2002 Progress Report: Beyond MTBE: Evaluating the Future Threats to Drinking Water Supplies from Chemicals in Our GasolineEPA Grant Number: R829023
Title: Beyond MTBE: Evaluating the Future Threats to Drinking Water Supplies from Chemicals in Our Gasoline
Investigators: Gschwend, Philip M.
Institution: Massachusetts Institute of Technology
EPA Project Officer: Packard, Benjamin H
Project Period: September 1, 2001 through August 31, 2004 (Extended to August 31, 2005)
Project Period Covered by this Report: September 1, 2001 through August 31, 2002
Project Amount: $239,524
RFA: Exploratory Research to Anticipate Future Environmental Issues (2000) RFA Text | Recipients Lists
Research Category: Economics and Decision Sciences , Ecological Indicators/Assessment/Restoration , Water , Ecosystems
The objective of this research project is to develop a methodology suited to evaluating the potential for new (and old) fuel additives to contaminate drinking water.
Continuing modifications of fuels such as gasoline should include evaluations of the proposed constituents for their potential to damage environmental resources such as subsurface water supplies. Consequently, we developed a screening model to estimate well water concentrations and transport times for gasoline components migrating from underground fuel tank releases to typical at-risk community water supply wells. Representative fuel release volumes and hydrogeologic characteristics were used to parameterize the transport calculation. Subsurface degradation processes were neglected in the model to make risk-conservative assessments. The model was tailored to individual compounds based on their abundances in gasoline, gasoline-water partition coefficients (Kgw), and organic matter-water partition coefficients (Kom). Transport calculations were conducted for 20 polar and 4 nonpolar compounds found in gasoline, including methyl t-butyl ether (MTBE) and other ether oxygenates, ethanol, methanol, and some aromatic hydrocarbons. With no calibration, the screening model successfully captured the reported magnitude of MTBE contamination of at-risk community supply wells. Such screening indicates that other oxygenates would cause similar widespread problems unless they were biodegradable. Analysis of field parameter variability concluded that community supply well contamination estimates had order-of-magnitude reliability. This indicated that such pre-manufacturing analyses may reasonably prevent widespread environmental problems and/or inspire focused investigations into chemical properties (e.g., biodegradability) before industrial adoption of new fuel formulations.
We are working to predict partitioning coefficients for organic solutes based on their structures partitioning between water and mixtures of substances likely found in fuels.
Journal Articles on this Report : 2 Displayed | Download in RIS Format
|Other project views:||All 4 publications||3 publications in selected types||All 3 journal articles|
||Arey JS, Gschwend PM. A physical-chemical screening model for anticipating widespread contamination of community water supply wells by gasoline constituents. Journal of Contaminant Hydrology 2005;76(1-2):109-138.||
||Kawamoto K, Arey JS, Gschwend PM. Emission and fate assessment of methyl tertiary butyl ether in the Boston area airshed using a simple multimedia box model: comparison with urban air measurements. Journal of the Air & Waste Management Association 2003;53(12):1426-1435.||