Similarity assessment is one of the means of optimally using scarcely available experimental data on the fate and hazards of nanoforms (NFs) for regulatory purposes. For a set of NFs that are shown... Show moreSimilarity assessment is one of the means of optimally using scarcely available experimental data on the fate and hazards of nanoforms (NFs) for regulatory purposes. For a set of NFs that are shown to be similar it is allowed in a regulatory context to apply the information available on any of the NFs within the group to the whole set of NFs. Obviously, a proper justification for such a similarity assessment is to be provided. Within the context of exemplifying such a justification, a case study was performed aimed at assessing the similarity of a set of spherical metallic NFs that different with regard to chemical composition (three metals) and particle size (three different sizes). The endpoints of assessment were root elongation and biomass increase of lettuce (Lactuca sativa L.) seedlings and exposure assessment was performed in order to express the actual exposure concentration in terms of time-weighted average particle concentrations. The results of the study show that for the specific endpoints assessed, chemical composition is driving NF toxicity and this is mostly due to impacts on the fate of the NFs. On the other hand, particle size of Cu NFs had a negligible impact on the dose-response relationships for the specific endpoints assessed. It is thus concluded that hazard data available on spherical Cu NF tested in our case can be used to inform on the hazards of any spherical Cu NF within the size range of 25-100 nm, but only applies for the certain endpoints. Also, toxicity data for the Cu2+-ion are suited for such a similarity assessment. Show less
Fragmentation of plastic waste in the environment can lead to the formation of nanoscale plastic debris (NPD) of size < 1 μm. Although it is reported that NPD can be taken up by organisms, the... Show moreFragmentation of plastic waste in the environment can lead to the formation of nanoscale plastic debris (NPD) of size < 1 μm. Although it is reported that NPD can be taken up by organisms, the current lack of knowledge regarding its toxicokinetics is a problem. It is currently unknown whether/how NPD passes through physiological barriers, and subsequently is biodistributed, biotransformed and/or excreted from organisms. New methods and techniques are being developed at a rapid pace that facilitates gaining insights into the uptake and toxicokinetics of NPD even in complex biotic samples. However, the required knowledge is generated slowly, which hinders environmental risk assessment. In this perspective, we outline the current understanding of the toxicokinetics of NPD in organisms by transferring the acquired knowledge on the toxicokinetics of engineered polymeric NMs to NPD. We briefly discuss the absorption, distribution, metabolism (e.g., biotransformation), and excretion (ADME) of NPD and highlight the knowledge gaps and research required to address them. Building on this, a perspective on toxicokinetics modeling of NPD using physiologically based pharmacokinetic (PBPK) models is presented, discussing the factors that might influence the modeling data and providing recommendations on the factors that need to be considered for developing PBPK models for NPD. Show less
Similarity assessment is one of the means of optimally using scarcely available experimental data on the fate and hazards of nanoforms (NFs) for regulatory purposes. For a set of NFs that are shown... Show moreSimilarity assessment is one of the means of optimally using scarcely available experimental data on the fate and hazards of nanoforms (NFs) for regulatory purposes. For a set of NFs that are shown to be similar it is allowed in a regulatory context to apply the information available on any of the NFs within the group to the whole set of NFs. Obviously, a proper justification for such a similarity assessment is to be provided. Within the context of exemplifying such a justification, a case study was performed aimed at assessing the similarity of a set of spherical metallic NFs that different with regard to chemical composition (three metals) and particle size (three different sizes). The endpoints of assessment were root elongation and biomass increase of lettuce (Lactuca sativa L.) seedlings and exposure assessment was performed in order to express the actual exposure concentration in terms of time-weighted average particle concentrations. The results of the study show that for the specific endpoints assessed, chemical composition is driving NF toxicity and this is mostly due to impacts on the fate of the NFs. On the other hand, particle size of Cu NFs had a negligible impact on the dose-response relationships for the specific endpoints assessed. It is thus concluded that hazard data available on spherical Cu NF tested in our case can be used to inform on the hazards of any spherical Cu NF within the size range of 25–100 nm, but only applies for the certain endpoints. Also, toxicity data for the Cu2+-ion are suited for such a similarity assessment. Show less
