April 12, 2011 by wca Staff

As a result of the December 2010 REACH registration deadline, a large amount of ecotoxicity data for chemicals will soon be available from ECHA via its REACH dissemination portal. Could the Predicted No-Effect Concentrations (PNECs) derived for REACH during registration be used as Environmental Quality Standards (Environmental Quality Guidelines) for non-European Countries?

This was the question posed by the Canadian Council of Ministers of the Environment (CCME) in a project that we recently completed for them. The aim of the project was to evaluate whether PNECs that have been developed under REACH for freshwater and marine compartments could be adopted or adapted for use asCanadian Water Quality Guidelines (CWQGs).

On face value, adopting REACH PNEC values would certainly seem to be advantageous for non-european countries. They would, for example, benefit from work already conducted and avoid unnecessary duplication of ecotoxicological studies. It could also provide a reliable and consistent approach to rapidly increasing the number of quality guidelines in the adopting country and could also provide a stepping stone for the international harmonisation of environmental quality benchmarks.

However, when considering the adaptation of EU PNECs to non-European systems for setting environmental quality standards, there are a number of aspects to consider before thay can be adopted. In particular, non-European systems for regulating chemicals often have different requirements for the quality and quantity of data used to derive quality standards.

We were asked to consider a list of candidate substances identified by the CCME and establish whether any of the PNECs for these substances developed under REACH were also suitable for implementation as CWQGs. Unfortunately, the timeline for publication of the PNECs for chemicals registered under the first tranche of REACH meant that, at the time of the project, none of the PNECs developed under REACH (for the CCME list of candidate substances) were available for evaluation. However, many of the pre-REACH Existing Substance Regulation Risk Assessment Reports (ESR RARs), containing data on which REACH PNECs are likely to be based, were readily available and were used as a substitute for REACH PNECs. In addition, PNEC values developed as Environmental Quality Standards (EQS) under the European Water Framework Directive (WFD), which uses a similar derivation methodology to that applied under REACH, were also evaluated.

The two main aspects that were considered when evaluating the EU PNECs for their potential to be adopted as CWQGs were the species tested and the quality criteria used to assess the reliability of the study. The protocols for derivation of CWQGs require that data used to derive no or low-effect values are from test species native to Canada or a reliable surrogate for Canadian species. In addition, the specific quality requirements for each study are somewhat more stringent than the Klimisch criteria generally applied during the derivation of EU PNECs.

To address these differences, we developed two systematic evaluation procedures. An initial process assessed each test in the EU PNEC dataset to determine whether the species used was a suitable surrogate for Canadian species (if not native) according to defined criteria, and if the quality of the study was sufficient to be used in deriving a CWQG. Suitable studies were then evaluated according to a further set of criteria (including requirements for quantity of remaining data, critical PNEC value, low versus no effects thresholds, deterministic versus probabilistic approaches and safety factors applied) to determine if the EU PNEC could be adopted directly or adapted for use as a CWQG.

We concluded that a number of the EU PNECs for chemicals considered a priority by the CCME were suitable for direct adoption as CWQGs, while a further set of EU PNECs would need to be modified (e.g. application of an additional safety factor) before they could be considered suitable for adoption. In addition, a large number of substances were identified for which the actual EU PNEC was unsuitable for use as a CWQG, but the ecotoxicology dataset used to derive the PNEC was considered suitable for potential re-evaluation to determine a new ‘PNEC’ which could then be used as a CWQG.

While the procedures developed for the evaluation of EU PNECs were specifically designed for use by the CCME in evaluating EU PNECs, they incorporate a degree of flexibility that makes them adaptable for application to other systems for the derivation of environmental quality standards or for predicting ‘safe’ environmental concentrations of chemicals, which could be of use to other non-EU countries.