Crop irrigation with untreated wastewater

 

Photo credit: IWMI

Basudev Mondal irrigates a farm near the busy EM Bypass road of Calcutta, India growing brinjal or egg plant. Photo: Chhandak Pradhan / IWMI

A major health and environmental menace

The use of wastewater to irrigate crops is far more widespread than previously estimated, according to a new study, exposing hundreds of millions of people to health risks and posing a major environmental hazard.

Study results, based on on advanced modeling methods, show that 65% of all irrigated areas within 40 kilometers downstream from urban centers – amounting to about 35.9 million hectares (Mha) worldwide – are affected by wastewater flows to a large degree. Of this total area, 29.3 Mha are in countries where wastewater treatment is very limited, exposing 885 million urban consumers as well as farmers and food vendors to serious health risks.

Five countries – China, India, Pakistan, Mexico and Iran – account for most of this cropland. The new findings supersede a widely cited 2004 estimate, based on case studies in some 70 countries and expert opinion, which had put the cropland area irrigated with wastewater at a maximum of 20 million hectares.

Read the full article: IWMI