Development of a methodology for identifying and quantifying mining environmental liabilities in aquatic ecosystems: A case study of Segovia, Colombia

Abstract

Untreated discharges from mining activities threaten aquatic ecosystems, affecting water quality and biodiversity. This study develops a methodology for estimating environmental liabilities in aquatic systems, focusing on Segovia, Colombia (2010–2017). Using historical data (2010–2017), recent monitoring (2021–2023), and modelling tools (HEC-RAS and WASP), water and sediment quality indices were applied to quantify impacts, emphasizing heavy metals and cyanide. The methodology integrated diverse indices to evaluate contamination levels, including the Aquatic Toxicity Index (ATI) for water quality and the Pollutant Load Index (PLI) for sediments. Results revealed increased contaminant concentrations downstream, such as lead (0.4 mg/L) and suspended solids (61 mg/L), exceeding regulatory limits. While local pressures like domestic and illegal mining discharges complicate the pollution scenario, the findings confirm significant environmental liabilities from untreated discharges, impacting ecosystem services and community health. The study demonstrates that, despite pre-existing contamination, mining activities notably degrade water and sediment quality. It highlights critical deposition zones where contaminants accumulate, serving as focal points for remediation. The developed methodology offers a replicable framework, integrating past and current data, modelling, and tailored indices to assess aquatic liabilities effectively. This research provides actionable insights for mitigating mining pollution and restoring affected ecosystems. Bridging gaps in environmental liability quantification supports informed decision-making for environmental management and policy development in mining-impacted regions.