Carbon Nanoparticles Toxic to Adult Fruit Flies, but Benign to Larvae Identified

by Rajashri on Aug 11 2009 8:22 PM

Certain types of carbon nanoparticles that can prove environmentally toxic to adults, but which are benign when added to food for larvae have been identified in experiments on fruit flies conducted by Brown University researchers.

Writing about their work in the online edition of the journal Environmental Science and Technology, the researchers say that their findings may further reveal the environmental and health dangers of carbon nanoparticles.

The findings attain significance because carbon nanoparticles are widely used in medicine, electronics, optics, materials science, and architecture, but their health and environmental impact is not fully understood.

During the study, the researchers observed that adult flies immersed in tiny pits containing two varieties of carbon nanoparticles died within hours.

Upon analysing the dead flies, the researchers found that the carbon nanoparticles had stuck to their bodies, covered their breathing holes, and coated their compound eyes.

Scientists are unsure whether any of these afflictions led directly to the flies' death.

Conducting another experiment, the researchers showed that adult flies transported carbon nanoparticles, and then deposited them elsewhere when they groomed themselves.

David Rand, a professor of Biology who specializes in fruit fly evolution, says that the findings help to show the risks of carbon nanoparticles in the environment.

He says that the point is that the same compounds that were not toxic to the (fruit fly) larvae were toxic to the adults in some cases, so there may be analogies to other toxic effects from fine particles.

Rand and Robert Hurt, director of Brown's Institute for Molecular and Nanoscale Innovation and the other corresponding author, said that the findings were important because they show that permutations of the same material could have different effects in the environment.

The researchers now have several related experiments in the works, and they plan to test fruit flies' responses to nanosilver and other nanomaterials with different chemistries, and they will investigate why the adult Drosophila died from varieties of the carbon nanoparticles.