Acronym for benzene, toluene, ethylbenzene, and the three xylene isomers: the four monoaromatic hydrocarbons of greatest regulatory concern in petroleum-impacted groundwater. Benzene is a Class 1 human carcinogen; the four are jointly tracked at virtually every petroleum site.
BTEX are the soluble, mobile aromatic fraction of gasoline, diesel, jet fuel, and crude oil. They partition readily from LNAPL into groundwater and form long, fast-moving dissolved plumes. Benzene drives most regulatory and risk-management decisions: it is a confirmed human carcinogen with U.S. EPA and Health Canada drinking water limits of 5 micrograms per litre.
BTEX is among the most biodegradable contaminant classes at petroleum sites: aerobic biodegradation is fast and well-characterized; anaerobic degradation under iron-, sulfate-, and methane-reducing conditions is slower but reliable. Monitored Natural Attenuation, biosparging, and biostimulation are commonly accepted remedies. Ex-situ treatment is rare for BTEX-only contamination; thermal and chemical oxidation are reserved for source zones or co-contaminant cases.
Also known as: BTEX, benzene toluene ethylbenzene xylenes.
BTEX (Benzene, Toluene, Ethylbenzene, Xylenes): treatment approach
The four aromatic hydrocarbon compounds — benzene, toluene, ethylbenzene, and the three xylene isomers — that dominate gasoline plumes and drive risk-based cleanup at UST and refinery sites because of benzene's carcinogenicity and low regulatory threshold.
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.