Toxic Metals Reduction in Acid Mine Drainage Through the Use of Calcium Carbonate: A Case Study in Canchayllo, Peru”

Environmental liabilities comprise facilities, effluents, contaminated sites, and residues or waste deposits that have a real, potential, or permanent impact on people's health and environmental quality. This study focuses on the evaluation of calcium carbonate extracted from limestone as a neutralizing agent due to its abundance, low cost, and low toxicity for the treatment of acid mine drainage in the “La Calzada” mining environmental liability in Canchayllo, Peru. Wastewater analyses were conducted at Continental University, where metal levels and pH were determined. The results revealed that “La Calzada” mining liability has high levels of iron (3,266–9,287 mg/L), arsenic (0.24–0.35 mg/L), copper (1,560–2,313 mg/L), and an acidic pH of 3.14, exceeding environmental quality standards for water. To address this issue, calcium carbonate with 87% purity, obtained from crushed limestone, was used as a neutralizing agent. The application of this compound in the samples resulted in an increase in pH from 3.14 to 7.50, as well as a reduction in concentrations, yielding final concentrations of arsenic (0.039 mg/L), copper (0.107 mg/L), and iron (0.056 mg/L). These findings demonstrate the effectiveness of calcium carbonate as a flocculant in the treatment of acid mine drainage in the “La Calzada” mining liability, suggesting its potential application in other areas affected by similar mining environmental liabilities.