Bioassay of toxicity of acid mine drainage treated and untreated with lime ash using the bioindicator Pisum sativum L.

Abstract

Acid mine drainage (AMD) is an important source of environmental pollution that affects water quality and biodiversity in areas near mining activities. This study evaluated the efficiency of the treatment of AMD with lime ash, through physicochemical analysis and toxicity tests on the bioindicator Pisum sativum L. Samples of AMD were collected in a mining area of Norte de Santander and characterized physicochemically in terms of Al, Cu, Fe, Mn, Zn, and Pb concentrations, as well as pH. The AMD was treated with lime ash to evaluate its ability to neutralize pH (2.3 ± 0.1-7.2 ± 0.7) and remove metals. Toxicity tests showed that the lime ash treatment was able to neutralize pH and significantly reduce metal concentrations, with removal efficiencies greater than 97.2%. In addition, P. sativum showed improved germination, root growth, mitotic index, and a reduction in the frequency of chromosomal abnormalities after treatment. This approach proves to be an effective strategy to reduce AMD contamination, improving physicochemical parameters and decreasing toxicity in model organisms. Further long-term studies are recommended to optimize the process and ensure its effectiveness in the restoration of ecosystems affected by mining.