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Sewage Used to Water Crops Near Many Third World Cities, Survey Finds

Widespread use of raw sewage to irrigate crops threatens to expose millions of people in developing countries to epidemics, an international conference on water heard in Sweden today.

The news was presented to the annual World Water Week conference in Stockholm, capital of Sweden, where 2,500 experts from 140 countries are pondering solutions to the world’s water crisis.

The International Water Management Institute told the conference that more than half of farmland near three dozen cities surveyed in developing countries is watered with untreated sewage.

Irrigating with wastewater occurs especially in Asian countries, like China, India and Vietnam, but also around nearly every city of sub-Saharan Africa and in many Latin American cities, the Institute reported. Sewage is used mostly to produce vegetables and cereals, especially rice, creating a major health risk to consumers of uncooked vegetables.


Photo by David Alan Harvey
Two girls in Cambodia fetch water. Photo by David Alan Harvey/NGS


In many parts of the world people must walk miles every day to get their water. While progress has been made in recent years, something like a billion people still do not have access to clean drinking water.

Today’s news from Stockholm encapsulates the global water crisis:  Poor countries that have no money to treat sewage, tap into safe groundwater, or transport safe produce into cities have no choice but to use sewage or polluted rivers to produce food.

Nearly half of the world’s six billion people do not have access to proper toilets. Their waste contaminates rivers and groundwater and contributes to waterborne diseases that kill thousands of children every day.

Climate change could make matters a lot worse. Melting glaciers in Asia and South America would deprive millions of people of mountain runoff once they are gone. Parts of the planet could become a lot more arid as rainfall declines and weather patterns shift.

In many countries aquifers are being drained much faster than natural precipitation replenishes them. Rivers are so dammed and channeled that many of them no longer make it all the way to the sea.

There is a widening water deficit. Simply put, humans take more water out of the system than nature puts in.

As our numbers continue to grow we will have to deal with this situation. Less wasteful forms of irrigation must be found, we will have to mend broken pipes, we will have to eat less meat (meat production uses an enormous amount of water). And yes, we will have no choice but to recycle our (treated) sewage.

National Geographic News will continue to report on the world’s water crisis and what is being and can be done about it. Our editor Tasha Eichenseher is covering events at World Water Week in Stockholm and our contributors are monitoring the situation around the world.

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[This post has been reformatted for Water Currents.]