PBT assessment

Annex XIII to the REACH Regulation sets criteria for substances that are persistent, bioaccumulative and toxic (PBT) or very persistent and very bioaccumulative (vPvB).

Under REACH, a PBT/vPvB assessment is required for all substances for which a chemical safety assessment is carried out. A chemical safety assessment is required for substances manufactured or imported in amounts of 10 tonnes or more per year, unless exemptions apply.

All biocidal active substances have to undergo a formal PBT assessment. You can see the status of biocides assessments on the Biocidal Active Substances page.

The PBT Expert Group supports Member States in their assessments. The substances undergoing a PBT/vPvB assessment under REACH or the Biocidal Products Regulation that have been brought for discussion to ECHA’s PBT Expert Group are included in the PBT assessment list.

The PBT/vPvB concern

Substances that persist for long periods of time in the environment and have a high potential to accumulate in biota are of specific concern because their long-term effects are rarely predictable. Once they have entered the environment, exposure to these substances is very difficult to reverse, even if emissions are stopped.

Protection of pristine remote areas from PBT/vPvB substances is particularly difficult, as these substances do not degrade near emission sources but may be gradually transported into remote areas. A ‘safe’ concentration in the environment cannot be established using the methods currently available.

A particular concern with vPvB substances is that even if no adverse effects can be demonstrated under laboratory testing conditions, long-term effects might be possible, as high but unpredictable levels may be reached in humans or the environment over extended time periods.