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McBillin Real Estate Investment - 3 - 6 September 2016 2154 S. El Dorado Street Stockton, San Joaquin County While downgradient wells MW-8 and MW-9 have been below reporting limits for all analyzed constituents, deep groundwater has not been adequately delineated downgradient of these wells (northeast, east and southeast of the Site property). Deep borings 6-7 and B-8, near MW-8 and MW-9, detected benzene at concentrations of 760 ug/L and 410 ug/L, respectively, at a depth of 87-90 feet bgs. The lateral and vertical extent of groundwater impacts down-gradient of these borings, northeast, east, and southeast of the Site, needs to be delineated. In the Second Addendum due 31 October 2016, please include proposals for the installation of shallow wells near proposed deep wells MW-11 and MW-12, and for the collection of a sufficient number of groundwater samples to provide lateral and vertical delineation of petroleum pollution to the water quality objectives, northeast, east, and southeast of the Site, and in the intermediate water-bearing zone identified in the area. It does not appear that soil samples have been collected from less than 9 feet bgs at the Site. As such, LTCP Direct Contact risks cannot be adequately assessed. Shallow soil (0-5 feet bgs) at the Site needs to be assessed. Additional soil samples should be collected in areas where piping and dispensers may have been on the property, though we understand that no product piping was discovered during the tank removal in 2010, and thus the exact locations of piping and dispensers may not be known. Historical aerial photographs should be reviewed to provide clues as to the locations of former dispensers and piping. In the Second Addendum due 31 October 2016, please propose the collection of an adequate number of samples to sufficiently assess shallow soils between 0-5 feet bgs at the Site, including areas where piping and dispensers may have been, for comparison to Low Threat Closure Policy (LTCP). Soil samples should be analyzed for total petroleum hydrocarbons as gasoline (TPHg), benzene, toluene, ethylbenzene, xylenes (BTEX), and naphthalene. It is possible that the 550-gallon tank removed from the site (Tank #1) was a former waste oil tank. In order to properly assess the nature of the release, sample analysis related to waste oil tanks is required to include semi-volatile organic compounds (SVOCs), volatile organic compounds (VOCs) including tetrachloroethylene (PCE) and trichloroethylene (TCE), poly chlorinated biphenyls (PCBs), and Title 22 metals. It does not appear that soil samples collected from beneath former Tank #1 were analyzed for these constituents. In the Second Addendum due 31 October 2016, please include a proposal for the collection of soil samples below the former Tank #1. In summary, by 31 October 2016, please submit a Work Plan Second Addendum to include the following: A proposal for the installation of permanent soil gas wells constructed in accordance with the DTSC guidance. A proposal for shallow monitoring wells near proposed wells MW-11 and MW-12,