A comparison procedure based on Multi-Criteria Decision Analysis (MCDA) and expert judgment was developed in order to allow the comparison of bioavailability tests to implement the chemical Line of Evidence (LoE) within a TRIAD based site-specific Ecological Risk Assessment framework including three tires of investigation. The proposed methodology was included in the Module 1 of the Decision Support System DSS-ERAMANIA and the obtained rank supported the selection of a suitable set of available tests to be applied to the case study. A simplified application of the proposed procedure is described and results obtained by the system software are discussed.