In theory, recycling water in China’s parched cities, including Beijing, makes ecological sense. But when wastewater is inadequately treated before being used to water urban parks—or redirected through scenic downtown canals—it can become an environmental health hazard.
Six researchers in Beijing and Xiamen working for the Chinese Academy of Sciences recently decided to compare conditions in city parks watered with fresh water vs. recycled water. Their findings, reported in a July 24 article in the journal Environmental Science & Technology, may make you squirm.
Conventional wastewater treatment plants are designed to remove solids, organic matter, and nutrients from water, but they aren’t properly equipped to treat the kinds of waste that may be found in used water from hospitals and pharmaceutical facilities. In particular, most wastewater plants in China don’t remove traces of antibiotics and may even become “reservoirs” for them, as the researchers put it.
Even treated wastewater can therefore become a vector for spreading antibiotics, as well as “antibiotic resistant genes”—chance genetic mutations that make bacteria resistant to drugs. The researchers found that urban parks in China doused with recycled water contained dangerously elevated levels of antibiotic resistant genes, with quantities from 100 times to 8,655 times greater than in other parks.
An April 30 report from the World Health Organization sounded the alarm about growing antibiotic resistance worldwide: “This serious threat is no longer a prediction for the future, it is happening right now in every region of the world. … Antibiotic resistance–when bacteria change so antibiotics no longer work in people who need them to treat infections–is now a major threat to public health.”
Apparently lousy sewage systems and some irrigated parks in China, and likely elsewhere, are helping to accelerate the threat. China’s situation is particularly risky because of a culture of rampant overprescription of antibiotics, which the government is trying hard to bring under control.
A 2012 study reported that people in China consume on average 138 grams of antibiotics per year; that’s 10 times the per capita average in the U.S. That means a steady and dangerous stream of antibiotics get washed down the drain, into ill-equipped sewage plants, and possibly sprinkled onto the grass you or your friends in Beijing walk across.