New research* shows that while engineered nanomaterials can be transferred up the lowest levels of the food chain from single celled organisms to higher multicelled ones, the amount transferred was relatively low and there was no evidence of the nanomaterials concentrating in the higher level organisms. The preliminary results observed by researchers from the National Institute of Standards and Technology (NIST) suggest that the particular nanomaterials studied may not accumulate in invertebrate food chains.
The same properties that make engineered nanoparticles attractive for numerous applicationsbiological and environmental stability, small size, solubility in aqueous solutions and lack of toxicity to whole organismsalso raise concerns about their long-term impact on the environment. NIST researchers wanted to determine if nanoparticles could be passed up a model food chain and if so, did the transfer lead to a significant amount of bioaccumulation (the increase in concentration of a substance in an organism over time) and biomagnification (the progressive buildup of a substance in a predator organism after ingesting contaminated prey).
In their study, the NIST team investigated the dietary accumulation, elimination and toxicity of two types of fluorescent quantum dots using a simple, laboratory-based food chain with two microscopic aquatic organismsTetrahymena pyriformis, a single-celled ciliate protozoan, and the rotifer Brachionus calyciflorus that preys on it. The process of a material crossing different levels of a food chain from prey to predator is called "trophic transfer."
Quantum dots are nanoparticles engineered to fluoresce strongly at specific wavelengths. They are being studied for a variety of uses including easily detectable tags for medical diagnostics and therapies. Their fluorescence was used to detect the presence of quantum dots in the two microorganisms.
The researchers found that bot
|Contact: Michael E. Newman|
National Institute of Standards and Technology (NIST)