Study of the Mobility of Some Metallic Trace Elements (MTEs) of Certain Lowlands of the City of Daloa (Côte d’Ivoire)

Metallic Trace Elements (ETM) are naturally transported to the shallows by runoff. As the lowlands are exploited for market gardening, ETM can be found in the products of these crops and present risks of contamination for the populations. It is with this in mind that we decided to study the mobility of metallic trace elements in the soils of the market garden lowlands of the city of Daloa. To achieve this goal, nine (9) soil samples were taken from 3 sites at different depths (0 - 15 cm, 15 to 30 cm and more than 30 cm). The determination of the water pH and of the organic fraction of the sediments were carried out according to ISO 10390 and NF ISO 10694 standards respectively. The ETM contents were obtained by an Atomic Absorption Spectrometer (AAS). The results obtained showed that the majority of the sediments studied are acidic. In addition, they contain a more or less large organic fraction of between 10 and 50%. In addition, our studies demonstrated a mobility of certain ETMs, in particular As, Cr, Hg and Zn, depending on the different sediment profiles studied. Also, Cd, Cr, Mg, Ni, Pb are linked to organic matter and to the clay fraction of the sediments. However, their mobility would be influenced by pH.