Silver nanoparticles (AgNPs) may reach the soil compartment via sewage sludge or nanoagrochemical applications. Understanding how NPs interact with biological systems is crucial for an accurate ...hazard assessment. Therefore, this study aimed at determining the Ag toxicokinetics in the mealworm Tenebrio molitor, exposed via Lufa 2.2 soil or via food to different Ag forms (uncoated 50 nm AgNPs, paraffin coated 3–8 nm and PVP-stabilised 60 nm, Ag2S NPs 20 nm, and ionic Ag). Mealworms were exposed for 21 days followed by a 21-day elimination phase (clean soil/food). A one-compartment kinetics model with inert fraction (simulating a storage compartment, where detoxified forms are located) was used to describe Ag accumulation. Fully understanding the uptake route in mealworms is difficult. For that reason several approaches were used, showing that food, soil and pore water all are valid uptake routes, but with different importance. Silver taken up from soil pore water or from soil showed to be related to Ag dissolution in soil pore water. In general, the uptake and elimination rate constants were similar for 3–8 nm and 60 nm AgNPs and for AgNO3, but significantly different for the uncoated 50 nm AgNPs. Upon food exposure, uptake rate constants were similar for 50 nm AgNPs and AgNO3, while those for 60 nm and 3–8 nm AgNPs and for Ag2S NPs also grouped together. NP exposure in soil appeared more difficult to characterize, with different patterns obtained for the different NPs. But it was evident that upon soil or food exposure, particle characteristics highly affected Ag bioavailability and bioaccumulation. Although Ag2S NPs were taken up, their elimination was faster than for other Ag forms, showing the lowest inert fraction. The significantly different elimination rate constants suggest that the mechanism of elimination may not be the same for different AgNPs either.
Display omitted
•Mealworms accumulate Ag2S NPs despite its low dissolution in soil pore water.•Ag2S NPs were accumulated less than pristine AgNPs and ionic Ag in mealworms.•Mealworms exposed via soil and via food showed different Ag uptake kinetics.•AgNPs dissolution in soil pore water influences its uptake in the mealworms.•Mealworms eliminate Ag through the faeces and by shedding exuviae.
Rosuvastatin Affecting Aortic Valve Endothelium to Slow the Progression of Aortic Stenosis Luis M. Moura, Sandra F. Ramos, José L. Zamorano, Isabel M. Barros, Luis F. Azevedo, F. Rocha-Gonçalves, ...Nalini M. Rajamannan Calcific aortic stenosis is the most common indication for surgical valve replacement in the U.S. For years this disease was thought to be a degenerative process that could only be treated with surgical therapy. The RAAVE (Rosuvastatin Affecting Aortic Valve Endothelium) study is the first prospective trial to target the treatment of low-density lipoprotein in patients with aortic stenosis. This study shows the beneficial effect of a 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitor in the slowing of the progression of aortic stenosis by echocardiography. These results provide the first clinical evidence showing that the aortic valve has an active biology that can be targeted with medical therapy.
Land application of sewage sludge containing increasing levels of silver nanoparticles (AgNPs) raises concerns about the risk for plant exposure. This study compared the uptake kinetics and ...distribution of Ag in Brassica rapa seedlings grown in Lufa 2.2 natural soil spiked with 20 nm Ag2S NPs, with those from 3 to 8 nm AgNPs, 50 nm AgNPs and AgNO3 exposures (10 mg Ag/kg dry soil). A two-compartment model was used to describe the uptake kinetics of Ag in plants, distinguishing two stages: stage I with increasing Ag uptake followed by stage II with decreasing Ag uptake. The concentration of Ag in roots from Ag2S NPs was about 14 and 10 times lower than for the other AgNPs and AgNO3 exposures, respectively, at the end of stage I, with root translocation rate constants being higher for Ag2S NPs. In stage II, Ag uptake occurred only for the 50 nm AgNPs. The distribution of Ag in B. rapa exposed to pristine, ionic and sulfidized AgNPs differed at the end of exposure. This study shows that Ag uptake and distribution in plants depends on the Ag form in soil, highlighting the importance of studying the environmentally relevant chemical species in NPs risk assessment.
