Metal-based nanoparticles exhibiting antimicrobial activity are of emerging concern to human and environmental health. In addition to their direct adverse effects to plants and animals, indirect... Show moreMetal-based nanoparticles exhibiting antimicrobial activity are of emerging concern to human and environmental health. In addition to their direct adverse effects to plants and animals, indirect effects resulting from disruption of beneficial host-microbiota interactions may contribute to the toxicity of these particles. To explore this hypothesis, we compared the acute toxicity of silver and zinc oxide nanoparticles (nAg and nZnO) to zebrafish larvae that were either germ-free or colonized by microbiota. Over two days of exposure, germ-free zebrafish larvae were more sensitive to nAg than microbially colonized larvae, whereas silver ion toxicity did not differ between germ-free and colonized larvae. Using response addition modeling, we confirmed that the protective effect of colonizing microbiota against nAg toxicity was particle-specific. Nearly all mortality among germ-free larvae occurred within the first day of exposure. In contrast, mortality among colonized larvae increased gradually over both exposure days. Concurrent with this gradual increase in mortality was a marked reduction in the numbers of live host-associated microbes, suggesting that bactericidal effects of nAg on protective microbes resulted in increased mortality among colonized larvae over time. No difference in sensitivity between germ-free and colonized larvae was observed for nZnO, which dissolved rapidly in the exposure medium. At sublethal concentrations, these particles moreover did not exert detectable bactericidal effects on larvae-associated microbes. Altogether, our study shows the importance of taking host-microbe interactions into account in assessing toxic effects of nanoparticles to microbially colonized hosts, and provides a method to screen for microbiota interference with nanomaterial toxicity. Show less
Whether toxicity of silver nanoparticles (AgNPs) to organisms originates from the nanoparticles themselves or from the dissolved Ag-ions is still debated, with the majority of studies claiming that... Show moreWhether toxicity of silver nanoparticles (AgNPs) to organisms originates from the nanoparticles themselves or from the dissolved Ag-ions is still debated, with the majority of studies claiming that extracellular release of Ag-ions is the main cause of toxicity. The objective of this study was to determine the contributions of both particles and dissolved ions to toxic responses, and to better understand the underlying mechanisms of toxicity. In addition, the pathways of AgNPs exposure to plants might play an important role and therefore are explicitly studied as well. We systematically assessed the phytotoxicity, internalization, biodistribution, and antioxidant responses in lettuce (Lactuca sativa) following root or foliar exposure to AgNPs and ionic Ag at various concentrations. For each endpoint the relative contribution of the particle-specific versus the ionic form was quantified. The results reveal particle-specific toxicity and uptake of AgNPs in lettuce as the relative contribution of particulate Ag accounted for more than 65% to the overall toxicity and the Ag accumulation in whole plant tissues. In addition, particle toxicity is shown to originate from the accumulation of Ag in plants by blocking nutrient transport, while ion toxicity is likely due to the induction of excess ROS production. Root exposure induced higher toxicity than foliar exposure at comparable exposure levels. Ag was found to be taken up and subsequently translocated from the exposed parts of plants to other portions regardless of the exposure pathway. These findings suggest particle related toxicity, and demonstrate that the accumulation and translocation of silver nanoparticles need to be considered in assessment of environmental risks and of food safety following consumption of plants exposed to AgNPs by humans. Show less
Dovidat, L.C.; Brinkmann, B.W.; Vijver, M.G.; Bosker, T. 2020
We investigated the effect of nano‐ and microplastics on the freshwater duckweed species Spirodela polyrhiza, a vascular plant. S. polyrhiza was exposed for 120 h to concentrations ranging from 102... Show moreWe investigated the effect of nano‐ and microplastics on the freshwater duckweed species Spirodela polyrhiza, a vascular plant. S. polyrhiza was exposed for 120 h to concentrations ranging from 102 to 106 particles·mL−1. We assessed effects on growth and chlorophyll production, and explored adsorption and absorption by way of confocal microscopy. For both nano‐ and microsized particles, no concentration‐dependent effects on growth were found (expressed as fresh weight, frond, and root sizes). In addition, chlorophyll concentrations were not significantly affected. Confocal microscopy indicated that nanosized plastic particles adsorbed externally to the duckweed, especially to the roots. Internalized plastic particles could not be detected. Nevertheless, given their important role in ecosystems as a food source for a range of organisms, the adsorption of plastic particles to S. polyrhiza roots as detected in this study can result in the transfer of plastic particles to diverse herbivorous species within the ecosystem. Show less
