ABC News, 18 August 2008
Waste water is widely used to irrigate urban agricultural land in developing countries, a practice that has both advantages and disadvantages, a 53-city study presented at a water conference in Stockholm has shown.
The International Water Management Institute report, showed that 80 per cent of cities studied were using untreated or partially treated waste water for agriculture.
Waste water irrigation contributes to urban food supplies and helps provide a livelihood for the poor, but can be a health risk if the food is consumed uncooked.
In over 70 per cent of the cities studied, more than half of the urban agricultural land produced vegetables and rice using waste water.
Waste watere was being used on 20 million hectares of land, throughout China, India, Vietnam, sub-Saharan Africa and in many Latin American cities.
In Ghana's capital Accra, some 200,000 city residents purchase vegetables produced on just 100 hectares of urban agricultural land irrigated with waste water.
The report urged local authorities to develop policies for safer waste water use, and advocated low-cost measures such as the use of drip irrigation and correct washing of produce.