Water pollution. Facts you should know.

Water is a natural resource that supports life. However, pollution and uncontrolled use is endangering this resource.

Water pollution occurs when foreign substances are released in the water. These contaminants can be physical, chemical, biological or radiological materials, degrading its quality and turning it into a dangerous resource for consumption and to the environment.

Pollution by pesticides in irrigation waters from Arequipa, Peru. Source: TOXICROP project.

Water pollution can have a natural origin or can be caused by human activity. Human beings are the main source of water pollution, brought by the economic development and industrialization, followed by intense exploration of water resources and by a large amount of waste production.
Generally, natural factors  such as climate changes or geological conditions) do not cause high concentrations of pollutants, except in very specific places such as mineral deposits.

Usually, water pollution comes from some of human activities and their consequences:

  • Global Warming: the increase of terrestrial temperature, caused mainly by CO2 emissions, heats up the water and leads to a decrease in oxygen level.
  • Agriculture: manure and urine that contains contaminants such as pathogenic microorganisms, solids in suspension, organic matter, nitrogen and phosphorus.
  • Livestock activities: including fertilizers, pesticides, herbicides, water salts from irrigation, etc.
  • Industrial activities: industries utilize water for various purposes (processing, refrigeration, transportation, etc.) generating contamination by cyanides, greases, phenols, solids, toxic chemical and biological materials, among others.
  • Fuel spills: the transport and storage of oil and its derivatives give rise to leaks that can reach water sources.

Industrial water discharge causing river pollution

Pollutants can generally be classified as follows:

  • Physical contaminants: sediments or suspended materials.
  • Chemical contaminants: they can be of natural or artificial origin, including nitrogen, bleach, salts, pesticides, metals and toxins produced by bacteria or animals.
  • Biological contaminants: They are organisms in water known as microbes that include bacteria, viruses, protozoa, and parasites.
  • Radiological contaminants: they are chemical elements that due to their instability emit radiation such as cesium, plutonium and uranium.


Water sources are deteriorating rapidly, as a result of the majority of activities that we do in day- to-day life, therefore, as society we must act urgently, and become more aware of the importance of this resource.