Freshwater pollution

What causes pollutants in freshwater ecosystems?

There have been listed some 1500 substances as pollutants in freshwater ecosystems, and each of them occurs in the following types of freshwater pollutants. Here is a generalized list of them:

Acids & alkalis
Anions
Detergents
Domestic sewage and farm manures
Food processing wastes (including processes taking place on the farm)
Gases (e.g. chlorine, ammonia)
Heat
Metals (e.g. cadmium, lead, mercury)
Nutrients (especially phosphates, nitrates)
Oil and oil dispersants
Organic toxic wastes (e.g. formaldehyde, phenols)
Pathogens
Pesticides
Polychlorinated biphenyls
Radionuclides

The different pollutants exert different problems to different freshwater waterways. Mostly expressed in the amount of oxygen that is available for fish and other species. This sometimes results in habitat destruction and extinction of local populations.

You can click on the pollutants above to learn more about their characteristic feature and their fate in freshwater ecosystems when they show up in there. Species are often used for toxicity tests, and there responses also may differ.