Research on polycyclic aromatic hydrocarbon pollution in sediments and waters of northern Lebanon: rivers, transition zones, and port sites

Contamination of the marine environment is associated with continental activities, marine activities and accidental spills. Providing answers to the origin of the contamination of the aquatic environment by PAHs is an objective of the present work. The originality of this work is to study pollutants in two types of matrix (water and sediments) during 2 seasons (dry and wet) for an environmental monitoring of 6 years. This study provides a more complete overview of the state of contamination in three coastal rivers, their transition zones and harbors in the Eastern Mediterranean following the Jiyyeh oil spill in 2006.

Contaminants concentrations were expressed as the sum of the 16 PAHs classified as priority substances by the United States Environmental Protection Agency (US-EPA). Overall, contamination was noted for all the analyzed sites. Oil spill seemed to be one of the main sources of pollution in the area, as the highest levels of PAH (> 9,000 ng.g-1 p.s and > 8,000 ng.L-1 ) were reported in the coastal environment of the three rivers and harbors.

High levels of PAHs were also observed in the transitional zones of rivers, revealing the importance of terrestrial inputs (untreated wastewater discharge, leachate, solid wastes, etc.).

Comparing the PAHs concentrations measured in the sediments of the sites analyzed with the empirical sediment quality criteria "SQG" for the support of the general assessment of sediment toxicity, we can notice that some individual PAH and their sum can present a significant ecotoxicological risk to aquatic organisms. Further research through monitoring campaigns and toxicity tests is encouraged, as the exposure of the resident aquatic organisms and human population to these chemicals might be expected to increase over the years.