Environmental Impacts by Fragments Released from Nanoenabled Products: A Multiassay, Multimaterial Exploration by the SUN Approach

Abstract

Nanoenabled products (NEPs) have numerous outdoor uses in construction, transportation or consumer scenarios, and there is evidence that their fragments are released in the environment at low rates. We hypothesized that the lower surface availability of NEPs fragment reduced their environmental effects with respect to pristine nanomaterials. This hypothesis was explored by testing fragments generated by intentional micronisation ("the SUN approach"; Nowack et al. Meeting the Needs for Released Nanomaterials Required for Further Testing: The SUN Approach. Environmental Science & Technology, 2016 (50), 2747). The NEPs were composed of four matrices (epoxy, polyolefin, polyoxymethylene, and cement) with up to 5% content of three nanomaterials (carbon nanotubes, iron oxide, and organic pigment). Regardless of the type of nanomaterial or matrix used, it was observed that nanomaterials were only partially exposed at the NEP fragment surface, indicating that mostly the intrinsic and extrinsic properties of the matrix drove the NEP fragment toxicity. Ecotoxicity in multiple assays was done covering relevant media from terrestrial to aquatic, including sewage treatment plant (biological activity), soil worms (Enchytraeus crypticus), and fish (zebrafish embryo and larvae and trout cell lines). We designed the studies to explore the possible modulation of ecotoxicity by nanomaterial additives in plastics/polymer/cement, finding none. The results support NEPs grouping by the matrix material regarding ecotoxicological effect during the use phase. Furthermore, control results on nanomaterial-free polymer fragments representing microplastic had no significant adverse effects up to the highest concentration tested.

Characterisation of titanium oxide nanomaterials in sunscreens obtained by extraction and release exposure scenarios

“…The findings strengthen the calls for more release and aging type of studies when Fig. 1 The UV-Vis spectra obtained from the analysis of SUN A, B and C extracts examining the environmental implications of ENMs from NEPs, as experimentally it has been demonstrated that the product matrix is often associated with released ENMs [1], and data drawn from studies with pristine ENMs is of poor value. Results obtained from TEM coupled with EDS also indicated the release of TiO 2 ENMs in both wastewater types (Fig.…”

Environmental exposure of a simulated pond ecosystem to a CuO nanoparticle-based wood stain throughout its life cycle

“…Based on these hydrodynamic diameter values, we expected that the aggregation and settling down of the CuO_Acryl_FP would be fast in the water column of the mesocosms. Such strong colloidal instability was also observed in artificial freshwater using FP of epoxy, polyolefin, polyoxymethylene, and cement containing nanoparticles 24 .…”

“…The physical-chemical mechanism of hetero-aggregation of the CuO-NOAA at pH = 8.1 ± 0.1 is related to the electrostatic attraction between the positively charged CuO and the negatively charged clays (as the lateral charges of kaolinite 28 ) but also picoplankton (as bacteria, algae) 29 . CuO_Acryl_FP as others breakup/fragmented/released particles of plastics, cement, and paints 24,30,31 were found very instable as soon as they are put in suspension. Their aggregation in the water column of the mesoscosm was attributed to the large size of the FP (D 10 =20±4 μm, D 50 =73±29 μm and D 90 =190±86 μm) leading to their fast settling down (Figure 4).…”

Impact of freeze–thaw weathering on integrity, internal structure and particle release from micro- and nanostructured cement composites

“…33 Further release analyses by mechanical shear (sonication) during immersion in water showed a high fragment release rate that was slightly reduced by embedded CNT fillers, 34 and where recently followed up by high-throughput ecotoxicity screening of the hazards of released fragments. 37 A high fragment release was also observed during leaching (7 d, ultrapure water, stirring) of photocatalytic cement nanocomposites (approx. 2.85 wt-% photocatalytic TiO 2 ).…”