Laserfiche WebLink
Tosco's technical opinion is that the most prudent approach to detemune the presence of TBA and ether compounds is <br /> an initial screening process m the source area As stated in the workplan, groundwater monitoring well MW-2 will be <br /> sampled in the fourth quarter 1997 for ether based oxygenates and TBA by EPA Method 8260 If oxygenates are <br /> detected(other than MtBE) in this sample,Tosco will propose a program to assess the monitoring well network for <br /> their presence However,if oxygenates are not detected during this initial screening process,Tosco will discontinue <br /> these analysts from MW-2 and will not analyze other water samples from the wells at the site by EPA Method 8260 <br /> Tosco believes that with the installation of the monitoring well proposed in the attached GSI workplan,will delineate <br /> the dissolved hydrocarbon plume The effectiveness of the treatment system in removing residual hydrocarbons from <br /> the unsaturated zone will be evaluated by the proposed boring Samples collected from MW-2 during the third quarter <br /> I998 will assess the effectiveness of ORC in enhancing the natural attenuation of the dissolved hydrocarbons Should <br /> data indicate a continued decline in hydrocarbon concentration beneath the site,Tosco will propose consideration of <br /> this site for low risk closure <br /> If you have any questions,please feel free to contact me at(5 10)277-231 I <br /> Sincerely, <br /> C - � <br /> Edward C Ralston <br /> Project Manager <br /> cc Elizabeth Thayer, CVRWQCB <br /> Greg Gurss,GSI <br /> 4 <br />