Study of Water Quality of Tigris River Upstream Al-Kut Barrage

The study was conducted on the water quality of Tigris River in upstream of AL-Kut Barrage during the period of August 2018 to June 2019. Six vertical sections have been selected upstream of Al-Kut Barrage. The distance between one section to another was 100 m, the first section begins at 350 m from the origin of Barrage. The result showed that the values of cadmium ion were 0.0346 ug/L to 0.0707 ug/L. The Lead values of the Tigris River water samples were 4.29 ug /L to 8.33 ug /L. The values of nickel ion have been ranged between 7.59 ug/L to 9.75 ug/L. Zinc ions have been recorded 53.5 ug /L to 72.1 ug /L. The concentration of above ions was situated within Iraqi and world Health organization (WHO) criterions that relating with propriety of water of Tigris River for drinking and irrigation.


I. INTRODUCTION
Water quality is indicator of the suitability of water using by humans, animals and plants [1]. The purpose of evaluating irrigation water depend on the risks that this water poses to the soil and the growth of crops and animals, as well as the people who consume these crops [2]. The most important indicators that affect water quality is chemical (salts and other chemical compounds), physical (heat and radiation), and (taste, color, and smell) [3]. Hilgard (1906) [4], was the first researcher that mentioned the importance of irrigation water quality based on the chemical composition and total concentration of dissolved salts, followed by many researchers in this field like [1,5]. The water quality in Iraq has been affected by different forms of pollutants as a result of human activities, including, waste water and waste from cities, and factories that flow into riverbeds without treatments. Agricultural is one of the factors contributing to the deterioration of water quality [6]. Juttner [7], have been explained that the most important biochemical indicators that effect on water quality come from wastewater by humans, and these indicators are temperature, turbidity, oxygen dissolved, nutrients and factories.
The used water that used in different activity contains a lot of dissolved salts in different concentration and ionic composition. This is coming with negative results on chemical and physical properties of the soil and productivity of plants. According to International Food and Agriculture Organization (FAO), the water quality depends on the total concentration of salts as the main quality factor for the use of irrigation water [8].
Heavy metals in the environments indicate that it is exposure to contamination [9], indicated that the concentration of these elements in the river depends on the temperature, salinity, pH, organic and mineral materials. Heavy elements are present in a dissolved state, in suspended loads, sediments, or within the crystalline composition of the minerals. The sediment particles with a volume of less than (2µ) contain high concentrations of heavy elements due to their high content of clay minerals that have a high adsorption capacity for these elements .
The aims of this study: 1-Study of the elements in Tigris River and their effect on water quality. 2-Determine the heavy elements in the Tigris River. 3-Study the water quality and its suitability for agriculture.

II. MATERIALS AND METHODS
This research has been conducted on the Tigris River (in front of Al-Kut dam). The study period was (11 months), six sites sections has been selected, in advance of the Kut dam. One hundred meters was the distance between one site and another.

 Water samples
Water samples were taken from each section of the river for three sites. The first site is located on the right side, the second site is,in the middle of river and the third site is on the left side of the river. Two water samples were taken from each location, the first at a depth of 0.2from the, and the second at a depth of 0.8 from the river's water level. Samples of water were collected one time/month from different sites, starting on August 2018 till June 2019. The time for collecting the sampleas was morning time for all period of study. Samples were taken using model-taking equipment. this samples has been used for conducting physical and chemical analysis. The samples analysis using 1 ml of (manganese sulfate solution and 1 ml alkyl iodide azide solution). This is for maintain the oxygen level until laboratory work. Also, 2.250 L of polyethylene has been used after washed well with river water.

 Evaluate heavy elements
Heavy elements has been determined using Atomic Absorption spectrometer (AAS) equipment. This equipment has been used for estimate lead, cadmium, copper, zinc, and manganese. According to [10], each element has its own wavelength.

 Statistical analysis
The data has been analysis by using Genstat program for found least significant differences L.S.D (0.05) between samples.   The results showed that the lead values in the Tigris River water samples and for all sections were within the permissible limits. according to the Iraqi and the World Health Organization WHO and Canadian standards, samples were recorded 0.01, 0.2, 0.007 ppm respectivety, except the sections S1, S3, and S6, whose water samples were brought on 27/4/2019 and were outside the permissible limits (Fig. 2).  The results in Figure (3) showed that the nickel values in the Tigris River water samples for all sections were within the permissible limits and according to the Iraqi and WHO and Canadian standards, which were 0.02, 0.2, 0.15 ppm Respectively. The differences between the nickel values samples were mostly not significant, while the samples were significant differences between the samples for the time 15/12/2018 (Fig. 3).