Types of water pollutants
Disease causing agents include bacteria, viruses, protozoa and parasitic worms that enter water sources through domestic sewage and animal wastes.
Inorganic chemicals which are soluble in water consists of acids, salts and soluble compounds of toxic metals like mercury and lead, which make water unfit to drink, harm fish and aquatic life, affect crops, and corrode materials. A large number of inorganic chemicals find their way into both surface water and ground water from sources such as industries, mines, irrigation runoff, oil drilling, and urban runoff from storm sewers.
Inorganic plant nutrients like water soluble nitrates and phosphates to name a few, cause excessive growth of algae and other aquatic plants. When these aquatic plants die and decay, they decompose. This causes depletion of oxygen in water. This is harmful to underwater life.
Heat and warm waters released from industrial discharges as part of their cooling processes raises water temperature and affects health and life cycles of aquatic flora and fauna.
Radioactive substances include the waste from mining and the refinement of radioactive metals as well as the pollution caused by their use.