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r Page 2, 2360 Grant Line Road Prior to the February 14, 2005 letter In addition, from another quarter, possibly15' SECOR appears to have included data has not been reported to either SJCIEHD or 5, OnGeotrfigure u re in the eddendumr This data reported, S.JC/EHD can review and comment on it P operly 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 onginat extraction test, the differences being that SECOR is proposing a longer test and to use fewer monitorin Points than in the original test. SECOR did not Include any design Modifications to g 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 tlde? previously approYed by SJCIEHD. To verify earth t des�cSEHD recorrimeting another tnds water level nl nitortrtg in a well mare 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 o infusion test as proposed. SECOR has proposed to conduct the testagain, oxygen originally proposed and approved method Note that this test should JOorradeq�rate time for oxygen to migrate 5-10 feet cross-gradient into the observations wells; SJCIEHD 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-hexanol and that it was Possiblyfrom Pipe dope, SJCIEHD requested this conclusion be explained in response SECOR has submitted comments from Kiff Analytical stating that while they no material could find safety data sheets listing thhis chemical as an ingredient of pipe dope, ridiff 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 riot seethe 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 64 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 contarntriant in the aquifer that requires additional assessment It it is a CrosS-contaminant, how and at what point did it enter the sample? Haw can the answer be verified? In addition to 2-ethyl-l-hexanol, the sample in gr�estiort was reported to contain 0 74 4g/l 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 SJCIEHD 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,lune 17, 2005