Table 3 Central considerations to be addressed for deriving a defined “mixture allocation factor” to take account for unintentional environmental co-occurrences of chemicals
Open question | Options | Needs and challenges |
|---|---|---|
Process and responsible actor? | MAF set by authorities to be implemented in legal text, supported by ECHA GD. Applicable during Chemical safety assessment of registrants and/or Downstream user assessments | The premise is that chemicals are not reaching environmental compartments alone but co-occur and may produce joint effects and risks—which is currently not addressed during the single substance’s CSA nor DU assessments Takes account for limited information and resources of REG and DU and follows the legal setup of REACH that safe use ensured during CSA |
Location for implementation in legal text? | In Annex I on CSA factor could be introduced on: PNEC (reflects intrinsic properties and includes AFs for 1 substance) PEC (reflects exposure for compartment/use) RCR (reflects predicted risk for use and compartment) Msafe (reflects safe use amounts) | Communication along supply chain to be ensured Confusion with existing uncertainty factors to be avoided Clear wording, definitions and references in legal text and guidances |
Uniform or specific factors? | Either the same or specific factors for: different environmental compartments different uses and product categories different tonnages | One uniform MAF more pragmatic, assumed to affect substances close to RCR of 1, easier to communicate Implications, evidences and benefits would need to be justified for possible differentiated factors |
Definition of the appropriate order of magnitude? | The order of magnitude or “size” of a MAF can be based on: Evidence on averaged environmental co-occurrences and predicted risks Knowledge on predicted exposures or emissions from substances/mixtures Analysis of current chemical safety assessments and potential impact of a factor on the reduction of safe use amounts, predicted emissions or risks | Review and analyses of available scientific studies on environmental co-occurrence and possible risks of chemicals. Use of modelling approaches to estimate EU level co-exposures and current risk underestimations Analyses of current CSAs |
Refinements or exemptions? | Refinements may justifiable: in certain situations (no exposure due to close system) if sufficient and reliable data are available to conduct specific assessment | Conceivable that a generic default factor may be refined via specific assessments in cases where data available or exposures can be excluded |
Chemicals and types of mixtures covered? | It needs to be defined whether a MAF should cover possible risks due to exposures of chemicals regulated under REACH co-occurring other substances, such as pesticides, biocides or pharmaceuticals | The coverage needs to be clearly defined Covering substances not falling within REACH is legally challenging |
Possibilities for a later review? | The magnitude or specification of a MAF could be readjusted After a fixed time span In case of new scientific evidence | A re-assessment could be in accordance with the REACH Review and could imply a surveillance of chemicals exposures and predicted risks |