Water Pollution Water is the most precious environmental asset and natural resource on earth. Approximately seventy percent of the earth's surface is covered by water and it affects every facet of life and ecology. However, despite this obvious and crucial fact, many rivers, lakes and oceans are becoming increasingly more polluted, creating a serious ecological and environmental problem. Not only is pollution the cause of the death of many organisms essential to ecological balance, but human drinking water has also been affected. This is particularly relevant with regard to the spread of disease. " Estimates suggest that nearly 1.5 billion people lack safe drinking water and that at least 5 million deaths per year can be attributed to waterborne diseases." (Krantz D. And Kifferstein, B. )

The waterways and oceans of the world have been seen as an easy dumping ground for refuse and waste. This includes pollution from raw sewage and oil spills. Ocean and river pollution have increased in line with industrial human development, with more toxic wastes being drummed in water than ever before. This has reached the stage when bacteria from sewage disposal, and marine wildlife is beginning to suffer." ( ibid)
The causes of water pollution are usually divided into two main categories; namely, direct and indirect sources of contamination. Direct sources of pollution refer to "effluent outfalls from factories, refineries, and waste treatment plants etc. that emit fluids of varying quality directly into urban water supplies. " (Rubin K.) An example of direct pollution would be the Exxon Valdez oil spill. This occurred in 1989, when the Exxon Valdez grounded on Bligh Reef, and "spilled nearly 11 million gallons of oil into the biologically rich waters of Prince William Sound." (The Exxon Valdez Oil Spill) Indirect sources of pollution include contaminants entering water systems from soil or groundwater systems or via rainfall. These forms of pollution can

... contain the residue of human agricultural practices (fertilizers, pesticides, etc..) and improperly disposed of industrial wastes. Atmospheric contaminants are also derived from human practices (such as gaseous emissions from automobiles, factories and even bakeries). (Rubin K.)

The effect of water pollution is varied and extensive. A stated, because of the importance of water, the pollution of oceans and rivers has a dramatic impact on ecosystems. This can vary from poisoned water sources for both humans and animals to the distortion of natural balances in delicate ecosystems, which can affect food and sustenance. The effect can also…