A study to assess environmental pollution by aromatic hydrocarbons (PAHs) in sediments of the coast of Tripoli City, Libya

Abstract

This study assessed the distribution, environmental risks, and sources of sixteen priority (PAHs) in surface sediments collected from ten sites along the coast of Tripoli, Libya. Total (ΣPAHs) concentrations range from 7.569 to 12.250 ng/g dry weight, with an average of 9.696 ng/g, indicating low pollution levels. The highest concentration was recorded at Station 6 near Tripoli Seaport, while the lowest was recorded at Station 9. Environmental risk assessment, based on sediment quality criteria such as ERL, ERM, TEL, and PEL, showed that all PAHs concentrations were well below the threshold values, indicating a minimal risk to aquatic organisms and marine life. Combustion-derived ΣPAHs (ΣCOMB) range from 5.493 to 10.190 ng/g, while fossil fuel-derived ΣPAHs (ΣTFPAH) ranged from 1.251 to 1.887 ng/g, and carcinogenic ΣPAHs (ΣCARC) ranged from 5.493 to 9.627 ng/g. Principal component analysis (PCA) identified two main sources of  (PAHs): combustion inputs, consisting of high molecular weight compounds (BaP, BbF, BkF, and BghiP) associated with ship emissions and industrial activities around the port of Tripoli, and petroleum-derived inputs, consisting of low molecular weight compounds (Ace, Phe, and Anth) associated with fuel spills and oilfield activities in coastal fishing areas. In general, the sediments along the Tripoli coast show low levels of (PAHs) and minimal environmental risks, but continued environmental monitoring is recommended to ensure the long-term protection of the marine ecosystem.