Effect of sediment composition and accumulation on pharmaceutical product spatial distributions at the suburban pond scale (Beulie pond, SNO Observil, France)

Abstract

Pharmaceutical products (PPs) are found in several compartments of the environment, and are mostly emitted by wastewater treatment plants effluents. Their occurrence in the particulate phase, in opposition with the dissolved one, also promotes their occurrence in retention areas, where particles transported by streams settle. The study focuses on understanding how different constituents of pond sediment are distributed within a suburban pond, revealing patterns or hotspots of PPs accumulation. Results confirmed the heterogeneous spatial distributions of the granulometric fractions, total organic carbon, quantitative palynofacies, crystalline phase distributions and PPs contents. The delta preferentially concentrates total organic carbon (14.5 ± 2.2 %), and particularly terrigenous organic matter and neutral PPs, while the main decantation area accumulates mostly fine particles (58.2 ± 7.7 %), kaolinite, algal organic matter and cationic PPs. The potential role played by OM and kaolinite in PPs adsorption is supported by their respective spatial trends at the pond scale. Further attention should be paid to surface sediments components and PPs sensitivity to seasonal variations, especially in terms of flow, pH and oxygenation of the water-column. This spatial approach allowed to identify preferential accumulation and concentration areas within the pond, where the following extensive characterization of interface sediments highlighted the factor likely to influence PPs trapping within the pond.