Metallic contamination assessment of the Lévrier Bay (Mauritanian Atlantic coast), using Perna perna and Venus rosalina

Abstract

By its proximity to Nouadhibou city (the economic capital of Mauritania), Lévrier bay (Atlantic coast of Mauritania) is closely exposed and influenced by port and industrial activities effluents. Its coastline is highly coveted for the establishment of several industrial firms accompanied by a growing urban development. In this context, the present study focuses on the marine coasts evaluation of the trace metals contamination (Cd, Hg, Pb, Fe, Co, Cr, Cu, Mn and Zn) in two different species of bivalves (mussels and clams) using ICP- AES. The results showed significant coastal contamination by iron and Cd. Their recorded results have to be considered in any integrated coastal zone management in Mauritania. The trends of trace metal concentration values, recorded from 1991 to 2009, showed an undeniable increase in Cd and iron, mainly attributed to industrial and urban domestic wastes. Cd concentration values ranged from 3.9 mg/kg dry weight (dw) in 1991 to 23 mg/kg dw in 2009. On the other hand, iron concentrations increase has been found both in mussels and clams. Actually, mussels showed increasing concentration values ranged from 155.5 mg/kg dw in 1999 to 460 mg/kg dw in 2009 while in clams, concentration values ranged from 322 mg/kg dw in 1991 to 663.6 mg/kg dw in 2009.