INTEGRATED ALGORITHM FOR TOXICITY ASSESSMENT OF MINE TAILINGS AND SURROUNDING SOILS BASED ON CHEMICAL AND GERMINATION ASSAYS

Abstract

The evaluation of the environmental impact arising from mine tailing toxicity can be accomplished by chemical and biological assays. Several research groups and environmental agencies established working protocols for heavy metal determination and risk assessment. Nevertheless, there is no standardized methodology that integrates chemical and biological approaches for the toxicity assessment of soils and waters contaminated with heavy metals and metalloids. This study presents a comprehensive algorithm designed to assess the environmental toxicity of mine tailings and surrounding soils by applying a germination assay. Therefore, wheat germination bioassays and
evaluation of bioconcentration of As, Pb, Cu, Zn, Cd, Ag, Fe, Mn, Ni, and Cr in contaminated  environmental samples
are carried out. The germination index showed results greater than 80 % classified as “excellent” in soil samples
P1 and P2, and less than 40 % in soil sample P3 due to high Pb toxicity. The capability of plant species to remediate
soils was evaluated by the Bioconcentration factor (BCF) and the Translocation factor (TF). The average results for
BCF, based on Pb, As, Zn, and Cu, were 0.25, and a low TF was obtained, with values ranging between 0.05 and 0.2.