Genotoxicity of spent pot liner as determined with the zebrafish ( Danio rerio ) experimental model

Abstract

Spent pot liner (SPL) is a solid waste generated during the primary smelting of aluminum, and its toxicity is attributed to the presence of fluoride, cyanide, and aluminum salts, which can be leached into aquatic ecosystems. Since the effects of this waste on aquatic life forms have not yet been investigated, the objective of our study was to evaluate the toxicity of simulated leachates of SPL on zebrafish (Danio rerio). Animals were exposed to 0 (control), 0.32, 0.64, or 0.95 g L⁻¹ of SPL for 24, 72, and 96 h, and genotoxicity was accessed through micronucleus and comet assays. All of the tested treatments induced DNA fragmentation, and the observed frequency of micronuclei and damaged nucleoids generally increased with increasing SPL concentration. The highest frequency of micronuclei (3.3 per 3000 erythrocytes) was detected after 96 h of exposure with 0.95 g L⁻¹ SPL. In the comet assay, nucleoids classified with highest level of damage in relation to the control were observed principally after 24 and 96 h of exposure. The data obtained in this study confirm the genotoxicaction and mutagenic potential of SPL and indicate that open-air deposits of the waste material could represent a health risk to humans and ecosystems alike.

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