Methyl tert-butyl ether: a gasoline oxygenate phased out in much of North America after it created widespread groundwater plumes. Highly soluble and mobile; tert-butyl alcohol (TBA) is its principal degradation product and a regulated contaminant in its own right.
MTBE was added to gasoline through the 1990s to reduce tailpipe emissions. Its high water solubility and low sorption meant that any leaking underground storage tank produced a fast-moving, far-travelling plume, often reaching municipal water supplies. Most U.S. states and Canadian provinces have since restricted or banned MTBE in gasoline, but legacy plumes remain a major part of the petroleum-site portfolio.
Treatment options include enhanced aerobic bioremediation with specialized cultures (Methylibium petroleiphilum and related strains), advanced oxidation, and ex-situ air stripping followed by GAC or synthetic resin polishing. The degradation product tert-butyl alcohol (TBA) is more persistent than MTBE itself under some conditions and requires explicit confirmation in closure monitoring.
Also known as: MTBE, methyl tert-butyl ether, TBA, tert-butyl alcohol.
Petroleum Hydrocarbons: treatment approach
The full spectrum of petroleum-derived organic compounds — crude oil, condensate, diesel, gasoline, jet fuel, and bunker fuel — reported analytically as total petroleum hydrocarbons (TPH) in gasoline-range (C6–C10), diesel-range (C10–C28), and heavy-range (C28–C40) fractions.
Per- and polyfluoroalkyl substances: a class of more than 12,000 synthetic compounds built around exceptionally stable carbon-fluorine bonds. PFAS is the family name, not a single chemical. PFOA and PFOS are two specific members of this class.
Perfluorooctanoic acid: a specific eight-carbon long-chain PFAS compound, historically used in non-stick coatings and AFFF firefighting foam. Classified by IARC in 2023 as Group 1, carcinogenic to humans.
Perfluorooctane sulfonic acid: a specific eight-carbon long-chain PFAS compound, historically the active surfactant in 3M Scotchgard and AFFF firefighting foam. Classified by IARC in 2023 as Group 2B, possibly carcinogenic to humans.
Polychlorinated dibenzo-p-dioxins and related furans: highly persistent, fat-soluble chlorinated compounds formed as unintended byproducts of combustion, chlorine-based manufacturing, and herbicide production, with TCDD among the most toxic substances ever characterized.