Laserfiche WebLink
1600 Durham Ferry Road <br /> Page 2 <br /> analysis at a greater depth than 11 feet. However, characterizing the vertical distribution of soil <br /> contamination will enable the estimation of the mass of soil contamination available to impact <br /> groundwater. Within the next quarterly report, that will include groundwater monitoring data <br /> and results, an addendum to this work plan should be submitted that explains how the vertical <br /> extent of soil contamination will be determined. <br /> As you may be aware, methyl tertiary butyl ether (MTBE), was introduced into gasoline in the <br /> late 1970's. MTBE is added to gasoline as an oxygenator to increase combustion efficiency. <br /> PHS/EHD, has received recommendations from the Regional Water Quality Control Board, State <br /> Water Resources Control Board and the Department of Health Services, Drinking Water Branch <br /> to initiate a sampling protocol for MTBE and requests that groundwater samples undergo analysis <br /> utilizing EPA Method 8020 (602) with a one time only confirmation analysis utilizing EPA <br /> Method 8260 (624). Subsequent to confirmation, MTBE can be identified and quantified during <br /> routine BTEX analysis. Geological Technic proposed to review the sales records of the petroleum <br /> distributor to determine if the fuel delivered to the station may have contained MTBE. Since <br /> MTBE can be detected and quantified using routine analysis, and PHS/EHD is requesting only a <br /> one time confirmation, it would appear to be more cost effective to perform the confirmation <br /> analysis. <br /> PHS/EHD agrees that a well survey should immediately be undertaken. It is likely that it will be <br /> necessary to extend the bounds of the survey to greater than 500 feet. PHS/EHD suggests that <br /> the survey encompass a 2000 feet radius. <br /> If you have any questions or wish to schedule a meeting to discuss further investigation or a <br /> sampling inspection, please contact Mary Meays at (209)468-0337. <br /> Donna Heran, REHS, Director <br /> �Environmental <br /> Health Division <br /> Mary Meays, Senior REHS Diane M. Hinson, REHS <br /> Site Mitigation Unit Supervisor <br /> MM/1600DURH <br /> cc: Elizabeth Thayer, Central Valley Regional Water Quality Control Board <br /> George Lockwood, State Water Resources Control Board, Clean up Unit <br /> Geological Technics, Inc - Ray Kablanow, II <br /> Del-Tech - Don Light <br />