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  2. Nonpoint source pollution - Wikipedia

    en.wikipedia.org/wiki/Nonpoint_source_pollution

    These toxins are a particular problem in systems used for drinking water because some toxins can cause human illness and removal of the toxins is difficult and expensive. Bacterial decomposition of algal blooms consumes dissolved oxygen in the water, generating hypoxia with detrimental consequences for fish and aquatic invertebrates. [11]

  3. Hypoxia (environmental) - Wikipedia

    en.wikipedia.org/wiki/Hypoxia_(environmental)

    An aquatic system lacking dissolved oxygen (0% saturation) is termed anaerobic, reducing, or anoxic. In water, oxygen levels are approximately 7 ppm or 0.0007% in good quality water, but fluctuate. [5] Many organisms require hypoxic conditions. Oxygen is poisonous to anaerobic bacteria for example. [3]

  4. Streeter–Phelps equation - Wikipedia

    en.wikipedia.org/wiki/Streeter–Phelps_equation

    The Streeter–Phelps equation is also known as the DO sag equation. This is due to the shape of the graph of the DO over time. The biological oxygen demand (BOD) and dissolved oxygen (DO) curves in a river flowing right reaching equilibrium after a continuous input of high BOD influent is added into the river at x = 15 m and t = 0 s.

  5. List of most-polluted rivers - Wikipedia

    en.wikipedia.org/wiki/List_of_most-polluted_rivers

    Fish were able to survive in the water for only 3 to 5 hours even after samples were diluted. Almost zero dissolved oxygen. [34] [36] Ganges India: Tens of millions of people [38] The most sacred river to Hindus. [39] Levels of fecal coliform bacteria from human waste in the river near Varanasi are more than 100 times the Indian government's ...

  6. Water aeration - Wikipedia

    en.wikipedia.org/wiki/Water_aeration

    Decreased levels of dissolved oxygen (DO) is a major contributor to poor water quality. Not only do fish and most other aquatic animals need oxygen, aerobic bacteria help decompose organic matter. When oxygen concentrations become low, anoxic conditions may develop which can decrease the ability of the water body to support life.

  7. Poland: 'Huge' amounts of chemical waste dumped into river

    www.aol.com/news/poland-investigates-ecological...

    Poland's prime minister said Friday that “huge amounts of chemical waste” were probably dumped intentionally into the Oder River, which runs along the border with Germany, causing ...

  8. Water pollution - Wikipedia

    en.wikipedia.org/wiki/Water_pollution

    Elevated water temperatures decrease oxygen levels (due to lower levels of dissolved oxygen, as gases are less soluble in warmer liquids), which can kill fish (which may then rot) and alter food chain composition, reduce species biodiversity, and foster invasion by new thermophilic species. [48]: 179 [15]: 375

  9. Eutrophication - Wikipedia

    en.wikipedia.org/wiki/Eutrophication

    Algal blooms limit the sunlight available to bottom-dwelling organisms and cause wide swings in the amount of dissolved oxygen in the water. Oxygen is required by all aerobically respiring plants and animals and it is replenished in daylight by photosynthesizing plants and algae. Under eutrophic conditions, dissolved oxygen greatly increases ...