This alarming figure is from a new report by the UN Environment Programme (UNEP), which says millions of tonnes of solid waste are being flushed into water systems every day, spreading disease.
"More than two billion tonnes of wastewater are being flushed into our fresh water and oceans every day, every year," Christian Nelleman, the lead author of the report, 'Sick Water?' told IRIN.
The wastewater, a cocktail of agricultural and industrial runoffs and sewage, was seeping into groundwater and polluting drinking sources, like wells, in low-lying areas where the bulk of the world's population live.
Countries should not only invest in infrastructure to manage wastewater but also in ecosystems, for instance by replanting mangroves, which acted as natural filters in coastal areas, said Nelleman.
"What is also very alarming is the amount of phosphate and nitrogen that is lost as agricultural refuse - projections show that we can run out of phosphate very soon," he warned.
Nearly half the agricultural phosphate applied each season got washed away and ended up in rivers and oceans, where it contributed to triggering algae blooms that could damage ecosystems and fish stocks, Nelleman said. Wastewater treatment plants should be sophisticated enough to harvest the phosphates.
The report urged countries to draw up national and local strategies to cope with the wastewater production and invest in infrastructure to manage it.
Some facts from the report:
- Around 90 percent of diarrhoea cases, which kill some 2.2 million people every year, are caused by unsafe drinking water and poor hygiene.
- Over 50 percent of malnutrition cases globally are associated with diarrhoea or intestinal worm infections.
- Over half the world's hospital beds are occupied by people suffering from illnesses linked to contaminated water.
- Almost 900 million people lack access to safe drinking water, and an estimated 2.6 billion people lack access to basic sanitation. South Asia (around 221 million) and sub-Saharan Africa (330 million) have the highest proportion of people living without basic sanitation.
- Ninety percent of the wastewater discharged daily in developing countries is untreated. Eighty percent of all marine pollution originates on land - most of it wastewater - damaging coral reefs and fishing grounds.
- People in developed countries generate five times more wastewater per person than those in developing countries, but treat over 90 percent of their wastewater, compared to only a few percent in developing countries.
- Agriculture accounts for 70 to 90 percent of all water consumed, mainly for irrigation, but large amounts return to rivers as run-off; nearly half of all organic matter in wastewater comes from agriculture.
- Industrial wastes, pesticides from agriculture, and tailings from mining also create serious health risks and threats to water resources, costing billions of dollars to monitor, much more to clean.
- Use of bottled water is increasing, but it takes three litres of water to produce one litre of bottled water. In the USA alone an additional 17 million barrels of oil per year are used to make the plastic containers. Worldwide, 200 billion litres of bottled water are produced every year, creating an enormous problem of how to dispose of the used plastic bottles.
- Wastewater generates methane, a greenhouse gas 21 times more powerful than carbon dioxide (CO2). It also generates nitrous oxide, which is 310 times more powerful than CO2.
- It is estimated that in just a decade, wastewater-linked emissions of methane will rise by 25 percent and that of nitrous oxide by 50 percent.
- Increased flooding as a result of climate change can overwhelm ageing sewage infrastructure in cities and towns.
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