Presence and accumulation of pharmaceutical compounds in agricultural soils receiving six years of biosolid applications.

The use of biosolids derived from municipal wastewater treatment sewage solids in agriculture has raised concerns regarding the presence and potential accumulation of contaminants of emerging concern (CEC) in soils. This study investigated the influence of six consecutive years of applications of an alkaline treated biosolid (ATB) in an agricultural field on the concentrations of seven pharmaceutical compounds considered as CECs including, carbamazepine (CBZ), caffeine (CAF), dimethylxanthine (DMX), norfloxacin (NOR), gemfibrozil (GEM), diclofenac (DIC), and warfarin (WAR). Soils from a research site receiving annual ATB application rates (0, 14, and 42 Mg ha-1) over six years (2009-2014) were analyzed for the target pharmaceuticals. Soil samples were analyzed using a combination of accelerated solvent extraction, solid phase extraction (SPE), and liquid chromatography with mass spectrometry (LC-MS). CEC concentrations increased significantly (p < 0.05) with ATB application rate, with CBZ, CAF, and NOR reaching maximum concentrations of 35.2, 41.6, and 47.9 ng g-1, respectively, in the highest application rate plots. Seasonal changes in CEC concentrations were measured, with an increase directly after application of biosolids but significant reductions at post-harvest. Incremental increases in target CEC concentrations were observed in the soils at the post-application and post-harvest sampling periods over the six years. The findings highlight the need for comprehensive management strategies to mitigate potential risks associated with the presence of biosolids derived CECs in agricultural soils.