Investigation and intervention in the fate of PFAS

When it comes to emerging contaminants like per- and poly-fluoroalkyl substances (PFAS), our body of knowledge is growing daily. But there’s still a lot to understand.

As an environmental consultant, scientist and researcher, my work is all about examining how these substances move in the environment, the environmental risks that creates, and how this information can be used to minimise those risks.

 

The many faces of PFAS

PFAS is a vast family of more than 5,000 individual chemicals. These substances are known by many names and acronyms (PFOS, PFOA, PFAAs, diPAPs, fluorotelomers…) and have been used for different purposes over time, from firefighting foams to non-stick frypans, stain-resistance treatments for carpets, and food packaging.

The use of the more hazardous PFAS has been phased out in most countries, but PFAS use is still widespread. The sheer volume of individual compounds has the potential to make their management complex. That’s why many are calling for a more segmented approach to PFAS classification to help focus and direct our research, remediation, and regulation.

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Dividing to conquer

Globally, a number of authorities and industry groups are advocating for the grouping of PFAS into classes with similar toxicological or environmental properties.

The benefit is that rather than embarking on endless rounds of testing and weaving a complex web of regulations focused on individual chemicals, we can begin to identify and address potential impacts, risks and responses at a more manageable macro-level. 

Segmentation in action

For the environmental management of PFAS that has been used in firefighting foams specifically, we are at a point in the science where we know there are relatively few PFAS chemicals that dominate in soil or groundwater scenarios. We understand which PFAS to look for, and therefore don’t need to invest in detailed searches for the extended PFAS family members.

However, knowing how to manage the seemingly never-ending list of new PFAS being introduced by industry is an entirely different story. A grouped classification approach could help demystify and simplify processes for understanding the hazards from these chemicals, and determining what needs to be done.

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It’s about the destination, and the journey

Understanding how and when chemicals move in the environment is key to understanding the true risks they pose. If a chemical can’t get to a ‘receptor’ - a person, a wetland, or an animal - it poses no environmental risk.

Research tells us that PFAS cut complex pathways throughout the environment.

They have unusual attributes that influence their transport in comparison to other contaminants, and local environmental conditions and land uses deeply impact where they end up.

For the most part, contaminants that are soluble in water will begin to move downwards through soil when the ground becomes wet from rainfall, eventually leaching into groundwater. Subsurface aquifers then become a primary transport pathway for contaminants to be carried to new locations. It makes sense then that our management strategies for them are usually highly focused on groundwater.

Despite being quite soluble in water, PFAS also seem to do something different. While the same leaching processes do occur, recent research is showing they can be drawn to the surface and washed away in surface runoff.

This has important consequences for how we approach PFAS management. Rather than focusing primarily on groundwater like we have so often done in the past, more attention must be paid to stopping PFAS getting into surface water.

This isn’t to forget that in places that rely heavily on groundwater for drinking water, like much of the United States and Sweden, impacted groundwater cannot be ignored.

 

Expanding the horizons of investigation

Programs to investigate, assess and remediate common sources of PFAS contamination have been underway for a long time.

RPS has been working with the Australian Department of Defence for years now on a nationwide program to review, investigate and management PFAS on, and in the vicinity of some of its bases.

We’ve also been working with the aviation sector, where industry and authorities are investing millions to transition away from PFAS-containing firefighting foams at airports and address the contamination resulting from their use in the past.

But with media reports full of studies revealing that PFAS can be found in everything from ski wax to yoga pants and the anti-fogging sprays that stop your glasses misting up over your COVID mask, the question we must ask is where else PFAS chemicals are used? And where do they end up both short-term, and further down the track?

 

New battlegrounds for PFAS management

Most of the PFAS referred to in these media-cited studies ends up in either landfill, or wastewater treatment plants (WWTPs). This reveals new areas of focus for PFAS investigation, research, and potential regulation.

As most WWTPs in operation today weren’t designed to remove PFAS, these chemicals come in, and quickly go out again either in the treated effluents that are released to waterways, or in the sludge that is often turned into biosolids and used as an amendment to add nutrients to agricultural soil.

At the moment, wastewater treatment plants are a mere stop on the road for PFAS, not the final destination. 

In the USA, the biosolids issue has been particularly noted, with a few dairy farms even having to stop production due to PFAS from biosolids making their way into livestock and contaminating milk.

Since the range of PFAS used in all of these domestic and commercial products is much more diverse than some of the high priority sources we are already addressing (eg firefighting foams), everything from investigation to treatment starts to become more complex.

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So, what can we do?

The first step is not to panic.

There are many ways to manage chemicals in the environment. And when it comes to legacy contamination from chemicals that are largely phased out, it is generally a matter of continuing what we are already doing. Completing investigations to understand the extent of impacts, implementing remediation measures where they make a meaningful difference to risks, and managing any remaining risks by other measures: providing dietary advice on consuming seafood or providing clean water sources, for example.

While technologies for remediating PFAS-impacted land are still limited, they are advancing rapidly. So too is our understanding of the environmental risks PFAS pose.

The key to management is implementing a proportional response and understanding what level of remediation is reasonable and practicable in order to manage risks to human and ecological health.

This approach is being increasingly adopted in the PFAS space, but can be difficult to define when to stop (how much remediation is enough), and solutions are yet to be fully tested.

Where PFAS production is continuing, and chemicals are making their way into the wide range of products in our households and commercial premises, the waste sector will have an increasing responsibility for managing PFAS points of entry to the environment. But the responsibility cannot and should not fall solely to waste sector organisations. Improvements to upstream product approvals and controls are another vital part of the solution. 

Hazard and risk assessment of chemicals by government agencies such as the Australian Industrial Chemicals Introduction Scheme (AICIS) in Australia and under the Registration, Evaluation, Authorisation and Restriction of Chemicals (REACH) legislation in the EU, are aimed at identifying chemicals that need specific controls, or in the worst cases, need to be banned from use in products. The Australian Government is also working with specific industries to understand where PFAS is used and promoting strategies to phase out these uses. 

In coming years these approaches will see reductions in environmental risks from PFAS, but the journey will be long and with inevitable twists in the tail. While there’s more work to do, we need only look at how far we, and the science have already come in the management of PFAS to know that the problems are not insurmountable.

For managing environmental risks, having a deep understanding of PFAS and the complex issues tied to them, is the key to simplifying and making sensible decisions about investigation and management.

 

Read more insights from Karl about PFAS investigation and management, or get in touch about your next project.

Karl Bowles

Technical Director - Remediation Project Management

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