Biological-water-quality parameters

Biological-water-quality parameters get help from the advantage of water, which may serve as a medium in which literally thousands of biological species spend part, if not all of their life cycle.

Aquatic organism range in size and complexity from the smallest single-cell microorganism to the largest fish.

All members of the biological community are, to some extent, water quality parameters, because their presence or absence may indicate in general terms the characteristics of a given body of water.

Biologist often use a species-diversity index(related to the number of species and the relative abundance of organism in each species) as qualitative parameter for streams and lakes.

For example, a body of water hosting large numbers of species with well balanced numbers of individuals is considered to be a healthy system.

Based on their known tolerance for a given pollutant, certain organisms can be used as indicators of the presence of pollutants.

Pathogen is the most important biological organism in water from the prospective of human use and consumption, those organisms capable of infecting, or transmitting diseases to humans.

In fact these organism are not active to aquatic systems and usually require an animal host for growth and reproduction. They can however, be transported by natural water systems, thus becoming a temporary member of the aquatic community.

Many species of pathogens are able to survive in water and maintain their infections capabilities for significant periods of time.

These water born pathogens include species of

• Bacteria
• Viruses
• Protozoa
• Helminthes

Bacteria are single-cell microorganism, usually colorless, it has different shapes(rod, spherical, or spiral shaped).

Bacteria is an important parameter for the Biological-water-qualityThe gastrointestinal disorders are common symptoms of most diseases transmitted by water born pathogenic bacteria. Some of the disease transmitted by bacteria shown below:

• Francisella tularensis
• Leptospirae
• Salmonella paratyphi (A, B, C)
• Salmonella typhi
• Shigella
• Vibrio comma ( vibrio cholera )

Viruses also another parameter for Biological-water-quality which are the smallest biological structures known, so small that they can only be seen with the aid of an electron microscope.Viruses are obligate parasites that require a host in which to live.

The symptoms associated with water borne viral infections usually involve disorders of nervous system rather than of the gastrointestinal tract.

Some of the diseases caused by viruses shown below

• Enteric cytopathogenic human orphan (ECHO)
• Poliomyelitis(3 types)
• Unknown viruses

Protozoa are unicellular organisms more complex in their functional (it is one of considered Biological-water-quality parameter)activity then bacteria or viruses. They are self contained organisms that can be free living or parasitic, protozoa are widely distributed in natural waters, although only a few aquatic protozoa are pathogenic.Some of the diseases caused by protozoa shown below:

• Entamoeba histolytica
• Giardia lamblia

The life cycle of helminthes(parasitic worms) often involve two or more animal hosts, one of which can be human, and water contaminated by human or animal waste. While aquatic systems can be the vehicle for transmitting helminthal pathogens. Thus helminthes pose hazards primarily to those persons who come into direct contact with un treated water. The persons usually in risk of helminthes diseases as following:

• Sewage plant operators
• Swimmers in recreational lakes polluted by sewage
• Contact with storm water runoff from cattle feedlots
• Farm laborers employed in agricultural irrigation operation

Some of the diseases caused by Helminthes shown below:

• Dracunculus medinensis
• Echinococcus
• Schistosoma