Human pharmaceuticals enter the water cycle via wastewater – often in the form of their metabolites. These metabolites are rarely monitored, even though they may affect drinking water quality. The research project HuMeWaTri addresses this issue: Using advanced HRMS analytics, pharmaceutical compounds and their metabolites are comprehensively investigated throughout the water cycle, enabling well-founded assessments of their relevance for drinking water supply.
HHuman pharmaceuticals and their metabolites enter the water cycle via municipal wastewater. This issue is also addressed in the new EU directive on urban wastewater, which for the first time requires pharmaceutical manufacturers to contribute financially to the costs caused by their products. The goal is to reduce negative impacts on the environment and drinking water production in the long term. Especially in this political context, it is crucial for drinking water providers to have a comprehensive understanding of pharmaceutical residues in raw water sources.
Current wastewater and surface water monitoring typically addresses the issue of pharmaceuticals through targeted analysis of active ingredients. However, many pharmaceuticals are excreted as metabolites, which are often insufficiently covered by current monitoring strategies. As a result, their potential impact on drinking water quality cannot be reliably assessed due to a lack of data. Targeted monitoring is further complicated by the fact that, unlike pesticide metabolites, only a few reference substances for pharmaceutical metabolites are commercially available.
The HuMeWaTri research project tackles this challenge by combining non-target and suspected-target screening using high-resolution mass spectrometry (HRMS) to detect pharmaceutical compounds and their metabolites throughout the water cycle. This enables a better understanding of their relevance for drinking water supply.
As a basis for suspected-target screening, a list of pharmaceutical compounds already detected in the water cycle – as well as the most frequently used ones, especially those with high metabolite formation potential – is compiled through literature review and comparison with the German annual report on medical prescriptions. Additional, previously unknown or overlooked substances can be identified through non-target screening.
To realistically assess the presence of metabolites in the aquatic environment, water samples from the urban water cycle (from wastewater treatment plant effluent to raw water used for drinking water production) are analyzed using the developed method. For reliable identification of detected features, metabolites that are not commercially available are synthesized from pharmaceutical parent compounds using liver enzymes (S9 mix) and used as reference substances.
This study provides a solid data foundation that strengthens the ability of the German water sector to engage in future discussions about the relevance of pharmaceutical compounds and their metabolites.
