Ecological risk assessment of polycyclic aromatic hydrocarbons in sediments: identifying sources and ecological hazard.

Polycyclic aromatic hyftovst ond (PAH) are nearly ubiqutous contaminants of freshwater and marine sediments. Sediment PAHs are derived from combustion of organic matter, fossil fuels, and biosynthesis by microbes. Pyrogenic PAHs, particularly those associated with combustion particles (soot), have a low accessibility and bioavailability in sediments.