The fish bioconcentration factor (BCF) is an important aspect within bioaccumulation assessments. Several factors have been suggested to influence BCF values – including species, developmental... Show moreThe fish bioconcentration factor (BCF) is an important aspect within bioaccumulation assessments. Several factors have been suggested to influence BCF values – including species, developmental stage, mixture exposure, and calculation method. However, their exact contribution to variance in BCF values is unknown. Within this study we assessed the relative impact of these test characteristics on BCF values and analyzed the reproducibility of aquatic exposure bioconcentration tests.Linear mixed effects analyses were performed on a newly develop database to investigate the relationship between the response variable (i.e. lipid normalized log BCF values) and several test characteristics as fixed effects.Lower BCF values were observed for substances that were simultaneously applied with high molecular weight polycyclic aromatic hydrocarbons compared to single substance exposure (with an average difference of −0.81 log BCF). Also, lower BCFs upon kinetic determination were observed compared to steady-state BCFs (log BCF -0.27), and lower BCFs for species from the Ostariophysi subcohort level (log BCF -0.17 to −0.15). In addition, data analysis showed high variation within BCF values for single substances (average SD = log BCF 0.21), which questions the robustness of the current bioaccumulation assessments. For example, the 95% confidence range of a BCF value of 2500 ranges from 953 (‘not-bioaccumulative’) to 6561 (‘very bioaccumulative’).Our results show that the use of one single BCF leads to a high uncertainty in bioaccumulation assessments. We strongly recommend that within future bioconcentration studies, the used experimental design and test conditions are described in detail and justified to support solid interpretation. Show less
Innovation in photovoltaics (PV) is mostly driven by the cost per kilowatt ratio, making it easy to overlook environmental impacts of technological enhancements during early research and... Show moreInnovation in photovoltaics (PV) is mostly driven by the cost per kilowatt ratio, making it easy to overlook environmental impacts of technological enhancements during early research and development stages. As PV technology developers introduce novel materials and manufacturing methods, the well‐studied environmental profile of conventional silicon‐based PV may change considerably. Herein, existing trends and hotspots across different types of emerging PV technologies are investigated through a systematic review and meta‐analysis of life‐cycle assessments (LCAs). To incorporate as many data points as possible, a comprehensive harmonization procedure is applied, producing over 600 impact data points for organic, perovskite (PK), dye‐sensitized, tandem, silicon, and other thin‐film cells. How the panel and balance of system components affect environmental footprints in comparable installations is also investigated and discussed. Despite the large uncertainties and variabilities in the underlying LCA data and models, the harmonized results show clear positive trends across the sector. Seven potential hotspots are identified for specific PV technologies and impact categories. The analysis offers a high‐level guidance for technology developers to avoid introducing undesired environmental trade‐offs as they advance to make PV more competitive in the energy markets. Show less
A single-cell inductively coupled plasma mass spectrometry technique was used to explore the influence of particle properties on the association of nanomaterials (NMs) with algal cells. We... Show moreA single-cell inductively coupled plasma mass spectrometry technique was used to explore the influence of particle properties on the association of nanomaterials (NMs) with algal cells. We investigated the effect of particle size, shape, and surface chemistry [citrate and natural organic matter (NOM) coating] on the association of gold (Au) NMs with algal cells using particle mass, particle number, surface area (SA), and volume-specific surface area (VSSA) as dose metrics. Particle number was found to be a better dose metric than particle mass, SA, and VSSA in view of the strong correlation obtained between the number of associated Au NMs with cells and the number of Au NMs in the exposure medium. When particle number was used as the dose metric, there was no selectivity of Au NM cellular association irrespective of particle size and shape, and the cellular association was proportional to the effective number of particles to which the cells were exposed. The surface chemistry of the Au NMs, however, decreased the level of cellular association of some NMs (60 nm spheres). Particle number is the main element used for the classification of NMs according to the recommended definition for NM by the European Commission. The key finding of our study supports the implementation of this definition for safety purposes. Show less
