Pharmaceutical transfer from treated wastewater to edible crops: occurrence, bioaccumulation, and dietary exposure in a semi-arid agroecosystem

Abstract

This work provides the first systematic evidence of pharmaceutical residues in vegetables irrigated with reclaimed wastewater in Mendoza, Argentina, expanding current knowledge of pharmaceutical contamination in semi-arid agroecosystems and underscoring the need for risk-based monitoring and management to ensure environmentally safe wastewater reuse. The reuse of treated wastewater for irrigation is increasingly promoted by governments as a sustainable strategy in water-scarce regions; however, this practice may facilitate the transfer of bioactive and hazardous pharmaceutical residues into agroecosystems and food crops. This study assessed the occurrence, uptake, and potential dietary exposure of 13 pharmaceuticals in 4 vegetables irrigated with treated effluent. Wastewater and vegetable samples were analyzed by HPLC–MS/MS, with recoveries of 73–113% and limits of quantification in the low-ng g −1 range. Total pharmaceutical concentrations reached up to 333 ng mL −1 in effluent and 554 ng g −1 fresh weight in lettuce. Principal Component Analysis revealed distinct accumulation patterns, with analgesics predominating in tomato and antibiotics in leafy vegetables. Estimated daily intakes were several orders of magnitude below therapeutic thresholds; however, given the persistence and biological activity of the detected compounds, continued monitoring under chronic exposure scenarios is warranted. These findings demonstrate that wastewater reuse represents a diffuse source of pharmaceutical pollution and a pathway for transfer into the food chain, contributing new evidence from Latin America to address regional gaps in knowledge on dietary exposure.