Assessment of Heavy Metal Contamination (Cd, Pb, Hg) and Typological Characterization of Smoked Fish Commonly Consumed in Abidjan, Ivory Coast

Abstract

This study assesses contamination by cadmium, lead, and mercury (Cd, Pb, and Hg) in smoked sardines, mackerel, and tuna in Abidjan and characterises the typological structure of these concentrations at two smoking sites (Abobo-Doumé and Vridi-Zimbabwe), based on 180 fish analysed before and after smoking using ANOVA-Tukey, principal component analysis (PCA), and Pearson correlation. Smoking significantly increases Cd and Pb levels in most species, whereas Hg levels decrease, likely because of evaporation associated with moisture loss. At Abobo-Doumé, Pb levels remain within the Codex limit (0.3 mg/kg), with tuna reaching only 38% of the threshold. At Vridi-Zimbabwe, however, Pb levels exceed the limit in mackerel (+46%) and reach 80% of the threshold in tuna, indicating a real health risk. The PCA accounts for 82.37% of the total variance, structured by Hg and Cd on axis 1 and Pb on axis 2, with Cd-Pb (r = -0.223) and Cd-Hg (r = -0.452) oppositions and a Pb-Hg association (r = 0.331). Three distinct typological profiles emerge: a group dominated by Hg (sardines and tuna from Vridi-Zimbabwe and sardines from Abobo-Doumé), one by Pb (mackerel from Vridi-Zimbabwe), and one by Cd (mackerel and tuna from Abobo-Doumé). Mackerel, the species most exposed at both sites, is confirmed as the preferred model for future toxicological studies.