Periphytic Algae and Cyanobacteria from the Rio Doce Basin Respond Differently to Metals and Salinity, Showing Different Potential for Bioremediation

Abstract

We have studied the isolated and combined effects of metals (Fe and Mn) and NaCl the on growth, physiology, and metal-uptake capacity of two photosynthetic periphytic species—Synechococcus elongatus (Cyanobacteria) and Chlorococcum infusionum (Chlorophyta)—isolated from an impacted area of the Rio Doce River (Brazil) after the Fundão dam collapse. The effective concentrations found to reduce 10 and 50% growth were 15.2 and 31.6 mg Fe L−1, and 2.5 and 7.9 mg Mn L−1 for S. elongatus and 53.9 and 61.6 mg Fe L−1, and 53.2 and 60.9 mg Mn L−1 for C. infusionum. Although the metal toxicity was related to oxidative stress, both species showed activation of antioxidant systems under phytotoxic concentrations of Fe and Mn. By binding large concentrations of metals on its cell surface and thus avoiding their entrance into the cells, C. infusionum presents greater resistance to Fe and Mn than S. elongatus. Under environmental realistic concentrations of Fe and Mn in river water from the Rio Doce Basin, S. elongatus and C. infusionum showed a metal removal efficiency of 42 and 65% and 53 and 79%, respectively after 96 h. These species were insensitive to increased NaCl concentrations which, in addition, did not disrupt the metal removal capacity of the species. Due to their salt and metal tolerance, S. elongatus and C. infusionum can be used for the remediation of waters contaminated with Fe and Mn.

COVID-19 pharmaceuticals in aquatic matrices: The threatening effects over cyanobacteria and microalgae

“…Extracts were obtained from fresh material collected on filters with one ml of extraction solution containing 100 mM of potassium phosphate buffer (pH 7.8), 100 mM of EDTA, 1 mM of ascorbic acid and 2 % of polyvinylpyrrolidone (PVP) (m/v) ( Gomes et al, 2021 ). Subsequently, the total protein concentration was determined following the method of Bradford (1976) and the activity of catalase enzyme (CAT; E.C1.11.1.6) ( Aebi, 1984 ) was measured.…”

“…Similarly, the combination of 5-fluorouracil and cisplatin had synergistic deleterious effects over the growth of S. leopoliensis ( Brezovšek et al, 2014 ). The mixture of metals (Fe or Mn) with NaCl was also shown to have more preeminent effects on growth and photosynthesis of Chlorococcum infusionum (Chlorophyceae) and S. elongatus (Cyanobacteria) than each metal alone ( Gomes et al, 2021 ).…”

“…Additionally, we assessed the impact of these drugs both individually and in combination on the growth, photosynthesis, and oxidative metabolism of S. elongatus (Cyanobacteria) and C. vulgaris (Chlorophyceae). These species are recognized as bioindicators of water quality ( Gulzar et al, 2017 ) and have been utilized in toxicological studies before ( Bravo et al, 2016 ; Figler, 2019 ; Gomes et al, 2021 ; Singh et al, 2018 ) ( Bravo et al, 2016 ; Singh et al, 2018 ; Figler, 2019 ; Gomes et al, 2021 ). Our aim is to contribute to the ecotoxicological evaluation of COVID-19 pharmaceuticals, combining chemical analysis and effect-based methods as an important tool to identify its environmental risk.…”