Vera Lúcia Maria

The intensive use of rare earth elements (REEs) raises concerns about their effects on soil organisms, particularly under mixture exposure scenarios. This study evaluated the toxicity of lanthanum oxide (La₂O₃) and yttrium oxide (Y₂O₃) nanoparticles (NPs) and bulk forms on Folsomia candida. Single (0-2500 mg/kg) and dual mixture exposures were tested for effects on survival, reproduction, avoidance behavior, and biochemical markers. No effects on survival and avoidance behavior were observed. NPs were more toxic than bulk forms. La₂O₃ NPs reduced reproduction (≥ 1250 mg/kg) and acetylcholinesterase (AChE) activity (2500 mg/kg), whereas Y₂O₃ NPs exhibited greatest toxicity, reducing reproduction (≥ 313 mg/kg) and increasing catalase (CAT) (156 and 625 mg/kg) and glutathione reductase (GR) (625 and 2500 mg/kg) activities. Mixture exposures revealed complex interactions (synergism, antagonism, or no interaction), with toxicity depending on concentration, endpoint, and material form. Besides, higher number of biochemical endpoints were affected by mixture exposures, but dissimilar responses were observed with different concentrations: 2500 mg/kg Y₂O₃ NPs + 2500 mg/kg La₂O₃ NPs decreased reproduction and increased GR, glutathione S-transferases (GST) and AChE activities; 2500 mg/kg Y₂O₃ NPs + 625 mg/kg La₂O₃ NPs increased CAT, GR, GST and AChE activities; 625 mg/kg Y₂O₃ NPs + 625 mg/kg La₂O₃ NPs increased GR activity; 156 mg/kg Y₂O₃ NPs + 2500 mg/kg La₂O₃ NPs decreased AChE activity, increased GR activity and lipid peroxidation levels. This study highlights that REE exposures, particularly mixtures, can pose risks to soil organisms and emphasizes the need to include mixture interactions in risk assessments.

The detrimental impacts of plastic nanoparticles (PNPs) are a worldwide concern, although knowledge is still limited, in particular for soil mesofauna. This study investigates the biochemical impact of 44 nm polystyrene PNPs on three soil models-Enchytraeus crypticus (Oligochaeta), Folsomia candida (Collembola) and Porcellionides pruinosus (Isopoda). Exposure durations of 3, 7 and 14 days (d) were implemented at two concentrations (1.5 and 300 mg kg(-1) PNPs). Results revealed PNPs impact on the activities of the glutathione-dependent antioxidative enzyme, glutathione S-transferase (GST) and on the neurotransmitter acetylcholinesterase (AChE) for all three species. Catalase (CAT) played a minor role, primarily evident in F. candida at 300 mg kg(-1) PNPs (CAT and GST response after 14 d), with no lipid peroxidation (LPO) increase. Even with the antioxidant defence, P. pruinosus was the most sensitive species for lipid oxidative damage (LPO levels increased after 7 d exposure to 300 mg kg(-1) PNPs). Significant AChE inhibitions were measured already after 3 d to both PNP concentrations in F. candida and E. crypticus, respectively. Significant AChE inhibitions were also found in P. pruinosus but later (7 d). Overall, the toxicity mechanisms of PNPs involved antioxidant imbalance, being (mostly) the glutathione-associated metabolism part of that defence system. Neurotoxicity, linked to AChE activities, was evident across all species. Sensitivity to PNPs varied: P. pruinosus > F. candida congruent to E. crypticus. This pioneering study on PNPs toxicity in soil invertebrates underscores its environmental relevance, shedding light on altered biochemical responses, that may compromise ecological roles and soil ecosystem fitness.

In the fast-evolving landscape of nanotechnology, the widespread applications of engineered nanomaterials (ENMs) have undoubtedly revolutionized various industries, ranging from healthcare and electronics to agriculture and environmental remediation

The increasing use of molybdenum disulfide (MoS₂) nanoparticles (NPs) raises concerns regarding their accumulation in soil ecosystems, with limited studies on their impact on soil organisms. Study aim: To unravel the effects of MoS₂ nanosheets (two-dimensional (2D) MoS₂ NPs) and bulk MoS₂ (156, 313, 625, 1250, 2500 mg/kg) on Enchytraeus crypticus and Folsomia candida. The organisms’ survival and avoidance behavior remained unaffected by both forms, while reproduction and DNA integrity were impacted. For E. crypticus, the individual endpoint reproduction was more sensitive, increasing at lower concentrations of bulk MoS₂ and decreasing at higher ones and at 625 mg/kg of 2D MoS₂ NPs. For F. candida, the molecular endpoint DNA integrity was more impacted: 2500 mg/kg of bulk MoS₂ induced DNA damage after 2 days, with all concentrations inducing damage by day 7. 2D MoS₂ NPs induced DNA damage at 156 and 2500 mg/kg after 2 days, and at 1250 and 2500 mg/kg after 7 days. Despite affecting the same endpoints, bulk MoS₂ induced more effects than 2D MoS₂ NPs. Indeed, 2D MoS₂ NPs only inhibited E. crypticus reproduction at 625 mg/kg and induced fewer (F. candida) or no effects (E. crypticus) on DNA integrity. This study highlights the different responses of terrestrial organisms to 2D MoS₂ NPs versus bulk MoS₂, reinforcing the importance of risk assessment when considering both forms.

Despite the growing concern over nanoplastics’ (NPls) environmental impacts, their long-term effects on terrestrial organisms remain poorly understood. The main aim of this study was to assess how NPls exposure impacts both the parental (F1) and subsequent generations (F2 and F3) of the soil-dwelling species Folsomia candida. After a standard exposure (28 days), we conducted a multigenerational study along three generations (84 days), applying polystyrene nanoparticles (PS NPs; diameter of 44 nm) as representatives of NPls. Endpoints from biochemical to individual levels were assessed. The standard test: PS NPs (0.015 to 900 mg/kg) had no effect in F. candida survival or reproduction. The multigenerational test: PS NPs (1.5 and 300 mg/kg) induced no effects on F. candida survival and reproduction along the three generations (F1 to F3). PS NPs induced no effects in catalase, glutathione reductase, glutathione S-transferases, and acetylcholinesterase activities for the juveniles of the F1 to F3. Oxidative damage through lipid peroxidation was detected in the offspring of F1 but not in the juveniles of F2 and F3. Our findings underscore the importance of evaluating multigenerational effects to gain comprehensive insights into the contaminants long-term impact, particularly when organisms are continuously exposed, as is the case with NPls.