The European Green Deal outlines ambitions to build a more sustainable, climate neutral, and circular economy by 2050. To achieve this, the European Commission has published the Chemicals Strategy... Show moreThe European Green Deal outlines ambitions to build a more sustainable, climate neutral, and circular economy by 2050. To achieve this, the European Commission has published the Chemicals Strategy for Sustainability: Towards a Toxic-Free Environment, which provides targets for innovation to better protect human and environmental health, including challenges posed by hazardous chemicals and animal testing. The European project PATROLS (Physiologically Anchored Tools for Realistic nanOmateriaL hazard aSsessment) has addressed multiple aspects of the Chemicals Strategy for Sustainability by establishing a battery of new approach methodologies, including physiologically anchored human and environmental hazard assessment tools to evaluate the safety of engineered nanomaterials. PATROLS has delivered and improved innovative tools to support regulatory decision-making processes. These tools also support the need for reducing regulated vertebrate animal testing; when used at an early stage of the innovation pipeline, the PATROLS tools facilitate the safe and sustainable development of new nano-enabled products before they reach the market. Show less
The conventional Hill equation model is suitable to fit dose-response data obtained from performing (eco)toxicity assays. Models based on quasi-quantitative structure-activity relationships (QSARs)... Show moreThe conventional Hill equation model is suitable to fit dose-response data obtained from performing (eco)toxicity assays. Models based on quasi-quantitative structure-activity relationships (QSARs) to estimate the Hill coefficient ( n H ) ${n}_{{\rm{H}}})$ were developed with the aim of predicting the response of the invertebrate species Daphnia magna to exposure to metal-based nanomaterials. Descriptors representing the pristine properties of nanoparticles and media conditions were coded to a quasi-simplified molecular input line entry system and correlated to experimentally derived values of n H ${n}_{{\rm{H}}}$. Monte Carlo optimization was used to model the set of n H ${n}_{{\rm{H}}}$ values, and the model was trained on the basis of reported dose-response relationships of 60 data sets (n = 367 individual response observations) of 11 metal-based nanomaterials as obtained from 20 literature reports. The model simulates the training data well, with only 2.3% deviation between experimental and modeled response data. The technique was employed to predict the dose-response relationships of 15 additional data sets (n = 72 individual observations) not included in model development of seven metal-based nanomaterials from 10 literature reports, with an average error of 3.5%. Combining the model output with either the median effective concentration value or any other known effect level as obtained from experimental data allows the prediction of full dose-response curves of D. magna immobilization. This model is an accurate screening tool that allows the determination of the shape and slope of dose-response curves, thereby greatly reducing experimental effort in case of novel advanced metal-based nanomaterials or the prediction of responses in altered exposure media. This screening model is compliant with the 3Rs (replacement, reduction, and refinement) principle, which is embraced by the scientific and regulatory communities dealing with nano-safety. Environ Toxicol Chem 2022;00:1-12. (c) 2022 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC. Show less
Onze planeet stikt zo langzamerhand in de plastics en chemicaliën. Dat bedreigt inmiddels hele ecosystemen die nodig zijn om de aarde leefbaar te houden. Tijd voor een verhelderend gesprek met... Show moreOnze planeet stikt zo langzamerhand in de plastics en chemicaliën. Dat bedreigt inmiddels hele ecosystemen die nodig zijn om de aarde leefbaar te houden. Tijd voor een verhelderend gesprek met Martina Vijver, hoogleraar Ecotoxicologie aan de Universiteit Leiden. Ze vertelt hoe we steeds meer leren over de schadelijke gevolgen van chemicaliën. Als we niet meer inzetten op hergebruik, kan dit uitgroeien tot misschien wel de volgende grote milieucrisis. Ons Groene Geweten is Martijn Dekker van Perpetual Next. Show less
Various modern products have metallic nanoparticles (MNPs) embedded to enhance products performance. Technological advances enable nowadays even multiple hybrid nanoparticles. Consequently, the... Show moreVarious modern products have metallic nanoparticles (MNPs) embedded to enhance products performance. Technological advances enable nowadays even multiple hybrid nanoparticles. Consequently, the future co-release of multiple MNPs will inevitably result in the presence of MNP mixtures in the environment. An important question is if the responses of mixtures of MNPs can be dealt with in a similar way as with the responses of biota to mixtures of metal salts. Moreover, natural organic matter (NOM) is an important parameter affecting the behavior and effect of MNPs. Herein, we determined the joint toxicity and accumulation of copper nanoparticles (CuNPs) and zinc oxide nanoparticles (ZnONPs) in Daphnia magna in the absence and presence of Suwannee River natural organic matter (SR-NOM), compared to the joint toxicity and accumulation of corresponding metal salts. The results of toxicity testing showed