Engineered nanomaterials (ENMs) have a global spreading in the environment. Once in the environment, biota will uptake them. Their chemical nature is diverse, from inorganics (e.g. SiO2) to organics (e.g. carbon nanotubes-CNTs). Currently, of major concern, are also nanoplastics (considered here as a group of ENMs) enclosing polymer binders and nano-fillers/additives. Additionally, ENMs can be functionalized, i.e., suffer a chemical alteration in their surfaces; and it is vital to calculate whether or not surface coating plays a role in the toxicity. Thus, we cannot ignore that the biological effects may not be limited to the primary toxicity, but also on the effect of ENM interactions with chemicals (secondary toxicity) on the ecosystems.
Studies have been often focused on marine ENMs ecotoxicology, being limited to those that considered a freshwater approach (e.g. zebrafish, Danio rerio), namely regarding nanoplastics and SiO2 ENMs. For soil environment (e.g. Oligochaetes, Eisenia sp.), the effects of these ENMs are unknown, except a few CNTs studies. Functionalized nanoplastics, SiO2 ENMs and CNT have been applied in few D. rerio ecotoxicological works, particularly with synthetic sex hormone, flame retardants, Ni and persistent organic pollutants. Nonetheless, only two researches on functionalized CNT (with endocrine disruptors) were applied to soil invertebrates (e. g. Eisenia species). Biological responses related to enzymes, DNA injury, behaviour have been explored in D. rerio (for both 3 ENMs) and Eisenia species (only for CNTs). Developmental toxicity was also applied in D. rerio.
D. rerio are accepted as a standard aquatic model to study many biological processes in an ecotoxicological view. The soil model, Enchytraeus crypticus is recently used for functional genomic studies. It is ideal for NM studies since there is a physiological background data (i.e. genus Enchytraeus).
The investigation at molecular (e.g target gene expression) and biochemical (e.g. enzymes, DNA and lipid damage) levels will be decisive to get earlier effects on these organisms inhabiting vulnerable ecosystems. This information will be compared with those obtained by standard toxicity tests (OECD guidelines) at organism/population level (e.g. fertility, mortality), and will provide knowledge about the ENMs mode-of-action. We aim to identify hazards and assess exposure evaluating the risks of the selected ENMs. Then, this may define the future acceptance of ENMs in commercial products. Environmentally preferable ENMs may be chosen relying first on assessing hazards and then on exposure assessment.
Concisely, the main goal of UNRAvEL is to study the integrated responses of a suite of biomarkers covering diverse organizational levels for the valuation of the ENM (functionalized and not) effects. To attain this purpose, an important and cohesive interdisciplinary group will understand and model the impact of ENMs with both abiotic and biotic matrices.