Recycled sewage water found safe for crop irrigation

Science 2.0: Low levels of pharmaceuticals and personal care products (PPCPs) were in crops irrigated with recycled sewage water, according to the first study conducted under realistic field conditions.   The research, which eases some concerns over using treated wastewater for agriculture, was launched because drought and water shortages in the American southwest and in other arid parts of the world are using water recycled from municipal sewage treatment plants to irrigate food crops as the only option.

Water from toilets and sinks enters those facilities from homes and offices, and undergoes processing to kill disease-causing microbes and remove other material. Processing leaves that water, or "effluent," from most sewage treatment plants clean enough to drink. Traditionally, however, sewage treatment plants simply discharge the water into rivers or streams.

The effluent still may contain traces of impurities, including the remains of ingredients in prescription drugs, anti-bacterial soaps, cosmetics, shampoos and other PPCPs that are flushed down toilets and drains so they wanted to know what levels remain.

"The levels of pharmaceuticals and personal care products that we found in food crops growing under real-world conditions were quite low and most likely do not pose any health concern," said Jay Gan, Ph.D., who led the study. "I think this is good news. These substances do not tend to accumulate in vegetables, including tomatoes and lettuce that people often eat raw. We can use that information to promote the use of this treated wastewater for irrigation."

Sprinkler irrigation, shot by Fir0002, Wikimedia Commons, under the Creative Commons Attribution-Share Alike 3.0 Unported license