Bioanalytical characterization and source identification of a high glucocorticoid contamination in a river under urban and industrial pressures
Résumé
Synthetic glucocorticoids (GCs) are a group of steroids that are massively used as anti-inflammatory drugs to treat a broad spectrum of deseases such as asthma or arthritis. They may enter surface waters via urban, hospital and/or pharmaceutical industry effluents and were already detected in surface waters at concentrations ranging from < 1 to tens of ng/L. In organisms, GCs are designed to act through the glucocorticoid receptor (GR) and some studies have reported adverse effects on aquatic vertebrates, such as fish. Overall, there is still a need for knowledge on the sources and driver compounds for GR activity in different contexts. In the frame of a French national survey of EDCs in surface waters using in vitro bioassays, we previously identified a hotspot river site with high GR activity. To further identify the source(s) and the nature of this contamination, an investigative monitoring based on bioassay (MDA-Kb2) and chemical analyses was implemented in the current study. A contamination mapping was established on the basis of bioassay data, along a 40 km streatch upstream and downstream of the contaminated site allowing identification of the discharge of the contamination in the river and of its highly probable industrial origin in the sewerage network, although the contribution of waste waters from a hospital could not be excluded. By using a suspect screening approach based on HR-MS, fluticasone propionate as well as few other GCs were identified in the samples. Mass balance analysis based on quantitave chemical analysis confirmed fluticasone propionate main role in the measured GR activity. The high mobility and persistence of this contamination points out possible high environmental concern in terms of its fate and hazard for aquatic organisms.