Overview#
PBT and vPvB describe substances by how they behave in the environment rather than by a single acute effect. A PBT substance is persistent, meaning it resists breaking down, bioaccumulative, meaning it builds up in the tissues of living things, and toxic. The vPvB category sets an even higher bar on the first two traits while not requiring a toxicity threshold, because extreme persistence and accumulation are concerning in their own right.
Persistent, bioaccumulative and toxic. All three properties must be met against the REACH criteria.
Very persistent and very bioaccumulative. The persistence and accumulation thresholds are stricter, and no separate toxicity test is needed.
Why it matters#
These properties are a recognised basis for identifying a substance of very high concern, alongside CMR effects and equivalent concern such as endocrine disruption. Substances that persist and accumulate are hard to remove from the environment once released, so action tends to be precautionary.
The same traits feed into global controls. Many persistent organic pollutants earn their listing precisely because they are persistent and bioaccumulative on a global scale.