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1 . <br /> LEEDSMILL•MERRENHOFF.FMC. <br /> i� <br /> 4 . <br /> REGULATORY GUIDELINES <br /> 5.1 EVALUATION OF SOIL <br /> In 1985, State of California Department of Health Services (DOHS) and the State <br /> Water Resources Control Board (SWRCB) jointly published the LUFT Field Manual as <br /> a guidance manual to aid representatives of the state and local agencies and <br /> consultants in conducting underground tank investigations and the evaluation of <br /> ;.., hazards created by unauthorized releases of gasoline and diesel products. <br /> „.. One section of the LUFT Manual provides guidance in establishing site-specific <br /> soil clean-up levels for BTX&E and TPH. The manual suggests.the investigator use <br /> two analyses for determining appropriate clean-up levels, first a leaching <br /> potential analysis and second, a general risk appraisal. The leaching potential <br /> analysis will result in maximum allowable residual soil levels obtained for each <br /> P discrete sample. The general risk appraisal is then used to determine whether <br /> the BTX&E residuals left in the soil will pose a continuing threat to groundwater <br /> resources. <br /> The lea , ing potential analysis looks at five site specific characteristics which <br /> tend to greatly increase vertical contaminant migration: (1) groundwrater depth, <br /> v (2) average annual precipitation, (3) subsurface fractures_, (4) man-made <br /> conduits, and (5) unique site features. Each of the aforementioned <br /> characteristics is evaluated using a numerical scoring system from O to 10, with. <br /> a score of 10 indicating low potential for leaching. The LUFT Manual sets <br /> �_.. guidelines for scoring each of the characteristics. The sum of each of the <br /> t individual scores is then used to set maximum allowable residual BTX&E and TPH <br /> - levels that can be left in place without posing a threat to the groundwater <br /> ;u resources of the area. <br /> Using the recommended LUFT procedure, the following table lists the site feature, <br /> r' LH's interpretation of the scor;; and the sum for the Weber Point Property: <br /> Site Feature Score <br /> ,.. ,.: I. Minimum Distance to Groundwater from soil sample 0 <br /> (less than 25 feet) <br /> 2. Fractures in subsurface(none) 10 <br /> (applies to foothills and mountain areas) <br /> 3. Average.Annual Precipitation (14.4 inches) g <br /> 4. Man-made conduits (nune) 10 <br /> includes recharge area, nearby well, coarse <br /> 5:----Unique-site-features-(none)— --- --- - - - -- -- —'_-- - —IO- <br /> .� { g <br /> soil, etc.) <br /> Approximate score by LH following LUFT recommendations - Total 34 <br /> 23 <br /> m <br /> sr <br /> I Ill=Elm <br /> r,_ <br />