Center for Environment and Energy Research and Studies (CEERS)
Abstract
In the present study sediment and water samples collected from Kowsar
Dam reservoir in Kohkiluye and Boyerahmad Province, southwest of Iran,
are subjected to bulk digestion and chemical partitioning. The
concentrations of nickel, lead, zinc, copper, cobalt, cadmium,
manganese and iron in water and bed sediment were determined by atomic
absorption spectrometry. The concentrations of metals bounded to five
sedimentary phases were estimated. On this basis, the proportions of
natural and anthropogenic elements were calculated.The anthropogenic
portion of elements are as follows: zinc (96%)> cobalt (88%)>
iron (78%)> magnesium (78%)> nickel (78%)> copper (66%)>
lead (63 )> cadmium (59%). The results show sediment contamination
by nickel, cadmium and lead, according to the world aquatic sediments
and mean earth crust values. Manganese and copper have strong
association with organic matter and are of high portion of sulfide
bounded ions. Finally, The degree of sediment contamination was
evaluated using enrichment factor, geo-accumulation index (Igeo) and
pollution index (IPoll). The sediments were identified to be of high
cadmium and lead pollution index. The pattern of pollution intensity
according to enrichment factor is as follows; manganese (1.25) <
copper (1.63) < zinc (1.93) < cobalt (2.35) < nickel (3.83)
< lead (12.63) < cadmium (78.32). Cluster analysis was performed
in order to assess heavy metal interactions between water and sediment.
Accordingly, nickel, cadmium and copper are earth originated. Zinc,
copper and manganese are dominated by pH. All the elemental
concentrations in water and sediment are correlated except for
sedimental copper