An evaluation of methyl tertiary-butyl ether (MTBE) in the ambient air above a petroleum spill: A vapor transport analysis

A computer model for evaluating the transport of MTBE from groundwater to the ambient air within a commercial building is presented. The analytical infinite source model modifies and improves upon the Johnson and Ettinger (1991) Model, which simulates contaminant vapor migration by both diffusion and convection using site-specific parameters. The model was applied to data collected from a site where benzene, toluene, ethylbenzene, xylene, and MTBE were detected in the groundwater beneath a commercial building. The concentration of MTBE was 9,700 parts per billion.;This model predicted that MTBE vapor diffusion through the building foundation would result in a maximum indoor air concentration of 5.7 × 10 −5 mg/m3 or 0.0158 parts per billion. The data may be used in a risk assessment to further define potential site concerns. This model is also designed to be adaptive and may be easily modified for application to a specific sites problems or criteria (108 pages, 10 figures, 5 tables).