Effects of Some physical and chemical factors of Lower Zab water on Tigris River

Abstract

Four stations were selected for water sample collections, to study the effects of some water characteristics of Lower Zab tributary on the Tigris river, during the period from November 2001 to October 2002. Air and water temperature were (10-38)oC and (10-28)oC respectively. Salinity values ranged (0.25-0.33)%o . Turbidity varied from (22) NTU at station 2 to (34.4) NTU at station 3. pH values ranged (7.5 - 8.6). Dissolved Oxygen values were higher in Lower Zab water compared to that of Tigris River. BOD were high at summer and low during winter.Total hardness ,calcium and Alkalinity were (222-306) mg/L, (133-165) mg/L and (134-165) mg/L respectively.Nutrition values of the water samples were low, (0.4g/L) for nitrite, (0.27g/L) for phosphate, and (2.1 mg/L) for silica at station 4 after the confluence. While these values were higher at station 3 before the confluence (0.6g/L), (0.4g/L) and (2.9mg/L) respectively. Chloride ions values ranged (33.5-38.6) mg/L .Discussion of the results of this study clarify that Lower Zab effects the environment of the Tigris river at station 4 through the values of the turbidity, total hardness and negative iones which is located in the river after the confluence, in addition to the decrease of nutritive compared to station 3 in the river. This is certainly due to the favorable conditions at station 4, which cause blooming and diversity of aquatic organisms. This was obvious from the BOD5 values at station 4. The high BOD5 values was proportional to organic pollutants.