Nanotechnology have emerged more than ten years ago in many different applications and scientific domains that share in common the study and the engineering of materials at the nanometric scale, i.e at the molecular and atomic level.
In nanotechnology, a nanoparticle is defined as a small object for which one of its dimension is below 100 nanometers and that exhibit size-related properties that differ significantly from those observed in bulk materials. Nanomaterials generally composed by nanoparticles which contrary to the fine particles stemming from processes of combustions or from natural origin, are made by respecting an order and a precise arrangement of atoms. This ‘order’ is responsible for the new or significantly different properties. Some refers to a Nano effect that has the potential to create many materials or devices in a wide range of applications, such as medicine, electronics and energy production.
In the environmental and energy domain, the enhance reactivity of nanoparticles make then unique and promising candidates to sorb pollutant and to develop new generation of processes. Thanks to their capacity to resist to extreme temperatures as those reached in plasma of nuclear fusion reactors nanomaterials are certainly going to allow significant headways in the field of the fusion (ITER project). The modification of the electronic properties under the influence of light enable the development of photovoltaic systems but also for the treatment of effluents (drinking water, organic effluents, smells treatment…).
Naturally the “nano†breaker brings also a lot of questioning concerning the risks that the proliferation of nanomaterials can pose. With properties that differ from bulk materials, the issue of how the ‘new’ properties of nanoparticles may lead to ‘new’ toxicity is central. Even though information on NPs effects on health and the environment are largely lacking, some properties of nanoparticles and nanomaterials fear possible risks. Their nanometric size may permit intracellular transfer. Their chemical composition may induce pathogen effects. Surface modifications may be engineered to design specific properties for given applications; But these surface modifications can strongly impact their toxic effects or harmlessness. More over biological effects as well as solubility can arise from form factors (fibers, tubes, platelet…). Aggregation is an other property that can strongly modify nanoparticle behavior.
Preliminary risk assessments of manufactured nanoparticles (NPs) are emerging, information on NPs bioavailability to aquatic biota and trophic transfer are largely lacking, and early studies on NPs aquatic toxicity, more observational than mechanistic, have yielded incomplete and contradictory results.