Fırat River sediment and water geochemistry

The study includes that the shore sediments and waters of the Euphrates River have been analyzed for major and trace elements, and also Sr-Nd isotpic compositions of the sediments. The obtained results show that the characterize more chemical weathering and less mechanic transport of the regional lithologic units are important factor on the studied river sediments and waters chemical composition. The calculated threshold values in the river sediments indicate that Ag, As, Pb, Mn, Hg, Cu, Ba, Au, Mo, Hg and Zn content are attributed to physical erosion and chemical weathering due to abandoned mining waste such as Keban mining area. Neodymium and stronsium isotope compositions are range 0,512654 to 0,512836 ‰, and 0.7048 to 0.7057‰, respectively. The moderate Nd isotopic compositions show Nd from granodioritic source rocks. The lower Sr isotopic compositions indicate Sr from source rocks during weathering carbonate-rich meta sedimentary rocks. Comparison of 87Sr/86Sr ratio and Ca/Sr ratio suggest evaporitic formations due to subtropical conditions. The cations (Ca, Na, Cd, Zn, As etc.) of lower ionic potential may be riched by adsorbing on fine size fractions (<75 µm). Thus, these metals and As may be considered to both sediment and water chemical compositions by hydromorphic transportation. The heavy metal concentrations (Au, Ba, Cr, Hf and Zr) in the river sediments are higher in the river sediments due to mechanic transporting. Comparition of average content of metals in the river water and river sediments indicate that the some heavy metals (Ba, Cr, Hf and Zr) are extremely stable (refractory, hard and dense) that the element concentrations in the river waters are lower than the studied river sediments because of their extremly stable. Key words: Euphrates River, geochemistry, isotopes, sediment, water