## 5 Potential Drivers, Barriers, and Prospects for IBA Use
Moreover, none of the EU member states has yet established national criteria for IBA [15; 104]. A potential end-of-waste status should not result in the assumption that no further assessment of IBA properties is necessary. In fact, testing is essential to confidently appraise the environmental behavior of the material for any accepted application. In this context, the setting of well-defined \"end-of-waste\" criteria, particularly in the Iberian Countries, is meaningful. Furthermore, the classification of \"mirror entry\", as set out in the LoW, itself results in major differences in IBA management among countries, as previously mentioned. The study carried out by [PERSON] et al. (2017) [105] for European IBA indicated that, from the 15 hazardous properties (HP) of waste that render it hazardous according to Commission Regulation 1357/2014, HP 10 (Toxic for reproduction) and HP 14 (Ecotoxic) are the ones possibly leading to the \"hazardous waste\" classification of IBA. Regarding HP 10, the study concluded that IBA is considered hazardous if the total content of Pb is above 3500 mg/kg. In Portugal, the total content of Pb has been found to be below that limit both for mainland and island IBA (Table 3; [PERSON] et al. [106]). Likewise, Spanish IBA has exhibited a total content of Pb below the threshold of 3500 mg/kg (Table 3). Regarding HP 14, related to potential environmental impacts, the classification is not that linear. By following the summation method (for total elemental concentrations) laid down in EU Council Regulation 2017/997 for HP 14 assessment, [PERSON] et al. (2017) found that IBA may be considered hazardous. However, considering total content and worst-case scenarios for elemental speciation likely leads to ecotoxicity overestimation and does not reflect the real hazard level of waste. HP 14 is responsible for most of the hazardous entries in the LoW [102,107]. Thus, the proper assessment of this hazardous property is of major importance to classify mirror entries. Moreover, \"non-ecotoxic\" classification through proper assessment should assist disqualification as waste, thus facilitating the valorization of the material. Currently, there is no consensus in the scientific community on the approach that should be followed to appropriately assess HP 14, and there are different proposals in the literature. Different authors have proposed methodologies involving leaching data and subsequent geochemical speciation modeling to find the relevant compounds for ecotoxicity prediction and the equilibrium concentrations on leachates [105,108-1010]. On the other hand, different studies have focused on IBA ecotoxicity through biotests, covering both the aquatic and the terrestrial compartments [108,111-116]. Thus, the development and standardization of applicable methodologies for HP 14 assessment are needed for an accurate and informed evaluation of the environmental behavior of IBA. In the EU Member States, including in Portugal and Spain, different approaches have been used for HP 14 assessment [73]. The Portuguese Environmental Agency has published a waste classification guide [117], recommending the assessment of HP 14 based on EU Regulation 2017/997. The guide states that there is no need to perform experimental assessment when that Regulation is followed. However, the EU Regulation 2017/997 indicates that it is possible to perform experimental tests following Regulation (EC) No. 440/2008 (for chemicals) or other internationally recognized methods. At the national level, there are no guidelines on biotests. In Spain, the assessment of HP 14 is performed based on biotests only, using the luminescence inhibition of the bacterium _Vibrio fischeri_ (ISO 11348) or the lethality to _Daplnia magna_ (ISO 6341). One of the two tests can be performed, and there is no need to perform both. It should be noted that a potential classification as \"hazardous waste\" is not necessarily directly linked to the environmental risks associated with its use as a product and should not automatically lead to valorization barriers.