Wastewater-based epidemiology, an analytical chemical approach for the investigation of human consumption of lifestyle chemicals

The research presented in this thesis supports the hypothesis that wastewater-based epidemiology (WBE) approach can be used as an alternative and non-intrusive technique that provides information about a population’s health and lifestyle habits. The focus is in the essential role of analytical chemistry in the development of advanced methodology for the reliable determination of illicit drugs, and also other licit and illicit substances, in the aquatic environment. To this end, liquid chromatography hyphenated to different mass spectrometers, employing both low and high resolution, and using target and suspect acquisition strategies, have been investigated. The results obtained in chapter 2 tackled different analytical challenges affecting the monitoring of illicit drugs, such as the inclusion of cannabis or new psychoactive substances in WBE studies, or the lack of WBE data from different world regions. In chapters 3 and 4, the aim was to go a little further and extrapolate the WBE approach to including other pharmaceuticals with potential for abuse, such as counterfeit medicines, and (il)licit substances used in the sport doping context. To this aim, two new analytical methods were developed, validated and applied to wastewater samples. This work contributed to the maturation of WBE as a complimentary epidemiological source of information, so that authorities can have a better picture of the prevalence of illicit drugs or other known compounds in a specified area or group, albeit at the (averaged) group level. In addition, the approach appeared to be successful for tracking the use of rogue pharmacies and counterfeit medication

Wastewater-based tracing of doping use by the general population and amateur athletes

The present study investigates the applicability of the chemical analysis of wastewater to assess the use of doping substances by the general population and amateur athletes. To this end, an analytical methodology that can identify and quantify a list of 15 substances from the groups of anabolic steroids, weight loss products, and masking agents in wastewater has been developed. The method uses solid phase extraction to increase the detection sensitivity of the target analytes, expected to be present at very low concentrations (ng L−1 range), and decrease possible matrix interferences. Instrumental analysis is performed by liquid chromatography coupled to high-resolution mass spectrometry, allowing data acquisition in both full scan and tandem MS mode. The method has been successfully validated at two concentration levels (50 and 200 ng L−1) with limits of quantification ranging between 0.7 and 60 ng L−1, intra- and inter-day precision expressed as relative standard deviation below 15%, procedural recoveries between 60 and 160% and matrix effects ranging from 45 to 121%. The stability of the analytes in wastewater was evaluated at different storage temperatures illustrating the importance of freezing the samples immediately after collection. The application of the method to 24-h composite wastewater samples collected at the entrance of three wastewater treatment plants and one pumping station while different sport events were taking place revealed the presence in wastewater, and hence the use, of the weight loss substances ephedrine, norephedrine, methylhexanamine, and 2,4-dinitrophenol. The use of these stimulants was visible just prior and during the event days and in greater amounts than anabolic steroids or masking agents