What are coliforms? Coliforms are bacteria are always present in the digestive tracts of animals, including humans, and are found in their wastes. They are also found in plant and soil material. The most basic test for bacterial contamination of a water supply is the test for total coliform bacteria. Total coliform counts give a general indication of the sanitary condition of a water supply.
Total coliforms include bacteria that are found in the soil, in water that has been influenced by surface water, and in human or animal waste.
Fecal coliforms are the group of the total coliforms that are considered to be present specifically in the gut and feces of warm-blooded animals.
Because the origins of fecal coliforms are more specific than the origins of the more general total coliform group of bacteria, fecal coliforms are considered a more accurate indication of animal or human waste than the total coliforms.
(E.coli) is the major species in the fecal coliform group. Of the five general groups of bacteria that comprise the total coliforms, only E. coli is generally not found growing and reproducing in the environment. Consequently, E. coli is considered to be the species of coliform bacteria that is the best indicator of fecal pollution and the possible presence of pathogens.
Coliforms are relatively easy to identify, are usually present in larger numbers than more dangerous pathogens, and respond to the environment, wastewater treatment and water treatment similarly to many pathogens. As a result, testing for coliform bacteria can be a reasonable indication of whether other pathogenic bacteria are present.
If pathogenic (disease-causing) organisms are present, they may be passed as well. When a stream is polluted by fecal material, pathogenic bacteria, viruses, and parasites may be introduced, posing a health hazard to those who come in contact with the water. Municipal and rural water supplies can transmit human diseases such as cholera (Vibrio cholerae), typhoid fever (Salmonella typhi), salmonellosis (Salmonella), and gastroenteritis.
The threat of such disease transmission becomes more serious as the population density increases and more sewage pollutes public water supplies, carrying with its human intestinal pathogens.
If fecal coliform counts are high (over 200 colonies per 100 ml of water sample) in the river or stream, there is a greater chance that pathogenic organisms are also present. A person swimming in such water has a greater chance of getting sick from swallowing disease-causing organisms, or from pathogens entering the body through cuts in skin, the nose, mouth, or the ears. Diseases and illnesses such as typhoid fever, hepatitis, gastroenteritis, dysentery, and ear infections can be contracted in waters