Fig. 3.
Map of the Pb isotope database (n = 135; see SI Appendix, Supplementary Text for references) of Tunisian metal ores (mainly galena) represented as a function of the Tmod (A) and κ (B) parameters. The Pb-Ag mining districts shown with black and white stars (A) caused the Pb pollution recorded in the sediment cores because they (i) form the subcomponents β' and β″ (Fig. 3), respectively, and (ii) are located inside the Medjerda catchment (unlike the mining districts of Hamra, Chaamb-Agab, and Sekarna, whose Pb isotopic signatures also are similar to those of component β). The cores of the present study are located around Utica (white circle).