Spatially and Seasonally Resolved Predictions Reveal Widespread Ecotoxicological Risk from Pharmaceutical Mixtures in...

Area of Science:

• Environmental Chemistry
• Ecotoxicology
• Water Quality Management

Background:

• Pharmaceutical pollution is a growing concern, exacerbated by demographic and environmental shifts, hindering the EU's toxic-free environment objective.
• Assessing the ecological impact of pharmaceuticals in aquatic ecosystems is crucial for effective environmental protection.

Purpose of the Study:

• To develop and validate a spatially resolved model for predicting pharmaceutical concentrations and ecological risks in rivers.
• To evaluate the ecotoxicological risks posed by individual pharmaceuticals and their mixtures to aquatic organisms.

Main Methods:

• A spatially resolved model was developed to predict concentrations of five key pharmaceuticals (carbamazepine, gabapentin, ciprofloxacin, sulfamethoxazole, metformin) in 1 km river stretches.
• Model accuracy was validated against observed data (2008-2014), and ecological risk assessments were conducted for single and mixture toxicities on algae, daphnia, and fish.

Main Results:

• The model demonstrated high accuracy (95-100% within 1 order of magnitude) across spatial and temporal scales.
• Significant ecological risks were identified in over half of Saxon rivers for single pharmaceutical exposures, increasing to 99% for mixtures.
• Carbamazepine showed improved model skill due to frequent observations, while ciprofloxacin performance was reduced by low environmental concentrations.

Conclusions:

• Pharmaceutical pollution presents widespread ecotoxicological risks in rivers, particularly from chemical mixtures.
• The developed modeling framework effectively identifies pollution hotspots and trajectories, enabling spatiotemporal predictions under global change.
• Proactive measures informed by this framework are essential for mitigating pharmaceutical pollution and ensuring a healthier aquatic environment.