This paper focuses on evaluating the metallic pollution of the superficial sediments of the Potou lagoon (Coast of Côte d'Ivoire) during the low water period. The method used for this study is based, first of all, on the sampling of the sediments and on the determination of their respective concentrations in MTE (Metal Trace Element) using the spectrometric technique. The estimation of the level of metallic pollution of the sediments was made by comparing the concentrations of the metals obtained with those of the continental Wedepohl crust (1995) and those of the unpolluted sediments of Calamari and Naeve (1994) and Kikouama et al. (2009). It was also achieved by calculating several pollution indices including the enrichment factor and the geo-accumulation index. The methodological approach was finally completed by assessing the risks of sediments in place from the TEC (Threshold Effects Concentrations) and PEC (Probable Effect Concentration) guide values and by studying the spatial distribution of the various contaminants at the site within the study area. A total of 15 MTE were identified in the sediments of the medium, namely: aluminium (Al), arsenic (As), calcium (Ca), cadmium (Cd), chromium (Cr), copper (Cu), iron (Fe), potassium (K), magnesium (Mg), manganese (Mn), sodium (Na), nickel (Ni), lead (Pb), antimony (Sb), and zinc (Zn). These MTE have variable contents ranging on average between 0.81 and 46693.33 mg / kg. This important variability is also found in the MTE enrichment values. These are on average between 0.03 and 4.15. Regarding the geo-accumulation index, the values

This study with a morphology and hydrosedimentology character was done to carry out a with an understanding the evolution of the channels and sedimentation in Potou lagoon in Ivory Coast starting from the realization of the bathymetric map. The bathymetry of this lagoon avered that the depths are lower than 2.11 m out of 22 km2, and presente three types of channels. In fact the channels in "U" represent a balance between the agents of accumulation and erosion. Channels resulting from processes of erosion which are in "V" and channels intermediate indicating an evolution of the type "V" in "U". In particular during these fourteen last years the Potou lagoon has sudden great phenomenon of deposit is a volume of +66791000.18 m³of sediments deposed on a surface which is thus estimated at 65.2 % of chenal surface. These deposits are certainly causes of full high funds in this lagoon. The mean velocity of sedimentation on Potou lagoon is thus estimated at 26.5 cm/year. As for the erosion, it could be estimated at-8487601 m³ a volume of on a surface wich is thus estimated at 34 % of chenal surface. The sedimentary budget would be thus estimated at+58303398.68449 m³ on a surface of 12.45 m2. A surface which is thus estimated at 0.8 %hasn’t sudden phenomenon of deposit or erosion. The bathymetric chart and the sedimentary budget of Potou lagoon are tools necessary for use of the stretch of water by the users. Thus, the zones at the risks determined on the bathymetric chart, such as the high bottom and the points of swirl generated by the depressions, will be easily avoided.

Morphoscopic and exoscopic analysis of quartz grains collected on the Ivorian beaches of the gulf of Guinea between Abidjan (Côte d'Ivoire) and Aforenou (Ghana) during topographic surveys between March 2007 and March 2009 on the examination of quartz at the binocular loupe, reveals blunting grains shining on all beaches (50% to 70%). In Abidjan area, the majority of the grains are reddish, indicates a ferrous and inherited environment. The exoscopy for the fine and detailed study of the morphology and the surface of the quartz grains was made with the Scanning Electron Microscope (SEM). This approach makes it possible to interpret traces related to events (energy level) or environments (transport, transition and storage environments). These observations indicate that the quartz after a long transport in a fluvial environment have been reworked in a marine environment. They were finally deposited in a low-energy aquatic continental medium marked by the polishing of the crystalline points and the siliceous corpuscles dotting the surface of the grains. The energy of the transport environments crossed is high in a turbulent environment through traces of shock, as large and numerous as they are. SEM examination of the samples reveals that beach quartz has generally been transported by river and recovered in an intertidal and/or subtidal environment. They have a continental and marine origin.