Critical Evaluation on the Risk Assessment for Contaminants of Emerging Concern within the EU Regulation on Wastewater Reuse in Agriculture: A Case-Study

Reclaimed wastewater (RWW) reuse in agriculture represents one of the key strategies fostered by the EU governance to reduce the pressures on water sources. The new Regulation on water reuse, entered into force in 2023, defines the minimum requirements for water reuse in agriculture and introduces the fit-for- purpose approach subjected to risk management; furthermore, it introduces the possibility to establish additional requirements especially for contaminants of emerging concern (CECs), based on “scientific evidence”. However, some elements about the implementation of the water reuse risk management plans should be still elucidated. The present study was carried out with the aim to evaluate by the risk assessment the potential reuse of the reclaimed wastewater from a Wastewater Treatment Plant (WWTP) in the Lazio region, Italy, for crop irrigation focusing on CECs. Since official guidelines are still not available at the European level, the risk quotient (RQ) was calculated following the procedure proposed by Prosser and Sibley (2015). The analysis was carried out twice, i.e. using the values measured on the final effluent and values from the literature. The results obtained were different depending on the data, highlighting a high risk due to carbamazepine and benzotriazole in the latter case and an almost acceptable risk using the measured concentrations. A pilot scale study with the effluent from the same plant reused for crop irrigation will be implemented and used for a comparison and validation of these results.