... Aerosols of hydrocarbons with more than 16 carbons were absorbed in liver and lungs of mice. These long-chain aliphatic compounds may be oxidatively metabolized via cytochrome P450 oxidases. Aliphatic hydrocarbons with between five and eight carbons may be oxidized to several alcohol, ketone, and carboxylic acid derivatives. Aliphatic hydrocarbons with 9-16 carbons are oxidatively metabolized via cytochrome P450 isozymes to fatty acids and alcohols. Evidence indicates that metabolism of these hydrocarbons may be quite slow... In general, the oxidative metabolism of /polycyclic aromatic hydrocarbons/ PAHs involves epoxidation of double bonds, a reaction catalysed by cytochrome P450-dependent mono-oxygenases, rearrangement or hydration of the epoxides to yield phenols or diols, respectively, and conjugation of the hydroxylated derivatives with glutathione, sulfate, or glucuronic acid. However, in certain cases, radical cations and sulfate esters of hydroxymethyl derivatives may also be important...
There is inadequate evidence that bitumens alone are carcinogenic to humans. There is sufficient evidence for the carcinogenicity of extracts of steam-refined bitumens, air-refined bitumens and pooled mixtures of steam- and air-refined bitumens in experimental animals. There is inadequate evidence for the carcinogenicity of undiluted air-refined bitumens in experimental animals. There is limited evidence for the carcinogenicity of undiluted steam-refined bitumens and for cracking-residue bitumens in experimental animals. /Bitumens/
Mixtures do not lend themselves to kinetic analysis. Because asphalt is a complex mixture, its pharmacokinetic pattern will vary depending upon the properties and interactions of the individual constituents... The long-chain aliphatic hydrocarbons constitute major components of asphalt; routes of uptake include inhalation, ingestion, and dermal uptake. Data indicate that following inhalation, hydrocarbons with 9-16 carbons were absorbed in the blood, brain, liver, kidneys, and fat of rats. Aerosols of hydrocarbons with more than 16 carbons were absorbed in liver and lungs of mice... In general, these compounds are slowly eliminated in the urine and feces. The major routes of uptake of /polycyclic aromatic hydrocarbons/ PAHs in humans are the lungs and respiratory tract after inhalation of PAHcontaining aerosols or of particulates to which a PAH in the solid state has become absorbed; the gastrointestinal tract after ingestion of contaminated food or water; and the skin as a result of contact with PAH-bearing materials... Whole body distribution of PAHs has been studied in rodents. These studies have demonstrated that detectable levels of PAHs occur in almost all internal organs and that organs high in adipose tissue can serve as storage depots from which the PAHs are generally released. In general, these compounds are eliminated by urinary or biliary excretion of metabolites.
