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Soil Suitability/Nitrate Loading Study 1rerracon Vacant Commercial Property w Stockton, California December 7, 2018 ® Terracon Project No. NA187056 laboratory detection limits for the contaminants of concern with the exception of MW-3 which reported 60 micrograms per liter (ug/L) MTBE and extraction well EW1 which reported TPHg (13,000 ug/L), benzene (210 ug/L), toluene (350 ug/L), xylenes (2,100 ug/L)and MTBE (390 ug/L) above the San Francisco Bay Regional Water Quality Control Board Tier 1 Environmental Screening Levels (ESLs). The TPHg and MTBE groundwater plume were reported at the southwestern comer of the site at depths greater than 50 feet bgs. Based on a review of the Site Closure Request, between the years 2003 and 2010 the on-site domestic groundwater well reported below laboratory detection limits for BTEX, MTBE, di- isopropyl ether (DIPE), ethyl tert-butyl ether (ETBE), tert-amyl methyl ether (TAME), tert-butyl alcohol (TBA), 1,2-dichloroethane (1,2-DCA) and other volatile organic compounds (VOCs). The adjoining northern, eastern and southern property groundwater wells were reported below laboratory detection limits for the contaminants with the exception of a single hit of chloromethane (1.3 ug/L) identified at the adjoining northern address of 4508 Gnekow in the year 2006. Analytical data did not include nitrate as N and/or DBCP. The Central Valley Regional Water Quality Control Board granted Speedy Food Mart regulatory closure in the year 2010. The client should be aware of potential environmental concerns associated with the former petroleum hydrocarbon release. 1.4.3 Water Sample Location According to Mr. Baglietto, the existing groundwater well is currently not in operation and has not been used for approximately ten years. Mr. Baglietto in i�d there is currently no electricity to the well and was not aware of a way to access the well to collect a groundwater sample. During Terracon's field activities the well was inaccessible due to a locked fence; however, based on observations of the well through the fence, a spigot was observed to be connected to the well tank. There did not appear to be any other access points to the well. Based on owner interviews and reported nonoperational well status, a groundwater sample was not collected. 1 .4.4 Groundwater Sample Analysis For the purpose of this report, the EHD requires the on-site groundwater well be sampled and analyzed for nitrate as N and dibromochloropropane (DBCP); however, based on reported nonoperational well status, a groundwater sample was not collected Refer to Section 1.4.2 for further discussion. 1 .4.5 Groundwater Sample Handling Not applicable (See Section 1.4.3). Responsive ® Resourceful s Reliable 10