Bacteria do not like nanoparticles

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Fullerenes (C60) would be a good risk to ecosystems, according to the latest work of a team of Rice University (Texas) and the Georgia Institute of Technology published in Environmental Science & Technology Journal.

These quasi-spherical form of carbon nanoparticles are increasingly used in industry (Frontier Carbon Corporation believes that production should be around 10 tons per year by 2007) and the question of their impact on the environment is debate. With less than a few picograms per liter solubility, fullerenes are generally considered to be poorly soluble in polar solvents like water, so little dangerous. However John Fortner and his colleagues were able to show that under certain conditions depending eg pH, C60 can form colloidal aggregates baptized nano-C60.

These new structures, with a diameter of at 25 500 nm are therefore much more soluble with rates of up to 100 milligrams per liter. Moreover
is, they are perfectly stable for at least 15 weeks in medium ionic strength less than 0,05, which is the case of most natural waters. By studying their effects in solution on two types of prokaryotic (e. Coli and B. subtilis), the researchers found slower growth of bacterial cultures, both in aerobic than anaerobic, for a concentration of nano-C60 over 0,5 parts per million. If these results are confirmed, it would probably, as recommended by the team reviewing pollution standards C60 (currently based on those of graphite) taking into account their possible interaction with the environment.

It should be noted that other teams contest these conclusions.

WP 16 / 05 / 05 (Bacteria and buckyball clumps)


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