Organic Micropollutants in the Agricultural Chain of Production of Strawberries by Irrigation with Treated Wastewater and Assessment of Human Health Implications

Treated water reuse is vital for sustainable water management and reducing the strain on freshwater resources, particularly in agriculture, which has a great impact on freshwater withdrawal. Despite the benefits, the reuse of treated wastewater carries risks due to residual chemical and microbiological contaminants, such as the organic micropollutants polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs), which are not fully removed by current treatment processes and can affect plant growth and human health when used for irrigation. This study focuses on monitoring the PAHs and PCBs in wastewater used for irrigating strawberries, assessing their transfer to crops and potential health risks. The effluents of four wastewater treatment plants were monitored for two years (2017 and 2018) and used to irrigate strawberries grown in plot installations. Effective and robust analytical methodologies (60-99% recoveries, optimal reproducibility) were developed for wastewater and strawberry analysis. The analysis of the treated wastewaters showed the presence of residual PAH and PCB concentrations at hundreds of ng/L. The strawberry crops were further analyzed to measure the PAHs and PCBs. Since two PAHs were present in strawberries, a risk assessment was performed (EPA methodology), finding that the residual contamination of treated waters does not pose a significant health risk, for both adults and children, through the consumption of fruits.