SITE INFORMATION AND CORRESPONDENCE

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page 2, 2360 Grant Line Road prior to the February 14, 2005 letter. In addition, SECOR appears to have included data from another quarter, possibly 1St quarter 2005, on figure 2 in the Addendum. This data has not been reported to either SJC/EHD or Geotracker. When the data is properly reported, SJC/EHD can review and comment on it. The March 2005 work plan to conduct an extended groundwater extraction test is almost word for word the same work plan SECOR submitted for the original extraction test, the differences being that SECOR is proposing a longer test and to use fewer monitoring points than in the original test. SECOR did not include any design modifications to demonstrate and compensate for the earth tidal effects they reported as being a factor in the previously conducted 24-hour extraction test. In lieu of answering SJC/EHD's request for a demonstration that the observed drawdown was an effect of earth tides, SECOR simply gave reference information. This is not sufficient justification to support a site- specific conclusion. There are several potential causes for groundwater level fluctuations of a few hundredths of a foot. What are the characteristics of the fluctuations previously observed that are the signature of an earth tide? Conducting another extraction test was previously approved by SJC/EHD. To verify earth tides, SJC/EHD recommends water level monitoring in a well more distant from the pumping well. Also, although its shorter screen length may cause some response lag, being only 5 feet from EX-1 well S-1 should also be utilized for water level monitoring. In lieu of demonstrating,justifying or explaining why they did not conduct the oxygen infusion test as proposed, SECOR has proposed to conduct the test again, per their originally proposed and approved method. Note that this test should allow for adequate time for oxygen to migrate 5-10 feet cross-gradient into the observations wells; SJC/EHD requests that calculations showing this be submitted with the report. Thank you for the copy of the chromatogram from the analysis of sample CPT-1-60. The inference that SECOR made in their September 30, 2004 report was that the detection of TPHg reported in this sample was actually 2-ethyl-1-hexanoi and that it was possibly from pipe dope. SJC/EHD requested this conclusion be explained. In response SECOR has submitted comments from Kiff Analytical stating that while they could find no material safety data sheets listing this chemical as an ingredient of pipe dope, Kiff believes there is a relationship between the detection of this analyte in groundwater samples and pipe dope based on their many years of testing water samples from groundwater treatment systems. SJC/EHD still does not see the connection between this explanation for the detection and the sample in question for this site, which was collected from a discrete CPT hydropunch boring at 60 feet below surface. Please provide the mechanism for this compound to be detected in the CPT water sample. In other words, how did it get there? What SJC/EHD is trying to get to is a technically sound demonstration by SECOR that 2-ethyl-1-hexanol is or is not a contaminant in the aquifer that requires additional assessment. If it is a cross-contaminant, how and at what point did it enter the sample? How can the answer be verified? In addition to 2-ethyl-1-hexanol, the sample in question was reported to contain 0.74 µg/I MtBE. Please submit to SJC/EHD documentation that 7-Eleven has taken possession of the Valero monitoring well within 30 days of the date of this letter or SJC/EHD will direct the current well owner to have it properly destroyed, and a work plan for 7-Eleven to continue their investigation will be due no later than June 17, 2005.