Over two thirds of Earth’s surface is covered by water; less than a third is taken up by land. As Earth’s population continues to grow, people are putting ever-increasing pressure on the planet’s water resources. In a sense, our oceans, rivers and other inland waters are being “squeezed” by human activities—not so they take up less room, but so their quality is reduced. Poorer water quality means water pollution.
Water pollution is the contamination of water bodies. This form of environmental degradation occurs when pollutants are directly or indirectly discharged into water bodies without adequate treatment to remove harmful compounds.
Water pollution affects the entire biosphere – plants and organisms living in these bodies of water. In almost all cases the effect is damaging not only to individual species and population, but also to the natural biological communities.
Sources of water pollution
Water is typically referred to as polluted when it is impaired by anthropogenic contaminants and either does not support a human use, such as drinking water or undergoes a marked shift in its ability to support its constituent biotic communities, such as fish. Natural phenomena such asvolcanoes, algae blooms, storms and earthquakes also cause major changes in water quality and the ecological status of water. Sources of surface water pollution are generally grouped into two categories based on their origin.
- Oxygen-depleting substances may be natural materials such as plant matter (e.g. leaves and grass) as well as man-made chemicals. Other natural and anthropogenic substances may causeturbidity (cloudiness) which blocks light and disrupts plant growth and clogs the gills of some fish species.
- Alteration of water’s physical chemistry includes acidity (change inpH), electrical conductivity, temperature, and eutrophication. Eutrophication is an increase in the concentration of chemical nutrients in an ecosystem to an extent that increases in the primary productivity of the ecosystem.
The microorganisms sometimes found in surface waters that have caused human health problems include:
- Burkholderia pseudomallei
- Cryptosporidium parvum
- Giardia lamblia
- Norovirusand other viruses
- Parasitic wormsincluding the Schistosoma type
Organic, inorganic and macroscopic contaminants
Organic water pollutants include:
- Disinfection by-productsfound in chemically disinfected drinking water, such as chloroform
- Food processingwaste, which can include oxygen-demanding substances, fats and grease
- Insecticidesand herbicides, a huge range of organohalides and other chemical compounds
- Petroleumhydrocarbons, including fuels (gasoline, diesel fuel, jet fuels, and fuel oil) and lubricants (motor oil), and fuel combustion byproducts, from storm water runoff
- Volatile organic compounds, such as industrialsolvents, from improper storage.
- Chlorinated solvents, which aredense non-aqueous phase liquids, may fall to the bottom of reservoirs, since they don’t mix well with water and are denser.
Inorganic water pollutants include:
- Ammonia from food processing waste
- Chemical waste as industrial by-products
- Fertilizers containing nutrients–nitrates and phosphates—which are found in storm water runoff from agriculture, as well as commercial and residential use
- Heavy metals from motor vehicles (via urban storm water runoff) and acid mine drainage
Macroscopic pollution – large visible items polluting the water – may be termed “floatables” in an urban storm water context, or marine debris when found on the open seas, and can include such items as:
- Trashor garbage (e.g. paper, plastic, or food waste) discarded by people on the ground,
- Nurdles, small ubiquitous waterborne plastic pellets
- Shipwrecks, large derelict ships.
Causes of Water Pollution
- Industrial waste:. The toxic chemicals have the capability to change the color of water, increase the amount of minerals, also known as Eutrophication, change the temperature of water and pose serious hazard to water organisms.
- Sewage and waste water: The sewers of cities house several pathogens and thereby diseases. Microorganisms in water are known to be causes of some very deadly diseases and become the breeding grounds for other creatures that act like carriers. These carriers inflict these diseases via various forms of contact onto an individual. A very common example of this process would be Malaria.
- Mining activities:Mining is the process of crushing the rock and extracting coal and other minerals from underground. These elements when extracted in the raw form contains harmful chemicals and can increase the amount of toxic elements when mixed up with water which may result in health problems.
- Marine dumping:The garbage produce by each household in the form of paper, aluminum, rubber, glass, plastic, food if collected and deposited into the sea in some countries. These items take from 2 weeks to 200 years to decompose.
- Accidental Oil leakage: For e.g.: a ship carrying large quantity of oil may spill oil if met with an accident and can cause varying damage to species in the ocean depending on the quantity of oil spill, size of ocean, toxicity of pollutant.
Effects of water pollution
- Human Health
We all drink water that comes from a source: this may be a lake or local river. In countries that have poor screening and purification practices, people often get water-borne disease outbreaks such as cholera and tuberculosis.
Nutrient pollution from upstream (creeks and streams) often flow downhill and even travel miles into other larger water bodies. The effect is that, it breeds algae growth and causes the growth of many more water organism. This algae attack affects fish and other aquatic animals by absorbing and reducing their oxygen supply.
- Death of animals
Animals, including water animals die when water is poisoned for various reasons. Other animals are stressed and their populations are endangered. That water pollution caused a lot of damage and deaths of many animals. Animals are also affected by solid waste thrown into water bodies, as they harm them in many ways.
Control of water pollution
The various methods for the control of water pollution are
- Sewage pollutants are subjected to chemical treatment to change them into non-toxic substances
- Water pollution due to organic insecticides can reduced by the use of very specific chemicals
- Domestic and industrial wastes should be stored in large but shallow ponds for some days. Due to the sunlight and the organic nutrients present in waste there will be mass scale growth of those bacteria which digest the harmful waste matter
- Reuse of treated water by waste water treatment
- Legal policies can strictly followed to monitor waste water treatment from industries