Screening analysis of human pharmaceutical compounds in U.S. surface waters

Area of Science:

• Environmental Chemistry
• Environmental Science
• Pharmacology

Background:

• Pharmaceuticals are increasingly detected in surface waters.
• Assessing environmental concentrations of active pharmaceutical ingredients (APIs) is crucial.
• Existing models may not fully capture API fate and transport.

Purpose of the Study:

• To introduce and validate the Pharmaceutical Assessment and Transport Evaluation (PhATE) model.
• To estimate predicted environmental concentrations (PECs) of APIs in U.S. surface waters.
• To evaluate the model's performance against measured data and assess API fate information.

Main Methods:

• Utilized a mass balance approach to model API concentrations in 11 representative U.S. watersheds.
• Divided rivers into discrete segments to track API mass flow and loss.
• Estimated publicly owned treatment works (POTW) discharge loads based on population, usage, metabolism, and removal rates.

Main Results:

• PhATE-generated PECs were generally within an order of magnitude of measured concentrations for surrogate compounds.
• Model predictions were consistent with nationwide distributions of measured API concentrations.
• Simulations for 11 APIs showed varying degrees of consistency with measured data, highlighting potential for further investigation into depletion mechanisms and sampling representativeness.

Conclusions:

• The PhATE model provides a reliable tool for predicting screening-level API concentrations in the environment.
• PhATE can help identify data gaps and evaluate the suitability of existing API fate information.
• The model supports environmental risk assessment for pharmaceuticals in surface waters.