“…Because of their different physico-chemical properties, they might behave differ- ently in the environment with characteristic Phe/An values for the identification of the PAH origin. Generally, a Phe/An ratio <10 and Flu/Pyr ratio > 1 indicates that the contamination by PAHs results from a combustion process (Soclo et al, 1999). Similarly, fluoranthene (Flu) is less thermodynamically stable than pyrene (Pyr); they are often associated with each other in natural matrices and a predominance of Flu over Pyr is characteristic of a pyrolytic process, while in petroleum-derived PAHs, pyrene is more abundant than fluoranthene.…”