Organic–inorganic perovskite solar cells (PSCs) are promising candidates as photovoltaic cells. Recently, they have attracted significant attention due to certified power conversion efficiencies... Show moreOrganic–inorganic perovskite solar cells (PSCs) are promising candidates as photovoltaic cells. Recently, they have attracted significant attention due to certified power conversion efficiencies exceeding 23%, low–cost engineering, and superior electrical/optical characteristics. These PSCs extensively utilize a perovskite–structured composite with a hybrid of Pb-based nanomaterials. Operation of them may cause the release of Pb-based nanoparticles. However, limited information is available regarding the potential toxicity of Pb-based PSCs on various organisms. This study conducted a battery of in vitro and in vivo toxicity bioassays for three quintessential Pb-based PSCs (CH3NH3PbI3, NHCHNH3PbBr3, and CH3NH3PbBr3) using progressively more complex forms of life. For all species tested, the three different perovskites had comparable toxicities. The viability of Caco–2/TC7 cells was lower than that of A549 cells in response to Pb-based PSC exposure. Concentration–dependent toxicity was observed for the bioluminescent bacterium Vibrio fischeri, for soil bacterial communities, and for the nematode Caenorhabditis elegans. Neither of the tested Pb-based PSCs particles had apparent toxicity to Pseudomonas putida. Among all tested organisms, V. fischeri showed the highest sensitivity with EC50 values (30 min of exposure) ranging from 1.45 to 2.91 mg L-1. Therefore, this study recommends that V. fischeri should be preferably utilized to assess.PSC toxicity due to its increased sensitivity, low costs, and relatively high throughput in a 96–well format, compared with the other tested organisms. These results highlight that the developed assay can easily predict the toxic potency of PSCs. Consequently, this approach has the potential to promote the implementation of the 3Rs (Replacement, Reduction, and Refinement) principle in toxicology and decrease the dependence on animal testing when determining the safety of novel PSCs. Show less
Temperate aquatic communities are highly diverse and seasonally variable, due to internal biotic processes and environmental drivers, including human‐induced stressors. The impact of drivers on... Show moreTemperate aquatic communities are highly diverse and seasonally variable, due to internal biotic processes and environmental drivers, including human‐induced stressors. The impact of drivers on species abundance is supposed to differ fundamentally depending on whether populations are experiencing limitations, which may shift over the season. However, an integrated understanding of how drivers structure communities seasonally is currently lacking. In order to partition the effect of drivers, we used random forests to quantify interactions between all taxa and environmental factors using macrofaunal data from 18 agricultural ditches sampled over two years. We found that, over the agricultural season, taxon abundance became increasingly better predicted by the abundances of co‐occurring taxa and nutrients compared to other abiotic factors, including pesticides. Our approach provides fundamental insights in community dynamics and highlights the need to consider changes in species interactions to understand the effects of anthropogenic stressors. Show less
Microplastics attract widespread attention, including for their potential to transport toxic chemicals in the form of plasticisers and associated hydrophobic organic chemicals, such as... Show moreMicroplastics attract widespread attention, including for their potential to transport toxic chemicals in the form of plasticisers and associated hydrophobic organic chemicals, such as polybrominated diphenyl ethers (PBDEs). The aims of this study were to investigate how nylon (polyamide) microplastics may affect PBDE accumulation in snails, and the acute effects of nylon particles and PBDEs on survival, weight change and inherent microbiome diversity and community composition of the pond snail Lymnaea stagnalis. Snails were exposed for 96 h to BDEs-47, 99, 100 and 153 in the presence and absence of 1% w/w nylon microplastics in quartz sand sediment. No mortality was observed over the exposure period. Snails not exposed to microplastics lost significantly more weight compared to