benzoapyren

Benzo[a]pyrene, often abbreviated BaP, is a polycyclic aromatic hydrocarbon (PAH) with the chemical formula C20H12. It consists of five fused aromatic rings, giving it a planar, highly hydrophobic molecule that is insoluble in water but soluble in organic solvents. BaP is widely used as a reference compound in studies of PAHs due to its well-established carcinogenic properties.

Structure and chemistry: BaP is derived from combinations of fused benzenoid rings. Its planar structure facilitates strong binding to hydrophobic environments, and its metabolic activation depends on cytochrome P450 enzymes to form reactive metabolites.

Occurrence and sources: BaP is produced during incomplete combustion of organic matter. Major sources include tobacco smoke, grilled or charred foods, vehicle and industrial exhaust, and wood or coal fires. It is commonly found attached to particulate matter in air and can accumulate in soils and sediments.

Toxicology and mechanism: BaP is classified as a human carcinogen (IARC Group 1). Metabolically activated to benzo[a]pyrene diol epoxide (BPDE), it forms covalent DNA adducts, particularly with guanine residues, which can lead to mutations and cancer. BaP exposure is associated with increased risks of lung, skin, and other cancers, and it can contribute to oxidative stress and inflammation.

Environmental fate and monitoring: BaP is persistent in the environment and tends to bind to organic matter. Humans are exposed via inhalation, ingestion of contaminated foods, and dermal contact. BaP and its metabolites are used as biomarkers for PAH exposure in toxicology and environmental monitoring.

Regulation and research: BaP is subject to regulatory controls as part of broader PAH management programs. It serves as a model compound in toxicology, carcinogenesis research, and assessments of environmental contamination.