BackgroundThe use of gold nanoparticles (Au-NP) based medical applications is rising due to their unique physical and chemical properties. Diagnostic devices based on Au-NP are already available in the market or are in clinical trials and Au-NP based therapeutics and theranostics (combined diagnostic and treatment modality) are in the research and development phase. Currently, no information on Au-NP consumption, material flows to and concentrations in the environment are available. Therefore, we estimated prospective maximal consumption of Au-NP from medical applications in the UK and US. We then modelled the Au-NP flows post-use and predicted their environmental concentrations. Furthermore, we assessed the environment risks of Au-NP by comparing the predicted environmental concentrations (PECs) with ecological threshold (PNEC) values.ResultsThe mean annual estimated consumption of Au-NP from medical applications is 540 kg for the UK and 2700 kg for the US. Among the modelled concentrations of Au-NP in environmental compartments, the mean annual PEC of Au-NP in sludge for both the UK and US was estimated at 124 and 145 μg kg−1, respectively. The mean PEC in surface water was estimated at 468 and 4.7 pg L−1, respectively for the UK and US. The NOEC value for the water compartment ranged from 0.12 up to 26,800 μg L−1, with most values in the range of 1000 μg L−1.ConclusionThe results using the current set of data indicate that the environmental risk from Au-NP used in nanomedicine in surface waters and from agricultural use of biosolids is minimal in the near future, especially because we have used a worst-case use assessment. More Au-NP toxicity studies are needed for the soil compartment.Electronic supplementary materialThe online version of this article (doi:10.1186/s12951-015-0150-0) contains supplementary material, which is available to authorized users.

The application of nanotechnology and nanoscience for medical purposes is anticipated to make significant contributions to enhance human health in the coming decades. However, the possible future mass production and use of these medical innovations exhibiting novel and multifunctional properties will very likely lead to discharges into the environment giving rise to potentially new environmental hazards and risks. To date, the sources, the release form and environmental fate and exposure of nano-enabled medical products have not been investigated and little or no data exists, although there are a small number of currently approved medical applications and a number in clinical trials. This paper discusses the current technological and regulatory landscape and potential hazards and risks to the environment of nano-enabled medical products, data gaps and gives tentative suggestions relating to possible environmental hotspots.

In the next couple of decades, nanotechnology-enabled healthcare applications will significantly influence the diagnosis, prevention and treatment of human diseases. Since pharmaceutical products (PPs) have been detected in various environmental compartments, and low-level chronic exposure to PPs has induced adverse and sometimes unexpected effects on non-target organisms, the question of potential environmental risks from increased usage of nanomedical products arises. The risks and benefits to patients from nanomedicines are the focus of exhaustive evaluation by regulatory agencies; by contrast, risks to the environment from nanomedicines are only briefly considered by regulators and are rarely discussed by nanoscientists. To start to fill this gap, 66 experts from nanomedicine R&D, representatives of research funding agencies and of institutions involved in safeguarding public health and the environment were interviewed using a semi-structured questionnaire regarding possible hazards and risks from nanomedicine and on the adequacy of current the environmental risk assessment (ERA) framework for medicines. The interview recordings were transcribed verbatim and analysed via qualitative content analysis. Experts interviewed commented that hazards were possible but risks were unlikely from nanomedicines due to expected minimal exposure. They qualified their statements by comparing risks from nanomedicine with risks from nanomaterials in other industries, conventional pollutants and larger global issues like climate change. Regarding adequacy of the current risk framework for assessment of environmental risks from nanomedicines, perceptions of experts were more varied; some argued that complete overhaul of the ERA framework was required including changes in toxicity endpoints, whereas others suggested that the framework was adequate, though some adjustments were needed.

Significant advances have been made in the development of Adverse Outcome Pathways (AOPs) over the last decade, mainly focused on the toxicity mechanisms of chemicals. These AOPs, although relevant to manufactured nanomaterials (MNs), do not currently capture the reported roles of size-associated properties of MNs on toxicity. Moreover, some AOs of relevance to airborne exposures to MNs such as lung inflammation and fibrosis shown in animal studies may not be targeted in routine regulatory decision making. The primary objective of the present study was to establish an approach to advance the development of AOPs of relevance to MNs using existing, publicly available, nanotoxicology literature. A systematic methodology was created for curating, organizing and applying the available literature for identifying key events (KEs). Using a case study approach, the study applied the available literature to build the biological plausibility for 'tissue injury', a KE of regulatory relevance to MNs. The results of the analysis reveal the various endpoints, assays and specific biological markers used for assessing and reporting tissue CONTACT Jo Anne Shatkin