PRIO – A tool for Risk Reduction of Chemicals

Why are environmentally hazardous substances with long-term effects priority risk-reduction substances?

This relates to substances that fulfil classification criteria H410 or H413 according to CLP- classification and labelling or N;R50-53 or for R53 in accordance with KIFS 2005:7** (the Swedish implementation of EU Council Directive 67/548/EEC, as amended).

The background to why these particular classification criteria have been chosen is the long-term effects substances classified H410 and H413 can give rise to. This is also in line with the intentions of the Swedish Environmental Objective for a Non-Toxic Environment to reduce exposure to substances that can cause long-term effects.

A substance classified H410 is very toxic to aquatic (*13) organisms and may cause long-term adverse effects in the aquatic environment. A substance classified H413 may cause long-term adverse effects in the aquatic environment. This latter classification apply when acute toxicity data are not available but the substance, based on available evidence concerning persistence, potential to accumulate, and predicted or observed environmental fate and behaviour, nevertheless may present a long-term and/or delayed danger to the structure and /or functioning of aquatic ecosystems. For example, if the substance is poorly water-soluble (<1mg/l) and not readily degradable (*14) and the substance's log Pow ³  3 (*15).

Substances that are classified H411, H412 do not fulfil this PRIO criterion. The background to why substances for which these classifications apply have not been prioritized is that these have an observed lower acute toxicity to aquatic organisms which, in many cases, indicate a less severe long-term adverse effect. Read more about the classification criteria in Regulation (EU) No 1272/2008 (CLP).


** Observe that regulation KIFS 2005:7 will be replaced by CLP 


*13 Aquatic = pertaining to or formed in water. Aquatic environments are lotic (flowing water), limnic (freshwater), brackish-water and marine.

*14 Degradability is determined for example in accordance with OECD guideline 301.

*15 Pow (Partition coefficient octanol/water) is the distribution coefficient for a substance between octanol and water determined in accordance with OECD guideline 107. The partition coefficient is used to estimate the potential of a substance to bioaccumulate.