The Metallic Trace Elements (MTE) pollution of aquatic ecosystems and their intrusion and inclusion into the food chain exposes public health to enormous risks. This study assesses the risks associated with the pollution of surface sediments from Ouémé delta with Pb. Cu and Cd. In these sediments stratifications, the physicochemical characteristics of the sediments were evaluated. Total metal contents are determined by the inductively coupled plasma mass spectrometer. Risk indices are evaluated, followed by statistical processing in software R 3.3.2. On average, the pH is 5.50; the CEC is 84.24 meq / 100g and the organic carbon (OC) is 0.84 % of mass sediment. Means of Al2O3, Fe2O3 and CaO are respectively 8.14 %; 3.9 % and 6.08 %. The means of copper, lead and cadmium are respectively 32.92 ppm; 23.63 ppm and 1.43 ppm. Overall the degrees of risk related to contamination and ecological risks are low to high. Sites with a high degree of contamination and high ecological risk reflect the importance of the contribution of solid waste from Dantokpa market and the domestic discharges into the metal pollution of Ouémé delta.

In the offshore basin of Benin, some sediments of Albian age were identified. These sediments are gathered in formation named “Albian Formation”. At regionally scale, they are targeted for petroleum exploration and production. This paper aims to precise the petrographic and structural features of these sediments. Petrographic analyzes reveal the presence of two dominant facies (a main sandy facies and a shale facies which is thicker in deep offshore). Sandstones are very compact, gray to dark gray, and composed mainly of sharp and subrounded quartz grains of various sizes. Shales are massive, gray to blackish and friable to compact. Seismic sections interpretations show that Albian formation is generally continuous, of more or less constant thick and little varied lithological composition in East-West direction. In North-South direction, the formation gradually thick towards the offshore and become significantly reduced in very deep water. The formation is affected by normal and combined faults as well as by reverse faults of NE-SW and NW-SE trends. Structural traps of hydrocarbons are more present in shallow deep offshore while, in deep offshore, traps are essentially of stratigraphic type.