A wood-preservative DNAPL distilled from coal tar, containing 75 to 90 percent PAHs plus phenolics and heterocyclic compounds. The dominant contaminant at historical wood-treating plants in North America, Europe, and Australia.
Creosote was applied to railway ties, utility poles, and marine pilings at hundreds of wood-treating plants from the 1880s through the 1980s. Spills, sludges, and drip-track contamination left behind DNAPL source zones up to tens of metres deep at many of these sites. Creosote is dense (specific gravity 1.05 to 1.10), viscous, and dominated by 2- to 6-ring PAHs.
Creosote source zones are among the most difficult DNAPL problems to address. Thermal treatment (in-situ TCH, ex-situ rotary kiln or thermal desorption) is the dominant destruction route; in-situ chemical oxidation has been deployed with mixed success. Many former creosote sites are now managed under risk-based closure with engineered controls because full source removal is economically infeasible at depth.
Also known as: creosote, coal tar creosote.
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.