that the joint toxicity of CuNPs + ZnONPs was greater than the single toxicity of CuNPs or ZnONPs. The joint toxic action of CuNPs + ZnONPs was additive or more-than-additive for D. magna. A similar pattern was found in the toxicity of the mixtures of Cu- and Zn-salts from the literature data. The presence of SR-NOM had no significant impact on the joint toxicity of CuNPs + ZnONPs. The calculated component-specific contribution to overall toxicity indicated that SR-NOM increased the relative contribution of dissolved ions released from the MNPs to the toxicity of the binary mixtures at high-effect concentrations of individual MNPs. Moreover, dissolved Zn-ions released from the ZnONPs were found to dominate the joint toxicity of CuNPs + ZnONPs in the presence of SR-NOM. Furthermore, the results of the accumulation experiment displayed that the presence of SR-NOM significantly enhanced the accumulation of either CuNPs or ZnONPs in D. magna exposed to the MNP mixtures. Show less
In recent years, various ecotoxicological test guidelines and (technical) guidance documents have been evaluated and updated with regard to their applicability to nanomaterials (NMs). Several of... Show moreIn recent years, various ecotoxicological test guidelines and (technical) guidance documents have been evaluated and updated with regard to their applicability to nanomaterials (NMs). Several of these have currently reached official regulatory status. Ensuring their harmonized implementation with previously recognized methods for ecotoxicitytesting of chemicals is a crucial next step towards effective and efficient regulation of NMs. In the present study, we evaluated the feasibility of assessing multigenerational effects in the first generation of offspring derived from exposed Daphnia magna whilst maintaining test conditions in accordance with regulatory test guidelines and guidance documents for NMs. To do so, we integrated the recommendations for ecotoxicological testing of NMs as defined in OECD Guidance Document 317 into an extended long-term D. magna reproduction test method (OECD Test Guideline 211) and assessed effects of two poorly soluble NMs (nTiO2 and nCeO2). Our results show adverse effects on life-history parameters of D. magna exposed to the selected nanomaterials within the range of reported environmental concentrations. We argue that conforming to OECD test guidelines and accompanying guidance for nanomaterials is feasible when performing D. magna reproduction tests and can minimize unnecessary duplication of similar experiments, even when extensions to the standardized test setup are added. Show less
The current debate on hazards associated with sub-micron sized plastics is hampered by a lack of quantitative data on the uptake and biological fate of plastics in organisms. Analytical methods... Show moreThe current debate on hazards associated with sub-micron sized plastics is hampered by a lack of quantitative data on the uptake and biological fate of plastics in organisms. Analytical methods should be developed to identify, characterize, and quantify sub-micron particulate plastic in biota to understand their biological fate in terms of biodistribution, localization, bioaccumulation and clearance. Here we give a perspective on a promising workflow of sample preparation methods and techniques that could enable analysis of sub-micron plastics in biological matrices and discuss their application for biological fate studies of particulate plastic in organisms. We also expect these methods to be largely transferrable to studies considering sub-micron plastics in food, consumer products, human and some environmental compartments. (c) 2021 Elsevier Ltd. All rights reserved. Show less
There is an ongoing unprecedented loss in insects, both in terms of richness and biomass. The usage of pesticides, especially neonicotinoid insecticides, has been widely suggested to be a... Show moreThere is an ongoing unprecedented loss in insects, both in terms of richness and biomass. The usage of pesticides, especially neonicotinoid insecticides, has been widely suggested to be a contributor to this decline. However, the risks of neonicotinoids to natural insect populations have remained largely unknown due to a lack of field-realistic experiments. Here, we used an outdoor experiment to determine effects of field-realistic concentrations of the commonly applied neonicotinoid thiacloprid on the emergence of naturally assembled aquatic insect populations. Following application, all major orders of emerging aquatic insects (Coleoptera, Diptera, Ephemeroptera, Odonata, and Trichoptera) declined strongly in both abundance and biomass. At the highest concentration (10 mg/L), emergence of most orders was nearly absent. Diversity of the most species-rich family, Chironomidae, decreased by 50% at more commonly observed concentrations (1 mg/L) and was generally reduced to a single species at the highest concentration. Our experimental findings thereby showcase a causal link of neonicotinoids and the ongoing insect decline. Given the urgency of the insect decline, our results highlight the need to reconsider the mass usage of neonicotinoids to preserve freshwater insects as well as the life and services depending on them. Show less
