SITE INFORMATION AND CORRESPONDENCE_CASE 2

Home Browse Search

Sierra Lumber Case#2 September 2014 375 Hazelton Avenue, Stockton Claim No: 8478 Rationale for Closure under the Policy • General Criteria: The case meets all eight Policy general criteria. • Groundwater Specific Criteria: The case does not meet Policy criteria because the contaminant plume that exceeds water quality objectives is not defined. • Vapor Intrusion to Indoor Air: The case meets Policy Criterion 2b. Although no document titled "Risk Assessment" was found in the files reviewed, a professional assessment of site-specific risk from exposure through the vapor intrusion pathway was performed by Fund staff. The assessment found that there is no significant risk of petroleum vapors adversely affecting human health. The Site is paved and accidental exposure to site soils is prevented. The onsite building is a warehouse with multiple rollup doors that would prevent the accumulation of soil vapors in the building. In addition, as an active lumber mill, there is adequate air exchange provided by the building's ventilation systems required to control dust generated during site activities. • Direct Contact and Outdoor Air Exposure: 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 for a 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 used as a surrogate 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. Objections to Closure and Responses According to the Path to Closure page in GeoTracker, finalized on December 16, 2013, the County opposes closure because: • Inadequate conceptual site model. RESPONSE: Adequate data is available in GeoTracker to prepare a conceptual site model. • Secondary source remains. RESPONSE: Secondary source as defined by the Policy was removed by excavation and active remediation. • The case does not meet Policy groundwater criteria. RESPONSE: We concur. • The case does not meet Policy vapor criteria. RESPONSE: The case meets Policy Criterion 2b. Page 2 of 3