Endocrine disrupting activities profiling of monitored French river sites based on in vitro bio-analytical tools
Résumé
Regarding thousands of chemicals occurring in aquatic systems at trace levels and as mixtures, current regulatory tools -in the frame of the water framework directive (WFD)- give an incomplete scope of environmental complexity. In this context, development and evaluation of new strategies allowing holistic contamination characterization and identification of environmental pollutants contributing to deleterious effect (e.g. endocrine disruption) on exposed organisms is relevant. To tackle this challenge, the use of in vitro bio-analytical tools is a promising approach since they allow specific, sensitive and quantitative detection of all compounds presenting similar mechanism of action (e.g. binding to nuclear receptors) within environmental mixtures. Hence, monitoring active pollutants by using a panel of complementary bioassays should increase the detection capacity of contaminants and allow a better hazard assessment through biological activity-based profiling. In the frame of a large study on surface waters monitoring in France in 2012 (Botta et al. accompanying communication), we applied a battery of receptor-based in vitro assays (estrogen (ER), androgen (AR), glucorticoid (GR),pregnane (PXR), and aryl hydrocarbon (AhR) receptors) for establishing endocrine disrupting profiles of 20 French rivers sites subject to various anthropogenic pressures (i.e. urban, agricultural, industrial, mixed, reference). This was performed on both sediment and surface water (both grab and POCIS) extracts. Estrogenic (1-10 ng-E2eq/g d.w range), PXR-like (1-10 µg-SReq/g d.w range) and dioxin-like (1-100 ngTCDD-eq/g d.w range) activities were detected in both sediment and surface water while anti-androgenic activity (10-100 µg-DHTeq/g d.w range) was only detected in sediment and glucorticoidic activity (100 µg-DEXeq/g d.wrange) was only detected in one surface water.Overall, the levels of detected activity differed according to sites and to compartments. Altogether, the use of in vitro bio-analytical tools combined to multi-compartment approach offers a cost-effective integrated quality assessment of the chemical status and permits to classify and identify hotspot polluted sites.They constitute a relevant complementary approach to current regulatory chemicals analyses for routine monitoring of chemical quality status.