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Map ID MAP FINDINGS Direction Distance EDR ID Number Elevation Site Database(s) EPA ID Number TRACY DEFENSE DEPOT(USARMY) (Continued) 1000182407 requirements of the ROD. DSERTS 67: DSERTS 67,also known as the Northern Depot Soils Area,is north of the storm drain and sewage lagoons.The site was reportedly used as a storage area for the National Stockpile of Strategic Metals.From shortly after World War 11(WWII)until the 1980s,ferrous chromium ore was stored at this site.From shortly after WWII until the 1970s, manganese ore was also stored in this area.From 1980 to 1986,lead ballast was stored in this area. Between 8 April 2002 and 31 July 2002,construction activities were conducted to install the aggregate base(AB)cover in the southeastern portion of DSERTS 67.The area of the AB cover measures 65,700 square feet,which is greater than the 63,500 square feet estimated in the Project Closeout Plan(Remedial Action Report),Northern Depot Area(DSERTS 67) Cover Installation,DDJC-Tracy. Gravel previously installed over 16,400 square feet to the north of the AB cover is consistent with the ESD,but is not the equivalent of the AB cover(see Section 6.3 for details on maintenance requirements for all gravel surfaces).Preexisting asphalt covers an additional 5,200 square feet to the north of the AB cover.In addition,the Ground-water Treatment Plant 1 (GWTP1)facility covers an area of 2,000 square feet of DSERTS 67,preventing exposure to contaminated shallow surface and near-surface soils.The remaining 11,900 square feet is covered by soil supporting a dense growth of grass.Three design data collection effort(DDCE)samples collected within the grassy area and one sample collected immediately north of the grassy area found arsenic and manganese concentrations to be below the cleanup standards of 48 milligram per kilogram(mg/kg)and 812 mg/kg for arsenic and manganese,respectively.These findings were documented in the approved Remedial Action Plan and,as a result,the grassy area was not disturbed during the remedial action. DSERTS 72 A stone drain and catch basin were installed in the Defense Site Environmental Reporting and Tracking System(DSERTS)72 site during 1998 and 1999.The site is predominantly covered with pavement,and is located westward of the sewage lagoons(SWMUs 2 and 3)and eastward of the stonnwater detention basin(SWMU 4).Results from the chemical analysis of soil excavated during the installation activities prompted the identification of this area as a new(with respect to the ROD),potentially contaminated area, and the site-investigation process was initiated. Between December 1998 and February 1999 a new storm drain and catch basin was installed west of SWMUs 2 and 3.Soil excavated as part of the storm drain installation was removed from a trench running north to south along the length of the sewage lagoons.This soil was temporarily stockpiled and sampled to classify it for use as backfill or for off-site disposal;the stockpiles have since been removed.Analytical results from the soil stockpiles indicated that several chemicals of potential concern(COPCs)were present and that further sampling was warranted.The area was subsequently identified as DSERTS 72. In October 1999 and March 2000, soil and groundwater were sampled to determine whether contamination existed beyond the area of excavation for the new storm drain.The results of the sampling effort are reported in the No Further Response Action Planned for Defense Site Environmental Reporting and Tracking System 72 report.This report also includes the results of a site-specific water quality assessment, performed to evaluate impacts to groundwater quality,and a risk assessment. The DSERTS 72 site is not a potential source of future groundwater contamination.Given the current land use,the contaminants at DSERTS 72 do not pose an unacceptable risk to human health.The risk assessment assumed continued industrial use at the depot and did not account for changes in land use.Because of the current and anticipated future industrial use of the depot,the remedial decision for DSERTS 72 is not based on risk to potential residents. Northern Depot Soils Area The Northern Depot Soils Area is a nonvegetated area immediately north of the Storm Water Detention Pond.The site was reportedly used as a storage area for the National Stockpile of Strategic Metals.From 1980 to 1986,lead ballast was stored in this area. TC3372962.1s Page41