Modifying multi-criteria decision analysis for assessments of chemical alternatives

Effectual assessment of chemical alternatives is necessary to avoid “regrettable” substitution. In a preceding study, an analysis of seven assessment-of-alternatives (AoA) methods found that none of them is fully aligned with Article 57 of the European REACH regulation, indicating a need for a method better reflecting European regulations. This paper presents a modified multi-criteria decision analysis (MCDA) method for the assessment of chemical alternatives (MCDA-ACA). We investigate and recommend MCDA method parameters for the assessment of chemical alternatives, specifically scope of objectives considered, aggregation of objectives, curvature of the value functions, weights, and the introduction of a classification threshold. The MCDAACA 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 MCDA-ACA 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 frameworks, GreenScreen® and Article 57 of REACH alone. The results show that MCDA-ACA can easily be adapted to other jurisdictions as required.