Monitoring emerging contaminants in the drinking water of Milan and assessment of the human risk

Emerging Contaminants (ECs) are ubiquitous in waters, arousing concern because of their potential risks for human health and the environment. This study investigated the presence of multiple classes of ECs in 21 wells over the drinking water network of Milan, in the most inhabited and industrialized area of Italy, and assessed the risks for consumers. Samples were analyzed using liquid chromatography coupled to mass spectrometry. Human risk assessment (HRA) was conducted by comparing the measured concentrations with drinking water thresholds from guidelines or calculated in this study; first considering the exposure to each single EC and then the entire mixture. Thirteen ECs were measured in the low ng/L range, and were generally detected in less than half of the wells. Pharmaceuticals, perfluorinated substances, personal care products, and anthropogenic markers were the most frequently detected. The results of the HRA excluded any risks for consumers in each scenario considered. This is one of the most comprehensive studies assessing the presence of a large number of ECs in the whole drinking water network of a city, and the risks for human health. Results improve the limited information on ECs sources and occurrence in drinking water and help establishing guidelines for regulatory purposes.