Application of a model for supporting risk assessment of emerging contaminant in the context of wastewater reuse for irrigation

About 17% of the European territories suffer from water scarcity. The situation is expected to worsen over the next years, with potentially severe socio-economic implications. Recently, EU member states agreed that agricultural reuse of reclaimed urban wastewater should be enhanced whenever this is safe, leading to the proposal of minimum requirements for safe reuse [1]. The proposal also recognized the need of including in the risk assessment (where relevant) contaminants of emerging concern, whose threat for environment and human health is well recognized. Given the general lack of measurements and the challenges inherent to field monitoring, integrated chemical fate models represent valuable tools to (i) predict exposure concentrations (for assessing the current risk) and (ii) to evaluate alternative scenarios (i.e. identify risk minimization strategies). However, these models are usually applied within the boundaries of urban areas or for hypothetical wastewater reuse scenarios [2], lacking significant validation for real cases. In this study, an integrated dynamic model was developed and tested for a highly urbanized area in northern Italy, where treated municipal wastewater is discharged into an irrigation canal. Calibration and validation were performed at different locations and risk indicators were calculated to assess environmental and human health safety associated to the exposure to several emerging contaminants.