Bioindicators and Heavy Metal Pollution in High-Andean Peruvian Lakes: A Limnological Approach

Abstract

Introduction. High-Andean lakes represent vital sociocultural, economic, and environmental assets for local communities and are ecologically significant ecosystems that require protection and conservation. Understanding their limnological characteristics is key to guiding both conservation and sustainable use strategies. Objectives. To assess the limnological characteristics of three high-Andean lakes in Quiruvilca, La Libertad region, Peru, located in an area influenced by mining activities. Materials and Methods. Semiannual sampling was conducted between 2017 and 2019. Measurements included physicochemical parameters—temperature, conductivity, pH, dissolved oxygen (DO), oxygen saturation, and transparency—as well as concentrations of heavy metals in water and sediments. Aquatic macroinvertebrates were identified to the family level. Water quality was evaluated using the Biological Monitoring Working Party (BMWP) index and the Andean Biotic Index (ABI). Descriptive statistics, ANOVA, and correlation analyses were applied to explore trends and variability. Results. The average values recorded for the physicochemical parameters were temperature of 12.6 ºC, pH of 4.5, conductivity of 20.4 μS/cm, dissolved oxygen (DO) of 6.5 mg/L, oxygen saturation of 99.8%, and water transparency ranging from 0.37 to 3.0 meters. Heavy metals—arsenic, copper, mercury, and lead—exceeded permissible thresholds. The most abundant macroinvertebrate families were Corixidae, Dytiscidae, Hyalellidae, Planariidae, and Chironomidae. Conclusions. The lakes exhibited relatively stable limnological conditions but moderate contamination levels. Despite supporting aquatic life, the water is unsuitable for human or livestock consumption. Remediation strategies are therefore necessary to mitigate contamination risks.