India using wastewater for irrigation, says study

Source: The Hitavada      Date: 06 Jul 2017 08:42:49


 

COLOMBO,

INDIA and four other countries -- China, Pakistan, Mexico and Iran -- account for the most cropland in the world irrigated by dirty wastewater, putting millions of lives at serious health risks, new research has found.
The global use of untreated wastewater from cities to irrigate crops downstream is 50 per cent more widespread than previously thought, according to the study published in the journal Environmental Research Letters.


The study relies on advanced modelling methods to provide a comprehensive estimate of the global extent to which farmers use urban wastewater on irrigated cropland. Researchers analysed data with Geographic Information Systems (GIS). According to the study, farmers’ use of wastewater is most prevalent in regions where there is significant wastewater generation and water pollution.


In these circumstances, and where safer water is in short supply, wastewater offers a consistent and reliable means of irrigating fields, including high-value crops, such as vegetables, which often require more water than staple foods.
Where raw wastewater is available, farmers may tend to prefer it because of its high concentrations of nutrients, which can lessen the need to apply purchased fertilisers.


Farmers’ use of this water is motivated by basic needs. They simply do not have alternatives, the study showed.
“The de facto reuse of urban wastewater is understandable, given the combination of increasing water pollution and declining freshwater availability, as seen in many developing countries,” said Anne Thebo from University of California, Berkeley in the US.