Water may be polluted in different ways. It effects enormous on aquatic life, environment and human beings. Some effects of water pollution are described below:

Effects of oxygen demanding wastes
The bacterial degradation of waste in water requires oxygen. In this process the bacteria consume the dissolve oxygen in water. If there are huge amount of oxygen demanding wastes, then the oxygen concentration of water may drop so low that it is difficult to survive for the aquatic lives. On the other hand some anaerobic microorganisms begin to bloom. Since they generate harmful toxins as like ammonia and sulfides so it may harmful to people and animals.

Effects of plant nutrients
Plant nutrients as like nitrates, phosphates, potassium may be added to the water bodies through human activities and over nutrition may cause extreme growth of algae and other water plants. In this process a good number of aquatic lives decay; moreover as the plant and algae die, it may collect a good amount of organic matters and is filled with sediment. It lowers the oxygen level in the water. Furthermore, to biodegrade this sediment again lowers the oxygen level; such a phenomenon is known as eutrophication. It disturbs the ecological balance.

Effects of organic pollutants
Organic pollutants as like oil, plastics, petrochemicals and pesticides are harmful to humans and all plants and animals in the water. Plastic waste can soak up toxic chemicals from ocean pollution. If any marine birds or animals consume, it may reduce appetite or even starvation. Oil is lighter than water; it does not mix with water, as an alternative it form a thick layer on the surface. It works as a barrier for photosynthesis; hence it is harmful for aquatic life, fish and birds.

Effects of inorganic pollutants
Water soluble inorganic pollutants as like acids, salts and toxic metals make water unfit to drink and will cause the death of aquatic life. Toxic metals as like lead, mercury can cause health and environmental problems, including humans. Many non-metallic substance as like Sulphur is harmful for aquatic life.

Effects of radioactive compounds
Water soluble radioactive compounds are extremely dangerous for health. They can cause cancer, birth defects and genetic damage.

Effects of thermal pollution
Thermal pollution of the water bodies can decreases oxygen levels and may have a terrible effect on aquatic life.

Effects of microorganisms
If Disease-causing microorganisms (pathogenic microbes) are found in surface waters, it may cause human health problems including typhoid, diarrhea, hepatitis and may have negative impacts on aquatic life. Sewage often carries harmful viruses and bacteria into the water bodies and environment.

Effects of agricultural waste
Many agricultural farms often use large amounts of toxic substances as like herbicides and pesticides. These chemicals are particularly dangerous to aquatic life in water bodies.
Asbestos fibers are another serious pollutant; it can cause asbestosis, mesothelioma and cancer.
Effects of water pollution are the major problem for developing countries. They do not supply enough pure water. Moreover they are not concern about effects of water pollution.