Behavior of trace metals in sedimentary cores from marine and lacustrine environments in Algeria

Abstract

This study highlights the potential risks of pollution due to the presence of trace metals in sediment samples from six sediment cores from four wetlands (Chott Melghir, Fontaine des Gazelles dam, Lake Mellah, and Algiers Bay) in Algeria, assessing the level of contamination of these trace metals, and understanding the behavior of metals as a function of the depth of the sediment cores and the nature of the different sampling media. A total of 130 sediment samples were collected and subjected to chemical analysis (loss on ignition, inductively coupled plasma mass spectrometry, and atomic absorption spectroscopy to determine M.O. and trace metal contents) and physical analysis (X-ray fluorescence and DRX to identify the chemical composition and mineralogy of the sediments). Calculation of the enrichment factor enabled us to differentiate between anthropogenic and natural sources of trace metals such as Zn, Pb, Cr, Ag, and Cd, showing contamination at various sites due to urban or agricultural inputs. The dominant mineralogical composition of the sediments at the four sites was quartz, carbonate, and sandstone. Principal component analysis revealed strong positive correlations in the chemical composition of sediment samples between chlorine and Na2O, K2O, TiO2, Al2O3, and Fe2O, the main components of clays. The presence of organic matter in the four study areas is directly linked to the introduction of organic matter from the wadis into the watershed. Sediments have a high redox activity, which facilitates the movement of trace metals.

Keywords

• sediment
• ef
• chemical and mineralogique compositions
• principal component analysis
• trace metals