Display omitted
•The accumulation of Ag in Brassica rapa differed during the plant life cycle.•Pristine AgNPs accumulated 14 times more Ag in B. rapa roots than Ag2S NPs.•A two-stage two-compartment model described the Ag uptake kinetics.•In Ag2S NPs, Ag was transferred to the shoots faster than for the other Ag forms.•NP stability determined different Ag uptake and translocation in plants.
Carbon-based nanomaterials exhibit unique properties that make them suitable for a wide variety of industrial and biomedical applications. In this work, we studied the acute toxicity of ...graphite-diamond nanoparticles (GDN) combined with the fungicide thiabendazole (TBZ) to the immobilization of the cladoceran Daphnia magna in the presence and absence of the micro green algae Raphidocelis subcapitata, supplied as food source. The toxicity of GDN to D. magna decreased in the presence of R. subcapitata, while that of TBZ increased, the latter suggesting a carrier effect to TBZ. GDN-TBZ mixtures were fitted to the most common conceptual models applied to mixture toxicity: Concentration Addition (CA), Independent Action (IA) and Combination Index (CI). For GDN-TBZ mixtures in the absence of food the best fit was obtained with dose ratio deviation from CA model, while in the presence of food, dose level deviation from CA gave a better fit. The binary mixtures of GDN and TBZ showed synergistic toxic interactions at low concentrations, which could be attributed to the increased bioavailability of TBZ adsorbed on GDN. For higher concentrations of GDN, the binary mixtures turned antagonistic due to particle agglomeration. Our study provides evidence that deviations from additivity are dose dependent and relevant for the risk assessment of mixtures of nanoparticles with other chemical pollutants.
Display omitted
•EC50 of graphite-diamond nanoparticles for Daphnia magna immobilization was 5.5 mg/L.•Daphnia magna immobilization decreased in the presence of algal cells as food source.•Nanoparticle-thiabendazole mixtures showed synergism at low concentrations.•High nanoparticle concentration resulted in antagonism due to particle agglomeration.
To fully understand the ecological and cumulative effects of mining activities on the surrounding aquatic systems of the Canadian oil sands region, it is essential to understand the consequences of ...exposure to bitumen-containing soils/sediment from natural geomorphological processes. Both physical and chemical stress on aquatic biota can potentially result from exposure to natural bitumen, resulting from hillslope erosional processes and slumping of bankside soils into the rivers, affecting both riverbed habitat and water quality. The magnitude and duration of bitumen-containing soil's fluvial soils/erosional input into receiving watersheds depends on the interannual variability in the regional hydroclimatology and related seasonal and extreme flow events. The primary objective of this study was to evaluate the potential ecotoxicological effects associated with erosional input of riverbank bitumen soils using controlled exposures. A series of integrated, laboratory-based ecotoxicological bioassays were conducted using organisms with different ecological and functional traits (Daphnia magna (Cladocera), Physa acuta (Gastropoda), and Aliivibrio fischeri (Bacteria)). All model organisms were exposed to elutriates produced from natural bitumen from four different regional rivers: fresh bitumen from shoreline outcrops at the Steepbank River upper and lower reaches (STB-CF and STB-MF, respectively) and the lower-Ells River (EL-MF) and aged, fluvially processed/weathered bitumen from the shoreline of the Athabasca River (ATB-MF). All tested organisms responded negatively to STB-MF and EL-MF elutriates. Low toxicity was also observed in the STB-CF and ATB-MF samples. These results follow the chemical analysis of the parental material and elutriates, where higher levels of metals, polycyclic aromatic compounds and naphthenic acids were detected in the EL-MF sample. In summary, this study shows that eroded and transported bitumen-containing soils and sediments could be a natural source of contaminant exposure to aquatic biota. This fluvial pathway should be considered when assessing background toxicity and the toxicological and ecological effects of oil sands mining activities.
