Laserfiche WebLink
1 <br />Oxygenate Analysis 0 is <br />2 30 August 1997 <br />The problem of identifying which oxgenates are present is further compounded because the oil <br />refineries ship gasoline around the state and then trade gasoline between geographic areas. <br />For instance, if gasoline is needed in the San Francisco Bay area by BogCo Oil, BogCo will <br />obtain some gasoline from, say, Generic Oil in the Bay area and, in exchange, Generic will <br />receive some BogCo gasoline in Southern California. The result is that we do not know what <br />oxygenate compound is in the gasoline at a particular gas station. TAME may be used by <br />Generic, but, because of this swapping, TAME, rather than MTBE, will end up in the ground <br />water at a BogCo site. <br />Research recently completed by DuPont -Dow (http://www.dupont-dow.com/products/viton/lkprev.html) <br />show that oxygenates may be incompatible with some elastomer seals used on underground <br />tank piping. One test, using several concentrations of MTBE, was short term (168 hours) and <br />showed swelling could occur with some elastomers at current gasoline mixture levels. <br />Presumably, this will be true, to some extent, for all ether oxygenate additives, and, over a <br />longer time, conceivably cause the failure of the seals; thereby, releasing the oxygenated <br />gasoline into the environment. We are particularly concerned that older tank seals or material <br />used to upgrade tanks may not be compatible with the oxygenates and may fail due to the <br />high concentrations of oxygenates in the alternative fuel sources. <br />0n 14 August 1997, a workshop was conducted at the Sacramento office of this Regional <br />Board, attended by representatives of Regional and State Boards, Local Implementing <br />Agencies, analytical Laboratories and the petroleum industry. The objective was to provide <br />guidance to the regulated community on how and where to analyze for the oxygenated <br />compounds in gasoline until definitive protocol can be established in several months. The goal <br />was to allow closure of underground tank sites with assurances that the interim methodology <br />can detect and quantify oxygenates. <br />The workshop attendees concurred that the methyl and ethyl alcohols can't be detected by <br />EPA Method 8260 with certainty and that detection limits for methyl and ethyl alcohols are <br />about two orders of magnitude higher than TBA and the ethers. Also, with the exception of <br />one oil company and special, alternative fuel vehicles (including the State of California <br />automobiles), ethanol and methanol are used infrequently in California, and can be isolated by <br />station and the more accurate analytical methods used. Therefore, at this time, unless ethanol <br />or methanol are specifically requested, we are requiring soil and water analysis only for TBA <br />and the ether compounds by EPA Method 8260 in order to determine which oxygenated <br />compound is present. <br />Presence or absence of the oxygenate must be reported whenever gasoline range hydrocarbons <br />are present. However, because free product or high petroleum concentrations raise the <br />detection limits of the oxygenates, the oxygenates cannot be detected with certainty. <br />Therefore, at this time, we do not recommend sampling where product is present on <br />groundwater. <br />