What causes water pollution?
Pure water is colourless, tasteless, and odourless and is chemically composed of just two elements, hydrogen and oxygen. Because water is such a good solvent, it dissolves almost everything that it comes into contact with. Water is known as a ‘universal solvent’. That is why the water we get from rain, well, streams, rivers, etc. is not pure. Many health problems can be caused by polluted drinking water. The main causes of water pollution are because of these three pollution contaminants in water:
- Dirt or Suspended Solids in water
- Biological contamination caused by living organisms like algae, bacteria, protozoa, pathogens, microbes, viruses, parasites and their eggs (cysts). These water contaminants are usually referred to as bacteria, germs or microorganisms.
- Chemicals in water: Many chemicals like fertilizers, pesticides, reaction products of Chlorine disinfectants, heavy metal chemicals from rocks and soil, etc. gets into water to cause dangerous pollution
Here below we elaborate more on each of the different types of impurities in water.
Dirt or Suspended Solids in water
These are the solids which are insoluble like dust, fine sand, clay, rust, etc. They remain suspended in the water and cause muddy water or cloudiness in water. 'Total Suspended Solids' or 'TSS' is the technical term used to measure how much of dirt there is in the muddy water. 'Turbidity' is the term to describe the muddy water and a unit of measurement of cloudy water is based on the transmission of light through the muddy or cloudy water.
A simple filter usually called a sediment filter, with pore size of 20 microns or lower can remove almost all of the suspended matter in muddy water. Also the use of flocculants like Alum is used widely to settle and clear muddy water.
Muddy water after passing through a simple filter may be good for drinking, as long as there is no contamination with germs and dissolved chemicals. We have a dedicated page for Suspended solids in water and turbidity in water
Types of Germs in Water
Biological contamination of water is caused by the presence of living organisms like algae, bacteria, protozoa, pathogens, microbes, Viruses, Parasites and their eggs (cysts), etc. known collectively known as microorganisms and commonly called 'germs'. The health effects of drinking water contaminated with germs may be severe, but easily curable with modern day medicine. These minute living organisms in water are the causes of diseases like typhoid, dysentery, cholera, gastroenteritis, etc.
Water tanks can sometimes be a breeding ground for microbes in water. In the usual test for microorganisms, only one group of bacteria known as Coliform or e-coli is tested for, this is because it is the most common species, and the first microorganism to infect water. Membrane purification of water actually filters out all bacteria from water unlike UV water purifier which kill bacteria in water but leaves their bodies in the drinking water. More from our page for Germs, Bacteria, Parasites and Viruses in water
Dangerous chemicals found in drinking water in India
The problem with chemicals in water is that they dissolve in water and cannot be removed by simple filtration. 'Total Dissolved Solids' or 'TDS' is the technical term used to give a measure of the amount of dissolved matter in the water and is usually expressed as 'ppm' which stands for 'parts per million' or as 'milligrams per liter' (mg/L). To remove dissolved chemicals in water, it has to be either distilled or purified by using an RO water purifier. Some of the most dangerous chemicals found in drinking water in India are listed with an explanation as to how it affects our health in our page for toxic poisonous chemicals in water.