Biodegradation kinetics of individual and mixture non-steroidal anti-inflammatory drugs in an agricultural soil receiving alkaline treated biosolids

Abstract

Land application of biosolids is one potential source of pharmaceuticals and personal care products (PPCPs) into agricultural soils. Degradation is an important natural attenuation pathway that affects the fate and transport of PPCPs in soil system and could be altered upon biosolids application. The present study was performed to assess the degradation kinetics of three commonly used non-steroidal anti-inflammatory drugs (NSAIDs), including naproxen (NPX), ibuprofen (IBU), and ketoprofen (KTF), in a sandy loam soil amended with alkaline treated biosolids (ATB) introduced either as individual compounds or as a multi-compound mixture. Results of this study indicated the disappearance of studied NSAIDs in all treatments were mainly attributed to biodegradation and followed the first-order exponential decay response. In soil receiving ATB amendment, degradation of NPX and IBF in all treatments, as well as KTF in individual treatment was inhibited over the 14 day incubation study. Inhibition effect from ATB amendment was also observed in sterilized treatment. The presence of NSAIDs in mixture treatment reduced the degradation rate of NPX and KTF in soil, while the opposite results were observed in ATB amended soil. Ibuprofen exhibited the inhibition of degradation in both soil and ATB amended soil. Inversely, mixture compound environment stimulated the disappearance of all studied NSAIDs in sterilized treatment, except NPX in soil. Results of this study demonstrated the complex degradation behavior of NSAIDs in the presence of ATB and chemical mixtures, which warrants future investigation that incorporates a broader range of biosolids, soil type, and pharmaceutical mixtures to better understand the fate of pharmaceuticals in the environment.