Application of fungal biomass of the genus Pleurotus in the bioremediation of Doce River waters after the disaster in Mariana/MG: an analysis between the years 2015 and 2018

The collapse of Samarco mining company's tailings dam in November 2015 was Brazil's most severe environmental calamity ever. The ensuing toxic sludge devastated towns along the Doce River, leaving an enduring legacy of socio-environmental and economic destruction. The Doce River basin continues to bear the scars of this disaster today. This study thus proposes to investigate the bioremediation potential of three Pleurotus spp. strains, assessing their parameters of pH and turbidity, as well as the ability of the tested isolates to eliminate toxic metals in solution, based on water samples collected in 2015 and 2018. The fungal strains studied acidified the medium, damaging the pH of the samples. In raw water, these strains effectively removed turbidity, achieving a decline of 86.2-95.0% and 28.1-40.7% in the first and second collections, respectively. High concentrations of aluminum, arsenic, barium, lead, iron, and manganese were detected in the Doce River water samples through Inductively Coupled Plasma Mass Spectrometry (ICP-MS). Batch system experiments showed that Pleurotus spp. could efficiently remove toxic metals from the solution in seven days of incubation, with average elimination rates ranging from 94.0-99.1% and 70.3-99.0% for the six evaluated elements in the 2015 and 2018 samples, respectively. Therefore, the findings suggest that the genus Pleurotus has significant biotechnological potential for the bioremediation of contaminated or deteriorated waters.