Industry has already commenced the large-scale production of some nanomaterials. Evidence for toxic effects of engineered nanoparticles (ENP) on model organisms is increasing. However, in order to assess the consequences of environmental hazards, a better understanding is required of the behavior of ENP in aquatic ecosystems and their impact on complex communities. In this research, through experimenting with different TiO(2) nanoparticles in stream microcosms, we have shown that microbial membranes were significantly compromised, even under ambient ultraviolet radiation and nano-TiO(2) concentrations predicted for surface waters. Our results suggest adverse effects are not necessarily only attributable to individual particles smaller than 100 nm but also to low concentrations of larger, naturally agglomerating TiO(2) nanoparticles. Cell membrane damage was more pronounced in free-living cells than in biofilm cells, indicating the protective role of cell encapsulation against TiO(2) nanoparticles. The generation of intracellular reactive oxygen species (ROS) further suggests nano-TiO(2)-induced effects inside the microbial cells. Our findings indicate a high sensitivity of microbial communities to levels of ENP concentration that are to be expected in the environment, with as yet unknown implications for the functioning and health of ecosystems.

Detecting and quantifying engineered nanoparticles (ENPs) in complex environmental matrices requires the distinction between natural nanoparticles (NNPs) and ENPs.

Microplastics (MPs) have been identified as contaminants of emerging concern in aquatic environments and research into their behavior and fate has been sharply increasing in recent years. Nevertheless, significant gaps remain in our understanding of several crucial aspects of MP exposure and risk assessment, including the quantification of emissions, dominant fate processes, types of analytical tools required for characterization and monitoring, and adequate laboratory protocols for analysis and hazard testing. This Feature aims at identifying transferrable knowledge and experience from engineered nanoparticle (ENP) exposure assessment. This is achieved by comparing ENP and MPs based on their similarities as particulate contaminants, whereas critically discussing specific differences. We also highlight the most pressing research priorities to support an efficient development of tools and methods for MPs environmental risk assessment.

The scientific community has invested effort into standardising methodologies for the regulatory ecotoxicity testing of engineered nanomaterials (ENMs), but the practical requirements for bioaccumulation testing of ENMs have been given less attention.

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Heteroaggregation of engineered nanoparticles with suspended particulate matter in theory and practice: a roadmap for understanding and determining attachment efficiencies.

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