Environmental release, fate and ecotoxicological effects of manufactured ceria nanomaterials

Recent interest in the environmental fate and effects of manufactured CeO2 nanomaterials (nanoceria) has stemmed from its expanded use for a variety of applications including fuel additives, catalytic converters, chemical and mechanical planarization media and other uses. This has led to a wave of publications on the toxicological effects of nanoceria in ecological receptor species, but only limited information is available on possible environmental releases, concentrations in environmental media, or environmental transformations. In this paper, we make initial estimates of likely environmental releases and exposure concentrations in soils and water and compare them to published toxicity values. Insufficient information was available to estimate aquatic exposures, but we estimated inputs to a hypothetical wastewater treatment plant that could result in effluent concentrations that would result in acute toxicity to the most sensitive aquatic organisms tested so far, cyanobacteria. The purpose of this exercise is to identify which areas are lacking in data to perform either regional or site specific ecological risk assessments. While estimates can be made for releases from use as a diesel fuel additive, and predicted toxicity is low in most terrestrial species tested to date, estimates for releases from other uses are difficult at this stage. We recommend that future studies focus on environmentally realistic exposures that take into account potential environmental transformations of the nanoceria surface as well as chronic toxicity studies in benthic aquatic organisms, soil invertebrates and microorgansims

Comparative Toxicity of Nanoparticulate CuO and ZnO to Soil Bacterial Communities

The increasing industrial application of metal oxide Engineered Nano-Particles (ENPs) is likely to increase their environmental release to soils. While the potential of metal oxide ENPs as environmental toxicants has been shown, lack of suitable control treatments have compromised the power of many previous assessments. We evaluated the ecotoxicity of ENP (nano) forms of Zn and Cu oxides in two different soils by measuring their ability to inhibit bacterial growth. We could show a direct acute toxicity of nano-CuO acting on soil bacteria while the macroparticulate (bulk) form of CuO was not toxic. In comparison, CuSO4 was more toxic than either oxide form. Unlike Cu, all forms of Zn were toxic to soil bacteria, and the bulk-ZnO was more toxic than the nano-ZnO. The ZnSO4 addition was not consistently more toxic than the oxide forms. Consistently, we found a tight link between the dissolved concentration of metal in solution and the inhibition of bacterial growth. The inconsistent toxicological response between soils could be explained by different resulting concentrations of metals in soil solution. Our findings suggested that the principal mechanism of toxicity was dissolution of metal oxides and sulphates into a metal ion form known to be highly toxic to bacteria, and not a direct effect of nano-sized particles acting on bacteria. We propose that integrated efforts toward directly assessing bioavailable metal concentrations are more valuable than spending resources to reassess ecotoxicology of ENPs separately from general metal toxicity

NANOPARTICULES D'OXYDES MÉTALLIQUES : <br />RELATIONS ENTRE LA RÉACTIVITE DE SURFACE ET DES RÉPONSES BIOLOGIQUES

The growing interest in nanotechnology is comparable to a new industrial revolution. It affects also the environmental field since nanoparticles (NPs) provide solutions to several environmental issues. For instance, we have shown the strong retention efficiency of As (8As/nm2) by iron oxide NPs (6nm). This is linked to their large specific surface area and their strong surface reactivity, due to the presence of unusual adsorption sites and to the significant decrease of surface energy during adsorption.But some questions concern the (eco)toxicological impact arising from an increasing NPs production. A classification of the toxicity of oxide NPs as a function of their redox properties has been proposed. While chemically stable NPs (γFe2O3) in biological media have no apparent toxicity, NPs with a strong oxydant (CeO2) or reductive (Fe°) power appear cytotoxic for Escherichia coli and genotoxic for human fibroblastsLes nanotechnologies génèrent un engouement assimilable à une révolution technologique. Le domaine de l'environnement est concerné car les nanoparticules (NPs) apportent des solutions à plusieurs problèmes de pollution. Par exemple, nous avons montré la forte capacité de rétention de l'As (8As/nm2) par des NPs d'oxydes de fer (6nm). Ceci est lié à leur grande surface spécifique et à leur forte réactivité de surface due à la présence de sites d'adsorption inédits et à la diminution significative de l'énergie de surface lors de l'adsorption. Mais des questions se posent sur l'impact (éco)toxicologique engendré par la forte production de NPs. Une classification de l'(éco)toxicité des nano-oxydes en fonction de leurs propriétés redox a été proposée. Alors que des NPs chimiquement stables (γFe2O3) en milieux biologiques ne montrent aucune toxicité, des NPs ayant un pouvoir oxydant (CeO2) ou réducteur (Fe°) sont cytotoxiques pour Escherichia coli et génotoxiques pour les fibroblastes humains

Nanotoxicology in the environment

International audienceno abstrac

Characterization of CeO2 nanoparticles and their heteroaggregate fate in aquatic mesocosms

International audienceno abstrac

Characterization of CeO2 nanoparticles and their heteroaggregate fate in aquatic mesocosms

International audienceno abstrac

Ontology-based NLP information extraction to enrich nanomaterial environmental exposure database

