Polyvinylpyrrolidone and arsenic-induced changes in biological responses of model aquatic organisms exposed to iron-based nanoparticles

Toxicity of superparamagnetic iron oxide nanoparticles to the microalga Chlamydomonas reinhardtii

“…It is interesting to note that at low concentrations we observed a certain growth stimulation or hormetic effect, although not statistically significant (p > 0.001). A similar hormetic effect was found by Llaneza et al (2016) in their study of the toxic effects of nano-Fe3O4 and nano-Fe2O3 on Pseudokirchneriella subcapitata and Daphnia magna (Llaneza et al, 2016), particularly at the lower concentrations tested. A suitable explanation for that could be that it is due to a nutrient effect as Fe is an essential element and there is some dissolution of Fe from the NPs (although negligible, otherwise there should be differences in the magnetization curves, see Fig.…”

“…Mitochondria have also been reported as highly important in environmental stress caused by pollutants (González-Pleiter et al, 2017) depolarization after 72 h of exposure (significant at p < 0.001). It has been previously reported that different NPs could depolarize the mitochondrial membrane of C. reinhardtii (Martín-de-Lucía et al, 2018;Xia et al, 2006), but this is the first time that depolarization in the mitochondrial membrane potential is found in a microalga after exposure to SPION.…”

“…A decrease of esterase activity has been reported before for C. reinhardtii after exposure to different pollutants such as triclosan or atrazine (Esperanza et al, 2015;González-Pleiter et al, 2017) indicating decreased in metabolic activity. A decrease of esterase activity was also observed in C. reinhardtii after exposure to graphene oxides (Martín-de-Lucía et al, 2018).…”

“…In both cases, a plasmolysis phenomenon and the presence of many starch grains were observed. Plasmolysis and the formation of starch grains have been previously reported in C. reinhardtii exposed to different NPs (Chen et al, 2012a;Martín-de-Lucía et al, 2018). They have been attributed to a self-defense mechanism.…”

“…Barhoumi et al (2015) used the aquatic plant Lemma gibba as model organism to test the toxicity of SPION finding growth inhibition, ROS formation, decrease in chlorophyll content and photosynthesis inhibition. The toxicity of nano-Fe3O4 and nano-Fe2O3 has been studied in the microalgae Chlorella vulgaris (C. vulgaris) (Barhoumi and Dewez, 2013;Chen et al, 2012b), Pseudokirchneriella subcapitata and in the cladoceran Daphnia magna (Llaneza et al, 2016), these NPs caused ROS formation and deterioration of photosynthetic activities in the algae and inhibition of division rate in Daphnia. Although different parameters were measured, the authors were mostly interested in describing these effects in a range of NP concentrations rather than in establishing mechanistic links between the measured functions and thus, more studies aimed at understanding the toxic mechanisms of SPION in aquatic environments are needed.…”