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' Emergency Remediation - 2480 Tracy Blvd., Tracy, CA. • Page 5 1 The results of the first soil and groundwater samples recovered from beneath the site were reported by Chromalab on April 8, 1996 and are summarized in Tables 1 and 2 respectively. (Note: The certificates of analysis and related chain-of-custody records for all subsurface soil and groundwater samples are compiled in Appendix A.) The laboratory results showed that the groundwater beneath the site is contaminated by gasoline with the concentration of total petroleum hydrocarbons (quantified as gasoline) measured in sample WATER 1 amounting to 1,500 pg/L (parts per billion) with commensurate concentrations of benzene, toluene, ethylbenzene and xylene isomers. Sample WATER 1 also contained MTBE at a concentration of 21 µg/L. The soil samples recovered from test pit in the basement excavation at depths between 8.5 ft. and 8.9 ft below the original ground surface were affected by gasoline at concentrations up to 2500 mg/Kg (parts per million), including proportionate quantities of the BTEX compounds. MTBE was present in these samples at concentrations between 4.7 and 5.4 mg/Kg. PLAN FOR EMERGENCY REMEDIATION At the close of the April 3rd meeting, after information about the status of the site and the ' extent and characteristics of the contamination that had been gathered up until that time had been reviewed and the first soil and groundwater sample had been recovered from the subsurface, it was agreed that a plan for emergency remediation should be developed as soon as possible. The emergency plan, if approved by the SJCPHS, would be used to guide further investigation into the extent and characteristics of the contamination and to provide for a remediation program that would permit the general construction contractor ' to resume work on the new car-wash and lubrication-service facility with minimum delay. It was further agreed that a strategic element of the emergency remediation plan would be excavation of the minimum volume of contaminated soil necessary to permit completion of construction. Short-term pumping, treatment, and discharge of contaminated water, sufficient to permit the basement structure to be completed in a dry excavation, would also be integral to the plan. The treatment of contaminated groundwater and soil would take place either on-site or off-site prior to disposal of the treated water. It was understood that, if the volume of contaminated soil that had to be managed was not too great for it to be adequately treated without it having to be taken off the site, preference would be given to on-site treatment and recycling of the treated material in beneficial use by incorporating it into the construction of the new car-wash and lubrication-service facility. Immediately following the on-site meeting, The San Joaquin Company prepared a plan for emergency remediation (Ref. 1 ) and submitted it to the SJCPHS for review. That agency approved the emergency plan that same day, April 3, 1996, and authorized work to proceed without delay.