Nanomaterials are small, biologically and environmentally stable and water-soluble, but their long-term environmental impact is not yet known. US researchers created a model food chain using two microscopic water creatures -Tetrahymena pyriformis and its predator Brachionus calyciflorus - to see whether nanoparticles moved up the food chain. They also investigated bioaccumulation (where the amount of a chemical in an organism increases with time) and biomagnification (where a chemical builds up in a predator because of the number of contaminated organisms it has eaten).
The nanomaterials studied – quantum dots - were taken in readily by T. pyriformis, and were transferred intact up the food chain to the B. calyciflorus. This means that aquatic organisms at higher levels in food chains may also be potentially exposed to nanomaterials through their diet. However, the amount transferred was relatively low and they did not accumulate in the B. calyciflorus, which the authors suggest may mean that they do not pose a significant threat in nature.
These findings may be relevant to various policy sectors concerned with the emerging area of nanotechnology, water pollution and ecosystem health. The authors said that while their results suggest that quantum dots may not pose a significant risk of accumulating in aquatic invertebrate food chains, additional research beyond simple laboratory experiments and a more exact means of quantifying transferred nanoparticles in environmental systems are needed to be sure. Another factor in the natural environment will be how other organic particles interact with the nanoparticles.
Nanotechnology is already widespread in the EU. It is expected to have far-reaching effects and help address many problems facing today's society. It is also expected to provide a new competitive edge to European industry and the European economy as a whole, creating many new jobs. Market analysts foresee a world market for nanotechnologies worth Euros 750-2000 billion by 2015. The European Commission supports research into the development of nanoparticles and nanotechnology based products as well as their potential impact on human health and the environment, via toxicological and ecotoxicological studies. Knowledge gaps, such as toxicity thresholds and test schemes, need to be addressed