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Wm. J. Hunter & .Associates � 2220 Loma Vista Dr Registered Geologists i- Sacramento, CA 95825 Petroleum& Mineral Appraisers (916) 972-7941 FAX (916) 972-1683 July 12 , 1994 Michael Collins , REHS San Joaquin County PHS Environmental Health Division 445 No San Joaquin Street Stockton, CA 95202 Ref FOURTH QUARTERLY GROUNDWATER MONITORING REPORT, 1876 Country Club Drive , Stockton, Site Code 1844 Dear Michael , We are enclosing the results of the fifth groundwater measure- ments , sampling & laboratory results done on April 29, 1994 , covering the above property Included are copies of the field logs made by Del-Tech, a table summarizing sampling results , laboratory reports , a site map showing the directions of the hydraulic gradients measured to date, and a map showing the results of a soil vapor survey that was conducted in March of this year A review of the most recent work is discussed below . 1 The water table was measured at an average depth of 21 32 ' bgl , this is the highest level since measurements began in April , 1993 The total change in elevation has been slightly over one foot in the past year 2 ]2,LATE I shows the direction of measured gradients over the past year; the latest one indicates an ESE direction Three of the five measurements have shown an easterly direction, although the gradient is very low at this location The latest measure- ment indicates an easterly gradient at approximately 1 3' per mile 3 As summarized on TABLE 1 . the levels of BTEX measured in MW-1 have increased since the last sampling in January Benzene in MW--2 was lower compared to the Nov 1993 sampling, but higher than in Jan 1994 Toluene, ethylbenzene & xylene were non- detect in the latest sampling, and TPHG had gone down compared to the last two tests MW-3 revealed lower levels of BTEX & THPG compared to the January sampling COMMENTS 1 . High levels of BTEX still exist in the groundwater beneath the site • 1