Laserfiche WebLink
Draft AAFS Work Plan - 3 - 23 November 2010 <br /> without losing any key information and replace these borings with the additional <br /> groundwater monitoring well(s). <br /> SPECIFIC COMMENTS <br /> 1. Page 3, Section 1.3: This section indicates there is an existing 15,000 gallon UST in the <br /> proposed investigation area, but it is not shown on the referenced figure. Add this UST to <br /> Figure 2. <br /> 2. Page 6, Section 2.3: This section discusses the results for Boring B-28, but this boring is <br /> not shown on the referenced figure. Add this boring to Figure 3. <br /> 3. Page 8, Section 3.3: Revise this description of the groundwater monitoring well <br /> installations to indicate water-tight lockable well caps or plugs will be used. <br /> Also, this section should indicate the proposed well screen interval from 30 to 60 feet bgs <br /> may be modified based on the data collected from the investigation borings. If solvents <br /> rather than petroleum hydrocarbons are the primary contaminants of concern in the <br /> groundwater, then the proposed screen interval may not be optimal. <br /> 4. Page 11, Section 3.7.2: Extensive soil vapor sampling is proposed in the Draft Work <br /> Plan, but the discussion of soil vapor sampling procedures is lacking in details. It is not <br /> sufficient to state CANG will follow Cal EPA's Draft Advisory—Active Soil Gas <br /> Investigation (March 2010). Revise this section to discuss shut-in testing (vacuum test) <br /> testing, purge volumes, purge volume testing, leak testing, the frequency that duplicate <br /> samples and blank samples will be collected, ...etc. <br /> Based on problems recently observed at other sites, Central Valley Water Board staff <br /> recommends use of a shroud and a portable instrument that can quantify the tracer <br /> compound selected for leak testing, so any loose fittings can be tightened or replaced <br /> prior to sample collection. Without these additional measures, CANG may incur <br /> significant remobilization and retesting costs. Per the Draft Advisory, if the tracer <br /> compound is detected in Summa samples at concentrations that exceed the target VOC <br /> reporting limits by a factor of 10 or greater, the results may not be defensible and <br /> resampling is recommended. <br /> 5. Appendix B: Central Valley \Vater Board staff did not review the Health and Safely Plan <br /> (HASP) attached to the Draft Work Plan. CANG and their consultant (Oneida Total <br /> Integrated Enterprises) are responsible for maintaining a safe working environment <br /> during the proposed field work. <br /> If you have any questions, please contact me at (916) 464-4733 or email me at <br /> mpierce@waterboards.ca.gov. <br />