Current limitations to chemical management in Australia include:

• Lack of lifecycle accountability from producers/importers
• Limited financial incentive to change how chemicals are managed and lack of incentive for evolution of the system
• Limited regulatory oversight and lack of resources to manage chemical manufacture and usage
• Considerable research gaps in our understanding of the behaviour of some chemicals or chemical groups in the environment

Forever Chemicals:
The emergence of per- and poly-fluoroalkyl substances (PFAS) as a group of chemicals that are highly mobile and persistent in the environment, with no natural mechanism via which full breakdown occurs, led them to be labelled as ‘forever chemicals’. Before forever chemicals, we were focused on ‘persistent organic pollutants’ (or POPs) as a group of chemicals that adversely affect human health and the environment around the world (USEPA, 2009). It has long been understood that human-made (synthetic) persistent chemicals are being used and released to the environment in ways that pose a risk to the natural environment. The publication of Silent Spring in 1962 highlighted the damage that pesticides (with a strong focus on DDT) and other human-made chemicals can do to the environment. In Silent Spring (1962), Rachael Carson stated that:

“For the first time in the history of the world, every human being is now subjected to contact with dangerous chemicals, from the moment of conception until death.’

Yet the production, use and environmental release of synthetic chemicals has only continued to increase since that time.

The research being conducted by scientists affiliated with the Stockholm Resilience Centre indicates that there are a range of global persistent pollutants that are being detected in the environment from the Artic to the Antarctic, with overwhelming evidence of negative impacts on Earth systems, including impacts to biodiversity and biogeochemical cycles (Persson et al., 2022). This sentiment is also supported by the work being conducted by the UNEP and highlights the need for governments to implement policies that will support a change in the way we produce and use chemicals and the way we manage chemical waste.

Environmental Releases:

In 2013, it was estimated that of the 4.9 million metric tonnes of industrial chemicals released to the environment in North America (Canada, Mexico, and the United States), close to 2 million metric tonnes consisted of persistent, bioaccumulative, and toxic chemicals, while a further million metric tonnes of chemicals with links to cancer effects were also released to the environment (UNEP, 2013).

The ways in which we use chemicals and their physical-chemical properties influence the potential for these chemicals to be released and transported through the environment. Some of the key environmental release mechanisms for industrial chemicals include:

• Disposal of waste chemicals to landfill or release to sewer via a trade waste agreement by chemical manufacturers or industrial facilities.
• Use of chemicals during manufacturing processes in such a way that they are released during wastewater disposal to sewer or stormwater.
• Leaching of chemicals from consumer products during laundering or washing.
• Release of chemicals from personal care products to sewer or stormwater, or direct to waterways during recreational activities.
• Leaching of chemicals from food packaging into food followed by human consumption and release to sewer.

Our current wastewater treatment technologies are not effective at destroying persistent synthetic chemicals, and so when they are directly released to sewer, stormwater, or wastewater systems they will ultimately be discharged to the environment either directly to surface water or through application of recycled water or biosolids to land. For persistent or ‘forever’ chemicals this will either mean:

• They sorb to soil, sediments, or biosolids which may limit long-range transport in the environment (Ockende et al., 2003) but may result in bioaccumulation in terrestrial food chains and/or
• They remain in dissolved form and become part of a global melting pot of chemicals that cycle around the planet where they may bioaccumulate into the aquatic food chain.

So which outcome is better?

Given the choices, and the seeming inevitability of environmental release, is it better for forever chemicals to be sorbed to solid environmental media (soil, sediment, or biosolids) or to be more mobile (but maybe more dilute) in the liquid phase?

Solid phase storage - If they remain sorbed to soils, sediments, or biosolids, and bound in place for long periods of time, we may have more ability to prevent them from being released more widely to the environment and thus reduce environmental exposures. We may also have greater ability to remediate these media or to destroy the chemicals altogether. But there are short-term environmental risks associated with storing impacted soil, sediments, or biosolids, for example:

• Climate change is resulting in more frequent flooding and large storm events. Storing and managing impacted soils or sediments and preventing them from entering the aquatic environment in these conditions may be problematic.
• Bioaccumulative forever chemicals may enter the terrestrial food chain and so will cycle through the environment.
• This option would require the space to manage impacted solids, but would become inviable if transportation over long distances was required to enable storage or management.

Liquid phase release - Releasing forever chemicals dissolved in treated wastewater to the aquatic environment at low concentrations means that risks to the local environment may be low at the time of release, but the persistence of these chemicals means that on a global scale we are slowly increasing the mass of forever chemicals. So, at some point, we may reach global scale concentrations that pose increasing risks to human health and the environment.

