Concentrations, partitioning and ecological risk of pharmaceuticals and personal care products in UK freshwater sediment

Pharmaceuticals and personal care products (PPCPs) have received increasing attention in recent years as emerging contaminants that could adversely affect human health and the environment. While previous studies focused mainly on water, little is known about the occurrence and risk of PPCPs in sediment. The present study investigated 30 widely used PPCPs in sediment samples from two rivers and two canals in the UK. Average Σ30PPCPs concentrations in sediments were 129, 79, 62 and 110 ng/g dry weight in the River Tame, Coventry Canal, River Severn, and Birmingham & Worcester canal, respectively. Amoxicillin, gabapentin, caffeine, propranolol, DEET, naproxen, diclofenac Na, meclofenamic acid and β-estradiol were detected in all studied locations. The highest concentration measured was 43.6 ng/g of diclofenac (Coventry Canal). The octanol-water partition coefficient (Log KOW) of target PPCPs, and their experimentally measured sediment–water distribution coefficient (Log KP), showed a significant positive correlation, indicating the partitioning of PPCPs between water and sediment may be attributed, at least partially, to their lipophilicity. The ecological risk of target PPCPs in sediment to aquatic biota was assessed using a risk quotient (RQ) approach. The estimated RQ values for amoxicillin on Cyanobacteria were > 1 in all studied locations, indicating high risk to freshwater Cyanobacteria, while 17-α-ethinyl estradiol and caffeine posed high ecological risk (RQ > 1) to fish. These results highlight the need for better removal efficiency of PPCPs by wastewater treatment plants to prevent their accumulation in sediment and call for further development of effect-based sediment quality standards.