.
<br /> 0 12.Reasons why background was/is TPHd contamination remains in groundwater in one monitoring well. The
<br /> unattainable using BAT,' -
<br /> .,remaining contamination does not present a significant threat to water quality.
<br /> .. r
<br /> N� 13.Mass balance calculation of substance Based on the limited gr undwater contamination, the remaining mass of
<br /> treated versus that remaining; contamination in soil and groundwater was not required.
<br /> N 14.Assumptions,parameters, calculations and model used in risk Based on the limited groundwater contamination, a risk
<br /> assessments, and fate and transport modeling; assessment was not required.
<br /> 15. Rationale why conditions remaining at site will not adversely R maining contamination is limited in extent, and
<br /> impact water quality, health, or other beneficial uses,and c ncentrations are decreasing. Contamination will
<br /> n turally degrade.
<br /> By: Comments:Independent Trucking and Delta Paper formerly o copied the site. One 550-gallon gasoline UST was
<br /> MH removed in September 1999, and another UST of unknown qu ntity and volume was removed prior to 1984. Soil and
<br /> groundwater samples collected during UST removal in Septe ber 1999 showed contamination, and multiple borings and
<br /> three monitoring wells were installed in December 1999. The Wells were monitored from December 1999 to
<br /> Date: January 2001, and only TPHd was confirmed in one of the three monitoring wells. Concentrations of TPHd decreased
<br /> 1/31/02 from 810 pg/7 to 210 Ng/l during the four quarters of monitoring MTBE was identified at a maximum of 1.4 pg/l in one well
<br /> in December 1999;but it was not confirmed in the following sa rnpling events. The remaining contamination in
<br /> groundwater is limited in extent, and will naturally degrade. B sed on the site investigation and activities completed to
<br /> date, Board staff concur with San Joaquin County's closure recommendation.
<br />
|