those exposed to microplastics. Increasing PBDE concentration in the sediment resulted in an increased PBDE body burden in the snails, however microplastics did not significantly influence total PBDE uptake. Based on individual congeners, uptake of BDE 47 by snails was significantly reduced in the presence of microplastics. The diversity and composition of the snail microbiome was not significantly altered by the presence of PBDEs nor by the microplastics, singly or combined. Significant effects on a few individual operational taxonomic units (OTUs) occurred when comparing the highest PBDE concentration with the control treatment, but in the absence of microplastics only. Overall within these acute experiments, only subtle effects on weight loss and slight microbiome alterations occurred. These results therefore highlight that L. stagnalis are resilient to acute exposures to microplastics and PBDEs, and that microplastics are unlikely to influence HOC accumulation or the microbiome of this species over short timescales. Show less
Titanium dioxide nanoparticles (TiO2NP) are often released into the soil through repeated discharge of wastewater and repetitive applications as fertilizers. Adverse effects of a single pulse on... Show moreTitanium dioxide nanoparticles (TiO2NP) are often released into the soil through repeated discharge of wastewater and repetitive applications as fertilizers. Adverse effects of a single pulse on soil bacterial communities have been widely studied, while the impact of repeated exposure is poorly understood. This study compared the impacts of single and repeated exposure scenarios on the soil bacterial community. The repeated exposure promoted the total bacterial biomass but reduced the community diversity and induced larger alterations in community composition compared to the single exposure. Regarding the dosing frequencies of repeated exposure, community divergence increased in initial dosing cycles, and community stability was re-established and remained in subsequent dosing cycles. According to the different tolerance to dosing frequencies, the dynamic response patterns of the featured OTUs and functional genes could be classified into four types: 1) promotion, 2) suppression-recovery-promotion, 3) promotion-suppression-stable, and 4) suppression. These results suggest that chronic exposure with repetitive low-dosing of nanoparticles induced a tendency towards larger alteration of both community composition and functioning than in case of application of a single pulse of the same dosage. This study brings new insight into understanding the compositional and predicted functional dynamics of the soil bacterial community in response to nanoparticles and identifies a data gap in realistic time-variable exposure testing. Show less
Brun, N.R.; Hage, P. van; Hunting, E.R.; Haramis, A.-P.G.; Vink, S.C.; Vijver, M.G.; ... ; Tudorache, C. 2019
Plastic nanoparticles originating from weathering plastic waste are emerging contaminants in aquatic environments, with unknown modes of action in aquatic organisms. Recent studies suggest that... Show morePlastic nanoparticles originating from weathering plastic waste are emerging contaminants in aquatic environments, with unknown modes of action in aquatic organisms. Recent studies suggest that internalised nanoplastics may disrupt processes related to energy metabolism. Such disruption can be crucial for organisms during development and may ultimately lead to changes in behaviour. Here, we investigated the link between polystyrene nanoplastic (PSNP)-induced signalling events and behavioural changes. Larval zebrafish exhibited PSNP accumulation in the pancreas, which coincided with a decreased glucose level. By using hyperglycemic and glucocorticoid receptor (Gr) mutant larvae, we demonstrate that the PSNP-induced disruption in glucose homoeostasis coincided with increased cortisol secretion and hyperactivity in challenge phases. Our work sheds new light on a potential mechanism underlying nanoplastics toxicity in fish, suggesting that the adverse effect of PSNPs are at least in part mediated by Gr activation in response to disrupted glucose homeostasis, ultimately leading to aberrant locomotor activity. Show less
Dovidat, L.C.; Brinkmann, B.W.; Vijver, M.G.; Bosker, T. 2019
We investigated the effect of nano- and microplastics on the freshwater duckweed species Spirodela polyrhiza, a vascular plant. S. polyrhiza was exposed for 120 h to concentrations ranging from 10... Show moreWe investigated the effect of nano- and microplastics on the freshwater duckweed species Spirodela polyrhiza, a vascular plant. S. polyrhiza was exposed for 120 h to concentrations ranging from 10(2) to 10(6) particles center dot mL(-1). We assessed effects on growth and chlorophyll production, and explored adsorption and absorption by way of confocal microscopy. For both nano- and microsized particles, no concentration-dependent effects on growth were found (expressed as fresh weight, frond, and root sizes). In addition, chlorophyll concentrations were not significantly affected. Confocal microscopy indicated that nanosized plastic particles adsorbed externally to the duckweed, especially to the roots. Internalized plastic particles could not be detected. Nevertheless, given their important role in ecosystems as a food source for a range of organisms, the adsorption of plastic particles to S. polyrhiza roots as detected in this study can result in the transfer of plastic particles to diverse herbivorous species within the ecosystem. Show less
