Surface sediments from Khnifiss lagoon (Morocco) were analyzed to evaluate the contamination degree of the area. Concentrations of V, Cr, Co, Ni, Cu, Zn, As, Cd, Hg, and Pb were determined on samples taken during the summer and the autumn of 2016. On the whole, higher concentrations were found in the summer season. The results revealed the following average concentrations (mg/kg), reported in descending order: Zn (51.7 ± 31.3) > V (38.8 ± 24.7) > Cr (26.6 ± 17.8) > Ni (16.5 ± 5.47) > As (8.50 ± 2.00) > Cu (6.60 ± 3.81) > Pb (6.13 ± 3.46) > Co (3.57 ± 2.09) > Cd (0.16 ± 0.11) > Hg (0.006 ± 0.001). Organic matter showed a positive significant correlation with some trace metals (mainly V, Cr, Co, Zn, Cd, Pb). Three pollution indices were calculated: Enrichment Factor (EF), Index of Geo−accumulation (Igeo), and Pollution Load Index (PLI). Minimal enrichments (for Zn, As, and Cd) were detected at some sampling points. Overall indices showed that the Khnifiss sediments can be classified as not contaminated, and that the trace metals amounts found are ascribable to the geogenic origin. The results of this work can be used as a starting point for further evaluations of trace metals distribution in Moroccan lagoons.

The investigation of sediment chronostratigraphy was performed in order to reconstruct heavy metals (Pb, Cd, Cu, and Zn) and major elements (Fe, Al and Mn) fluxes in a heavy traffic site located in Roma (Italy). This city represents an ideal situation from a geochemical point of view (outcropping rocks are enriched rocks in terms of heavy metals content) where anthropic emissions are exclusively associated to traffic and heating systems. The impact of biological activity and soil erosion on sedimentation process were investigated in one urban lake, where the sedimentation model was defined using radiometric determinations (137 Cs and unsupported 210 Pb). Fluxes calculations and isotopic composition of lead were performed in order to enhance the metal distribution through the collected core. Statistical analysis allowed discriminating elements in two main groups: traffic related metals and urban aero-disperse elements. Indexes, which can estimate the elemental affinity to the urban dust, were calculated for metal source definition. Lake sediments recorded the fall of Pb air content that occurred after leaded gasoline phasing out and after about 10 years the total amount of Pb decreased of about 90%.