BIOACCUMULATION DYNAMICS AND SEDIMENT QUALITY ASSESSMENT OF HEAVY METALS IN THE SOUTHERN IRAQI MARSHLAND ECOSYSTEM

The present study aims to assess the concentrations and accumulation of heavy metals in surface water, sediments and key aquatic macrophytes namely Ceratophyllum demersum, Phragmites australis, Arundo donax and Typhain the marshes of Iraqi south. Analysis of the water samples showed that the concentration of all the metals were found low and were within the safety limits of class II. But, sediments showed localized high level of V, Co, Cu, and Pb above background concentrations which indicates anthropogenic stresses. The bioaccumulation efficiency of the presence of the metals differed significantly from species to species with the submerged macrophyte C. demersum showing maximum of bioaccumulation, particularly for Ti, Cr, V, and Pb, which is attributed to the presence of large contact surface with water column for these metals mainly. Emergent species (P. australis and A. donax), on the other hand, were able to separate out the essential metals (Zn and Cu) and obstruct the movement of toxic metals to shoot tissues. In conclusion, aquatic plants, particularly those that are submerged, act as important bioindicators and natural biofilters which is a major role in phytoremediation and wetlands conservation.