Evaluation of substances of abuse consumption and enterovirus prevalence in Barcelona's (Spain) urban wastewater and their correlation with socioeconomic variables.

Wastewater-based epidemiology (WBE) is a powerful tool for tracking chemical and biological markers and for the analysis of population-level health trends. This study adopted a robust multi-stakeholder approach (bringing together key representatives from local administration, health centres, social organizations, water utilities, and academia) to conduct wastewater monitoring using the quadruple helix model, with the aim to enhance stakeholder engagement and improve population health assessments. The substances of abuse of greatest interest to stakeholders, such as cocaine, caffeine, and nicotine consumed in the Barcelona Metropolitan Area (North-East Spain), were evaluated to monitor lifestyle habits. Additionally, the prevalence of enterovirus genogroups (EVs), also selected by stakeholders, was assessed as an indicator of infectious agents. Findings were correlated with socioeconomic variables to gain insight into territorial disparities. This study proposes an innovative pathway for WBE by integrating social science to contextualise wastewater-derived data, thereby streamlining the interpretation of findings to inform decision-making.