Nanoparticles in the Aquatic Environment: The Risks Associated with Them and the Possibilities of Their Mitigation with Microalgae.

Nanoparticles (NPs) are dangerous micropollutants that exhibit biotoxicity even in low (ng/L range) concentrations. Apart from direct toxicity to living organisms, NPs can absorb and transfer organic or inorganic toxicants as well as potentiate the toxicity of other micropollutants. Increasing use of NPs in industrial and domestic applications leads to their increased production and discharge into the environment giving rise to diverse risks for ecosystems. These risks are exacerbated by the resilience of NPs to biodegradation in natural ecosystems and traditional wastewater treatment plants. Efficient NP removal technologies are complex and expensive, so they cannot be affordably replicated in common wastewater treatment plants. Despite the risks associated with NPs, humanity will not abandon their use in the nearest future, since NPs are now at the foundation of many modern technologies. The biodestruction and biosorption of NPs using microalgae cultures and algal-bacterial consortia are considered promising approaches regarding environmental safety and the conservation of natural resources. However, the progress of this approach is hindered by the paucity and fragmentary nature of the information about the effects of NPs on microalgae cells and microbial communities. This review attempts to fill this gap, at least partially, by considering common industrial NP types based on metals and their oxides as well as carbon nanomaterials. The pathways of their entry into aquatic ecosystems, toxicity to living organisms, accumulation and biotransformation in cells, synergistic effects of NPs in combination with heavy metals and antibiotics, as well as methods for the bio-removal of NPs and nanomaterials from aquatic ecosystems using microalgae are discussed. [ABSTRACT FROM AUTHOR]