SITE INFORMATION AND CORRESPONDENCE

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Raymond Greer -2 - 20 October 2015 15634 S. Steingul Road, Escalon San Joaquin County There does not appear to be any soil data from zero to 10 feet below ground surface, therefore, the threat from dermal contact or outdoor air risks cannot be determined based on criteria established in the State Water Resources Control Board Low Threat Closure Policy (LTCP). We request the following information to complete the SCM and Closure Request. 1. Cardino ATC stated in the SCM and Closure Report that the property owner of the private water supply well identified only as "Phillips" refused access to sample this off- site water supply well since purchasing the property in 2009. Please provide evidence of correspondence with the property owner indicating denial of access for sampling. Please submit copies of correspondence and a figure showing the location of the Phillips domestic well in a Site Conceptual Model Addendum, due by 30 December 2015 2. Construction details for the on-site and off-site water supply wells are needed to support the conclusion that these wells are not threatened from the residual pollution from this Site. Please submit well construction details in a Site Conceptual Model Addendum, due by 30 December 2015. 3. We request preparation of geologic cross-sections showing petroleum concentrations in soil and groundwater. Cross-sections should be constructed parallel to the groundwater flow direction and perpendicular to the groundwater flow direction through the underground storage tanks (USTs) pits and including the on-Site and "Phillips" water supply wells. This representation of the Site data is needed to evaluate potential data gaps in the delineation of the lateral and vertical extent of petroleum pollution in the subsurface. The cross-section should be submitted in a Site Conceptual Model Addendum due by 30 December 2015. 4. Cardino ATC did not include an assessment of threats from Direct Contact to contaminated soil and from Outdoor Air Exposure due to inhalation of contaminants volatilized to outdoor air. Please address Direct Contact and Outdoor Air Exposure using the soil data from 0 to 10' bgs, if it exists, or submit a Work Plan to collect shallow soil samples and anaylze for Benzene, Ethylbenzene, and Naphthalene in the Site Conceptual Model Addendum by 30 December 2015. In summary, the Central Valley Water Board staff expect to receive the following; • By 30 December 2015 submit an Addendum to the Site Conceptual Model including the following: o Correspondence from the property owner refusing access to allow access to sample the (Phillips) domestic water supply well. o Construction details for the on-site and off-site (Phillips) water supply wells. o Geologic cross sections, including soil and groundwater concentrations, oriented parallel and perpendicular to groundwater flow direction through the center of the former dispenser area, and including the "Phillips" and on-site water supply wells.