Nanomaterials and definition; Implications for risk assessment, - PowerPoint PPT Presentation

Nanomaterials and definition; Implications for risk assessment, regulation and the need for reference materials Dr Laura-Jayne Ellis L.a.ellis@bham.ac.uk University of Birmingham SCLF Conference: Advances in Land Contamination Assessment and Remediation Wednesday 7 th September

Structure  What are nanomaterials  EU Definition  Problems with the current definition  What are the risks (environmental contaminant)  Need for reference materials  Research at the University of Birmingham

What are Nanoparticles? EU Definition A natural, incidental or manufactured material containing particles, in an unbound state or as an aggregate or as an agglomerate and where, for 50 % or more of the particles in the number size distribution, one or more external dimensions is in the size range 1 nm - 100 nm. In specific cases and where warranted by concerns for the environment, health, safety or competitiveness the number size distribution threshold of 50 % may be replaced by a threshold between 1 and 50 %.

What are Nanoparticles? Types  Natural NPs : present in all compartments of the Earth including the hydrosphere, geosphere and atmosphere. Produced via volcanic eruptions, biological degradation, pollination, natural  weathering, and erosion.  Incidental NPs: by-products (waste) of industrial processes. Accidently released into the environment during manufacturing, mining processes and other anthropogenic activities.  examples are soot, exhaust fumes, wear of tyres, catalytic converters and fine particulates produced from combustion products  Manufactured NPs: purposefully produced and are specifically designed to carry a precise function uniform in size and shape and have surface coatings. 

What are Nanoparticles? Comparison by size a) Sewing needle head b) Human hair c) Section of a cell d) Bacteria cell e) Clump of viruses f) Macromolecules g) A single atom

Problems with the current definition  Insufficient legislation and understanding of nano-specific behavior  Lack of a standard definition for the term nanomaterial  A ‘one size fits all’ covering all general contaminants, fails to cover all the potential risks when materials are presented in the nanoscale  Definition avoids the important issues that engineered nanomaterials behave significantly different to natural and incidental nanomaterials due to their design in functionality  Nanotoxicological studies present findings from an array of exposures to specific size dependent toxic responses  Other studies may report on exposure to a boarder size fraction of particles  Often producing conflicting data when interpreting the risk and exposures

Problems with the current definition: How regulators address the problem  Generally, regulators categorize the associated risks with nanomaterials (NMs) under existing frameworks  The EU and the International Organization for Standardization (ISO) are the only jurisdictions to currently define NMs by a number size distribution

What are the risks?  Evidence suggest that NM properties differ considerably from the bulk material  The phenomena of NMs are derived from size and specific surface area: electronic spatial constraints and increased chemical reactivity  Smaller particles (>30 nm) are thermodynamically unstable and the confinement of electrons cause changes in the surface atoms leading to interfacial reactivity  These properties are exploited for consumer uses.

What are the risks? Toxicology issues  Depending on surface chemistry and reactivity, NPs have been demonstrated to interact with biological tissues  bioaccumulation leading to internalized toxicity

What are the risks? Increased use of Nanomaterials worldwide http://www.nanotechproject.org/cpi

What are the risks? Nano-Enabled Products From the 1628 nano-enabled products in 2013, 383 products that claim to contain nano- silver and 179 products contained titanium dioxide particles. Nano-Silver (Ag) Nano-Titanium Dioxide (TiO 2 )

Why is this a problem?  Measurements of environmental concentrations of NPs, and releases of NPs from consumer products are mostly absent in the available literature (Gottschalk et al, 2009).  The lack of information is mainly because funded research has concentrated its efforts on human health implications that NPs directly may impose, rather than environmental (Nowack and Bucheli, 2007). The potential implications for exposure will be to a number of  aquatic and terrestrial organisms, including bacteria (Wigginton et al, 2010). Silver can be released either as a nanoparticle, colloidal  aggregate or as a silver ion. How these transform in the environment is still uncertain…

What are the risks: Source-Pathway-Receptor =Risk/Hazard? Sources and flow of nanomaterials in the environment Batley et al , 2013

Sources and impacts from environmental releases of nanomaterials: risk assessment frame works Nowack et al , (2012)

Provide Environmental Health Risk Assessments Handy and Shaw (2007)

Prevent and Develop Response Strategies: Establish the problem Measurements of environmental concentrations of NPs, and releases of NPs from consumer  products are mostly absent in the available literature (Gottschalk et al, 2009).  The lack of information is mainly because funded research has concentrated its efforts on human health implications that NPs directly may impose, rather than environmental (Nowack and Bucheli, 2007). The potential implications for exposure will be to a number of aquatic and terrestrial  organisms, including bacteria , finally humans (Wigginton et al, 2010). Silver can be released either as a nanoparticle, colloidal aggregate or as a silver ion. How  these transform in the environment is still uncertain…  Increased use/releases of titanium dioxide- particularly from sunscreens.  Develop models

Research at the University of Birmingham  Provide a facility for environmental nanoscience analysis and characterisation (FENAC)  Public health impacts of environmental hazards of nanomaterial releases  Research: source-pathway-receptor =Risk/Hazard?  Provide public, environmental health and eco-toxicology risk assessments  Prevent and develop response strategies  Research provides information for regulators

Our research Facility: FENAC  FENAC underpins research on nanomaterial properties & behaviour, along with investigations of other types of nano- objects including incidental (combustion, industry etc) & natural (microbial, weathering etc).  FENAC provides access & sample analysis, acting in a fully collaborative manner with users, providing support through the whole process from experimental design to data analysis.  FENAC also provides training for DRs & PDRs during the sample and data analysis period and, more formally through summer schools.

Our research Facility: FENAC  Funded by the Natural Environment Research Council (NERC) in the UK  Research access by competitive applications  Commercial access charged for time and usage  Supports researcher work to help Understand the biological and environmental impacts of nanomaterials within the UK  Multi-method characterisation of nanoparticles  Support with experiment design

Mul -method� characterisa on� at� � FENAC� University� of� Birmingham� TEM� � (+� EDS,� EELS )� FFF� SEM,� � DLS� ESEM� Zeta� poten al AFM� NTA� XRD� ICP-MS�

Publications & citations

Reference materials: Labelled nanoparticles  Environmental sampling can be challenging, particularly when identifying inorganic nanomaterials from background concentrations.  Increase method robustness and traceability of characterisation/quantification  Serve as internal standards to track the extraction efficiency from complex matrices

Examples of labelled materials Commercial TiO 2 used in Sunscreens Synthesised labelled materials 1 0 0 n m 1 0 0 n m 1 0 0 n m 1 0 0 n m

Acknowledgements  Professor Eva Valsami-Jones  Professor Iseult Lynch  Dr Christine Elgy FENAC Manager