Concern after hearing about the contamination
The director of the Sonora State Civil Protection Agency said on Monday that contamination from the Buenavista del Cobre mine in Cananea made it into the San Pedro River, which runs north past Hereford, Sierra Vista and Benson.
Officials said they were still investigating how much leaked, or what exactly was in the spill, and said the material was "probably toxic."
Mexican government officials said the spill contained rainwater overflow containing ferrous elements below the threshold of what would pose a human health risk to human health. Authorities were analyzing whether it could contain heavy metals or other contaminants, like arsenic.
The Buenavista del Cobre mine, owned by Grupo Mexico, produces about 200,000 tons of copper each year.
Arizona ADEQ officials said they planned to send field representatives to collect and test samples of water taken from the San Pedro near the U.S.-Mexico border.
Residents in Cochise county expressed concern after hearing about the contamination, and wondered what this would mean for those who relied on well water.
EPA officials released a statement on Monday night saying they had not been contacted by local or state authorities for help. A spokeswoman said the International Boundary and Water Commission was coordinating with Mexican officials who would visit the mine site, develop a report, and send the report to the Commission on Tuesday.