The release came from the Buenavista del Cobre mine, which produces 200,000 tons of refined copper per year. Owned by the mining company Grupo México – the world’s third-largest copper producer – Buenavista del Cobre first released copper sulphate in August after heavy rainfall. A further release took place in September. The Sonora, a 250-mile river, flows into the Gulf of California.
The Federal Commission for Sanitary Protection and the National Centre for Disease Prevention and Control, the two Mexican health authorities dealing with the spill, have now identified 37 people that have been adversely affected. Investigators handed out health questionnaires to 528 people and identified individuals will receive compensation.
Mobile health units have been travelling across the region to identify people affected by the spill. The units include epidemiologists, psychologists and dermatologists.
Grupo México has pledged $3.5million to municipalities along the river to clean up the spill. Practical support has already included supplying 13 million litres of clean water to local communities, and 58 water tanks to deal with contaminated waters supplies, according to the company.
Copper mining can be a dirty business. Grupo México’s US subsidiary, ASARCO, is responsible for at least 80 contaminated sites across the US, according to National Public Radio. Clean up costs at those sites are estimated at $1.79billion.