The discovery and development of quantum dots (QDs), which are tiny luminescent nanoparticles (NPs), was awarded the Nobel Prize in Chemistry in 2023, highlighting the prospects of their technological applications. However, it is still not very well known how such NPs could affect aquatic ecosystems, especially given that natural conditions are varied and unpredictable. Thus, the aim of this study was to determine the influence of natural and artificial aqueous media on the interaction of CdSe/ZnS–COOH QDs with Desmodesmus communis algae using fast non-invasive optical methods. The cumulative short-term effects of QDs on algae growth and population structure were evaluated and changes in the photosynthetic activity of green algae were demonstrated using pulse-amplitude modulated (PAM) fluorometry. The present study demonstrated that natural and artificial cultivation media had different effects on the growth pattern, physiological processes and photoadaptation properties of algae as well as altering their responses to core/shell QDs. Thus, to fully assess the environmental risk of NPs, it is necessary to evaluate the simultaneous interactions of NPs with abiotic and biotic factors using a combination of physico-optical and ecotoxicological tools.

Graphene-based nanomaterials are exceptionally attractive for a wide range of applications, raising the likelihood of the release of graphene-containing nanoparticles into aquatic environments. The growing use of these carbon nanomaterials in different industries highlights the crucial need to investigate their environmental impact and evaluate potential risks to living organisms. The current investigation evaluated the nanotoxicity of graphene (nanoflakes) and graphene oxide (GO) nanoparticles on the cardiorespiratory responses (heart rate, gill ventilation frequency), as well as the swimming and nesting behavioral parameters of early stage larvae and juvenile salmonids. Both short-term (96 h) and long-term (23 days) exposure experiments were conducted using two common species: brown trout (Salmo trutta) and rainbow trout (Oncorhynchus mykiss). The findings demonstrated notable alterations in fish nesting behavior, swimming performance, and cardiorespiratory functions, indicating the potential toxicity of nanoparticles. This impact was observed at both physiological and whole-organismal levels in salmonids at early stages. Future investigations should explore different types of nanocarbons and their potential enduring effects on fish population structure, considering not only individual survival but also broader aspects of development, including feeding, reproductive, and other social dynamics.