Causes of Pollution: The quality of the worlds freshwater has declined dramatically since the late 1970s. They are becoming polluted with more complex and powerful poisons every day. Surveys made in Great Britain in the 1980’s revealed that more than 500 miles of the rivers studied had worsened significantly, with over 2,500 miles of rivers classified as “biologically dead.”

Human Waste: Hundreds of millions of gallons of sewage are being released daily into the worlds rivers. Much of this sewage enters the sea through streams and river systems. The toxins (poisons) released by the sewage allow the growth of sewage fungus, bacteria that feed on organic waste. The fungus on organic waste. The fungus spreads over green plants and uses up the oxygen in the water, suffocating wildlife species.

Industry: Industrial waste causes millions of tons of metallic toxins to be released into rivers every year. And fossil fuels stations and gasoline engines release millions of tons of sulfur dioxide and nitrogen oxide into the air. Sunlight changes these elements into sulfuric and nitric acid, and the pollutants return to earth and its waters as acid rain.

Agriculture: Pesticides, fertilizers, and herbicides enter waterways through rainfall and seepage. Ironically, fish farming, an attempt to restock trout and salmon destroyed by pollution is undermining the survival of other aquatic creatures. The use of pesticides to control fish lice is dangerous to freshwater lobsters, crabs, and mollusks.

Increase in Algae: The introduction of large deposits of nitrogen and phosphorus from sewage, industry, and farming into waterways causes a process called eutrophication. This means that a waterway can support more plant life, especially algae. When plants like algae flourish in the mineral enriched water, they blanket the water and cut off sunlight for underwater plants, which them die. The dead plants decompose, using up the remaining oxygen in the water. Fish and other river species them suffocated and die. Nitrogen deposits in British waterways, for example, are estimated at almost 400,000 tons a year.

Effects on Wildlife: Game fish varieties are the first to suffer from pollution. Trout and salmon need cool waters with plenty of oxygen, and their numbers have declined severely in many North American and European rivers. Even sturdy fish species such as carp and perch, which have adapted to the warmer, less oxygenated low land rivers, are now vulnerable to water toxins (poisons). Studies of slow flowing low land rivers systems in eastern England reveal that the mixed fisheries of the 1950s are now almost dominated by the roach, a sturdy fish that can survive in low oxygen water. 

Eel populations are dying in European rivers. And large numbers of lifeless spawn (fertilized eggs) on river surfaces suggest that frogs and toads are also dying out.  The decline in fish and insect varieties also affect freshwater birds like the gray heron, kingfisher, coot, swift, martin, dipper, and moorhen. The pollution also effects the otter, which is already rare.

Action File: River Pollution, A Global Concern: 

Western Europe: The Rhine River releases more than 100 tons of toxic heavy metals into the North Sea daily, after flowing through five major industrial nations. In 1986, a chemical plant in Switzerland accidentally released almost 35 tones of toxic waste almost 35 tons of toxic waste into the Rhine. The waste flowed through France, Germany, and Holland, killing almost everything in its path, including wildlife.

India: The Ganges is India’s most sacred river. Hindus have traditionally been buried in its waters when they died. Recently, the river has lost its natural ability to purity itself, as riverside populations have grown to 200 million. The Indian government is cleaning up the Ganges. The bodies put into the river each year at Varanasi are now cremated first.

Great Britain: For many years the River Thames supported little wildlife. Today, with waste control and sewage plant upgrades, salmon are returning to the river. The Thames is now considered one of the cleanest metropolitan rivers in the world.  But the Thames is still vulnerable to loss of oxygen. In July 1986 almost a million fish died when London’s sewage system broke down after a major rainfall.

The Future, What we can do?
Avoid pouring hair dyes, bleaches, medicines, or engine oil down drains.
Buy organic vegetables and meats to discourage the use of agricultural chemicals.
Use non-phosphate cleaning products. Avoid buying the products of companies known to pollute waterways.
Support local and national conservation groups dedicated to protecting waterways.
Lobby for the modernization of sewage systems and for tougher legislation on waste control and pollution management.

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