Sewage Waters a Tenth of World’s Irrigated Crops

The agricultural debate in the United States often revolves
around whether produce is — or should be — organic,
conventionally grown, or genetically modified. In countries such as
India, Pakistan, and Sri Lanka, though, the most pressing question
is whether or not crops have been irrigated by untreated sewage,
which is illegal and poses serious heath risks to both farmers and
consumers.

Government agencies in these countries are aware of the problem,
but tend to look the other way because untreated sewage is cheap
and easy. Farmers like the nitrogen- and phosphate-rich effluent,
because it acts as a fertilizer and is free of charge. And unlike
water in local irrigation canals, it flows even during droughts and
dry seasons.

‘Wastewater irrigation is an institutional no man’s land,’ said
Chris Scott of the Sri Lanka-based International Water Management
Institute. ‘Water, health and agriculture ministries in many
countries refuse to recognize that the practice is widespread.’

A survey co-edited by Scott’s organization and presented at the
Stockholm Water Symposium estimates that one-tenth of the world’s
crops are irrigated with sewage, much of it raw and untreated. The
problem is particularly acute in developing nations, where farms
that yield nearly one-fifth of the world’s food supply are in
either in, or on the fringes of a large, congested city , where
freshwater is scarce. In Hyderabad, India, for instance, the survey
estimates that 100% of the urban crops are irrigated by some sort
of sewage.

Raw sewage is full of disease-carrying pathogens and toxic
industrial waste, but if it were treated properly it could be used
for irrigation. In Mexico, Jordan, Israel, and Tunisia, for
example, sewage is specially treated to remove pathogens and make
it safe for irrigation.
— Elizabeth Dwoskin

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Sewage
Waters a Tenth of World’s Irrigated Crops

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