Environmental implications of nanomaterials: the case of silver nanoparticles and the assessment of its environmental toxicity

Description

his seminar is organized within the framework of WATER project.
http://www.water.imm.cnr.it
Speaker:
Enrique Navarro
Pyrenean Institute of Ecology-CSIC, Av. Montañana 1005, Zaragoza 50059, Spain
E-mail: enrique.navarro@ipe.csic.es
 
Abstract:
Developments of nanotechnology are leading to a rapid proliferation of nanomaterials that are likely to become a source of many different engineered nanoparticles (NP) in the environment, where their fate and behavior are largely unknown. The unique properties of ENPs, could potentially lead to unexpected health or environmental hazards. Its nano-size allows these materials to interact at molecular scale with cells, organisms and other compounds present at the environment. Some of these compounds may increase the NPs’ stability and thus its bioavailability, whereas others might foster the aggregation of NPs, thus reducing their bioavailability.
 
Among others, NPs’ effects on photosynthetic organisms may reduce the fixation of CO2; NPs adsorbed or deposited on photosynthetically active surfaces might reduce light availability or gas exchange and thus photosynthesis; NPs present in the atmosphere might increase the nuclei available for raindrop formation, thus altering precipitation; ENPs’ impacts on bacteria, fungi, and other edafic fauna might affect soil respiration, and other soil-texture-related processes such as transport of liquids or gases, also modifying symbiotic relationships. Together, this might lead to impairments in three key services provided by ecosystems, i.e., nutrient cycling, water depuration and biomass production. The study of such complex environmental scenarios here presented, will thus require a pluridisciplinary and collaborative approach including ecotoxicologists, toxicologists, biologists, chemists, biophysicists, analytical researchers, regulatory authorities and, of course, nanotechnologies-related firms.
 
Silver nanoparticles, because their biocide properties, are among the most used nanomaterials in consumer products. Here we are going to explain how to assess their environmental toxicity, using algal cultures, and how to disentangle the toxicity due to the release of ionic silver. It will be also presented how chemically different coatings may modify the toxicity of such nanoparticles.