Assessment of Heavy Metal in Surface Sediments of Day River at Beni-Mellal Region, Morocco

The Day River receives domestic and industrial untreated wastewaters from Beni-Mellal city and surrounding villages during the last decades. The present study was to obtain a preliminary assessment about the level and distribution of six heavy metals (Cd, Cr, Cu, Pb, Zn and Fe) in its surface sediment collected from 13 stations. The metal concentrations (in mg/kg) ranged: Cd, 0.6-6.27; Cr, 52.34-311.69; Cu, 32.69-740.75; Pb, 72.93- 140.36; Zn, 49.84-149.19; and Fe, 15670-36010. Significant spatial variation in concentrations was observed for all metals. Correlation analyses showed that metal content of sediment was controlled by organic matter and Fe contents. Pollution status was evaluated using the enrichment factor, geo-accumulation index and pollution load index and sediment quality guidelines. Based on geoaccumulation index and enrichment factors, Day sediment was treated as unpolluted to moderately polluted with Zn, Fe, Cr and Cu and moderate to considerable with Pb and Cd. Pollution load index and sediment quality guidelines showed that the metal levels exceed local and regional background concentrations, indicating contamination is high enough to be of risk to human health and ecosystem.