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Remediation Report - 152 East 1 I th Street, Tracy, California Page 16 contamination that had affected the site were located off the property at a location down the groundwater gradient, it was decided that groundwater pumping was not be required and may be counterproductive in the opinion of the SJCPHS representative, with which opinion the professional engineer in responsible charge of the remediation program concurred, essentially all contaminated soil had been successfully removed from beneath the property, and futher active remediation of the subsurface within the boundaries of the subject property would not be cost-effective, or necessary for closure of the site in accordance with the applicable regulations Also, such pumping would draw groundwater contaminated by high concentrations of gasoline upgradient from the source of the release into the area beneath the property from which contaminated soil had been successfully removed and replaced with clean, imported fill Accordingly the sump was removed and the sump pit carefully backfilled with compacted rock and Class II aggregate base On June 03, 1996 a notice requesting termination of authorization to temporarily discharge treated groundwater to the municipal storm-water sewer under the terms of NPDES Permit CA0082929 and General Order No 92-15025 was transmitted to the CRWQCB To complete the restoration of the site the curb and public side walk on the F Street frontage of the property that had been broken up during the excavation work was fully reconstructed according to the requirements and specifications of the City of Tracy Public Works Department That work was completed on, July 05, 1996 and the remediation contractor returned control of the 152 East l lth Street property to the owners on the same day TESTING AND PREPARATION OF SOIL PRIOR TO TREATMENT As previously noted, contaminated soil removed from beneath the 152 East l lth Street property was transported to a site on fallow agricultural land owned by the Navarras in a rural area off West Blewett Road southeast of Tracy in the Vernalis district of San Joaquin County That location is shown on Figure 7 It is more than 1000 ft from any structure Testing of Stockpiled Sail On March 22, 1996 the soil stockpile was quartered and sampled to determine the mean concentration of hydrocarbons it contained A total of five samples were taken - one from each quarter of the stockpile and one from the center The samples were recovered by driving a clean, 2 in , diameter by 4 in long, brass, sampling tube into the bottom of a pit dug into the stockpile at each of the five designated sampling locations until the tube was completely filled with soil Following sample recovery, each sample tube was cleaned externally, its ends covered with aluminum foil and it was closed with tightly fitting plastic caps The caps were secured with adhesiveless tape Each sample tube was then labeled for identification, t