From a wastewater management perspective, currently, we are generally using a combination of the above options, with treated wastewater commonly discharged directly to surface water (or reused via recycled water schemes) and solid phase (biosolids) waste products applied to land. Both of these options are presently resulting in the release of low concentrations of forever chemicals either directly to waterways and oceans or to land with potential for runoff to waterways and the ocean. The growing concern over land application of biosolids containing forever chemicals (including plastics) and the implications of buildup of these contaminants in soil over time are resulting in a need to re-evaluate the long-term viability of this practice.

What’s the Least Worst Place for Forever Chemicals?

Knowing what we do now, but not yet having all the tools in place to adequately assess or manage the risks associated with releases of persistent synthetic chemicals to the environment, what should we be doing differently to support our ability to tackle this problem in the future?

The scientists affiliated with the Stockholm Resilience Centre believe that a circular economy is key to tackling this problem, so that instead of creating and manufacturing new chemicals we are reclaiming chemicals that have already been used, before they are released to the environment, thus preventing us from adding to the growing mass of synthetic chemicals in the environment (Stockholm Resilience Centre, 2022). The UNEP (2019) has identified that knowledge sharing and addressing legislation and capacity gaps in developing countries and emerging economies is a high priority to support improved chemical management. There is also an increasing demand for green and sustainable chemistry innovation and education to support a change in the way we produce and use chemicals (UNEP, 2019).

Ultimately, there is no one answer to the question of what is the least worst place for forever chemicals, and so for now the best way to answer this is to pose more questions, and to constantly revisit the way we approach chemical management to make sure we are moving forward and not continually repeating the mistakes of the past.

So, I leave these questions with you:

• Is there anything that we can do differently right now to minimise the releases of these chemicals to the environment?
• Can we take a look at our waste management processes and manage our waste streams to prevent the mixing or dilution of industrial waste with residential waste?
• What government policies can we put in place now to support wholesale changes in the way we use and dispose of chemicals?
• What checks and balances do we need to ensure environmentally responsible decisions are made with regard to the manufacture of synthetic chemicals in the future?
• What can we do to educate the general public about the risks associated with persistent synthetic chemicals in a way that supports us to make better consumer choices?
• Should convenience and progress come at the cost of the health of the environment around us?
• How should we change the way we use and manage chemicals today, to help make it easier to manage them in the future?

References:

• Australian Government, 2024. Australian Industrial Chemicals Introduction Scheme. Industrial Chemicals Inventory.
• Muir, D.C.G., Getzinger, G.J., McBride, M., Ferguson, P.L. 2023. How Many Chemicals in Commerce Have Been Analyzed in Environmental Media? A 50 Year Bibliometric Analysis. Environ. Sci. Technol. Volume: 57. Page 9119 – 9129.
• Naidu, R., Biswas, B., Willett, I.R., Cribb, J., Singh, B.K., Nathanial, C.P., Coulon, F., Semple, K.T., Jones, K.C., Barclay, A., Aitken, R.J. 2021. Chemical pollution: A growing peril and potential catastrophic risk to humanity. Environment International. Volume: 156.
• Ockende, W.A., Breivik, K., Meijer, S.N., Steinnes, E., Sweetman, A.J., Jones, K.C., 2003. The global re-cycling of persistent organic pollutants is strongly retarded by soils. Environ. Pollut. Vol 121(1), Page 75-80. doi: 10.1016/s0269-7491(02)00204-x.
• Persson, L., Carney Almroth, B.M., Collins, C.D., Cornell, S., de Wit, C.A. Diamond, M.L., Fantke, P., Hassllov, M., Macleod, M., Ryberg, M.W., Jorgensen, P.S., Villarrubia-Gomez, P., Wang, Z., and Hauschild, M.Z., 2022. Outside the Safe Operating Space of the Planetary Boundary for Novel Entities. Environ, Sci. Technol. Vol 65, pages 1510-1521.
• Stockholm Resilience Centre, 2023. Planetary Boundaries.
• Stockholm Resilience Centre, 2022. Planetary Boundaries. Safe planetary boundary for pollutants, including plastics, exceeded, say researchers.
• Rachael Carson, 1962. Silent Spring. Published 27 September 1962.
• United States Environmental Protection Agency (USEPA), 2009. Persistent Organic Pollutants: A Global Issue, A Global Response. Created 2002, updated December 2009.
• UNEP, 2013. Global Chemicals Outlook: Towards Sound Management of Chemicals.
• UNEP, 2019. Global Chemicals Outlook II: From legacies to innovative solutions.