WATER POLLUTION

Pollution of fresh water ecosystems

Pollution of marine ecosystems

is contamination of water bodies by

pollutants that are directly or indirectly

discharged into water without adequate

treatment to remove harmful compounds .

PHYSICAL POLLUTION

CHEMICAL POLLUTION

RADIOACTIVE POLLUTION

BIOLOGICAL POLLUTION

PHYSICAL POLLUTION

-SOLID WASTE-

PHYSICAL POLLUTION -THERMAL POLLUTION-

Rise (or fall) in the temperature of natural water body caused by human influence, which results in changed physical properties of water. Sources of this kind of pollution are nuclear and hydro power plants and factories which use river water to cool their reactors or machinery, as well as urban runoff.

Consequences of thermal pollution:

Decreased level of dissolved oxygen in water- death of water animals

Altered food chains and biological cycles of water animals and plants

Invasion of thermophilic species

Loss of biodiversity

invasion of thermophilic algae due to

the increased water temperature

CHEMICAL POLLUTION

Represents releasing of different chemical substances in water ecosystems. Those substances could be:

Non degradable and hardly degradable (detergents; chemical waste; heavy metals: mercury, lead, cadmium, zinc; various pesticides; acid discharges from factories and highly toxic organic compounds such as phenols, volatile organic compounds)

Degradable by organisms living in water (mostly organic compounds, minerals and nutrients from fertilizers)

AUTOPURIFICATION

Bloom of algae due to increased organic compounds in water

Speeding up of natural process of succession due to organic pollution

OIL SPILLS Release of crude oil from tankers, oil platforms and drilling rigs into marine ecosystems, as well as discharging of refined petroleum products, heavy fuels used by large ships and waste oil (motor and hydraulic oil etc.) Pollution of water with oil is both physical and chemical. Oil is less dense than water, and also it can not dissolve in water, so it floats on its surface forming thick sludge and it can spread on huge distances. It is catastrophic for marine life: oil suffocates fish, gets caught in the fur of marine mammals and feathers of marine birds stopping them from flying; blocks light from photosynthetic aquatic plants and algae..

BBC Stephen Fry And The Great American Oil Spill

RADIOACTIVE POLLUTION

Radioactive contamination is the deposition or presence of radioactive substances on surfaces or within solids, liquids or gases, where their presence is unintended or undesirable. Such contamination presents a hazard because of the radioactive decay of the contaminants, which emit harmful ionizing radiation such as alpha or beta particles, gamma rays or neutrons.

It occurres due to deposition of radioactive waste at ocean bottom, especially in international waters.

Accidents and sinking of nuclear submarines

Underwater nuclear tests

The real danger of toxic an radioactive pollutants in water is that they are easily spread on huge distances by water flow. Also, they easily enter food chains which leads to processes of bioaccumulation and biomagnification.

BIOLOGICAL POLLUTION

Biological pollutants are pathogen microorganisms (bacteria, viruses, protozoa, parasites) which represent serious threat to human health causing wide range of diseases: typhoid, cholera and hepatitis A and B.

Also, biological pollution is appearance of introduced and allochthonous species in water ecosystems, which can cause serious damage to this ecosystems and lead to a biodiversity loss (many of those species are invasive and able to extinct native species).

Some invasive species which caused immense biodiversity and economical losses once they were introduced to their non native

ecosystems

HOW DO WE PROTECT WATER? Different laws and regulations are of the greatest importance.

Elimination of pollution source

Reduction of amount of pollutants that are discharged in water

Special methods of water cleaning and purification (preferably using biological and natural methods- different plants, bacteria, fungi and algae)

Local people can give great contribution in preserving fresh water and oceans

MARCH 22: WORLD WATER DAY

http://thewaterproject.org/water_conservation.asp

http://worldwaterconservation.com/

http://en.wikipedia.org/wiki/Water_conservation

http://www.worldwatermonitoringday.org

River Drina, Serbia