Seasonal variations in Concentrations of Trace elements in Sediments from Al-Garaf canal, one of the Main Branches of Tigris River/ Thi Qar province-Iraq

The present investigation is part of a comprehensive work aiming at surveying the ecological status to evaluate Al-Garaf canal at Thi Qar province. Variations in concentrations of various trace elements (Ni, Cd, Cu and Zn) in water were determined on monthly basis. The study extended from March 2004 to February 2005. Three stations were selected for comparison. The former supply Basrah, Thi Qar, Shatra and Garaf water s enterprises with crude water for domestic purposes .The second station is situated 8 kms apart from the former, whereas the latter site is selected at distance of 15 kms apart from the second one after the river pass Al-Garaf district. Element varies seasonally in their concentrations and analysis revealed that Zink occupied the first position and the highest concentration (105.89 μg/g dry wt) was encountered in fall and the lowest (78.89 μg/g dry wt) in winter. Ni occupied the second position as the highest (83.13 μg/g dry wt) was recorded in summer and the lowest (24.32 μg/g dry wt) in winter. Whereas Cu and Cd came third and forth in position ranging from 2.13-35.26 μg/g dry wt and 1.11-2.63 μg/g dry wt respectively. Elements can be arranged in the following order: zn Ni Cu Cd. A yearly average of Ni,Cd and Cu concentration were 56.72, 1.7 and 13.94 μg/g dry wt. respectively.