ARCHIVED REPORTS XR0001567 - Laserfiche WebLink

Home Browse Search

r1 ! • CONTAMINATED GROUNDWATER REMOVAL On July 7, 1999 approximately 7,000 gallons of contaminated groundwater was pumped from the excavation pit by D A Parrish and Sons Pumping Service The water was transported to the Stockton Wastewater Disposal Facility for disposal under City of Stockton permit Copies of the manifests are included in Attachment C CONTAMINATED SOIL DISPOSAL On April 15, 1999 a total of 144 cubic yards of soil generated during the UST removal were trucked to Forward Landfill for disposal 216 cubic yards of contaminated soil generated during the initial phase of excavation were trucked to Forward on June 23, 1999 54 cubic yards 1 generated during the final phase of excavation were trucked to Forward on July 7, 1999 Copies of the non-hazardous waste manifests are included in Attachment C MI CONCLUSIONS o1c- . • The lateral and vertical extent of soil contamination has been defined and the contaminated soil removed Approximately 270 cubic yards of contaminated soil was removed from the former UST _ �1 system location during the two phases of excavation An additional 144 cubic yards of contaminated tank pit backfill had been removed prior to this work This corrective action appears to have been successful in eliminating the threat to groundwater the material posed As indicated by the analytical results of the excavation soil samples, and the soil samples previously collected from borings, no contaminated soil of significance remains at the site A cross section depicting the original extent of soil contamination is shown on Figure 4 • Groundwater contamination has been identified TPHd and MTBE in the groundwater within the excavation pit were at elevated levels This confirms the results of the water sample previously collected from soil boring S134 However, results of groundwater sampling from boring SB3, northeast of the excavation, had non-detectable levels of target analytes Groundwater flow is expected to be northeasterly_in the site vicinity Impacted groundwater _ may be localized in the immediate vicinity of the former USTs • Concentrations of MTBE contained in the water samples collected from the excavation were elevated, however, the levels detected in the soil samples are several orders of magnitude less than those in groundwater It appears that the source for groundwater contamination by MTBE was localized between the former UST location and the former western dispenser island and has been removed Woolsey/repotts/sodxsum doe 5