Environmental Study to Used The Aquatic Organisms as Bioindicators to Euphrates River Pollution by Heavy Metals.

Abstract

The present study was conducted to used some aquatic organisms as bioindicators Euphrates river from Al-Hindia dam to south of Al-Kufa city (a distance of 15 Km) in the middle of Iraq, in seven selected sites along.The investigation was to study the concentration and distribution of some heavy metals (Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, and Zn) in the tissues of four aquatic plants species Ceratophyllum demersum L.; Potomogeton pectinatus L., Typha domingensis Pers. & Phragmites australis (Cav.) Trin. Steras. Accumulation of heavy metals in soft tissues of two freshwater clam species: Corbicula flumina (Muller 1774), Unio tigridis (Bourguignat 1852) and inner tissue and carapace of freshwater crab Sesarma boulengeri (Calman), were also studied.Mean concentration of heavy metals were similar in studied aquatic plants and there were seasonal variations. The highest concentration among heavy metals was for Fe (1176.10) μg/g in Potomogeton pectinatus and lowest concentration was for Ni (0.38) μg/g in Phragmites australis, and this concentration was higher than that in water and sediments. Values of bioconcentration factor (BCF) were higher than those for biosedimentation (BSF) in all mentioned plant species.The results also showed an increase in the concentration of heavy metals in soft tissues of two species of fresh-water clam (Corbicula flumina and Unio tigridis) which was correlated with the heavy metals in particulate state or phase in water because filter feeding of these organisms.The present study recorded high values of heavy metals in fresh water crab Sesarma boulengeri which ranged between (0.21) μg/g for (Ni) and (589.50) μg/g for (Fe) in inner tissues and carapace, but these concentrations were lower than in clam and aquatic plants.The results showed higher values of BCF than BSF in inner tissues and carapace of crab (3-6.99), (0.57-1.01) respectively in inner tissues and (3.7-6.98), (0.70-1.08) respectively in carapace.