Assessing city-wide pharmaceutical emissions to wastewater via modelling and passive sampling

Area of Science:

• Environmental chemistry
• Public health
• Chemical risk assessment

Background:

• Assessing human and environmental exposure to the growing number of chemicals is challenging.
• Wastewater-based epidemiology provides insights but measuring all registered chemicals is unfeasible and costly.
• Current methods struggle with comprehensive exposure assessment for data-poor compounds.

Purpose of the Study:

• To evaluate the feasibility of estimating chemical emissions based on usage data as an alternative to direct monitoring.
• To compare model-based emission estimations with actual wastewater measurements for active pharmaceutical ingredients (APIs).
• To highlight the importance of excretion fractions in emission estimation models.

Main Methods:

• Estimated emissions of 29 APIs to wastewater for a medium-sized Dutch city.
• Collected national and local usage data, including prescriptions, healthcare use, and over-the-counter sales.
• Accounted for routes of administration, excretion, and in-sewer back-transformation of conjugates.

Main Results:

• Model-based emission estimation for APIs at the city level is feasible.
• Estimated emissions showed good agreement with wastewater measurements obtained via passive sampling.
• The choice of excretion fraction significantly impacts model performance.

Conclusions:

• Estimating chemical emissions from usage data is a viable and efficient approach for exposure assessment.
• Incorporating excretion fractions is crucial for accurate emission modeling.
• This approach offers a systematic way to assess exposure to a wider range of chemicals.