Al-kut Dam Sediments Content of Some Heavy Metals and Its Relationship with Pollution

Abstract

This study has been carried out in Alkut city the center of Wasit province which is located about 180 km south of the capital Baghdad on one from the most important dams constructed on theriverTigris called Alkut Dam .Four pedons have been selected in this study, two pedons (A,B) are located in the lower part of dam and the other two pedons (C ,D) are located in the upper part of dam , sediments samples analysis for particle size distribution and total & available heavy metals concentration (Ni ، Cd ، Zn ، Pb ،Fe) in the water and sediments. Results show that the total concentration of nickel ranges between(104.2 - 178.4) mg.kg-1and the higher value has been found in the second depth (156-126)cm for pedon A and the lower value has been found in the second depth (50-30) for pedon D , while total cadmium concentration ranges between (6.1-2.2)mg.kg-1and the higher value has been found in the second depth (35-20) for pedon A at the lower part of dam and the lower value has been found in the sixth depth (73-93cm)for the same pedon , the values for total Zinc concentration ranges between (108-69) mg.kg-1 and the higher value has been found in the fifth depth (73-55)cm for pedon A at the lower part of dam and the lower value has been found in the last depth (120-100cm) for pedonD in the upper part of dam, the results of total lead concentration ranges between (24.2-11.35) mg.kg-1 and the higher value has been found in the first depth (0-20cm)cm for pedon A at the lower part of dam and the lower value has been found in the third depth (60-50cm) for pedonD in the upper part of dam , while the total concentration for iron (Fe) which ranges between (4595-2988) mg.kg-1 the higher value has been found in the second depth (20-50cm) for pedon A at the lower part of dam and the lower value has been found in the seventh depth (111-93cm) for the same pedon .As compared with critical limits , results show that total concentration of heavy metals for Cd, Pb, Zn and Ni in Sediments samples all has exceed the critical limits values except in some depths. The results for the available heavy metal concentrations show that the available nickel concentration ranges between(33.2-107.4)mg.kg-1 and the higher value has been found in the second depth (20-35)cm for pedon A at the lower part of dam and the lower value has been found in the second depth (30-50) for pedonD in the upper part of dam,while total cadmium concentration ranges between (0.21-0.48)mg.kg-1and the higher value has been found in the first depth (0-20)cm for pedon B at the lower part of dam and the lower value has been found in the sixth depth (73-93cm)for the pedon A at the lower part of dam , the values for the available Zinc concentration ranges between (56-111) mg.kg-1 and the higher value has been found in the tenth depth (191-231)cm for pedon A at the lower part of dam and the lower value has been found in the last depth (120-100cm) for pedonD in the upper part of dam, the results of available lead (pb) concentration ranges between (6.7-20.2) mg.kg-1 and the higher value has been found in the first depth (0-20cm)cm for pedon A at the lower part of dam and the lower value has been found in the third depth (60-50cm) for pedonD in the upper part of dam , while the available concentration for iron (Fe) which ranges between (39-74)mg.kg-1 the higher value has been found in the second depth (20-50cm) for pedon A at the lower part of dam and the lower value has been found in the eighth depth(111-126) for the same pedon,at the comparison of results for the available concentrations of the studied heavy metals it can be seenthat all values have exceeded the critical limits values according to Nunes etal 2014. in the other hand the results show that there is significant correlation between the total and available concentration for same heavy metalspairs of the correlation (r2) between the available and total concentration was 0.90 , 0.74 , 0.99, 0.99 and 0.58 for Ni , Cd , Zn , Pb and Fe respectively , in the other hand, the results show that the water concentration for heavy metals are 1.7 , 0.03 ,15 , 0.07 and 27 mg.l-1for Ni , Cd , Zn , Pb and Fe respectively , which indicate that all values have exceeded the critical limits according to Iraqi standards and FAW.