Multi-Criteria Decision Analysis for Assessments of Chemical Alternatives (MCDA-ACA)

A comprehensive assessment of chemical alternatives is necessary to avoid regrettable substitution. In a preceding study, an analysis of six hazard assessment methods found that none of them is fully aligned with the hazard assessment criteria of Article 57 of the European REACH regulation, indicating a need for a method better reflecting hazard assessment schemes in European chemical regulations. This paper presents a multi-criteria decision analysis (MCDA) method for the assessment of chemical alternatives (ACA) that takes the criteria of Article 57 of REACH into account. Investigated and presented are objective hierarchies, aggregation of objectives, curvature of the value functions, weights, and the introduction of a classification threshold. The MCDA-ACA method allows for the aggregation of hazards in such a way that poor performance in one hazard cannot be compensated for by good performance in another hazard. The method parameters were developed and tested using two datasets with the aim to classify chemical alternatives into acceptable (non-regrettable) and unacceptable (regrettable) alternatives according to the regulations set in Europe. The flexibility of the general method was explored by adapting the method to align with two hazard assessment schemes, Article 57 of REACH and GreenScreen®. The results show that MCDA-ACA is so flexible and transparent that it can easily be adapted to various hazard assessment schemes.