Fate and Ecotoxicity of Nanoparticles in the Environment: Current Status and the Way Forward
Janeck J. Scott-Fordsmand, Aarhus University, Denmark, Monica J.B. Amorim, Universidade de Aveiro, Portugal, Geert Cornelis, University of Gothenburg, Sweden, Koen Oorts, Arche, Belgium and Willie Peijnenburg, RIVM, Netherlands
Nanotechnology is a rapidly evolving technology with the potential to revolutionalise the modern world. Materials may take on entirely new chemical and physical properties at the nanoscale. The novel properties of engineered nanoparticles and nanomaterials (ENP & ENM) are not only reason for enthusiasm, but also a potential cause of human health and environmental hazards beyond that of corresponding materials at larger sizes or dissolved ions. Concern is amongst other reasons raised because of limited knowledge on the environmental characteristics and particle properties that potentially induce adverse effects.
Our understanding of the environmental fate and the ecotoxicity of ENPs has increased over the last decade, but the underlying science can still be considered to be in its infancy. There is, consequently, a lack of scientific support for the regulatory area and for the nanomaterial-producing industry to adopt safe-by-design strategies.
Most research, including several major EU framework six and seven projects, has focused on the impacts of nano-specific properties (particularly size) on fate and effects in aquatic environments driven by development of characterization methods for ENPs in aquatic media. Much less information is available for solid media such as soils, sediments and landfills, compartments that can be considered as sinks for ENPs. The available pool of methods for characterising ENP fate and effects in solid media is much more limited and often based on indirect measurements that are very susceptible to artefacts. There is currently no consensus on how scientifically sound estimates can be obtained. The development of robust and reproducible methods to assess the fate and ecotoxicity of ENPs in the environment is critical if we are to predict accurately the risks to the environment at the species, community and ecosystem level.
The 7th SETAC Europe Special Science Symposium brought together different stakeholders to discuss current and future research needs, addressing the potential of ENPs to bioaccumulate and to reach concentrations of concern in terms of environmental exposure, and to formulate approaches to integrate this knowledge into regulatory risk assessment. The scope was to produce a framework for prioritising future research within this area.
During the symposium, an overview of the state of the art was discussed and future directions in the area were pointed out. There were three interrelated themes: 1) measurement methods, 2) exposure estimation and 3) effect verification. There were 12 oral presentations and 15 posters, flanked by 2 breakout sessions. The speakers were Janeck J. Scott-Fordsmand, Bernd Nowack, Geert Cornelis, Frank von der Kammer, Willie Peijnenburg, Mónica JB Amorim, Teresa Fernandes, Robert F. Landsiedel, David Carlander, Koen Oorts, Tom van Teunenbroek (represented by Willlie Peijnenburg) and Jukka Ahtiainen. The chairs and speakers represented key persons in academic research, regulatory agencies and industry. There were 56 attendees from 17 countries representing business (33%), government (11%) and academia (56%).
A summary of the key issues covered by the speakers and during the panel discussions is presented below, reporting the critical knowledge gaps and research needs.
The first block of presentations discussed the state of the art of measurement, fate and effect methods for ENPs. It started with an overview of how novel probabilistic models can be used to estimate the environmental distribution of ENPs. These models can identify the likely environments in which nanoparticles accumulate and predict concentrations. However, there are currently very few methods available that allow the measurement of nanoparticles in solid media and hence experimental validation of the predicted environmental concentrations in these media. In this respect, the succeeding presentation highlighted the state of art in regard to methods for measuring nanoparticles in the solid media. The increased focus on measurement methods has enhanced the development of novel quantitative methods, but there is still a long way to go before routine measurement methods of ENPs in complex media are widely available. The following section focused on the possible effects of ENPs on environmental organisms, describing effects on plants and animals. The presentations showed that ENPs cause effects on a wide range of organisms, although relatively few materials have been tested. An observation is that ENPs cause sometimes similar effects as other stressors, e.g., oxidative stress in organisms, although in a different way than the respective non-nano–sized chemicals. Research shows that the use of high throughput tools integrated with various effect-level endpoints is the way forward to identify ENP-specific responses and hence aid prediction and risk assessment.
In a second block of presentations, the approaches, concerns and requirements that industry has in relation to the risk assessment and use of ENPs were outlined. The examples given show how industry is working on various ranking approaches that can handle the potential risk, and that there is a requirement to make a paradigm on how to deal with dissolvable ENPs. It was further highlighted that globally harmonized approaches are important, e.g., for quality and relevance-screening of available data and for predicting the environmental fate of ENPs. Approaches that focus on relevant materials and include tiered assessment are important, too.
The final presentations covered regulatory issues, for example, highlighting the requirement for sample preparation guidance and the need for valid guideline descriptions that fulfill mutual acceptance principles. It was outlined how some of these current regulatory concerns are covered in the new large European project NanoReg.
Finally, the discussions in the breakout sessions were merged into a closing plenary session. The major themes and highlights will be published in the open literature.
The 7th SETAC Europe Special Science Symposium was co-organised by the project MARINA (EU, FP7-263215) and supported by Arche.
Authors' contact information: email@example.com; firstname.lastname@example.org; email@example.com; firstname.lastname@example.org; Willie.Peijnenburg@rivm.nl
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