Nanotechnologies and water

Manufactured nanoparticles and water

Materials made up of nanometric particles, i.e. particles that are a billionth of a metre in size, sometimes turn out to have new and/or more powerful properties compared with conventional materials.
The development of nanotechnologies, which particularly involves controlling the manufacture of nanometric particles, therefore offers new technical possibilities, thereby explaining the growing interest that sectors from the automotive industry to medicine have in them. Water treatment is one of the fields where nanoparticles and nanomaterials are expected to be used.

Nanotechnologies and water

The Agency was solicited by the Directorate General for Health to review knowledge on nanotechnologies in the field of water for human consumption. It was particularly asked to identify the products concerned in this field, to quantify their use and to conduct a risk/benefit assessment of the use of such products. In response, the Agency conducted an expert appraisal on the basis of a bibliographical search, and heard specialist researchers of nanotechnologies and manufacturers in the water sector, who are potential users of these technologies. The two objectives of this work were to list drinking water treatments through the use of manufactured nanoparticles and to determine the capacities of these nanoparticles to persist in the environment and in drinking water sectors.
This work has produced a review of available knowledge and research projects under way in this field. It has also enabled recommendations to be drawn up on the marketing of products from the nanotechnology field and on the research that needs conducting to complete the knowledge required to carry out a more comprehensive health risk assessment.

Most applications are still at the research stage
According to the information gathered, it appears that the marketed water treatment processes using nanoparticles are very limited (five companies have been identified, including the Indian market of nanoparticles for domestic use announced on a website). No procedure using nanoparticles has been placed on the French market. However, much scientific work is being carried out in this field and most developments concerning water treatment are currently at the research stage.

A major research need
At present, there is no routine method for measuring nanoparticles in a soil or water sample. Accordingly, few data are available on the presence of nanoparticles in these two matrices, and knowledge on the fate of nanoparticles in the environment is therefore limited. For the same reasons, it is also difficult to study the effectiveness of current drinking and waste water treatments to eliminate nanoparticles, and it is subsequently hard to estimate population exposure to such particles through water.
One of the prerequisites to the improvement of knowledge needed to assess the risks of nanoparticle presence in water is therefore the development of data acquisition tools.

Afssa's recommendations

Given this context, the Agency stresses the need to set up a system for listing and controlling the marketing of all products containing nanoparticles.

Given the still fragmented knowledge on the fate of free nanoparticles in porous environments, Afssa also recommends setting measures guaranteeing the absence of any nanoparticle use by direct injection into ground water.
Finally, in order to complete the information available, the Agency suggests several research areas:
· Develop analytical tools for measuring nanoparticles in water
· Study their fate in different sections of the environment
· Assess the effectiveness of conventional treatment sectors used to produce drinking water and treat waste water
· Based on the knowledge acquired on the fate of nanoparticles in the environment, assess the means of entering the food chain via water

June 2008