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L/ �011� Christopher M. Palmer, PG, CEG, HG, Consulting Hydrogeologist 1345 Kimberly Drive San Jose, CA 95118 ph.408/267-5238;fax 408/267-7396 CMPRGCEGHG@aol.com Soil samples collected at that time showed 590 parts per million (ppm) Total Petroleum Hydrocarbons as Gasoline (TPHG), 9,200 ppm and a modified TPHD analysis that quantified up to 7,200 ppm TPH Motor Oil and 28,000 ppm of an unknown hydrocarbon. Low levels of Toluene, Ethylbenzene and Xylenes were also observed. The sample collected under the 650-gallon tank also showed 1 ppm Perchloroethylene (PCE). Approximately 125 cubic yards of contaminated soil was excavated from the UST locations and properly disposed off-site, and the sidewalk was repaved. Six exploratory borings were drilled and sampled in February 2003 around the former underground tank pits north of the 68 11th Street site. The 1993 tank removal data showed low levels of TPHD in soil and groundwater samples. Samples collected from under the former tank pit locations, and from across 11th Street in apparent down gradient direction revealed presence of interpreted degraded TPHD. TPHG was detected in groundwater under the tank pits in groundwater, but was not detected in the down gradient samples. One very low occurrence of MTBE at 16 micrograms per liter (ug/1) was considered anomalous since it occurred in the middle of the street. The nearby subsurface sewers were surmised to be a possible MTBE source. The PCE source was also anomalous and assumed to have originated from an upgradient source. SJCEHD required installation of three groundwater monitoring wells following a review of Wright's 2003 study. The main objective of the 2008 monitoring well installation and assessment was to evaluate the current groundwater conditions and to ascertain potential health hazard or risk due to petroleum hydrocarbon contaminants. The groundwater data indicated that a groundwater threat was not present based on monitoring data. The SJCEDH has concurred with this conclusion and indicated that the site qualified for no further action required status in their case closure summary letter dated August 27, 2012. 4.0 Field Methods —Well Destructions Monitoring wells MW-1, MW-2, MW3 were destroyed using approved methods approved by the SJCEHD. A SJCEHD representative observed the well destructions. The depth to groundwater and total depth of each well was measured prior to destruction and compared to each well boring log and well construction detail. The depth of destruction was selected (one foot below the completed depth shown on each log) and each well casing, screen, filter pack and grout sealant was completely removed by drilling. Any groundwater displaced to the surface was pumped and containerized. Page 2 of 4