Ecotoxicological risk of subsurface sediments, linked to inorganic pollutants, at the mouth of the Comoe River in Grand-Bassam

The diversion of water from the Comoé River to the Vridi canal has led to the closure of its mouth at Grand-Bassam. This situation has led to the sitting up of the bottom of water bodies, water pollution and deaths of fish. Studies in this environment have shown metal pollution but have not indicated the level of risk to the sediments and biota. The objective of this job is to highlight the intensity of the ecotoxicological risk at the outlet of River Comoe. It required the analysis of 23 samples of subsurface sediments. These sediments underwent total mineralisation before being analysed at the lCP-MS. Mūller's geoaccumulation index (Igeo) and the M-ERM-Q were used to determine the ecotoxicological quantity of sediments. The average concentrations of metals are 64.55 ug/g (Cr), 24.77 ug/g (Ni), 24 ug/g (Cu), 66.66 ug/g (Zn), 14.12 ug/g (As), 0.25 ug/g (Cd) and 13.88 ug/g (Pb). The level of pollution is in the unpolluted range (class 0) to the highly polluted range (class 5). Arsenic has the highest pollution intensity while lead has the lowest pollution intensity. The likely risk of sediments toxicity is between 9% to 21%. The majority of sediments (19/23; 82.61%) have a toxicity probability of 21%.