COMPLIANCE INFO - Laserfiche WebLink

Home Browse Search

Lee Higgins - 3 - 25 January 2011 Catellus Property Tracy, San Joaquin County • Shallow groundwater exceeds numerous California and Federal total dissolved solids standards for drinking water and agricultural purposes. Depth to onsite groundwater is approximately 36 to 40 feet bgs. Also, it is unlikely shallow onsite groundwater would be considered for a drinking water source and therefore the direct exposure route is incomplete. Therefore, health risks and hazards for potential residential exposure to onsite groundwater were not evaluated quantitatively. • The California Natural Diversity Database, 2009, maintained by California Department of Fish and Game, was reviewed to search for threatened, endangered, or sensitive species in the vicinity of the Site. Six threatened and endangered species sightings were listed in the vicinity of the Site. Two sightings of Swainson's hawk were noted within one mile. The property is within the sphere of influence of the 2004 City of Tracy General Plan designated "Urban Reserve 4" which indicates the area of the Site may be developed for industrial, commercial and office uses near California Interstate 205. There will be some low-density residential developments further from the highway. SAIC concluded that the future development is not likely to provide adequate habitat for the hawk or the other species noted in the vicinity. In summary, SAIC's report determined that the potential cancer risk to a potential future resident was 4E-06, which is within the range of risk management of 1 E-06 to 1 E-04. The non-cancer health hazard, at 0.003 is well below the de minimus level of 1 which is a conservative estimate of risk. This level of cancer risk and non-cancer health hazard exposure to onsite soils does not present an unacceptable risk to hypothetical future onsite residents. Based on my review, I have the following comments: • Consistent with other TAOC/OVP sites, a Soil and Groundwater Management Plan (SGMP) needs to be submitted. The SGMP designates Chevron as the responsible party and serves as a guideline for Chevron to implement for handling soil affected by the degraded crude oil that may be encountered during future Site activities. • Given that the areas of crude oil affected soil/groundwater are present within/beneath the W. Byron Road easement, UPRR tracks, active pipelines, it is unlikely drinking water wells would be installed or development allowed or completed in this utility corridor. • Central Valley Water Board staff concurs with the findings of the HHSE and related supporting documentation, and that the Site is a candidate for closure. A request for a No Further Action Required (NFAR) determination may be prepared. • Documentation to support a NFAR closure determination should be completed in accordance with California Regional Water Quality Control Board, Central Valley Region's 16 April 2004 update to Appendix A of the Tri-Regional Board Staff Recommendations for Preliminary Investigation and Evaluation of Underground Tank Sites - No Further Action Requests. Section 6.5 - NFAR for Cases Exceeding Water Quality Objectives should be followed for documenting Site conditions.