Nanotechnology risk assessment from a waste management perspective: are the current tools adequate?

The burgeoning nanotechnology industry is rapidly generating new forms of waste streams generically referred herein as nanowastes. However, little is known about the fate and behavior of these waste streams and their impacts thereof in different ecological systems despite their increasingly widespread dispersion into the environment through production, distribution, handling, and nanomaterials (NMs) incorporation into bulk products processes. In this paper, risk assessment of nanotechnology from a waste management perspective was examined to elucidate potential new forms of challenges nanowastes may likely pose to the current legislative and waste management systems. This was through the identification of several knowledge gaps that merit urgent attention in order to increase our collective understanding of managing nanowastes safely, responsibly, and sustainably. The paper presents the identified gaps and consequently proposes a qualitative risk assessment of nanowastes to address some of the current challenges. The applicability of the proposed model is illustrated through several examples. In addition, the first nanowastes classification protocol presented in this article show that a given nanomaterial may result in generating nanowaste streams of different forms with variant hazard levels ranging from benign to extremely being hazardous waste streams - a dramatic phenomenon from the conventional waste streams due to macroscale chemicals. The study shows that it is in the early days to draw broad generic classification of different nanowastes, and each stream may require their risk profile be assessed on a case-by-case basis. We conclude by presenting several recommendations on what needs to be done in dealing with nanowastes as means of avoiding unintended long-term consequences of nanotechnology.