Browsing by Author "Maria, Vera L."
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- A comprehensive ecotoxicity study of molybdenum disulfide nanosheets versus bulk form in soil organismsPublication . Santos, Joana; Barreto, Ângela; Fernandes, Cristiana; Silva, Ana Rita R.; Cardoso, Diogo N.; Pinto, Edgar; Daniel-da-Silva, Ana L.; Maria, Vera L.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.
- First approach to assess the effects of nanoplastics on the soil species Folsomia candida: A mixture design with bisphenol A and diphenhydraminePublication . Barreto, Ângela; Santos, Joana; Almeida, Lara; Tavares, Vítor; Pinto, Edgar; Celeiro, Maria; Garcia-Jares, Carmen; Maria, Vera L.The terrestrial environment is one of the main recipients of plastic waste. However, limited research has been performed on soil contamination by plastics and even less assessing the effects of nanoplastics (NPls). Behind the potential toxicity caused per se, NPls are recognized vectors of other environmental harmful contaminants. Therefore, the main aim of the present study is to understand whether the toxicity of an industrial chemical (bisphenol A – BPA) and a pharmaceutical (diphenhydramine – DPH) changes in the presence of polystyrene NPls to the terrestrial invertebrate Folsomia candida. Assessed endpoints encompassed organismal (reproduction, survival and behavior) and biochemical (neurotransmission and oxidative stress) levels. BPA or DPH, 28 d single exposures (1 to 2000 mg/kg), induce no effect on organisms' survival. In terms of reproduction, the calculated EC50 (concentration that causes 50% of the effect) and determined LOEC (lowest observed effect concentration) were higher than the environmental concentrations, showing that BPA or DPH single exposure may pose no threat to the terrestrial invertebrates. Survival and reproduction effects of BPA or DPH were independent on the presence of NPls. However, for avoidance behavior (48 h exposure), the effects of the tested mixtures (BPA + NPls and DPH + NPls) were dependent on the NPls concentration (at 0.015 mg/kg – interaction: no avoidance; at 600 mg/kg – no interaction: avoidance). Glutathione S-transferase activity increased after 28 d exposure to 100 mg/kg DPH + 0.015 mg/kg NPls (synergism). The increase of lipid peroxidation levels found after the exposure to 0.015 mg/kg NPls (a predicted environmental concentration) was not detected in the mixtures (antagonism). The results showed that the effects of the binary mixtures were dependent on the assessed endpoint and the tested concentrations. The findings of the present study show the ability of NPls to alter the effects of compounds with different natures and mechanisms of toxicity towards soil organisms, showing the importance of environmental risk assessment considering mixtures of contaminants.
- Nano versus bulk: Evaluating the toxicity of lanthanum, yttrium, and cerium oxides on Enchytraeus crypticusPublication . Santos, Joana; Neca, Inês; Capitão, Ana; Nogueira, João; Santos, José A. S.; Pinto, Edgar; Barreto, Angela; Silva, Ana L. Daniel da; Maria, Vera L.; Pinto, EdgarConsidering 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.