Wells In The Rio Sonora Valley Still Contaminated With Arsenic, Lead

By Kendal Blust
Published: Monday, October 5, 2020 - 5:05am

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Rio Sonora
Kendal Blust/KJZZ
The Rio Sonora flows through the town of Baviácora, Sonora, on July 30, 2019.

Residents of the Sonora River Valley have heard nothing from authorities since they were told last December wells in the area show signs of contamination. Now, they’re renewing calls for access to clean water.

It’s been six years since Grupo Mexico’s Buenavista copper mine spilled millions of gallons of toxic waste into the Rio Sonora. But an analysis of wells in the river valley by Mexican authorities in August 2019 shows 80% percent of the 60 wells tested still have levels of arsenic that exceed safety standards, and about 10% have traces of lead, according to a report from the nonprofit PODER, which obtained the data through a public information request.

PODER submitted further public records requests for additional information about the contamination in January, on behalf of river valley residents, said Samantha Camacho, an investigator with PODER. But authorities have not released information about the origin of the contamination, how it is being monitored and mitigated, and how local residents who depend on that water are being told of the risks. 

“Almost a year after we made the first request, we haven’t received any updated information about the monitoring of the wells and attention to the affected population. Denying this information is not only violates our rights to know, it also allows the continued violation of our rights to health and to water in communities affected by Grupo Mexico’s spilling into the Rio Sonora,” Camacho said. "Everything we’ve been investigating and working on leads us to the conclusion that the authorities have to do their job and resolve this issue."

She added that it's important to reiterate that communities in the river valley have been making demands for clean water, access to health care and comprehensive restoration of the area for more than six years, since the mining spill in 2014.

map of contaminated wells
This map shows the locations of wells that had levels of arsenic (red dots) and lead (yellow dots) that exceed the levels permitted under Mexican law.

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