What are the potential new types of challenges nanowastes may pose to current legislative and waste management systems?

The current legislative frameworks for any country worldwide do not take into account nanowastes. Each waste stream type needs a regulatory framework including nanowastes. When it comes to the management, for example, of landfills, the issue is that landfills may leach out nanomaterials into the environment as they were not designed to handle such waste streams. Secondly, wastewater treatment plants may allow some nanomaterials to pass untreated. Thirdly, nanomaterials in wastewater systems may potentially adversely affect bacteria communities used in wastewater treatment. Current scientific data suggest that some bacteria types are adversely affected by nanomaterials in wastewater treatment plants. Some are likely to be killed while viability of others may be compromised which ultimately affects the efficacy of wastewater treatment plants. This was never anticipated at the advent of nanotechnology.

A product containing nanomaterials may generate nanowaste streams of different forms with variant hazard levels. Can you give an example?

In many sunscreens different types of nanomaterials are used such as TiO2, ZnO and fullerenes. Each nanomaterial has different toxicity profile. When we shower those materials are released as effluent nanowastes into the wastewater plants. Fullerenes have been shown to be highly toxic while TiO2 has low toxicity. The same type of nanoproduct can therefore have different risk profiles due to different types of nanomaterials used.

What is the most surprising result you have got?

Besides the same type of nanoproduct having different risk profiles because of different types of nanomaterials used, I didn’t see any waste handling company worldwide which is actively trying to understand nanowaste streams. There are very few scientific papers in this research field. Universally there is lack of agreed classification of nanowastes. To protect our environment we need to understand nanotechnology risks because today’s nanoproducts will be tomorrow’s waste streams. We are firmly living in the nanotechnology age. We cannot go back so we need to learn how to deal with nanowaste streams adequately.

What is the next step in your research?

We did qualitative work in this paper, and now we are looking at existing data and developing quantitative models to increase our collective understanding of nanowastes. In addition, we will mimic a wastewater treatment system for nanomaterials in our lab. By labeling the nanomaterials, for example, with radioactive elements, we’ll try to understand what’s happening. Today it’s very challenging to detect nanomaterials in the environment as we lack proper tools; however, we have to begin somewhere.

What needs to be done in dealing with nanowastes to avoid unintended long-term consequences of nanotechnology?

The industry, governments and scientific community needs to form partnerships to find ways of dealing with nanowastes such as developing the equipment and governance framework needed. So that we won’t say 10 or 20 years down the line, woops, that should have been done ages ago!