Comparing risk-based approaches to jointly assess environmental and human health risks and prioritize emerging contaminants in agricultural wastewater reuse.

Despite mitigating water scarcity, agricultural reuse of treated wastewater introduces contaminants of emerging concern (CECs) into ecosystems, posing risks to environment and human health. The large number of CECs complicates their comprehensive monitoring, especially due to analytical limitations and data gaps in toxicology. This study prioritizes CECs based on their environmental and human health risks, by applying two complementary methodologies: Quantitative Chemical Risk Assessment (QCRA) and TyPol, following the One Health framework. Unlike most existing approaches, which assess environmental or human risks separately, our study jointly considers both endpoints in an integrated assessment. QCRA enables contaminant-specific prioritization by integrating concentration data and toxicological thresholds to estimate probabilistic risk distributions. TyPol provides cluster-based prioritization by grouping CECs according to molecular properties, environmental behavior, and toxicological characteristics. Applied to 37 relevant CECs, both methodologies identified estrogenic compounds as high-priority for both endpoints, while macrolides exhibited a significant environmental risk. Other contaminants showed divergent prioritizations. QCRA provides contaminant-specific insights but relies on complete datasets, while TyPol demonstrated adaptability in scenarios with missing data, although with reduced precision. Together, these methodologies provide decision-makers with versatile tools to support regulatory actions, from monitoring programs to treatment strategies, advancing sustainable agriculture and public health protection.