Laserfiche WebLink
401 North San Jose Street <br /> San Joaquin County - 2 - 18 August 2010 <br /> 1. We are concerned with the lack of information regarding the former facility and it's <br /> decommissioning. In recent work at fuel facility sites on the waterfront of the Stockton <br /> Sip Channel, old tanks and pipelines have been discovered during the course of <br /> excavation, even after geophysical surveys were done. Historical aerial photographs <br /> could be a useful tool for identifying former facility features. While the proposed <br /> geophysical survey at the site will also be useful, at some point, Chevron should <br /> consider investigation by trenching, especially along the former ship off-loading pipeline <br /> alignment. At other sites, trenching was the most successful method of identifying <br /> subsurface items (tanks, pipeline corridors, etc.) and determining the degree of <br /> contamination associated with those facilities. <br /> 2. The proposed investigation does not address the potential for contamination in deeper <br /> zones of soil and groundwater. At a nearby petroleum bulk plant site, petroleum has <br /> affected groundwater at a depth of approximately 150' below ground surface. <br /> Additional investigations will need to be performed in the deeper soils and groundwater <br /> to define the vertical extent of contamination, especially once contamination source <br /> areas are identified. <br /> 3. Existing site data show that the assumed source area at the center of the site contains <br /> the highest concentrations of contaminants. The work plan proposes to install four <br /> groundwater monitoring wells around the site, none of which are in the assumed source <br /> area. A monitoring well needs to be installed in the source area so that condition of the <br /> source area groundwater can be assessed. Given the likelihood of free product in that <br /> area, the well in the source area should be constructed so as to allow for testing of free <br /> product removal from the well. For example, a 4" diameter well, rather than a typical 2" <br /> monitoring well, would be better suited for such testing. <br /> 4. The work plan proposes to test for CAM 17 metals, TPH, and fuel oxygenates. Fuel <br /> oxygenates will be analyzed for using EPA Method 8260. Chevron should perform <br /> some limited testing for a full range of VOCs and SVOCs. While lead is an analyte in <br /> the CAM 17 metals, Chevron needs to analyze samples for lead with a lower detection <br /> limit than EPA Method 6010 provides. For example, Method 6010 has a lead detection <br /> limit of 3 pg/L in water. The California Public Health Goal is 0.20 pg/L in water. Also, <br /> tetraethyl lead (a former gasoline additive) has an IRIS reference dose of 0.0007 pg/L <br /> in water. EPA Method 6020 has a detection limit of 0.25 pg/L for lead in water. <br /> Chevron should analyze the soil and groundwater samples for lead using EPA Method <br /> 6020. Naphthalene in a commonly encountered constituent of concern at bulk fuel <br /> facilities. Chevron needs to analyze the soil and groundwater samples for naphthalene <br /> in addition to the previously mentioned analytes. <br /> 5. Chevron should collect some samples for laboratory analysis such that data can be <br /> compared to the otherwise qualitative ultra-violet optical screening (UVOST) data. <br /> 6. Section 3.4 of the work plan proposes to collect two shallow soil samples ranging in <br /> depth from 0 to 3 feet below ground surface. Please provide a rationale for the <br /> collection and depth selection of these shallow samples. <br />