A Massive Acid Spill in Mexico Has Turned This River Red and Toxic

More than 10 million gallons of sulfuric acid from one of the world’s largest copper mines spilled into two major rivers—the Sonora and the Bacanuchi—in northern Mexico earlier this month, cutting the water supply of 20,000 people and closing 88 schools. Some locals even fear eating food.

“If [a cow is killed], we don’t know if we can eat it,” housekeeper and farm laborer Ramona Yesenia said. “They say if the [cattle] drink just a little water [from the rivers], they get infected.”

Civil defense official Carlos Arias told The Associated Press that the spill in Sonora, Mexico, on Aug. 7 was caused by defects in new ponds that hold the acids used to filter metal. Residents discovered the reddened water, usually clear this time of year, the next day. Grupo Mexico, which operates the Buenavista mine, hadn’t told authorities. 

Mine operators alerted the Attorney General for Environmental Protection almost a full day after the leak, which was within the 24-hour filing requirement, according to Arturo Rodriguez, the agency’s head of industrial inspection. He said that careless supervision, rains, and construction errors seem to have resulted in the spill—noting that operators should have discovered the leak before a huge amount of sulfuric acid flowed into the rivers. Arias said the overflow has arsenic and other pollutants above normal levels.

Local Jesus Sabori told AFP that the water has become “more and more red every day… It was only [Aug. 11] that they told us to keep our animals away.”

“We’re angry because they didn’t take the time to tell us either that the spill had happened or that they cutting off our water,” said resident Israel Duran.

In this photo, the contaminated Sonora river makes its way near the town of Ures …

The mine’s executives simply blame “abnormal rains” for causing the acid to spill over from its tanks. They also claim to have notified the government by email, insisting that the acid is “not toxic in itself.”

Grupo Mexico’s international relations vice president, Juan Rebolledo, told a local radio station, “There’s no problem nor any serious consequence for the population, as long as we take adequate precautions and the company pours lime into the river, as it is currently doing.”

Lime, or calcium, will deacidify the Sonora and Bacanuchi rivers. “What you can’t get rid of are the heavy metals,” said Arias.

So far no serious injuries have been reported, but according to Centers for Disease Control guidelines, short-term exposure to sulfuric acid may irritate the eyes, nose, and throat. Direct contact with skin and eyes will cause severe burns, and inhaling the vapor may result in tooth erosion, sore mouth, and trouble breathing. Arsenic can cause cancer.

The Buenavista copper mine, which employs 9,000 people, hasn’t announced any plans to cancel or delay an upcoming expansion. By 2016, its output is expected to increase from 200,000 tons of copper to 510,000 tons.

Duran said, “Even if [the mine] creates jobs, it would be better if they close it if they’re going to behave like this every time something happens.”