Copper oxide nanoparticles (CuO NPs) are one of the most widely used materials owing to their excellent properties such as thermal and photochemical stability, superconductivity, and high... Show moreCopper oxide nanoparticles (CuO NPs) are one of the most widely used materials owing to their excellent properties such as thermal and photochemical stability, superconductivity, and high electrochemical activity. Once they enter the environment, Cu2+ may be released in water, which alters the behavior and toxicity of CuO NPs. The present study thus investigated the dissolution of CuO NPs (40 nm) in the presence of tannic acid (TA), a model chemical of dissolved organic matter. The adsorption of TA decreased the hydrodynamic diameter of CuO NPs and increased the zeta potential of the suspension. Although the adsorption of TA on particle surface improved the dispersion of CuO NPs, their dissolution extents were all reduced at TA concentration up to 55.4 mg C L−1. At pH 5, the contributions of TA complexed Cu to the overall dissolution increased up to 37.8% as a function of TA concentrations. All the findings shown above approved that the strong adsorption of TA played a dominant role in preventing the dissolution of CuO NPs. Show less
The coronavirus disease-19 (COVID-19) pandemic caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is rampant in the world and is a serious threat to global health. The SARS... Show moreThe coronavirus disease-19 (COVID-19) pandemic caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is rampant in the world and is a serious threat to global health. The SARS-CoV-2 RNA has been detected in various environmental media, which speeds up the pace of the virus becoming a global biological pollutant. Because many engineered nanomaterials (ENMs) are capable of inducing anti-microbial activity, ENMs provide excellent solutions to overcome the virus pandemic, for instance by application as protective coatings, biosensors, or nano-agents. To tackle some mechanistic issues related to the impact of ENMs on SARS-CoV-2, we investigated the molecular interactions between carbon nanoparticles (CNPs) and a SARS-CoV-2 RNA fragment (i.e., a model molecule of frameshift stimulation element from the SARS-CoV-2 RNA genome) using molecular mechanics simulations. The interaction affinity between the CNPs and the SARS-CoV-2 RNA fragment increased in the order of fullerenes < graphenes < carbon nanotubes. Furthermore, we developed quantitative structure-activity relationship (QSAR) models to describe the interactions of 17 different types of CNPs from three dimensions with the SARS-CoV-2 RNA fragment. The QSAR models on the interaction energies of CNPs with the SARS-CoV-2 RNA fragment show high goodness-of-fit and robustness. Molecular weight, surface area, and the sum of degrees of every carbon atom were found to be the primary structural descriptors of CNPs determining the interactions. Our research not only offers a theoretical insight into the adsorption/separation and inactivation of SARS-CoV-2, but also allows to design novel ENMs which act efficiently on the genetic material RNA of SARS-CoV-2. This contributes to minimizing the challenge of time-consuming and labor-intensive virus experiments under high risk of infection, whilst meeting our precautionary demand for options to handle any new versions of the coronavirus that might emerge in the future. Show less
Sample preparation for extraction of nanoscale plastic debris (NPD, size < 1 μm) from environmental samples is a critical step to prepare NPD for further identification and quantification.... Show moreSample preparation for extraction of nanoscale plastic debris (NPD, size < 1 μm) from environmental samples is a critical step to prepare NPD for further identification and quantification. Developing a NPD extraction method from soil matrices is particularly challenging due to the complexity of solid matrices. In the present study, we built upon the lessons learned from method development for extraction of microplastics and nanomaterials from environmental samples to develop a sample preparation method for extraction of NPD from soil matrices. The evaluation criteria for the extraction method are size distribution, particle number recovery, and particle mass recovery. Since there is no validated method available to trace and quantify the mass of NPD in complex matrices, we applied polystyrene particles doped with europium (Eu-PS NPs). Standard LUFA soil and field soil were spiked and mixed for 24 h with 1 mg of Eu-PS NPs and the particles were extracted from the matrices of the soils. The extraction method did not significantly influence the size distribution of the particles and the extraction agents did not degrade the Eu-PS NPs. Mass balance calculation suggested recoveries of 82 and 77% of the added Eu-PS NPs in LUFA soil and field soil, respectively. The number recoveries of the particles were 81 and 85% for LUFA soil and field soil, respectively. This method can be further optimized and used as the first building block to develop a generic sample preparation method for the extraction of NPD from soil samples. By combining this developed and verified extraction method with identification and quantification techniques, a fit-for-purpose workflow can be developed to quantify and subsequently understand the fate of NPD in soil. Show less
