Chris Hughes, Principal Regulatory Consultant at the National Chemical Emergency Centre (NCEC), attended a workshop hosted by the German Environment Agency (UBA) entitled ‘Proposal to standardise the analysis and persistence assessment of non-extractable residues (NERs)’. The workshop discussed recent research into the understanding of NERs in biodegradation tests and explored a proposal for how these could be considered in the future regulatory persistence assessment of chemicals. If the proposed changes are implemented, organisations are likely to face significant additional costs and challenges when seeking to comply with chemical regulations. NCEC’s environmental chemistry experts have vast experience of placing, monitoring and evaluating regulatory tests. NCEC also has specialist expertise in developing alternative approaches to standard testing requirements and can help you comply with any new regulations.

What is persistence?

Persistence is the extent to which a chemical resists degradation in the environment. Chemicals that persist in the environment tend to build up to higher concentrations and lead to greater exposure of people and other organisms. We evaluate persistence using standard tests that assess chemical degradation in different environmental compartments and express the results as half-lives, which are then compared to regulatory cut-offs. 

What are non-extractable residues?

NERs are the residual amounts of a chemical that cannot be recovered from soil or sediment in biodegradation tests. This is a common occurrence and all chemicals produce NERs to varying extents. These NERs can be the unreacted chemical, its degradation products, or harmless biomolecules produced by microorganisms as they degrade the chemical. The debate has been raging as to whether NERs pose a risk – are they a ‘hidden hazard’ or a ‘safe sink’? Significant scientific advances have recently been made to try to identify the nature of NERs in biodegradation tests.

Why is this important for regulation?

The regulatory community in Europe has recently shifted towards viewing NERs as a hidden hazard and, as such, is intending to include them in the assessment of environmental persistence. A recent European Chemicals Agency (ECHA) guidance update stated that, by default, all NERs should be considered as undegraded test chemicals and included in the determination of the degradation half-life. This would have the effect of grossly increasing the half-life of a chemical compared with how these have been assessed historically.

While attempts are being made to develop techniques that will better calculate persistence and, therefore, minimise this increase, the implementation of these techniques will still lead to significant additional costs and complexities in persistence assessments in the future. 

How will this impact your organisation?

The upshot is that persistence assessments are likely to bring significant additional costs and challenges to registrants of chemicals under REACH in the future. Ultimately, it may mean that a chemical is at risk of being banned in the long term if it is concluded to be persistent as a result of these new developments. Therefore, it’s vital for chemical producers to understand the implications of these developments and how they are likely to impact their business in the future. Given the highly technical nature of these evaluations, it is also of critical importance that your organisation brings in the right expertise to support these assessments and ensure they are done correctly.

How can NCEC help?

NCEC specialists have years of experience in evaluating the persistence of chemicals for industry clients in the regulatory context. This includes working with challenging test substances, such as volatile and hydrophobic chemicals, and complex substances. We have a deep understanding of the regulatory challenges and implications of the recent developments and have recently led a research project with CEFIC Long-Range Research Initiative (LRI) to advance the understanding and development of guidance for persistence assessments. Some of our recent publications can be viewed here.

NCEC experts have a comprehensive understanding of all legislation relating to the manufacture, distribution, use, treatment and disposal of chemicals. As such, they are ideally placed to guide clients through the complicated processes of maintaining regulatory compliance. 

For further information on how NCEC can support you to comply with the Globally Harmonized System of Classification and Labelling of Chemicals (GHS), EU and UK REACH and other global chemical registration laws, please contact us using the form to the right-hand side or email us at [email protected].