The study discusses engineered nanoparticles (ENPs), a diverse class of nanoscale particles that do not occur in nature, including nanotubes, metal oxides and quantum dots (a type of semiconductor, used in solar cells and transistors, among other applications). Although certain industrial uses of ENPs are covered under existing regulation, there are currently no specific regulations designed for these materials, in the EU or elsewhere. This is due to a lack of information on the behaviour of ENPs in environmental systems. For example, how do nanoparticles undergo degradation or accumulate in the environment? Are they hazardous to aquatic organisms?
In addressing this problem, the researchers, based in the UK and Sweden, consider a range of different methods for characterising and detecting ENPs in environmental systems. Since ecotoxicity depends on a number of different properties, including size, shape and structure, it is important to understand the exact properties of nanoparticles under scrutiny. Crucially, changes to any of these properties can change the environmental behaviour of nanoparticles and this must be taken into account when assessing the risk associated with each type of ENP.
The sheer range and diversity of ENPs, means that no single method can be used for detecting and quantifying such particles. For instance, microscope-based approaches might be suitable for detecting ENPs in water, while combinations of fractionation (separation) methods with sophisticated analytical techniques, such as mass spectrometry, will need to be employed for systems including sludge, soils and sediments.
The researchers call for environmental testing standards to be agreed that will allow for better comparison and interpretation of data from different studies. This science is in its infancy and requires the cooperation of researchers from many different fields, as well as collaboration between industry and academia. They also highlight the need for transparency when publishing applied methods for the analysis of nanoparticles.
In 2005, the European Commission adopted its Nanosciences and Nanotechnologies action plan to 'boost support' for research into the potential impact of engineered nanoparticles on human health and the environment1. This action plan is scheduled to end in 2009. However, continued efforts to ensure that effects on the environment are properly understood are clearly needed.