SEASONAL VARIATION AND ASSESSMENT OF HEAVY METALSPOLLUTION IN SEDIMENTS FROM SELECTED STATIONS INTIGRIS AND EUPHRATES RIVERS, CENTRAL IRAQ

Abstract

In this study, four sampling stations were selected from two locates on the
Tigris river (Baghdad region) and others on the Euphrates river (Al-Anbar
Governorate) in order to determine concentrations, seasonal variation and pollution
intensity assessment of heavy metals (Ni, Cu, Pb, Mn and Cd) in the two rivers
sediments. Distribution of studied metals showed that stations in the Tigris river
generally had higher concentrations than stations in Euphrates river. Manganese was
found at high concentrations in all studied stations and ranged between 200 - 500
ppm, while Cd was found at the lowest concentrations and ranged between not
detected to 1.8 ppm during study period. Based on index of geoaccumulation
(I-geo) for studied heavy metals indicates that the surface sediments in the studied
stations are unpolluted by Ni and Mn, while unpolluted to slightly polluted by Pb
and Cd except the Cd at south of Baghdad station (moderately polluted). The I-geo
for Cu indicate the sediments were unpolluted to slightly polluted in the Tigris
stations, and unpolluted in the Euphrates stations. The calculated enrichment factor
(EF) indicate that all stations can be classified as minimal enrichment for Ni,
moderate enrichment for Cu and significant enrichment for the elements Pb and Cd.