The Engineered Nanomaterial (ENM) industry is developing rapidly worldwide, bringing with it an expected increasing presence of ENMs in municipal wastewaters and ultimately, community water sources and supplies, over time. Happening in parallel, there is an increasing integration of the water cycle to help optimize use of our precious water resource – an integration that may increase exposure to ENMs. Given their increasing prevalence, what are the exposure pathways and public health risks posed by these ENMs? Can our water utilities really say we need not fear ENMs in our water supplies? How safe is the water we drink?
The Issue
The use of ENMs in the areas of electronics, energy, cosmetics, medical, defence as well as food and agriculture is increasing. It has been estimated that the global nanotechnology industry will grow to ~US$76 Billion by 2020.[i] ENMs range in size from 1 nm (0.001 micron) to 100 nm, with the majority being in the 1-10 nm range.[ii] The most extensively studied nanomaterials include nanoparticles of silver metal followed by zinc oxide, titanium oxide, cerium dioxide, silicon dioxide and carbon nanotubes. In short, these materials have found a use in almost every aspect of manufacture and their prevalence is increasing.
Why should we care?
Ingestion of ENMs through drinking water exposure could have adverse health effects such as elevated metal concentrations in livers, kidneys, brain and blood as shown by in vivo animal studies with rats and mice.[iii] Inhalation of aerosols is also another exposure route through which small particles can gain entry to the body, via the lungs, and then into the blood stream and vital organs. Research work in the US, Australia, Singapore and China has shown that ENMs are now present in the environment and that they can also be present in drinking water, even after using established treatment processes.i [iv] What we can say about ENMs therefore, is:
- They could have adverse health effects.
- Established drinking water treatment processes may be ineffective in removing ENMs to levels that pose little or tolerable risk.
- Ingestion and inhalation of drinking water may provide an exposure route.
We know enough to be concerned.
What can we learn?
There are many examples in past and recent history involving environmental and waterborne contamination incidents. In Australia, we are currently riding an emerging discovery wave of contamination from per- and poly-fluoroalkylated substances (PFAS). These chemicals were used in firefighting foams and have found their way into many ground and surface water sources, potentially rendering them unusable for human consumption, disrupting communities, decimating local economies, causing ripples of liability and imposing huge costs:
“PFAS bombshell as barramundi test positive for elevated chemical levels in Katherine waterways”
“Williamtown PFAS contamination red zone expands 50 per cent on expert panel advice”
“PFAS contamination: Katherine mango farmer seeks compensation from Defence”
It takes more time, effort and money to clean up (if indeed it is possible) our water sources than it does to protect them in the first place. It would seem prudent to learn from our past mistakes and take a diligent approach to understanding and managing the potential risks from ENMs – before the horse has bolted. Surely a precautionary approach should be applied, as our risk frameworks tell us?
What next?
Research is being carried out into ENMs in many countries of the world but with little focus on the actual needs of the water industry, particularly in terms of removal through the technologies commonly used in conventional water treatment plants as well as those used in advanced water recycling schemes. So, is our drinking water safe from ENM risks? At this point in time, the jury is not only out, it still does not have enough firm evidence on which to deliberate.
What is needed is a carefully structured, multi-disciplinary, multi-stakeholder research focus that addresses the risks posed by ENMs in our drinking water supplies. The research scope must be clearly set out not only by academics but also by water practitioners and regulators who have a vested interest in the production of a safe and wholesome water supply. We should not let ENMs become another PFAS.
Bio’s
Annette is a highly experienced certified auditor and award-winning risk manager in the water, environment, policy and mining fields. She has helped utilities implement water safety and risk management plans both in Australia and overseas. She has a multitude of journal, book chapter, books, technical papers, reports and other publications in several fields including bioremediation, biodiversity, microbial ecology, water utility due diligence and risk management. Annette is in demand as a conference and workshop presenter, for auditing of statutory and certified risk management plans, for developing utility risk management plans, ERM consultation and development and as a facilitator for board workshops.
M: 0411 049 544
A: PO Box 268 Killara NSW 2071 Australia
E: annette@riskedge.com.au
W: riskedge.com.au
Twitter: @AnnetteDavison
LinkedIn: linkedin.com/in/annettedavison
Skype: annettedavison
Ian Law is a Chemical Engineer with a Masters Degree in Public Health Engineering obtained from the University of Cape Town in South Africa in 1974 and is an Adjunct Professor at the University of Queensland. He runs his own business, IBL Solutions and has more than 30 years of experience in advanced treatment and reuse projects in Southern Africa, S E Asia and Australia.
He has published widely on the application of advanced reuse systems and the need to apply the concept of Total Water Management to all future water resource and wastewater planning and is actively promoting this concept in Australia.
[i] Research & Markets (2015). Global Nanotechnology Market Outlook 2020. June 12.
[ii] Eduok, S., Hendry, C., Ferguson, R., Martin, B., Villa, R., Jefferson, B. and Coulon, F. (2015). Insights into the Effect of Mixed Engineered Nanoparticles on Activated Sludge Performance. FEMS Microbiology Ecology. Jul; 91(7): fiv082. Published online 2015 Aug 4. doi: 10.1093/femsec/fiv082.
[iii] Chalew, T., Ajmani, G., Huang, H. and Schwab, K (2013). Evaluating Nanoparticle Breakthrough during Drinking Water Treatment. Environmental Health Perspectives. Oct 1; 121(10): 1161–1166. Published online 2013 Aug 9. doi: 10.1289/ehp.1306574.
[iv] Hou, L., Li, K., Ding, Y., Li, Y., Chen, J., Wu, X. and Li, X. (2012). Removal of Silver Nanoparticles in Simulated Wastewater Treatment Processes and its Impact on COD and NH4 Reduction. Chemosphere. 87 248-252.