Spatial distribution of Pharmaceuticals within the particulate phases of a peri-urban stream

Lauriane Ledieu (1, 2) , Anaëlle Simonneau (1, 2) , Thomas Thiebault (3) , Laëtitia Fougère (4) , Emilie Destandau (4) , O. Cerdan (5) , Fatima Laggoun-Défarge (1, 2)

1 ISTO - Institut des Sciences de la Terre d'Orléans - UMR7327
2 Biogéosystèmes Continentaux - UMR7327
3 METIS - Milieux Environnementaux, Transferts et Interactions dans les hydrosystèmes et les Sols
4 ICOA - Institut de Chimie Organique et Analytique
5 BRGM - Bureau de Recherches Géologiques et Minières (BRGM)

Pharmaceutical products (PPs) are consumed worldwide and are continuously released into hydrological environments, but are not efficiently removed by sewage treatment plants. Their occurrence within the dissolved phase has been extensively studied, but only a few articles concern solid matrices. The mechanisms and extent of sorption depend on the properties of both the molecules (degradability, charge, hydrophobicity) and the matrices (clay content, organic matter content), making the spatio-temporal distribution of PPs in natural environments complex and poorly elucidated. To improve our understanding of PP distribution at a catchment scale, this study investigated different groups of molecules with varying solubility and charges, in water, suspended particulate matter, bed-load and pond sediments. The Egoutier stream, which collects the sewage effluents from two health institutions sewage effluents, is a good candidate for this investigation. Results indicate that PP occurrences in the different particulate compartments were mainly regulated by their wastewater occurrences and charges. Particulate phases all along the Egoutier stream were characterized by a limited clay content (i.e. less than 1%) and significant organic carbon content (i.e. between 0.3% and 18.0%) favouring non-specific adsorption. Therefore, neutral PPs, exhibiting higher discharge rates, persistence and hydrophobicities in comparison with cationic and anionic molecules, were the most abundant PPs in the particulate phases of this catchment. In bed-load sediments, global PP spatial distributions reflected discharge sites and sedimentary accumulation zones, mostly that of organic matter. Spatial distributions of the more hydrophobic and persistent PP in the particulate phases thus followed the stream sedimentary dynamic.

Mots clés: Particulate phases; Pharmaceuticals; Spatial distribution

Domaines: Planète et Univers [physics]; Interfaces continentales, environnement

Lauriane Ledieu, Anaëlle Simonneau, Thomas Thiebault, Laëtitia Fougère, Emilie Destandau, et al.. Spatial distribution of Pharmaceuticals within the particulate phases of a peri-urban stream. Chemosphere, 2021, 279, pp.130385. ⟨10.1016/j.chemosphere.2021.130385⟩. ⟨insu-03183855⟩