+Study of metallic contamination of Oued Sebou sediments, Morocco

Abstract

The water of Oued Sebou has known for several years, an alteration in its quality. This is due to the discharge of pollutants of different natures and origins, which come from domestic, agricultural or industrial activities. In this study, we will try to carry out a spatiotemporal evaluation of the contamination of the sediments of the river in question by metallic trace elements. This assessment will focus on zinc, chromium, lead, copper, mercury, cadmium and nickel. To carry out this study, we selected a set of twelve sampling sites. Thanks to the ICP-MS method, or analysis by mass spectrometry coupled to an inductive plasma, the results obtained allowed us to quantify the degree of pollution by the aforementioned elements. We found an increase during the dry period in the concentrations of TME compared to the winter period. This applies to all metals except chromium. Indeed, the concentrations of this element obtained during the dry period are lower than those which concern the winter period. The acceleration of work at the tanneries in the city of Fez after Aïd al-Adha (August) in 2018 seems to us a logical explanation for this observation. In the evaluation of the pollution index of Cr, values between 6.65 in August and 9.1 in December were observed, thus indicating contamination by this element. The pollution indices which concern the other TME vary between 0.38 and 2.5 indicating a normal situation in relation to the reference station S1.