Fluoranthene

Fluoranthene is a polycyclic aromatic hydrocarbon (PAH) with the molecular formula C16H10. It consists of four fused benzene rings, forming a compact, bay-shaped structure related to other C16H10 PAHs such as pyrene. Its molecular weight is about 202.26 g/mol, and it is virtually insoluble in water but soluble in many organic solvents.

Fluoranthene occurs in the environment primarily as a product of incomplete combustion of organic matter. It is emitted from vehicle exhaust, industrial processes, wood and coal burning, and cigarette smoke, and is found in fossil fuels, coal tar, and grilled or charred foods. It is commonly detected in air, soil, sediments, and aquatic systems, typically as part of complex PAH mixtures.

Chemically, fluoranthene is stable and lipophilic, with a low vapor pressure. It is not widely used industrially, but serves as a standard reference compound in environmental monitoring and PAH toxicology studies. Its metabolism in mammals involves enzymatic oxidation to reactive intermediates that can interact with DNA; however, its carcinogenic potential in humans is not clearly established.

IARC classifies fluoranthene as not classifiable as to its carcinogenicity to humans (Group 3). Toxic effects observed in laboratory studies vary and are generally less pronounced than for some other PAHs, such as benzo[a]pyrene.

Environmental fate and risk assessment emphasize PAH mixtures rather than fluoranthene alone. The compound is persistent in the environment, tending to accumulate in sediments and biota, and it degrades slowly through photolysis and microbial processes.