Random walk

Last night, I was awaken at 4:30am by an important aspect of research which is actually not enough addressed in the templates of scientific project proposals. For example, I noticed that even Horizon 2020 of the European Union is rather limiting safety issues to ethical issues.

But in the frame of a sustainable research and development of the future technologies, I would be happy in stimulating project leaders to think about safety and environmental aspects of their project, such as generation of ionizing radiation, nanoparticle generation, and toxicity of the materials involved.

Okay, as a theoretician, I'm mostly generating $CO_2$ and $O_3$ with computers, and printing quite much papers... But I wonder how much exposed experimentalists do really protect themselves while irradiating samples with intense laser irradiations, and do project leader always plan the money for buying devices in order to protect experimentalists properly.

For example, laser irradiation can lead to the formation of an oxide layer at the surface of materials, and also lead to the generation of nanoparticles ejected in the medium of irradiation, usually ambient air. By looking a bit to Wikipedia, it rapidly appears that certain oxides made out of even biocompatible materials are actually quite toxic. Of course, nanoparticles are already known to be taken with care for lungs, and studies already underlined this years ago [http://safety.fsu.edu/training/hazwaste/Toxic%20Potential%20of%20Materials%20at%20the%20Nanolevel.pdf].

But now that my eyes are getting open on this question, I think it would be important to maintain a list of toxic materials we use in the field of laser ablation, and how to protect ourselves and others from risks. Here is a first attempt which will be enriched with time.

Personal list of some toxic materials

(sorted by some severity, not exhaustive)

• ZnSe : this material is mostly used in the frame of mobile phones and magnetic materials. It is actually very toxic. https://www3.nd.edu/~exafs/msds/ZnSe.htm
• TiO$_2$: although Ti is a biocompatible material, TiO$_2$ nanoparticle are toxic for cells as it catalyses its destruction. [http://safety.fsu.edu/training/hazwaste/Toxic%20Potential%20of%20Materials%20at%20the%20Nanolevel.pdf] TiO$_2$ is specifically one of the materials which produces a lot of oxide while being irradiated by a laser. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3503962/
• ZnO: vapor emitted from ZnO ablation can be toxic. Risk is summarized here. http://www.inchem.org/documents/icsc/icsc/eics0208.htm.
• Ge: "little oral toxicity" [Wikipedia].
• Si dust may cause lungs problems. [http://www.lenntech.com/periodic/elements/si.htm]
• Au: gold is not toxic in itself, but gold salts can be toxic for kidneys and liver [Wikipedia].