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SUMMARY:Engineered nanoparticles: a new challenge for ecotoxicologists
DTSTART:20090420T161500
DTSTAMP:20260407T115158Z
UID:f65c08c6f7502b8e516db67687e554ced991192c7e605f83f20cdbad
CATEGORIES:Conferences - Seminars
DESCRIPTION:Dr Renata Behra\, Eawag\nEngineered nanoparticles (ENP) are in
 creasingly produced and used for different applications and their entrance
  into aquatic environments is therefore predictable. Following a time of c
 ontroversial debates concerning potential environmental risks\, experiment
 al data on the ecotoxicity of various ENPs are now appearing in the litera
 ture although mechanisms leading to observed biological effects still rema
 in to be elucidated. ENPs might display direct effects through interaction
 s with target molecules leading to alterations of membranes and biochemica
 l processes. Indirect effects of ENPs may include physical restraints (clo
 gging effects)\, solubilization of toxic ENP compounds\, or production of 
 reactive oxygen species leading to oxidative stress. Considering that the 
 fate and bioavailability of ENP will depend on their physico-chemical char
 acteristics and their interaction with the receiving chemical environment\
 , the physico-chemical characterization of experimental ENPs is a prerequi
 site for a proper interpretation of ecotoxicity data. With the objective o
 f gathering scientific information on the ecotoxicity of silver nanopartic
 les (AgNP) we are examining the interactions between AgNPs and the alga Ch
 lamydomonas reinhardtii. AgNPs belong to the most important materials inco
 rporated in consumer products and are widely used because of their toxicit
 y to bacteria. The results indicate that the toxicity of the experimental 
 AgNPs to the photosynthesis of algae is mediated by ionic Ag+ and that Ag+
  is formed upon interaction of the particles with algae. A combination of 
 various microscopic techniques indicates that AgNP are present in algae ce
 lls. Considering that particles might also form upon precipitation of inte
 rnalized ionic silver\, further analyses are required before concluding on
  the uptake of silver nanoparticles in algae.
LOCATION:GR B30
STATUS:CONFIRMED
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