SITE INFORMATION AND CORRESPONDENCE_FILE 2

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Harry's Auto Mart November 2013 2662 North Wilson Way, Stockton Claim No: 15094 than 100 feet in length. There is no free product'-The nearest surface water body is greater than -1,000 feet from the defined plume boundary. The,regulatoryagency determines, based on an analysis of site specific conditions, which under urrent and reasonably anticipated near- term future scenarios,the contaminant plume posesa low threatto human health and safety and to the environment and water quality objectives will be achieved within a reasonable time frame. Indoor Vapor Risk from Residual Petroleum Hydrocarbons: The,case meets Policy Criterion 2a by Scenario 3a. The maAmum'benzene concentration in.,groundwater is less than 100 pg/L. The minimum depth to groundwater is greater than 5 feet, overlain,by soil containing less than 100 mg/kg of TPH. • Direct Contact Risk from Residual Petroleum Hydrocarbons: The°case meets Policy Criterion. 3a. Maximum concentrations in soil are less than those in Policy Table 1 for Commercial/Industrial use, and the.concentration limits fora Utility Worker are not exceeded. There are no soil sample results in the case record for naphthalene. However,-the relative concentration,of naphthalene in soil can be conservatively estimated using the.published relative concentrations of naphthalene and benzene in gasoline.. Taken from Potter and Simmons (1998), gasoline mixtures contain approximately 2 percent benzene and 0.25 percent naphthalene. Therefore, benzene can be directly substituted for naphthalene.concentrations with a safety factor of eight. Benzene concentrations from the Site are below the naphthalene thresholds in Policy Table 1.. Therefore, the.estimated naphthalene concentrations meet the thresholds in Table 1 and the Policy criteria for-direct contact by a factor of eight. It is highly unlikely that naphthalene concentrations in the soil, if any, exceed the threshold. Page 11-of 13