Why environmental persistence should be a top priority for safe and sustainable products
Producers of chemical products have a long list of issues to worry about. Beyond developing and marketing products that are effective, competitive and meet societal needs, there are matters of the safety of the product for both human health and the environment and, increasingly, sustainability.
However, one cross-cutting issue is fast becoming a top priority for companies: environmental persistence
Persistence concerns the extent to which chemicals will break down in the environment after their use. Chemicals that are persistent are slower to degrade and can build up to higher concentrations, potentially posing greater risks to people and the environment. Persistence is therefore a crucial property for both the safety and sustainability of chemical products.
Here are four reasons why the issue of persistence has become more relevant today, and why companies need to act now to address it.
1. New hazard classification requirements under CLP
The EU CLP regulation has recently been updated to include new hazard classes. Amongst these are four new hazard classes where persistence is a key element:
PBT – persistent, bioaccumulative, toxic
vPvB – very persistent, very bioaccumulative
PMT – persistent, mobile, toxic
vPvM – very persistent, very mobile
The introduction of PMT/vPvM hazards in particular has huge implications. This is a relatively new regulatory concept related to concerns for more polar chemicals to be transported in the environment and to get into drinking water. It brings a huge swathe of new chemicals into scope for detailed persistence assessments which are likely to not have been scrutinised before.
Few people realise that, with the introduction of the mobility criteria, the importance of persistence has been significantly elevated. This is because substances which are not bioaccumulative are generally more likely to be mobile, and vice versa. This means that it’s critically important to get the persistence assessments of your product ingredients right.
The nuances of CLP also mean that substances not previously looked at under other legislation now come into scope for assessment, such as polymers and low tonnage substances.
These changes are likely to turn on considerable work for producers of chemical products. In terms of timelines, all substances on the market will need to comply with the requirements by November 2026. This really isn’t much time when considering how many substances will need to be evaluated, and the complexity of these assessments.
If you’re a producer of formulated products, the compliance deadline of May 2026 for new products means that you may even be caught in the strange situation where you need to classify your new product before all of the raw materials have been assessed by their suppliers. In any case, formulators should be getting to work now to understand the implications of these changes for the classification, and subsequent market implications, of their products.
2. Big increases in biodegradation testing requests under REACH
With the increasing attention on persistence, regulators have been taking a closer look at data in registration dossiers. We’ve seen a huge increase in the number of biodegradation simulation tests being requested by ECHA as part of EU REACH dossier evaluation decisions in recent years.
ECHA has also issued clarifications on when simulation testing should be performed, stressing that these are part of REACH standard information requirements and tightening the conditions under which testing can be waived. This is important because, at the moment, very few substances registered under REACH have simulation tests available, and many dossiers present arguments to waive these studies that would not be acceptable based on current guidance. We should therefore expect this increasing trend in regulatory requests for simulation testing to continue.
3. Customers increasingly expect biodegradability as the norm
It is understandable that nobody wants to feel responsible for causing pollution. People have an implicit awareness when it comes to their own actions, and acts of littering are generally frowned upon. However, until recently the emissions of chemicals from the products we use in daily life have not been given as much scrutiny.
The growing interest here has been catalysed, in particular, by the issue of plastic pollution, which presented us all with a very salient comparison between the polystyrene single use cup and the polyethylene microbead in your shower gel. Both of these uses are now banned in the EU. However, the wider impacts on attitudes and expectations on biodegradability of chemicals are only just beginning.
In consumer-facing sectors, product biodegradability has been an issue of concern (and potential market differentiator) for some time. We are seeing an increasing focus on this in product innovation and marketing, especially in consumer-facing sectors. The most notable instance of this was the flagship announcement by Unilever in 2021 to make all their product formulations biodegradable by 2030. We also see this as a key focus area of the newly-established organisation, the International Collaboration on Cosmetics Safety (ICCS). These activities are likely to send ripples throughout supply chains and get many more companies talking about biodegradability in the future.
One particular category of chemicals that is getting more attention these days is polymers. In addition to microplastic particles, many polymers are used in liquid formulations across a huge range of applications, with an estimated $125 million dollar value and 36 million tonnes produced every year. This has led to questions around the biodegradability of these materials, and new research initiatives, such as by the Royal Society of Chemistry and Cefic-LRI.
Meanwhile, on the subject of product differentiation, it is worth mentioning that product biodegradability claims may also be heading into some challenges in the future, with new laws passed in California and France that place limits on when these claims can be made. These appear to be part of the general backlash against bogus greenwashing claims, particularly related to product packaging. It will be interesting to see how these issues develop and whether this more broadly impacts biodegradability claims on formulated products in the future.
4. Persistence assessments are complex and challenging
A final and crucial point is that persistence assessments are far from straightforward! They require a lot of information to be considered together in a process known as ‘weight of evidence’. The tests themselves are highly complex and prone to wide variability in results due to experimental factors, as well as changes in microbial communities and environmental conditions. Also, certain substances types, such as volatile chemicals and substances with complex compositions (known as UVCBs) are extremely difficult to work with and assess.
All these issues combine to make persistence assessments very challenging. Simulation tests cost anywhere between 100,000 and 400,000 euros, and their results can have far-reaching implications for subsequent regulation of substances. Testing therefore needs to be carefully planned and closely monitored to ensure that experiments take the specific physical and chemical properties of the substance into account, that the results are reliable, and that the risk of false positives is mitigated as much possible.
If you are planning on undertaking a persistence assessment, you should take a look at the Persistence Assessment Tool (PAT), which is designed to support with these challenging assessments. I worked with colleagues at Ricardo to develop the PAT, as part of a project sponsored by Concawe and ICCS, and supported by Cefic-LRI and the European Centre for Ecotoxicology and Toxicology of Chemicals (ECETOC). The tool is freely available to download, and will guide you to compile and evaluate relevant information, and arrive at robust conclusions following a transparent weight of evidence approach.
I would also recommend that, as well as considering the relevant ECHA guidance (documents R.11 and R.7b), you take a look at the reports developed as part of the Cefic-LRI ECO52 project, which address many challenging aspects of persistence assessments, including difficult test substances, complex substances (UVCBs), polymers, and weight of evidence.
Summing up
It’s clear to see that a lot is happening around the environmental persistence of chemicals. As well as being of critical importance for chemical safety, persistence is, more than any other property, intrinsically linked to sustainability because it concerns the degree to which we are able to alter and degrade the natural environment through human activities.
Regulatory developments and shifts in public attitudes on this topic are evolving at a rapid pace, and it is inevitable that chemical manufacturers, producers of formulated products, and brands, will be increasingly impacted. Persistence should therefore be rapidly rising up the list of priority issues that companies need to address.
