Impacts of compound properties and sediment characteristics on the sorption behaviour of pharmaceuticals in aquatic systems.
Sorption is a key factor in determining the persistence, attenuation and bioavailability of sediment-associated contaminants. However, our understanding of the sorption behaviour of pharmaceuticals in sediments is poor. In this study, we investigated the sorption behaviour of a diverse set of pharmaceuticals in a range sediment types. Sorption affinity of pharmaceuticals for all sediments was found to increase in the order mefenamic acid<cimetidine<atenolol<amitriptyline<diltiazem. Comparison of the experimental observations with predictions from an existing model for estimating sorption revealed the model worked poorly for the study pharmaceuticals. Multiple linear regression analysis was therefore used to develop new models for estimating sorption of individual pharmaceuticals based on sediment properties. The analyses indicated that sorption is related to properties such as Log Dow of a compound in the sediment (lipophilicity corrected for the sediment pH), cation exchange capacity, clay%, organic carbon content and exchangeable Ca(2+), although, with the exception of atenolol, robust relationships between sediment properties and sorption were not obtained. Overall, the results demonstrate how complex the processes are that drive the sorption of pharmaceuticals in sediments and highlight the need for generation of further experimental data and further model development work.
Environment Department, University of York, Heslington, Wentworth Way, York, YO10 5NG, UK.
Omar S A
OSA
Al-Khazrajy
Environment Department, University of York, Heslington, Wentworth Way, York, YO10 5NG, UK. Electronic address: alistair.boxall@york.ac.uk.
Alistair B A
ABA
Boxall
D000327:Adsorption; D019015:Geologic Sediments / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D007493:Iraq; D016014:Linear Models; D008956:Models, Chemical; D015394:Molecular Structure; D004364:Pharmaceutical Preparations / Q000032:analysis* / Q000737:chemistry; D013499:Surface Properties; D006113:United Kingdom; D014874:Water Pollutants, Chemical / Q000032:analysis* / Q000737:chemistry
D004364:Pharmaceutical Preparations; D014874:Water Pollutants, Chemical
Distribution coefficient (Kd); Modelling; Pharmaceuticals; Sediment characteristics; Sorption isotherms