Persistent chemicals take a long time to break down in the environment, and become widely distributed throughout water, soil, and air, even to places where they have never been used.

This post informs you of proposed EU Regulation of persistent chemicals as four new Hazard Classes within the CLP Regulation.

If you wish to find out more about our services for hazard classification, see our services page or contact us. For help with the jargon, check our glossary.

Introduction

The European Commission has published a draft Regulation [1] that incorporates new Hazard Classes for persistent chemicals into the CLP Regulation [2]. The draft Regulation is open for comment until 18 October 2022.

The Regulation introduces the following new Hazard Classes :

• endocrine disruptor for human health
• endocrine disruptor for the environment
• persistent, bioaccumulative and toxic (PBT)
• very persistent and very bioaccumulative (vPvB)
• persistent, mobile and toxic (PMT)
• very persistent and very mobile (vPvM)

The Regulation is expected to be finalised at the end of 2022, but the changes to classification and labelling will have a long transition period so that industry can make changes gradually:

• substances have to be classified in the new Hazard Classes 18 months after the Regulation’s ‘entry into force’ (EIF)
• substance already classified before the EIF date and placed on the market have 42 months before re-classification required
• mixtures have to be classified in the new Hazard Classes 36 months after the Regulation’s EIF
• mixtures already classified before the EIF date and placed on the market have 60 months before re-classification required

This post relates to the Hazard Classes for persistent chemicals, describing the problems associated with such chemicals and their proposed new classification and labelling.

The endocrine Hazard Classes were described in an earlier post.

Persistent chemicals

Mobile substances do not bind strongly to soil or sediment. Instead, they have an affinity for the water, and can travel within soils and water courses.

A previous post discussed the current regulation of chemical substances that persist in the environment.

Persistent Organic Pollutants (POPs) are man-made substances that take a long time to break down in the environment, and become widely distributed throughout water, soil, and air, even to places where they have never been used.

The persistent nature of these chemicals can be an advantage in their use, as they do not degrade. Potentially they are open to capture and recycling. Historically, the impact of persistent chemicals has been underestimated, leading to widespread contamination and harms. The EU and UK authorities have responded with tighter regulation and application of the ‘precautionary principle’.

Some POPs accumulate in fatty tissue of aquatic creatures, so that the concentration of chemical in a fish may be higher than the water concentration in which they live. This process is known as bioaccumulation.

Furthermore, species consuming such organisms develop even higher levels of POPs, a process known as biomagnification. So, although the environmental levels are low, POP concentrations in predator animals can be thousands of times higher.

A more recent concern for POPs is contamination of water sources, and drinking water in particular. This leads to exposure and accumulation in all species, including humans, so that a measurable amount can be detected in blood samples. The key properties of concern are persistence and mobility in the environment.

Mobile substances, instead of remaining in the area where they are spilled, do not bind strongly to soil or sediment. Instead, they have an affinity for the water, and can travel within the within soils and water courses. The affinity of a chemical for soil or water is measured by the organic-carbon-to-water partition coefficient (K_oc).

Perfluoroalkyl substances (PFASs), are a major concern for water contamination, as they are highly resistant to breakdown (‘forever chemicals’), and are soluble in water (see previous post).

In EU legislation, the POPs are collated into groups with a combination of the following properties:

• Persistent (P): half-life of > 40 days in fresh water (different threshold apply in different media)
• Very persistent (vP): half-life of > 60 days in fresh water (different threshold apply in different media)
• Bioaccumulative (B): bioaccumulation factor (BCF) > 2000
• Very bioaccumulative (vB): bioaccumulation factor (BCF) > 5000
• Mobile: organic carbon to water partition coefficient (K_oc) < 3
• Very mobile: organic carbon to water partition coefficient (K_oc) < 2
• Toxic: (a) long-term human-health hazard classification (carcinogenicity, mutagenicity, reproductive toxicant, STOT RE, or endocrine disruptor); (b) long-term environmental hazard classification (no-effect concentration in long-term study <0.01 mg/L); (c) other evidence based on epidemiology, toxicity in terrestrial organisms, etc.

The bioaccumulation factor (BCF) and organic carbon to water partition coefficient (K_oc) can be estimated from the octanol–water partition coefficient (K_ow), a commonly measured parameter.

Regulation of persistent chemicals

Historically, the impact of persistent chemicals has been underestimated, leading to widespread contamination and harms. The authorities have responded with tighter regulation and application of a ‘precautionary principle’.

Combinations of the above properties are identified in the REACH Regulation, Article 57, as ‘substances of very high concern’ (SVHCs), of equal concern to carcinogens, mutagens and reproductive toxicants (CMRs). These combinations are:

• Persistent, bioaccumulative and toxic (PBT): substances that remain in the environment, accumulate in organisms, causing long-term toxic effects
• Very persistent and very bioaccumulative (vPvB): substance that remain in the environment, and strongly accumulate in organisms, possibly causing long-term effects
• Persistent, mobile and toxic (PMT): substances that remain in the environment, disperse through water, and may contaminate drinking water possibly causing long-term effects
• Very persistent and very mobile (vPvM): substance that remain in the environment, and easily disperse through water, and may contaminate drinking water, possibly causing long-term effects.

