Remediation of PAH-Contaminated Soils and Sediments: A ...

and their mutagenic and carcinogenic potential, which is generally higher than
that of non-nitrated PAHs (Bamford et al., 2003).
Polycyclic aromatic hydrocarbon compounds in the atmosphere are either
present in the gaseous phase or associated with particulates and tend to
condense onto particles at temperature below 150° C temperatures (Schure and
Natusch, 1982). At ambient temperatures, most atmospheric PAHs are in the
particulate phase. The partitioning of PAHs into gas and particulate phases also
depends on vapor pressure of the specific PAH (Wania and Mackay, 1996). At
ambient air temperatures, 2- to 4-ring PAH and 2-ring nitrated PAH compounds
are the predominant PAHs in the gas phase, while PAH compounds with 5 or
more rings and 4-ring nitrated PAHs are associated with particulates (Arey and
Atkinson, 2003). The fate of atmospheric PAHs is influenced by whether the
PAHs are in the gaseous or particulate form. The residence time of small
particles in the atmosphere can be one to two weeks, which would permit long
range transport assuming there is no precipitation to cause wet deposition
(Atkinson and Arey, 1994).
PAHs in water
The main sources of PAHs in water bodies are atmospheric particulate matter
deposition, runoff of polluted ground sources and pollution of river and lakes by
industrial effluents, municipal wastewater discharge, and oil spills (Latimer and
Zheng, 2003; Dabestani and Ivanov, 1999). Since PAHs have low solubility and
tend to adsorb to particulate matter, they are usually found in low concentrations
in water bodies. Some PAH concentrations that have been measured in water
include: marine waters with levels of non-detected to 11 µg L -1 , wastewater in
North American and European municipalities with levels of