Commercial nano-enabled products as sources of engineered nanomaterials’ (ENMs) contamination in water: Release, behaviour, and ecotoxicity effects

Expanded functionalisation of engineered nanomaterials (ENMs) has increased commercialisation of nano-enabled products (NEPs) globally. The rise has also accelerated the use of NEPs that exhibit medium–high environmental exposure for ENMs; which represent the highest proportion across all NEP databases worldwide. Current data is insufficient to substantially conclude on the dynamics of environmental exposure, behaviour, and toxicity of NEPs -released ENMs. The current study quantified the environmental exposure, behaviour, and toxicity of product-released ENMs (PR-ENMs) from medium–high environmental exposure potential NEPs. Five products (two sunscreens, topical cream, socks, sports underwear), confirmed to be nano-formulated, had respective ENMs characterized in detail. The release and transformation of ENMs from the NEPs were investigated; toxicity on Raphidocelis subcapitata and Daphnia magna was investigated. The NEPs were found to contain needle-shaped (18 ×75 nm) and angular (52 ×69–87 ×97 nm) nTiO₂ in the rutile phase, angular (44 ×53 nm) zincite nZnO and near-spherical nAg with the sizes of 57 × 67 nm. All ENMs were coated with Al/Si. The NEPs released varying quantities of the ENMs (8.8–71.16 %) and total Ti, Zn, Zn^{2 +} , Ag, and Ag⁺; depending on product type. The increase of media ionic strength enhanced agglomeration of PR-ENMs in a directly proportional manner and altered the zeta potential of the PR-ENMs. PR-ENMs induced effects on R. subcapitata and D. magna at varying extents. The study confirmed NEPs to be potential nanopollution source for water resources and can induce effects on aquatic organisms. Therefore, robust exposure and effects assessments are recommended to facilitate mitigative measures for undesirable environmental implications of nanotechnology.