Display omitted
•Effects of natural exposure to fluvial erosional inputs of oil sands bitumen on aquatic organisms should be considered.•Effects on organisms depend on the geologic source, quantity and quality of the bitumen.•Bitumen from different geological sources and watersheds shows regional toxicity and chemical composition heterogeneity.•Fresh bitumen elutriates from bankside erosional sources were more toxic than fluvially processed, aged bitumen.
Groundwater represents one of the most important natural water resources worldwide. Contamination is a key driver in sustaining water quality to populations and the environment. Therefore, it is ...crucial to look at contamination and potential effects. Within the WaterJPI project “We-Need - WatEr NEEDs, Availability, Quality and Sustainability”, the Cremona and the Bologna Aquifers (Italy) were chosen as case studies since both aquifers represent two major Italian water resources of the Emilia–Romagna region. Aiming for a site-specific groundwater hazard assessment, the groundwaters from the Cremona and Bologna aquifers were simulated by preparing synthetic waters, CSW and BSW, respectively. Boron (as boric acid), fluoride (as sodium fluoride), and ammonium (as ammonium hydroxide), detected in the aquifers, were used to assess potential negative impacts on groundwater systems using aquatic organisms. Acute toxicity tests with Daphnia magna and Fish Embryo Toxicity Tests (FET) with Danio rerio were performed in the CSW and BSW synthetic waters and respective culture media, and toxicity was assessed for each organism. Boron, fluoride and ammonium had no ecological hazard effects at the concentrations detected in the groundwaters. Besides, a crucial result from this study regards the use of different media when addressing toxicity assessment. In this case, it was observed that toxicity was media and organism dependent. Therefore, adapting testing protocols for higher relevance should be considered for site-specific hazard assessment.
•Site-specific hazard assessment can improve groundwater risk assessment.•Toxicity of groundwater contaminants was media and organism dependent.•Improving exposure media leads to higher accuracy in ERA’s effects characterization.•Adapting test protocols for higher relevance is key for site specific assessments.
Engineered nanoparticles released into surface water may accumulate in sediments, potentially threatening benthic organisms. This study determined the toxicokinetics in Chironomus riparius of Ag from ...pristine silver nanoparticles (Ag NPs), a simulating aged Ag NP form (Ag2S NPs), and AgNO3 as an ionic control. Chironomid larvae were exposed to these Ag forms through water, sediment, or food. The potential transfer of Ag from larvae to adult midges was also evaluated. Results revealed higher Ag uptake by C. riparius upon exposure to Ag2S NPs, while larvae exposed to pristine Ag NPs and AgNO3 generally presented similar uptake kinetics. Uptake patterns of the different Ag forms were generally similar in the tests with water or sediment exposures, suggesting that uptake from water was the most important route of Ag uptake in both experiments. For the sediment bioaccumulation test, uptake was likely a combination of water uptake and sediment particles ingestion. Ag uptake via food exposure was only significant for Ag2S NPs. Ag transfer to the terrestrial compartment was low. In our environmentally relevant exposure scenario, chironomid larvae accumulated relatively high Ag concentrations and elimination was extremely low in some cases. These results suggest that bioaccumulation of Ag in its nanoparticulate and/or ionic form may occur in the environment, raising concerns regarding chronic exposure and trophic transfer. This is the first study determining the toxicokinetics of NPs in Chironomus, providing important information for understanding chironomid exposure to NPs and their potential interactions in the environment.
Display omitted
•Toxicokinetic studies are essential to assess interactions between species and NPs.•Different exposure routes tested for Ag NPs, Ag2S NPs and AgNO3 in chironomids.•Higher uptake/bioaccumulation of Ag2S NPs than other Ag forms by chironomid larvae.•Chironomids showed similar Ag kinetics upon exposure to pristine Ag NPs and AgNO3.•Pupal exuviae are likely an elimination route for ionic and nanoparticulate Ag.