International audienceIn recent years, nanotechnologies have led to undeniable progress in any domains, such as electronics, materials and medicine. Despite the benefits of such a technology, a careful assessment of the potential risks for Human and Environmental health have to be studied. Assessing exposure and hazard to nanomaterials is a major challenge in the field of environmental sciences. This task requires to gather a large amount of meaningful experimental data usually generated by laboratory experiments. A first database of environmental exposure to nanomaterials (EXPOSED database) has been developed to gather data generated during mesocosm experiments. The challenge is now to enrich this database with more data from scientific articles in related fields. Herein, we present an ontology-based Natural Language Processing (NLP) approach to automatically extract and transfer data from text sources to database. This approach combines the use of NLP techniques and a domain ontology to automatically extract environmental exposure and hazards information. This approach was tested to enrich the EXPOSED database and indicators of quality highlight that this approach is effective and promising

Monitoring the Environmental Aging of Nanomaterials: An Opportunity for Mesocosm Testing?

International audienceTraditional aging protocols typically examine only the e↵ects of a limited number of stresses, and relatively harsh conditions may trigger degradation mechanisms that are not observed in actual situations. Environmental aging is, in essence, the complex interaction of multiple mechanical, physicochemical and biological stresses. As yet, there is no (pre)standardized procedure that addresses this issue in a satisfactory manner. Mesocosm experiments can be designed to specifically cover the aging of nanomaterials while characterizing the associated exposure and hazard. The scenario of exposure and the life time of the nanomaterial appear as the predominant factors in the design of the experiment, and appropriate precautions need to be taken. This should the subject of guidance that may be divided into product/application categories. 1. The Importance of the Aging Factor There are still major knowledge gaps in the risk assessment of nanomaterials, especially in the post-production stages of their life cycle. However, in most cases, the use and end-of-life phases are by far the longest periods, and this extended duration is a potential concern with regard to exposure to nanomaterials, as well as associated hazards. Apart from a few exceptions, nanomaterials with the desired properties are not used "as is", but are embedded in the final product after several formulation steps (e.g., encapsulation, attachment/embedding into a matrix, etc.) for targeted functionality, better product safety, or simply ease of use. As a consequence, the pristine/isolated nanoparticle is no longer the only compound that needs to be considered in risk assessment. The nature and the structure of the bearing matrix control the exposure to the nanomaterial and the associated hazard. In other words, the entire nano-enabled product and its evolution with time, i.e., aging, become determining factors in the risk assessment. While a newly manufactured product should not be a concern for the consumer or the environment, aging is likely to change the mobility and the speciation of embedded nanomaterials, and may cause potential adverse e↵ects towards the consumer and/or the environment. As a consequence, attention needs to be paid to the degradation of the matrix, shell(s) and coating(s) surrounding the nanomaterial in order to avoid its release in a form that is, or might become, hazardous. It is noteworthy that understanding the (bio)physicochemical mechanisms of matrix degradation leading to nanomaterial release is challenging and requires the use of powerful characterization tools [1-3]. Therefore, even if release is a direct consequence of the degradation of the matrix, aging is often studied via the quantification of the release with simple metrics

Inorganic manufactured nanoparticles: how their physicochemical properties influence their biological effects in aqueous environments

International audienceAmong all environmental contaminants, those emerging from nanotechnologies constitute one of the most critical challenges for the coming years. The new properties of nanoparticles are at the heart of current scientific advances and the growing interest in harnessing them brings awareness of potential impacts that we cannot ignore. To date, scientists and industrialists have focused on the manufacture of nanomaterials more than on the assessment of the risks for humans and ecosystems. Few databases exist regarding the amounts released within ecosystems and no specific procedure of recycling has yet been established. However, nanoparticles cannot be considered as molecular pollutants or larger particles, and careful consideration is needed to establish a legal system that is specific. Their novel properties, surface energy and reactivity make it impossible to simply transfer our physicochemical, thermodynamic and toxicological knowledge from the micronscale to the nanoscale. This article highlights, nonexhaustively, the strong relationship existing between the unique properties of metallic and metal oxide nanoparticles and their biological effects on aquatic organisms

Multivariate analysis of the exposure and hazard of ceria nanomaterials in indoor aquatic mesocosms

International audienceThe vast diversity of applications using nanomaterials and enhanced physicochemical properties at the nanoscale have raised questions concerning their potential environmental risks. Assessing the risk of nanomaterials in a real ecosystem is extremely challenging because of the system complexity and the relevant environmental doses tested. To provide ultimate interpretations about nanomaterial risk assessment, we combined ceria nanomaterial behavior, fate and impact analysis within indoor aquatic mesocosms with multivariate analysis. Principal Component Analysis (PCA) showed that the exposure scenario to CeO 2 nanoparticles (NPs) constitutes the main parameter to consider while investigating the risk for a given ecosystem. Moreover, following single pulse dosing of CeO 2 NPs, the global response of the pond ecosystem was time dependent. However, multiple dosing contamination failed to significantly perturb the system over time. Finally, the NP surface coating was found to play a secondary role and to affect the global response of the pond ecosystem in the short term only