Use of Several Pollution Indices for Metal Contamination Assessment in Aquatic Ecosystems, A Case Study, Ebrié Lagoon-Côte d’Ivoire

In aquatic ecosystems, trace metals (TMs) are widely studied due to their harmful effects on living organisms and humans. The aim of the present study was to use different pollution indices to characterize the sediments contamination with six TMs (As, Cd, Fe, Hg, Mn and Pb). Sediments samples were collected in April 2006 with a Van Veen grab at five stations located in the Ebrie Lagoon (Côte d’Ivoire). TMs concentrations were determined using an ICP-MS Instrument for the calculation of the contamination index (CI), contamination factor (CF), pollution load index (PLI), enrichment factor (EF) and Muller’s index of geoaccumulation (Igeo). The CI revealed the sediments contamination in As, Cd and Pb, while CF highlighted their contamination in Hg, As, Fe and Cd. Regarding the PLI, the sediments were uncontaminated with TMs. The EF showed the sediments enrichment with Hg, Pb and As, while the Igeo revealed their pollution with As, Fe, Pb and Cd. In conclusion, the PLI is a useful tool for different locations characterization, while the others (CI, CF, EF, and Igeo) allow individual characterization regarding each TM. Due to high contents in As, Cd and Pb, the studied area need a particular attention.