It’s just hard to believe that the earth’s 70% or so of water can all get polluted in a way that we will all die someday as a result. On the face of it, its absurd, but looking at the figures carefully there is a real problem at hand.
Water sustains life. Water is needed for food and agriculture development.
It is needed for energy, human settlement, industry and ecosystems. In all these areas, the right amount and type of water required is essential. Many sea water animals will not survive for long in fresh water, just as many freshwater animals will not survive in the sea. Humans cannot drink sea water and frankly, because of the high salt content of seawater, we cannot use it in construction, because of the corrosive effect of salt. This means, if we alter the chemical composition of water in any way, we risk having negative repercussions. This is what makes water pollution so real and critical.
What is water pollution?
Any change or modification in the physical, chemical and biological properties of water that has a detrimental consequence on living things is water pollution1.
And how does this happen? Our water bodies are not protected adequately. It’s just a near impossible task, because of the way water is distributed on the earth’s surface. Rainwater that runoff may carry all the toxic stuff on the ground surface, trash and disease-carrying organisms along the way to wherever it ends up. If the water gets infiltrated, it carries all the dissolved toxins on the surface down into the water table. And think about it, the rainwater itself may be contaminated in the atmosphere even before it falls to the ground. This toxic stuff on the ground surface and in the air are all results of human action.
Pollutants may come from specific sources such as industry, dams, mines, animal farms, feedlots and wastewater treatment plants. This is called Point Source pollution, and it is usually easy to deal with those. The other type, called Diffuse or Non-Point sources, include pollutants from stormwater, the atmosphere, septic, landfills and forestry is a bit more difficult to control, because of its nature.
Ref: 1. http://www.whatiswaterpollution.org