Polycyclic Aromatic Hydrocarbons: Sources, Occurrence, Levels, Distribution and Ecotoxicological Fate at Coastal and Deep Ocean

Abstract

This chapter presents general aspects of polycyclic aromatic hydrocarbons (PAHs) as environmental pollutants and synthesizes information on the presence and levels of PAHs in the coasts and deep sea throughout the world. PAHs are a large group of compounds formed of two or more fused benzene rings or, in some cases, a pentagonal ring. PAHs are solid at room temperature and characterized by low steam pressures and low water solubility, as well as high melting and boiling points. PAHs can originate from three possible sources: petrogenic, pyrolytic and natural. Although PAHs can occur naturally, anthropogenic activities are generally considered the major source of PAHs released into the environment. PAHs can be introduced into marine environments by different ways: spillage of fossil fuels, ship traffic, atmospheric depositions, urban runoff, and municipal and industrial wastewater discharge. PAHs associated with sediments are considered to be less bioavailable to organisms and therefore less toxic for aquatic biota than PAHs dissolved in seawater.