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` .a,E 1~ <br /> M EMORAND NI <br /> I <br /> CaUEPA r�r P art <br /> 11-!!: 2z Governor <br /> state water TO: Regional Water Quality Control Board UST Program <br /> Resources Managers and Local Oversight Program Managers <br /> Control Board <br /> 20 14 T strKc <br /> Sim 130 <br /> SacameaW,CA <br /> 95814 <br /> Mail Code G-8 <br /> (916)227-4319 FROM: aa.natton,Aa.na,-z, <br /> FAX(9 t6)227-1349 <br /> Underground Storage Tank Section <br /> DIVISION OF CLEAN WATER PROGRAMS <br /> DATE: AUG 2 2 1996 <br /> SUBJECT: NEW GUIDANCE ON GROUNDWATER MONITORING OF <br /> METHYL-TERT BUTYL ETHER (MTBE) FROM ACTIVE LUFT <br /> CASES <br /> As discussed in our 7uly 30, 1996, memorandum we have asked for your assistance in <br /> accessing the occurrence of MTBE in groundwater at LUFT sites statewide. <br /> Specifically, we have requested that you add MTBE to the list of gasoline components <br /> which are being monitored in groundwater aty our active LUFT sites. <br /> Because there have been many discussions as to the choice of analytical methods for <br /> detection of YITBE, we asked the Lawrence Livermore National Laboratory to evaluate <br /> the efficacy of existing analytical methods used for monitoring of BTEX gasoline <br /> components for the detection of MTBE. A copy of their report is attached. Based on <br /> Their findings and recommendations, we offer the following ,guidance: <br /> • It is recommended that EPA method 8020A (or 8021B) be used to detect BTEX and <br /> MTBE compounds in LUFT groundwater samples. <br /> Due to a low occurrence of false positives, it is recommended that at least one <br /> groundwater sample per site which was positive for MTBE by EPA method 8020A <br /> (or 8021B) be analyzed by EPA method 8240B (or 8260A) to verify the correct <br /> identification of MTBE (i.e. split samples from a minimum of one well from each <br /> site). We recommend that confirmation analysis be performed for the sample <br /> containing the highest MTBE concentration from the site based on method 8020A <br /> (or 8021B) values. For these samples the 8240B (or 8260A) value should be <br /> reported. <br /> RC^rc:ed?r-er Our mus:an ism preserve and enham=the quc fv aj rs:lfarnaa's warer resources,and <br /> enure thea roCer ci:oc,ran cnd rtfarenr use for d-e�rre�ir ajare:ent and f true genererpnr. <br />