Laserfiche WebLink
40 C A M B R I A <br /> in flow direction are likely Continued quarterly monitoring and sampling is recommended to <br /> determine the predominant groundwater flow direction beneath this site <br /> RESPONSE TO AGENCY LETTER <br /> Equiva received SJCPHS/EHD's September 5, 2000 letter that documented the <br /> August 28, 2000 telephone conversation requesting additional analyses for this site <br /> Groundwater samples from all wells were analyzed for total purgeable hydrocarbons as <br /> gasoline, benzene, toluene, ethylbenzene, xylenes, MTBE, ethyl tertiary butyl ether, tertiary <br /> butyl alcohol, di-ispropyl ether, tertiary amyl methyl ether, 1,2-dichloroethane, and ethylene <br /> dibromide this quarter as requested Following are comments to the additional requests made <br /> in the letter <br /> Methanol and Ethanol Analyses Equiva did not have the groundwater samples analyzed for <br /> methanol or ethanol because neither of these is a constituent of Shell's fuel An additional <br /> concern is that methanol is a common laboratory contaminant, which may lead to false <br /> positive analytical results Ethanol was not detected during the fourth quarter 1999 event <br /> Continued Oxygenate Analyses* Your letter states that "changes in groundwater level and <br /> pumping rates throughout the season may affect the contaminant concentrations in the <br /> groundwater One round of sampling and analyses will not confirm the presence or absence <br /> of contamination in groundwater " We have been monitoring groundwater levels through <br /> one hydrologic cycle In each well, depth to water has fluctuated a maximum of five to eight <br /> inches throughout the entire year Therefore, there is no reason to think that groundwater <br /> concentrations will vary seasonally, and one quarter's data is sufficient to determine the <br /> absence of oxygenates in groundwater beneath the site Since no oxygenates were detected <br /> during the fourth quarter 1999 event or this quarter's event, Cambria recommends <br /> discontinuing oxygenate analyses, however, Equiva agrees to continue analysis for fuel <br /> oxygenates for three more quarters <br /> 0955 2 1 <br />