Joined: 16 Mar 2004
|Posted: Thu Jan 08, 2009 2:46 pm Post subject: Scientists Find Nanoparticles Affect Pollutant Toxicity
|Danish Scientists Find Nanoparticles Affect Pollutant Toxicity
Organic (carbon-based) chemicals are known to have an effect on the toxicity of pollutants to plant and animal life. But nanoparticles like C60 have unique and altered properties compared to larger particles, and so they may have a very different effect on the toxicity and availability of pollutant molecules. The nanoparticles themselves may also be inherently toxic.
Researchers from the Technical University of Denmark and the University of Copenhagen, Denmark tested the effect of four common pollutant chemicals: atrazine, methyl parathion, pentachlorophenol (PCP) and phenanthrene on green algae and freshwater crustaceans ("Toxicity and bioaccumulation of xenobiotic organic compounds in the presence of aqueous suspensions of aggregates of nano-C 60").
The researchers found that when C60 nanoparticles were present, they affected the availability of the toxic chemicals to the organisms. C60 made phenanthrene more toxic to algae at lower concentrations, for instance, but made it less toxic to the crustaceans. C60 made PCP less toxic to both algae and crustaceans. The C60 had little effect on the toxicity of the other two pollutants tested.
Nanoparticles also affected how quickly and how much of the pollutant was taken in by the organisms. Clumps of the C60 itself also stuck to the crustaceans’ bodies and inside their digestive systems.
The authors recommend that nanoparticle risk assessment take into account not just the toxicity of the particles themselves, but also the possible interaction with other environmental contaminants. They also suggest that further research into the effects of nanoparticles’ different phases (in particular their behaviour in water as they form suspensions or clumps of molecules know as aggregates) is also relevant to their potential toxicity in the aquatic environment.