Water is an abundant resource, yet in different regions safe, fresh clean water is critically short supply. The fresh water is considered one of the most vital resources in this planet. If water is polluted; it is not only devastating the environment, but also the human and animal health. Therefore, information on water is vital for monitoring, analyzing, evaluating, maintaining the quality, and sustainable use 1.

Blue Nile River in Sudan is of great concern for socio-economic and environmental aspects. Fortunately, its water is, for many of years, had been; and still of good quality for irrigation, domestic, industrial, fishing, bathing uses, and electric power production, therefore, it should be kept clean 2. The important water attributes is the water quality, whichrefers to the chemical, physical, and microbiological characteristics which show wide variability worldwide.

The physical properties are the color, turbidity, taste, temperature, and odor of water which can be determined by touch, taste, senses and smell. While chemical characteristics. The chemical is determined by the source such as refers to rocks, soil, industrial, etc. Any transformation in the chemical properties affects the water quality causing pollution. The major pollutant are in inorganic minerals, the cations, like calcium [(Ca⁺⁺), magnesium (Mg⁺+), sodium (Na⁺) and potassium (K⁺), (CaCO₃) etc.., and anions such like (Cl^-), (HCO₃^-)(NO₃^-)(SO₄^--), pH (Alkalinity, and Acidity). While the organic includes parameters includes hardness, total dissolved solids (TDS), electrical conductivity (EC).

Water is said to be polluted; if it is impaired by contaminants so that it does not support a human use (drinking water), or undergoes a marked shift in its ability to support its constituent of biotic communities. Pollution; typically refers to chemicals or other substances in concentrations greater than would occur under natural conditions. Major water pollutants include organic chemicals, nutrients, microbes, heavy metals, sediments, oil and heat which raise the temperature of the receiving water 3.

Water pollution occurs when a body of water becomes contaminated either by physical such as plastic, water bottles or rubber tires, or by chemical such as the run-off that finds its way into waterways from factories, cars, sewage treatment facilities. However, despite people have already started taking precautions, the water pollution levels are raising rapidly 4. Nevertheless, today, water pollution is likely to occur because of dramatic world population expansion and increasing human activities like industry, and agriculture which contribute to water pollution significantly.

Several studies on water pollution were carried out in different parts of the world. A researcher, 5 studied the Surface water quality contamination in Nigeria, Other researchers 6 assessed water quality of Ebro River in Spain. The influence of Anthropogenic activities on water quality in Karstic region was also studied 7Other studies of water quality included the White River Basin, Indiana, in the United States of America (USA) 8, and Melen River in Turkey 9.

Several factors cause water pollution, among thesethe human activities which play an important role in river water pollution. In Sudan, the establishment of factories like Tannery, soap, sugarcane industries in addition to chemicals used by farmers find their way to the river contaminate and pollute the water of the Blue Nile. This includes chemicals, pathogens, and physical changes like increased temperature and discoloration.

However, high concentrations of naturally occurring substances like calcium, sodium, iron, and manganese, can have negative impacts on aquatic flora and fauna. Oxygen -depletion has an effect on photosynthesis. Moreover, the anthropogenic activity may cause turbidity (cloudiness) which blocks light, disrupts plant growth, and clogs the gills of some fish species 10. Furthermore, pathogens can produce waterborne diseases 11.

Several studies revealed that alteration of water physical and chemical properties like change in acidity and electrical conductivity, eutrophication and temperature, has negative effect on aquatic living organisms. Similar effect can be produced by thermal if is released from cooling system by power plants and industrial manufacturers, when water temperatures will increase, consequently, oxygen levels will decrease. This can kill fish, alter food chain, reduce species biodiversity, and foster invasion by new thermophilic species 12.

Generally, several factors causes river water pollution such as residues, animal waste, garbage toxic materials, including heavy metals such as Lead (pb), Mercury (My), Cadmium (Cd), Arsenic etc., biological: Microbial waste carried by water, organic and inorganic pollutants, including plant and animal wastes.

Several methods are used for testing water quality, among these:

Physical tests; including temperature, solid concentrations e.g., total suspended solids (TSST) and turbidity.