PMTs and vPvMs are not specifically mentioned in REACH Article 57, but are included in the Candidate List of SVHCs (see previous post) as having ‘equivalent concern’.

Several common chemicals have been identified with such properties, cosmetic ingredients (D4: PBT, vPvB), textile treatment (PFAS: PMT), and dioxane (solvent: PMT).

SVHCs are subject to Authorisation (see previous post) and forced withdrawal from the market.

Evaluation of persistent chemicals

Hazard classification is the categorization of chemical harms (see our Compendium of chemical hazards) into easily identifiable, standard descriptions, such as flammable liquid, skin irritation, or specific target organ toxicity.

Hazard classification in the EU and UK is performed according to the CLP Regulation. This gives the criteria for each Hazard Class, and its subdivisions (ie Hazard Categories).

The CLP Regulation is based on the United Nation’s (UN) Globally Harmonized System of Classification and Labelling of Chemicals (GHS) [3]. Versions of the GHS are implemented in all industrialized nations. See our earlier post for more details of the GHS.

The new Hazard Categories are not part of the GHS, and will not be recognised beyond the EU. In the interest of speed, the EU preferred to press ahead with the new Hazard Classes. However, the EU have applied to the UN to have them incorporated into the GHS.

A detailed description of the classification process for substances is given in an earlier post.

PBTs and PMTs will fall into Hazard Classes already part of the EU/UK hazard classification system, as they show toxicity as part of their definition, particularly:

• toxic to reproduction,
• specific target organ toxicity
• carcinogenicity
• long-term toxicity in the aquatic environment.

PBT and vPvB properties must be assessed as part of the REACH Registration, so most commercial chemicals have already have been evaluated. Substances meeting the criteria will be assigned the new classification and labelling.

Substances will need to be newly assessed for PMT and vMvP properties, according to the timetable given above.

Proposal for classification and labelling of persistent chemicals

The European Commission has a draft Regulation [1] to create new Hazard Classes under the CLP Regulation specifically for persistent chemicals .

There are new Hazard Classes proposed for substances that are PBT, vPvB, PMT, and vPvM.

Mixtures containing such ingredients are usually classified using concentration thresholds. Mixture classification is described in a previous post. The generic concentration thresholds for ingredients in mixtures is 0.1 wt%. Therefore if an ingredient classified as PBT, vPvB, PMT, or vPvM is present at ≥ 0.1 wt%, then the mixture is generally classified in the corresponding Hazard Class.

Classification into the new Hazard Classes indicates labelling requirements as follows (Table 1):

	Persistent, bioaccumulative and toxic	Very persistent and very bioaccumulative	Persistent, mobile and toxic	Very persistent and very mobile
Abbreviated classification	PBT	vPvB	PMT	vPvM
Symbol/pictogram	To be determined	To be determined	To be determined	To be determined
Signal Word	Danger	Danger	Danger	Danger
Hazard Statement	EUH440: Accumulates in living organisms including in humans with long- lasting effects	EUH441: Strongly accumulates in living organisms including in humans with possible long- lasting effects	EUH450: Persistent substance which can pollute water resources	EUH451: Very persistent substance which can pollute water resources
Precautionary statements	P201: Obtain special instructions before use; P202: Do not handle until all safety precautions have been read and understood; P273: Avoid release to the environment; P391: Collect spillage; P501: Dispose of contents/container to …	P201: Obtain special instructions before use; P202: Do not handle until all safety precautions have been read and understood; P273: Avoid release to the environment; P391: Collect spillage; P501: Dispose of contents/container to …	P201: Obtain special instructions before use; P202: Do not handle until all safety precautions have been read and understood; P273: Avoid release to the environment; P391: Collect spillage; P501: Dispose of contents/container to …	P201: Obtain special instructions before use; P202: Do not handle until all safety precautions have been read and understood; P273: Avoid release to the environment; P391: Collect spillage; P501: Dispose of contents/container to …

References

[back to Introduction] [back to Evaluation of persistent chemicals] [back to classification and labelling]

[1] Commission delegated regulation (EU) amending Regulation (EC) No 1272/2008 as regards hazard classes and criteria for the classification, labelling and packaging of substances and mixtures; available at the European Commission website: https://ec.europa.eu/info/index_en.

[2] Regulation (EC) No 1272/2008 of the European Parliament and of the Council of 16 December 2008 on classification, labelling and packaging of substances and mixtures (as amended).

[3] Globally Harmonized System of Classification and Labelling (GHS); Eighth Revised Edition; United Nations; 2019.