Microalgae have received much attention in the last few years. Their use is being extended to different fields of application and technologies, such as food, animal feed, and production of valuable polymers. Additionally, there is interest in using microalgae for removal of nutrients from wastewater. Wastewater treatment with microalgae allows for a reduction in the main chemicals responsible for eutrophication (nitrogen and phosphate), the reduction of organic substrates (by decreasing parameters such as BOD and COD) and the removal of other substances such as heavy metals and pharmaceuticals. By selecting and reviewing 202 articles published in Scopus between 1992 and 2020, some aspects such as the feasibility of microalgae cultivation on wastewater and potential bioremediation have been investigated and evaluated. In this review, particular emphasis was placed on the different types of wastewaters on which the growth of microalgae is possible, the achievable bioremediation and the factors that make large-scale microalgae treatment feasible. The results indicated that the microalgae are able to grow on wastewater and carry out effective bioremediation. Furthermore, single-step treatment with mixotrophic microalgae could represent a valid alternative to conventional processes. The main bottlenecks are the large-scale feasibility and costs associated with biomass harvesting.

In recent years, interest in the impact of environmental pollutants on the ecosystem has increased significantly, with particular attention being paid to the relationship between climate change and the aquatic world. This is because increasing pollution is causing fundamental changes to the welfare of animals and the marine ecosystem. A primary focus is on the impact of microplastics (MPs) and nanoplastics (NPs), as evidenced by our bibliometric network analysis (BNA). However, while research is focused on the accumulation of these pollutants in aquatic organisms, their effects on redox homeostasis are still seldom discussed despite the role played by reactive oxygen species and mitochondrial well-being in maintaining an optimal state of health. However, some scientific evidence suggests that the accumulation of MPs and NPs in organisms at the base of the trophic chain can cause a transfer of these substances towards more complex organisms, reaching humans through the consumption of aquatic fauna as food. Therefore, in this review, we have tried to discuss the effects of these substances on oxidative stress in aquatic organisms, even if studies in this regard are still scarce.

The food industry widely uses dyes from animal and plant sources, but their discharge into water bodies can harm aquatic animals. Red food dyes increase reactive oxygen species (ROS) production, disrupting redox homeostasis in Artemia franciscana nauplii, although the underlying mechanisms are unclear. In this study, we exposed Artemia franciscana cysts for 48 h to three different red dyes: E124 (synthetic), E120 (animal-based) or Vegan red (plant-based) and evaluated the oxidative metabolism and redox status in the hatched nauplii. Only E120 and VEG increased oxygen consumption. E124 and VEG increased mitochondrial Complex I activity, while all dyes enhanced the activity of Complex III. The levels of reactive oxygen species (ROS) and NADPH oxidase activity were increased by all red dyes. E120 and E124 increased antioxidant enzyme activity to a greater extent than VEG. Additionally, only E120 and E124 increased total antioxidant capacity. Nevertheless, E124 exposure induced redox imbalance (increased lipid and protein oxidative damage). Our data, as a whole, allow us to conclude that red dyes can influence the oxidative capacity and redox state of Artemia franciscana nauplii with more harmful effects in the presence of E124, thus drawing attention to their potentially severe influence on aquatic life.