Temporal and spatial variation in pharmaceutical concentrations in an urban river system

Area of Science:

• Environmental Science
• Environmental Chemistry
• Public Health

Background:

• Pharmaceuticals are prevalent in the environment, but detailed spatiotemporal variability is understudied due to costs.
• Understanding pharmaceutical occurrence in wastewater and rivers is crucial for environmental and health risk assessment.

Purpose of the Study:

• To investigate the spatiotemporal occurrence of 33 diverse pharmaceuticals in York's wastewater system and the Rivers Ouse and Foss.
• To assess removal rates of pharmaceuticals in different wastewater treatment plant (WWTP) types.
• To evaluate a simple environmental exposure model for pharmaceuticals.

Main Methods:

• Collected samples from wastewater systems and the Rivers Ouse and Foss in York, UK.
• Analyzed 33 diverse pharmaceuticals using advanced techniques.
• Calculated removal rates in conventional activated sludge (CAS) and trickling filter WWTPs.
• Compared predicted environmental concentrations (PECs) with measured environmental concentrations (MECs).

Main Results:

• Removal rates varied significantly, from carbamazepine (not eliminated) to paracetamol (>99%).
• Pharmaceutical exposures exhibited significant spatial and seasonal variability in both rivers.
• Observed annual median concentrations were higher than previously reported in the EU and Asia.
• The environmental exposure model significantly underestimated MECs, particularly in the River Ouse (PEC/MEC ratio of 0.04).

Conclusions:

• Pharmaceutical pollution in rivers is highly variable, influenced by prescribing practices, hydrology, and wastewater management.
• Existing environmental models require refinement to accurately predict pharmaceutical concentrations.
• The study highlights the need for improved monitoring and management of pharmaceutical pollution in aquatic ecosystems.