Considering the increase in demand for rare earth elements (REEs) and their accumulation in soil ecosystems, it is crucial to understand their toxicity. However, the impact of lanthanum, yttrium and cerium oxides (La2O3, Y2O3 and CeO2, respectively) on soil organisms remains insufficiently studied. This study aims to unravel the effects of La2O3, Y2O3 and CeO2 nanoparticles (NPs) and their corresponding bulk forms (0, 156, 313, 625, 1250 and 2500 mg/kg) on the terrestrial species Enchytraeus crypticus. The effects on survival, reproduction (21 days (d)), avoidance behavior (2 d) and DNA integrity (2 and 7 d) of E. crypticus were evaluated. No significant effects on survival were observed. For La2O3, the bulk form affected more endpoints than the NPs, inducing avoidance behavior (1250 mg/kg) and DNA damage (1250 mg/kg- 2 d; 2500 mg/kg- 7 d). The Y2O3 NPs demonstrated higher toxicity than the bulk form: decreased reproduction (>= 1250 mg/kg); induced avoidance behavior (>= 625 mg/kg) and DNA damage (>= 156 mg/kg- 2 d; 2500 mg/kg- 7 d). For CeO2, both forms exhibited similar toxicity, decreasing reproduction (625 mg/kg for bulk and 2500 mg/kg for NPs) and inducing DNA damage at all tested concentrations for both forms. REEs oxides toxicity was influenced by the REEs type and concentration, exposure time and material form, suggesting different modes of action. This study highlights the distinct responses of E. crypticus after exposure to REEs oxides and shows that REEs exposure may differently affect soil organisms, emphasizing the importance of risk assessment.

A growing number of studies have demonstrated that microplastic (MP) contamination is widespread in terrestrial ecosystems. A wide array of MPs made of conventional, fossil -based polymers differing in size and shape has been detected in soils worldwide. Recently, also MPs made of bioplastics have been found in soils, but there is a dearth of information concerning their toxicity on soil organisms. This study aimed at exploring the potential toxicity induced by the exposure for 28 days to irregular shaped and differently sized MPs made of a fossil -based (polyethylene terephthalate - PET) and a bioplastic (polylactic acid - PLA) polymer on the earthworm Eisenia foetida . Two amounts (1 g and 10 g/kg of soil, corresponding to 0.1% and 1% of soil weight) of both MP types were administered to the earthworms. A multi -level approach was used to investigate the MP -induced effects at sub -individual and individual level. Changes in the activity of antioxidant and detoxifying enzymes, as well as in lipid peroxidation levels, were investigated at specific time -points (i.e., 7, 14, 21 and 28 days) as subindividual responses. Histological analyses were performed to assess effects at tissue level, while the change in digging activity was considered as a proxy of behavioral effects. Earthworms ingested MPs made of both the polymers. MPs made of PET did not induce any adverse effect at none of the biological levels. In contrast, MPs made of PLA caused the modulation of earthworms ' oxidative status as showed by a bell -shaped activity of superoxide dismutase coupled with an increase in glutathione peroxidase activity. However, neither oxidative and tissue damage, nor behavioral alteration occurred. These findings suggest that the exposure to bio-based MPs can cause higher toxicity compared to fossil -based MPs.

The implementation of recycling techniques represents a potential solution to the plastic pollution issue. To date, only a limited number of plastic polymers can be efficiently recycled. In the Italian plastic waste stream, the residual, non-homogeneous fraction is called 'Plasmix' and is intended for low-value uses. However, Plasmix can be used to create new materials through mechanical recycling, which need to be tested for their eco-safety. This study aimed to investigate the potential toxicity of two amounts (0.1% and 1% MPs in soil weight) of microplastics (MPs) made of na & iuml;ve and additivated Plasmix-based materials (Px and APx, respectively) on the earthworm Eisenia foetida. Changes in oxidative status and oxidative damage, survival, gross growth rate and reproductive output were considered as endpoints. Although earthworms ingested both MP types, earthworms did not suffer an oxidative stress condition or growth and reproductive impairments. The results suggested that exposure to low amounts of both MPs can be considered as safe for earthworms. However, further studies testing a higher amount or longer exposure time on different model species are necessary to complete the environmental risk assessment of these new materials.