Investigation and intervention in the fate of PFAS

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. 

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.

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.

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.

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.