The researchers found that both types of quantum dots were taken in readily by T. pyriformis and that they maintained their fluorescence even after the quantum dot-containing ciliates were ingested by the higher trophic level rotifers. This observation helped establish that the quantum dots were transferred across the food chain as intact nanoparticles and that dietary intake is one way that transfer can occur. The researchers noted that, "Some care should be taken, however, when extrapolating our laboratory-derived results to the natural environment."
"Our findings showed that although trophic transfer of quantum dots did take place in this simple food chain, they did not accumulate in the higher of the two organisms," says lead author David Holbrook. "While this suggests that quantum dots may not pose a significant risk of accumulating in aquatic invertebrate food chains in nature, additional research beyond simple laboratory experiments and a more exact means of quantifying transferred nanoparticles in environmental systems are needed to be certain." ###
* R.D. Holbrook, K.E. Murphy, J.B. Morrow and K.D. Cole. Trophic transfer of nanoparticles in a simplified invertebrate food chain. Nature Nanotechnology, June 2008 (advance online publication).
Contact: Michael E. Newman email@example.com 301-975-3025 National Institute of Standards and Technology (NIST)
Tags: Nano or Nanotechnology and Nanotech