Suitable methods and fit-for-purpose techniques are required to allow characterization of carbon-based nanomaterials (CB-NMs) in complex matrices. In this study, two methods were developed; a... Show moreSuitable methods and fit-for-purpose techniques are required to allow characterization of carbon-based nanomaterials (CB-NMs) in complex matrices. In this study, two methods were developed; a method for extraction and characterization of CB-NMs in biological media and a method for fractionation of natural organic matter (NOM) coated CB-NMs in environmental matrices. The former method was developed by extracting carbon nanotubes (CNTs: sized 0.75 × 3000 nm) and nanoplastics (sized 60, 200 and 600 nm) from eggshells and characterizing the extracted CB-NMs in terms of particle size distribution using asymmetrical flow field-flow fractionation (AF4) coupled with multi-angle light scattering (MALS). The latter method was developed using AF4-MALS to fraction NOM-coated CNT (sized 0.75 × 3000 nm) and nanoplastics (sized 60, 200 and 300 nm) in a simulated natural surface water and provide information about the size distribution of the CB-NM-NOM complexes. The developed AF4-MALS method successfully fractioned the CB-NM-NOM complexes based on hydrodynamic size and provided the size distribution of the complexes. The NOM corona did not shift significantly the median size of the CB-NMs. It influenced however the size distribution of the nanoplastics and CNTs. The sample preparation method failed to extract the CNTs (recovery < 20%) from the matrices of the eggshells while being successful for extracting the nanoplastics (recoveries > 60%). The AF4-MALS fractogram showed that the extraction method did not significantly influence the size distribution of the nanoplastics of 60 and 200 nm size, whereas the peak of 600 nm nanoplastics shifted towards a smaller hydrodynamic size. In conclusion, the developed sample preparation method followed by the developed AF4-MALS method can be applied for extraction, separation and characterization of CB-NMs in biological and environmental matrices. Thus, the methods have a high potential to be methods of choice to investigate CB-NMs in future studies. Show less
There is a strong demand for early stage identification of potential Substances of Very High Concern (SVHC). SVHCs are substances that are classified as carcinogenic, mutagenic or reprotoxic (CMR);... Show moreThere is a strong demand for early stage identification of potential Substances of Very High Concern (SVHC). SVHCs are substances that are classified as carcinogenic, mutagenic or reprotoxic (CMR); persistent, bioaccumulative and toxic (PBT) or very persistent and very bioaccumulative (vPvB); or as substances with an equivalent level of concern, like endocrine disruption (ED). The endeavor to improve the identification of potential SVHCs is also acknowledged by the European Commission, in their long-term vision towards a non-toxic environment. However, it has been shown difficult to identify substances as potentially harmful.With this goal in mind, we have developed a methodology that predicts whether a substance is a potential SVHC based on chemical similarity to chemicals already identified as SVHC. The approach is based on the structural property principle, which states that structurally similar chemicals are likely to have similar properties.We systematically analyzed the predictive performance of 112 similarity measures (i.e. all different combinations of 16 binary fingerprints and 7 similarity coefficients) classifying the substances in the dataset as (potential) SVHC or non-SVHC. The outcomes were analyzed for 546 substances that we collected within the Dutch SVHC database – with identified CMR, PBT/vPvB and/or ED properties – and 411 substances that lack these hazardous properties. The best similarity measures showed a high predictive performance with a balanced accuracy of 85% correct identifications for the whole dataset of SVHC substances, and 80% for CMR, 95% for PBT/vPvB and 99% for ED subgroups.This effective screening methodology showed great potential for early stage identification of potential SVHCs. This model can be applied within regulatory frameworks and safe-by-design trajectories, and hence can contribute to the EU goal of achieving a non-toxic environment. Show less
