Trace metal contamination in sediment cores from Algiers Bay (Algeria)

Industrial and urban waste is drained and dumped directly into Algiers Bay without any prior treatment. Increasingly. this waste has damaged the marine environment. The main objective was to evaluate the degree of contamination by trace metals in the continuous monitoring of the marine environment. The study was carried out in two different phases on three marine sediment cores from Algiers Bay. In the first phase. the identification of the mineral phases was carried out by XRD and the chemical composition of the sediment by XRF, and the determination of the organic matter rate and the carbonate rate. In a second phase, the study focused on the determination of lead 210 on the two cores (A and B) and the contents of 20 trace elements (Sc, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Sr, Ag, Cd, Sn, Sb, Cs, Ba, Pb, Th, and U). The trace elements were determined by ICP-MS. The enrichment factor EF and the correlation matrix between the trace metals were studied. The results show that the predominant mineralogical phases are carbonates, followed by silica and clays (illite, kaolinite, etc.). An enrichment in organic matter is observed in the deep layers of the cores. The trace metal contents show quite heterogeneous and variable distributions from one element to another and from one core to another. The first few centimetres of the sediment core are marked by a moderate to high enrichment in EF of the metallic elements. Very strong positive correlations are observed in the three cores such as V-Ni, Pb–Zn, and V-Fe.