Department Urban Water Management

In-Sewer Transormation of Illicit Drugs (SEWPROF)

As part of the European Marie Curie ITN “SEWPROF”, this PhD project focuses on the biotic and abiotic transformation processes of the illicit drugs during their transport in sewer networks. Ann-Kathrin investigates the role of sewer biofilms on the illicit drug transformation.

Critical review on the stability of illicit drugs in sewers and wastewater samples

Wastewater-based epidemiology (WBE) applies advanced analytical methods to quantify drug residues in wastewater with the aim to estimate illicit drug use at the population level. Transformation processes during transport in sewers (chemical and biological reactors) and storage of wastewater samples before analysis are expected to change concentrations of different drugs to varying degrees. Ignoring transformation for drugs with low to medium stability will lead to an unknown degree of systematic under- or overestimation of drug use, which should be avoided. This review aims to summarize the current knowledge related to the stability of commonly investigated drugs and, furthermore, suggest a more effective approach to future experiments. From over 100 WBE studies, around 50 mentioned the importance of stability and 24 included tests in wastewater. Most focused on in-sample stability (i.e., sample preparation, preservation and storage) and some extrapolated to in-sewer stability (i.e., during transport in real sewers). While consistent results were reported for rather stable compounds (e.g., MDMA and methamphetamine), a varying range of stability under different or similar conditions was observed for other compounds (e.g., cocaine, amphetamine and morphine). Wastewater composition can vary considerably over time, and different conditions prevail in different sewer systems. In summary, this indicates that more systematic studies are needed to: i) cover the range of possible conditions in sewers and ii) compare results more objectively. To facilitate the latter, we propose a set of parameters that should be reported for in-sewer stability experiments. Finally, a best practice of sample collection, preservation, and preparation before analysis is suggested in order to minimize transformation during these steps.
McCall, A.-K.; Bade, R.; Kinyua, J.; Lai, F. Y.; Thai, P. K.; Covaci, A.; Bijlsma, L.; van Nuijs, A. L. N.; Ort, C. (2016) Critical review on the stability of illicit drugs in sewers and wastewater samples, Water Research, 88, 933-947, doi:10.1016/j.watres.2015.10.040, Institutional Repository

In batch experiments with wastewater and sewer biofilms the influences of biological, chemical, and physical processes on the transformation of 30 illicit drugs and pharmaceuticals (or metabolites) were quantified. Rates varied among locations and over time which are published in a recent ES&T article.  

The current aim is to identify relevant variables to model drug transformation during in-sewer transport. This model will predict drug loss and uncertainty for different realistic scenarios (e.g., influence of catchment size, number of drug users).

Project description

SEWPROF:  “A new paradigm in drug use and human health risk assessment: Sewage profiling at the community level”. EU FP7, Marie Curie ITN (Initial Training Network, Grant agreement no.: 317205).

Contact

Dr. Christoph Ort Tel. +41 58 765 5277 Send Mail
Prof. Dr. Eberhard Morgenroth Tel. +41 58 765 5539 Send Mail