Grupo México’s Sonora River spill still contaminates water after 12 years

On 6 August 2014, Buenavista del Cobre, a subsidiary of mining conglomerate Grupo México owned by Germán Larrea, released millions of liters of acidic copper‑sulfate solution—estimated at about 40 million liters—into the Tinajas arroyo in Cananea, Sonora. The discharge entered the Río Sonora and the El Molinito reservoir, affecting more than 270 km of river that local residents had long used for drinking, irrigation, bathing and fishing.

Twelve years later, communities such as Arizpe still report unsafe water, health problems among children, and ongoing ecological damage. Local river‑basin committees have secured Supreme Court rulings that require environmental remediation, but the promised 2 billion‑peso Río Sonora Trust has funded only half of the pledged cleanup, and concrete actions remain absent. While the federal and state governments have announced a new hospital for affected residents, activists say the core remediation effort is still pending and Grupo México has avoided full responsibility for the disaster.