Riscos da urbanização para a biodiversidade aquática: uma perspetiva ecológica sobre a poluição e gestão das águas pluviais

URBAnWat3r addresses the ecological risks of stormwater to aquatic biodiversity in urbanized systems, integrating three lines of evidence (triad approach). The overarching aim is to relate stormwater runoff to the health of receiving aquatic ecosystems in three pilot (sub)urban areas, and from there engage citizens and institutional stakeholders to discuss stormwater management practices. The proposed research plan addresses an overlooked issue in urban planning, which typically view natural or managed watersheds in urbanized landscapes as drainage systems for rainfall. Consequently, urban streams and rivers serve as collectors of stormwater, which flows over the urban landscape during rainfall events, picking up soil particles, litter, and various contaminants such as traffic and other waste products. This mixture is then released into receiving water bodies through terrestrial runoffs and outfalls with minimal or no treatment. Some studies, primarily conducted in the US, have already demonstrated the detrimental pollution effects of urban runoffs. In Europe, there has been limited focus on micropollutants in stormwater, with existing studies primarily relying on a single line of evidence (pollutant profiles). Project URBAnWat3r serves as a crucial initiative aiming to adopt a comprehensive triad approach, transcending mere correlative evidence and seeking to elucidate cause-and-effect relationships. The specific goals of project URBAnWat3r are: (i) to define standard operating procedures for sample collection of stormwater and receiving waterbodies, for analysis of target micropollutants and the rationale behind their selection, as well as for bioassay protocols, inspired in good practices that warrant comparable procedures across the pilot areas and deliver reproducible methodologies; (ii) to determine the prevalence of a relevant subset of target micropollutants in urban and suburban stormwater runoffs and receiving waterbodies (analytical line of evidence); (iii) to assess the ecological status and ecosystem health of receiving waterbodies by analysing the structural and functional composition of macroinvertebrate communities and organic matter decomposition downstream of stormwater outlets (ecological line of evidence); (iv) to evaluate noxious effects of urban and suburban stormwater and receiving waters using a battery of ecotoxicological bioassays, incorporating species from key trophic levels and ecologically-relevant responses (ecotoxicological line of evidence); (v) to engage local communities and stakeholders – individually and collectively – in a discussion about the need for improved stormwater management in (sub)urban landscapes, through various dissemination and citizen science activities; (vi) to integrate the data of the 3 lines of evidence in the 3 pilot areas using a weight-of-evidence approach, considering their regional and temporal contexts, identifying sensitive metrics/indicators and susceptible areas (locally). These ambitious objectives integrate scientific inquiry with stakeholder involvement to foster participatory and cross-disciplinary approaches in promoting more sustainable cities. The project's advancements will support citizen awareness, drive much-needed public debate, and provide crucial scientific and societal insights for improving stormwater management in urbanized landscapes.