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1 <br /> M. Scott Mansholt -2 - 29 December 2004 <br /> ChevronTexaco <br /> Alden Park <br /> A wide range of polynuclear aromatic hydrocarbon compounds (PAHs) at or slightly above the detection <br /> limit was reported in MW-7; one well, MW-9 reported pyrene at 0.03 µg/L; with these exceptions, <br /> PAHs were ND in MW-9 and the remaining nine wells sampled. <br /> During this event, floating product thickness ranged from a sheen in one well (MW-21) and from 0.90 <br /> feet to a maximum of 3.58 feet in MW-18. Approximately 10 gallons of floating product was removed <br /> this quarter. Since product removal was initiated in April 1997, over 400 gallons have been removed <br /> from the monitoring wells containing product. <br /> Based on our review we have the following comments: <br /> • The report states that eleven samples (plus a duplicate) were collected for analysis. However, the <br /> text on page 2 discussing groundwater results and in the conclusions (page 3), states that MW-2 <br /> was sampled. Information provided on the field data sheets, figures, and in the tables, indicates <br /> that MW-2 was dry and could not be sampled; depth to water was not available as indicated. <br /> Additionally,MW-14 and MW-17 were omitted from this portion of the text,but according to <br /> other parts of the report it appears samples were collected for analysis. <br /> • Under the QA/QC discussion on page 3, the report stated that a"PAH" (pyrene)was reported in <br /> MW-3 and MW-3D. This appears to be an error since elsewhere in the text, tables and figures, <br /> MW-3 has contained floating product for some time. It appears that the correct well/samples for <br /> this discussion should be MW-9 and MW-9D. <br /> • The conclusions stated that three wells previously not reporting TPH-d now contain TPH-d. The <br /> explanation for the detections was that the new laboratory(Lancaster) analyzes groundwater <br /> samples using a TPH-d analysis reporting carbon chain values between CIO and Cts. The <br /> previous laboratory (Freidman and Bruya, Inc.) analyzed the carbon range from CIO to C25- <br /> • In conjunction, under the analytical results section on page 2,the TPH-d analysis indicated that <br /> the carbon range used this event was CIO to C25• However, the report on page 3 states that CLQ to <br /> Cts was used for the recent sampling event. Following review of the laboratory reports, it is not <br /> readily apparent which range of carbon chains was utilized for the current analysis. <br /> During the review of analytical groundwater data for delineation at OVP sites, one of several criteria <br /> Regional Board staff considers is a comparison of values relative to the taste and odor threshold of 100 <br /> µg/L for diesel. To maintain consistency between projects, the same approach is used for all OVP sites. <br /> If a different range of values is used by a new/different laboratory or analytical process to determine <br /> petroleum hydrocarbon concentrations, the results are inconsistent with previous results. <br /> The analytical discrepancies discussed above need to be reviewed to determine and confirm which <br /> method/processes the different laboratory(ies) used. To maintain consistency between previous, current, <br /> and future OVP investigations the analytical processes need to be the same. <br /> By 1 February 2005,please provide a plan and schedule (date) addressing the deficiencies noted above, <br /> including a discussion of corrective measures that will be implemented. The information needs to <br />