China Says 80% of Tested Wells Had Water Too Polluted to Drink

BEIJING — Although the Chinese have become used to hazy skies as a measure of environmental blight, statistics that received wide attention on Monday pointed to grim pollution below citizens’ feet, in underground water that is heavily used by farms, factories and households.

More than 80 percent of 2,103 wells for underground water tested across heavily populated plains of China were so badly contaminated by industrial and agricultural runoff that their water was unfit for drinking and home use, according to the numbers cited in a recent survey by the Ministry of Water Resources.

“From my point of view, this shows how water is the biggest environmental issue in China,” said Dabo Guan, a professor at the University of East Anglia in Britain who has been studying water pollution and scarcity in China.

“People in the cities, they see air pollution every day, so it creates huge pressure from the public. But in the cities, people don’t see how bad the water pollution is,” Professor Guan said. “They don’t have the same sense.”

The latest statistics are far from the first about the damage done to China’s underground water reservoirs and basins by runoff from farming and industry. But the numbers, issued recently but given extensive coverage by the local news media only on Monday, struck a nerve among Chinese citizens who have become increasingly sensitive about health threats from pollution.

“Does China have any clean underground water?” asked an online commentary by National Business Daily, which earlier brought widespread notice to the data. “The recently published truth is alarming.”

Just how much of the alarm was justified was unclear.

The survey measured water sources relatively close to the surface. But many Chinese cities draw on deeper reservoirs that are hundreds, even thousands, of feet deep for drinking water, although in many small towns and the countryside, residents still use shallower wells for domestic needs, said Ma Jun, an environmentalist who is a director of the Institute of Public and Environmental Affairs in Beijing.

“Fewer and fewer cities are using the heavily polluted shallow-depth underground water,” Mr. Ma said in an interview. “Most are digging deep wells for drinking. This is a very important distinction that must be made.”

For years, the Chinese government has acknowledged that wells and underground water reserves were endangered by overuse as well as widespread contamination from industry and farming. In 2011, the Ministry of Environmental Protection issued a plan to cut pollution of underground water resources by the end of this decade.

That plan said that China’s use of underground water grew from 57 billion cubic meters a year in the 1970s to 110 billion cubic meters in 2009, providing nearly a fifth of the country’s total supplies. In the arid north of the country, underground supplies provided about two-thirds of water for domestic needs, it said.

But estimates of pollution of underground sources have varied depending on the depth and location of wells tested. An annual report from the Ministry of Water Resources said that in 2014, nearly half of 2,071 monitored wells had “quite poor” water quality, and an additional 36 percent had “extremely poor” quality.

“Environmental pollution has become a hot topic in recent years,” Zheng Yuhong, an agricultural resources expert who is a member of China’s national legislature, said last month during the annual meeting of the legislature, according to a report at the time. “But pollution of underground water has virtually been forgotten.”

The latest study found that 32.9 percent of wells tested had Grade 4 quality water, which meant that it was fit only for industrial uses, National Business Daily said. An additional 47.3 percent of wells were even worse, Grade 5. The contaminants included manganese, fluoride, and triazoles, a set of compounds used in fungicides. In some areas, there was pollution by heavy metals.

The heavy contamination of supplies near the surface was forcing more cities to dig thousands of feet underground for clean water, and that was taxing the capacity of those deep aquifers, Professor Guan said.

“These latest statistics are an indicator of how bad the underground water quality is,” he said. “The sources of pollution are so widespread and include a lot of agriculture. I think that would be the main source of pollution.”