Influence Des Activites Anthropiques Sur La Degradation De La Qualite Des Sediments De La Lagune Ouladine (Sud-Est De La CÃ´te dâ€™Ivoire)
Authors: Keumean Keiba Noel , TraorÃ© Abou , Ahoussi Kouassi Ernest , DjadÃ© PÃ©hÃ©gninon Junior OphÃ©lie , Bamba Siaka BarthÃ©lÃ©my 
Published: June 2020

La contamination des sÃ©diments lagunaires par les Ã©lÃ©ments traces mÃ©talliques constitue un danger pour lâ€™eau, les espÃ¨ces vivantes et pour la santÃ© de lâ€™homme. Lâ€™objectif de cette Ã©tude est dâ€™Ã©valuer le niveau de contamination des sÃ©diments de la lagune Ouladine en Ã©lÃ©ments traces. Les Ã©lÃ©ments traces (Pb, Zn, Cu, Cd et Cr) ont Ã©tÃ© dosÃ©s dans les sÃ©diments lagunaires Ã lâ€™aide dâ€™un spectromÃ¨tre dâ€™absorption atomique de type VARIAN AA 20. Lâ€™intensitÃ© de la contamination des sÃ©diments a Ã©tÃ© estimÃ©e Ã partir du calcul de plusieurs indices, notamment le Facteur de Contamination (FC), le DegrÃ© de Contamination modifiÃ© (DCm) et lâ€™Indice de Pollution SÃ©dimentaire (IPS). La toxicitÃ© des sÃ©diments a Ã©tÃ© mise en Ã©vidence en comparant les concentrations des Ã©lÃ©ments traces dosÃ©s aux valeurs guides amÃ©ricaines SQGs (Sediment Quality Guidelines). Les rÃ©sultats mettent en Ã©vidence lâ€™ordre dâ€™abondance des teneurs en ETM (ElÃ©ments Traces MÃ©talliques) des sÃ©diments suivants : Cr (83,92 mg.kg-1)>Pb (62,03 mg.kg-1)>Zn (60,06 mg.kg-1)> Cu (13,76 mg.kg-1)> Cd (1,45 mg.kg-1). Le Facteur de Contamination (FC) et le DegrÃ© de Contamination modifiÃ©e (DCm) rÃ©vÃ¨lent une contamination faible Ã considÃ©rable. Les valeurs de lâ€™IPS montrent que les sÃ©diments de la lagune Ouladine sont faiblement polluÃ©s sauf Ã la station S7 oÃ¹ les sÃ©diments sont sains. Hormis le Zinc, les autres ETM dosÃ©s sâ€™avÃ¨rent nÃ©fastes pour les organismes vivants de la lagune Ouladine Ã toutes les stations qui ont fait lâ€™objet dâ€™Ã©chantillonnage.
Contamination of lagoon sediments by trace metal elements constitutes a danger to water, living species and human health. The objective of this study is to evaluate the level of trace element contamination in the sediments of the Ouladine lagoon. Trace elements (Pb, Zn, Cu, Cd and Cr) were assayed in lagoon sediments using a VARIAN AA 20. The intensity of sediment contamination was estimated from the calculation ofseveral indices, including the Contamination Factor (CF), the Modified Degree of Contamination (MDC) and the Sediment Pollution Index (SPI). Sediment toxicity was demonstrated by comparing the concentrations of the measured trace elements with the American Sediment Quality Guidelines (SQGs). The results show the order of abundance of the following sediment VEC levels: Cr (83.92 mg.kg1 )>Pb (62.03 mg.kg-1 )>Zn (60.06 mg.kg-1 )> Cu (13.76 mg.kg-1 )> Cd (1.45 mg.kg-1 ). The Contamination Factor (CF) and the Modified Degree of Contamination (MDC) indicate low to considerable contamination. The SPI values show that the sediments of the Ouladine lagoon are slightly polluted except at station S7 where the sediments are healthy. Except for Zinc, the other measured TE (Trace elements) were found to be detrimental to the living organisms of the Ouladine lagoon at all the stations that were sampled.