Study of Tigris River Pollution with Heavy Metals (Zinc and Lead) in Baghdad Government, Chemical and Biological Evaluation and Suitability for Civilian and Agricultural Uses

Abstract

ater samples were collected monthly from December 2007 - May 2009 from four sites on Tigris River in Baghdad, (Al-Etafiah, Al-Tahrer Bridge, Al-Jadiriah Bridge and Al-Wihdeh square near water treatment station). Three months average was taken. Hydrogen activity (pH) range was (7.3-7.5), Electrical Conductivity (EC) range was (0.80- 0.94) dS/m, with significant difference in relation to sites. Rang of Calcium ions concentration was (3.8- 4.2) mmolс/l, Magnesium ions (2.0- 2.7) mmolс/l, Sodium ions (2.1- 3.0) mmolс/l, Potassium ions (0.1) mmolс/l, Chloride ions (2.0- 3.3) mmolс/l, Sulfate ions (4.1- 5.0) mmolс/l, and Carbonate ions (1.3- 1.9) mmolс/l. Total Dissolved Salts (TDS) ranged from (512.0- 601.6) ppm, with significant difference in regard to sites. Sodium Adsorption Ratio (SAR) ranged from (1.15- 1.91) along all the River sites and through the months of the study. Tigris River can be considered adequate for civilian uses according to WHO and Iraqi Quality Assurance System after adequate treatment in filtration and sterilization stations. Three classification systems were used to evaluate water suitability for agricultural purposes, United State Department of Agriculture (USDA) Classification System (1954), and the result was class C3-S1 for all studied samples. FAO Classification System (1985), the result was “Water with mild-moderate problems” for salt concentration represented by EC. But for SAR and effect of Na concentration on soil permeability, the result was “No problem to use water for irrigation”. FAO Classification System (1992), its result was “Low salt irrigation water”, No sample was classified as “Danger possibilities” in regard to SAR and its effect on soil permeability. According to an Iraqi Classification System, these samples were classified as “good quality water for agricultural irrigation purposes”.