Trace metals in algae and sediments from the North-Eastern Tunisian lagoons.

The mean concentrations of copper, zinc, plomb, nickel and chrome were determined in algae and sediments collected from three aquatic areas of the Tunisian North-East (Sebkhet Sijoumi and Radès and Bizerte lagoon). The recorded metal levels, ranging (in μg g⁻¹) from 1.58 to 68.56 for macroalgae and from 8.70 to 234.40 for sediment samples, were low in most of the sampling locations and similar to those of sites qualified as «slightly polluted». However, certain locations showed significant differences with the remaining sites indicating some degree of contamination (ANOVA, p < 0.001). These locations were found in Sebkhet Radès and Bizerte lagoon for copper, zinc, nickel and chrome metals and in Sebkhet Sijoumi for plomb in algae. The study of the correlation between metal contents in algae and sediments showed highly significant positive values for zinc and plomb (p < 0.01). A significant correlation was also noticed for Cr (p < 0.05). However, there was no clear relationship between copper and nickel levels in both matrices.