Assessing the Risk of Wastewater Reuse in Agriculture: Is Irrigated Crops’ Food the main Exposure Route for Alkylphenols compared to Drinking Water?

The excessive exploitation and contamination of freshwater pose threats to public health, leading to cross-contamination among interconnected environmental compartments such as freshwater, soil and crops. In particular, contaminants of emerging concern (CECs) originating from human activities are not completely removed by wastewater treatments plants and the effluent discharged in surface waters as well as wastewater reuse determine their presence in drinking water (DW) sources, soil and crops intended for human consumption. Bisphenol A (BPA) and nonylphenol (NP) have been frequently detected in DW and food, namely the major exposure sources for humans, with adverse effect, respectively, on immune and renal systems. Currently, health risk assessments focus solely on individual exposure sources without considering the multiple exposure routes humans are exposed to. We propose an integrated approach to quantitatively assess health risk from CECs considering multiple exposure from both DW and food consumption across the relevant interconnected environmental compartments. This procedure was applied to BPA and NP to calculate their probabilistic Benchmark Quotient (BQ), demonstrating its ability to quantitatively apportion the risk between contaminants and exposure sources. Scenario analyses simulating BPA and NP reduction strategies were conducted, underscoring the quantitative risk assessment potential as a decision support tool for prioritizing mitigation actions. The estimated health risk from BPA was significantly higher compared to NP, with the consumption of food from edible crops posing a greater risk than tap water. Therefore, prioritizing mitigation actions for the prevention and removal of BPA from food would be more effective in minimizing the health risk.