Due to several anthropogenic activities, water bodies have been heavily impacted by contaminants identified in aquatic ecosystems, including pharmaceuticals, personal care products, agricultural and ...industrial chemicals. Risk assessment based on chemical mixtures is still default in many monitoring studies, with decisions being based solely on a chemical-by-chemical basis. The present study aimed to improve risk assessment procedures in water bodies by focusing on mixtures of chemical substances of different origins. The goal was to analyze potential interactions occurring at different complexity levels (binary and quaternary mixtures) using standardised toxicity assays. Mixture toxicity effects were assessed using Daphnia magna as the model organism and the compounds sodium fluoride, boric acid, ammonium hydroxide and acetaminophen as general representatives of contaminants in the aquatic ecosystem. The results revealed interactions between the compounds, mainly showing antagonism but also dose level and dose ratio-dependent deviations. Overall antagonism was the dominant deviation pattern, particularly at low doses, though synergism was also detected at higher doses or specific ratios. Synergism at low doses was found for the binary mixture of ammonium hydroxide and acetaminophen, two common pollutants, which denotes an enhanced risk to aquatic ecosystems. Independent Action provided more accurate predictions for the quaternary mixture, whereas Concentration Addition overestimated the toxicity of the mixture. Regarding the environmental risk assessment of water bodies, the interaction between chemicals in a mixture should not be neglected. The complexity of the mixture interactions found in the present study highlights the importance of complementing chemical screenings of water bodies with mixture toxicity data, particularly when considering chemicals of multiple origins whose joint action remains unknown.
Display omitted
•Complex interactions found in mixtures of multiple source substances.•Binary mixtures showed an overall antagonism.•IA model provided a more accurate prediction of the quaternary mixture.•Quaternary mixture elicited lower effects than predicted by the CA model.•Mixture toxicity data is a fundamental tool in predicting risk assessment.
The technological potential of poly(methyl methacrylate) (PMMA)-based composite films doped with lanthanide-doped sol–gel derived ionosilicas (IS-Ln) previously proposed for luminescent down-shifting ...(LDS) and luminescent solar concentrator (LSC) layers connected to photovoltaic (PV) cells is extended here to electrochromic devices (ECDs), targeting the fabrication of single energy harvesting/conversion/management LSC-LDS/PV/ECD systems. These integrated devices have foreseen application in the windows of future zero-energy buildings of smart cities. The proof-of-concept is given with the report of the electro-optical performance of an ECD comprising an optimized electrolyte film composed of PMMA, IS-Nd, and IS-Eu, and the 1-butyl-3-methylimidazolium hexafluorophosphate ionic liquid. This amorphous electrolyte is stable below 160 °C, exhibits high ionic conductivity (2.13 × 10
−4
and 8.76 × 10
−4
S cm
−1
at room temperature and 44 °C, respectively), and emits in the visible (red color) and near-infrared (NIR) spectral regions. The device demonstrated fast switching speed (50 s) and high transparency in the visible-to-NIR spectral regions (transmittance (
T
) = 79/96/89/77% at 555/1000/1500/1650 nm in the as-prepared state, respectively). Upon application of ±2.5 V for 200 cycles, at the same wavelengths, the
T
bleached
/
T
colored
values were 44/28, 46/26, 39/20, and 27/9%, respectively, and the coloration efficiency (CE) values CE
in
/CE
out
values were −302/+181, −381/+228, −446/+267 and −734/+440 cm
2
C
−1
, respectively.
Highlights
Red-emitting ECDs enabling dynamic control of sunlight and offering uninterrupted heat emission were fabricated.
The ECD electrolyte composition was based on the formulation used previously for films acting both as LDS and LSC layers.
The electrolyte included PMMA, Nd
3+
/Eu
3+
-doped ionosilicas, and 1-butyl-3-methylimidazolium hexafluorophosphate.
The electrolyte is amorphous, exhibits good ionic conductivity, and emits in the visible (red color) and NIR regions.
The ECD performance proves its applicability in an integrated LSC-LDS/PV/ECD system.
PDF
