SITE INFORMATION AND CORRESPONDENCE FILE 2

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California Tank Lines, Inc. Page 2 3105 South EI Dorado Street August 17, 2011 Stockton, California 95206 • The Five-year Review Summary Report, dated 10 January 2011, issued by the State Water Resources Control Board Underground Storage Tank Cleanup Fund, states that "It is likely the contamination detected in MW-4 is from gasoline USTs located south of the site." • The groundwater flow direction has been toward the east and southeast at this and the Pacific Pride site located adjacent to the south side of this site; however, the groundwater flow direction has also been reported toward the north at the Pacific Pride site. • Taber used the Rockworks© program to interpret preferential lithologic pathways for petroleum hydrocarbon contaminants to migrate between this and the Pacific Pride site. Taber identified the depth interval where the greatest concentrations of contaminants have been detected at the California Tank Lines site as approximately 20 to 35 feet below surface grade (bsg). Taber described this depth interval as "a relatively continuous zone of clayey silt with sand interbeds between the most contaminated regions from both sites (MW-4 and P-2 from California Tank Lines and MW-7 near borings P-7, P-8 and P-9 from Pacific Pride)." Taber concluded that "These lithology types can facilitate migration of TPH-g and benzene through the groundwater zone at these depths." The EHD has reviewed the bore logs for boreholes GP-2, cone penetration test (CPT) boring P-2, MW-4 and GP-1 at the California Tank Line site; and MW-12, CPT borings P-7 through P-9 and MW-7 at the Pacific Pride facility. Based on the EHD cross section, it is not obvious that connecting sand layers exist at approximately 20 to 35 feet bsg to provide a conduit between MW-7 at the Pacific Pride site and MW-4 at the California Tank Lines site. Furthermore, groundwater analytical data revealed the following: • TPH-g was detected at 57 micrograms per liter (Ng/L) and benzene was detected at 2.8 pg/L in grab groundwater samples collected from GP-1 at approximately 35 feet bsg; GP-1 was advanced approximately 44 feet south of MW-4; • Groundwater samples collected from MW-12A, screened between approximately 35 and 45 feet bsg, have historically been non-detect for contaminants of concern; MW-12 is approximately 80 feet southeast of MW-4; • Grab groundwater samples collected between 36 and 40 feet bsg from P-8 were non- detect for contaminants of concern; P-8 was advanced approximately 90 feet southeast of MW-4; • 3,200 pg/L of TPH-g, 18 pg/L of benzene, and 590 pg/L of 1,2-DCA were detected in grab groundwater samples collected between 36 and 40 feet bsg from P-7; P-7 was advanced approximately 16 feet northeast of MW-7 and approximately 155 feet southeast of MW-4; • MW-1, screened between 30 and 50 feet bsg, is the only other monitoring well at the Pacific Pride site with high concentrations of contaminants of concern detected in groundwater; this monitoring well is approximately 160 feet south/southeast of MW-4 at the California Tank Line site. There exists one monitoring well at the Pacific Pride facility, MW-4 screened between 30 and 50 feet bsg, which is located approximately halfway between MW-1 at the Pacific Pride facility and MW-4 at the California Tank Line site. Groundwater collected from MW-4 at the Pacific Pride facility was non-detect for contaminants of concern when last this well was sampled in December 2010.