| Introduction |
Types of freshwater pollution
Acids & alkalis
|A pathogen is an organism that produces a disease. It is an organic pollution (biological hazard) and occurs from fecal contaminations. Fecal contaminations of water can introduce a variety of pathogens into waterways, including bacteria, viruses, protozoa and parasitic worms. |
A very well known pathogenic bacteria is Salmonella. There are some 200 immunologically distinguishable types of Salmonella known to be pathogenic to humans. But there are many more that infect animals, including livestock. Cross-infection between people can occur via water pollution. The spreading of untreated sewage wastewater on land and its use for the irrigation of crops can also be a source of infection.
Currently there appears to be an increase in the spread of Salmonella and this has been related to modern living conditions, such as mass food production (e.g. of poultry) and communal feeding.