Levels and sources of heavy metals and PAHs in sediment of Djibouti-city (Republic of Djibouti)

• Published in: Marine pollution bulletin Vol. 120; no. 1-2; pp. 340 - 346
• Main Authors: Mahdi Ahmed, Moussa, Doumenq, Pierre, Awaleh, Mohamed Osman, Syakti, Agung Dhamar, Asia, Laurence, Chiron, Serge
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 15.07.2017; Elsevier
• Subjects: Chemical Sciences; Cities; Diagnostic ratio; Djibouti; Enrichment factor; Environmental Monitoring; Environmental Sciences; Geologic Sediments; Heavy metals; Marine sediments; Metals, Heavy - analysis; PAH's; Polycyclic Aromatic Hydrocarbons - analysis; Red sea; Water Pollutants - analysis; Water Pollutants, Chemical; Red sea; Marine sediments; Diagnostic ratio; Enrichment factor; PAH's; Heavy metals
• ISSN: 0025-326X; 1879-3363
• DOI: 10.1016/j.marpolbul.2017.05.055

Selected heavy metals and polycyclic aromatic hydrocarbons (PAHs) were determined in marine sediment from 28 sites Djibouti city. The concentrations of trace elements varied from 0 to 288.1mg/kg with relative abundance of trace metals in sediments was in the order of Zn>Cu>Ni>Cr>Co>Pb>Cd. Zn, Cu and Ni exceeded consensus based sediment quality guideline values 7, 14, 15 sites respectively. Enrichment factor and pollution load index showed relatively low to moderate contamination. The concentrations of total 16 PAHs varied widely depending on the sample location and ranged from 2.65 to 3760.11ng·g−1, with the mean concentration value of 387.87ng·g−1. Compositions and relative abundance of individual PAH using molecular diagnostic ratio using congener's m/z 178 and 202 indicated pyrolytic origin and reflecting a petroleum combustion, grass/wood and coal combustion and a petrogenic source. This study represents the first pollution baseline and a reference for future studies in Djibouti. •The first pollution of heavy metals and polycyclic aromatic hydrocarbons baseline for Djibouti city is assessed.•Djibouti-city has low to intermediate levels of selected metals similar to sediment of the Red Sea.•32% of the sites had a total content of PAHs>200ng/g which corresponds low to moderate pollution.•Anthropogenic pressure is highlighted by hotspots exceeding consensus based sediment quality guidelines.