In ten years wastewater epidemiology has developed into a mature field of knowledge which provides objective data on the use of narcotics by the population. Now the methodology has been further developed and is also being used in forensic, public-health and anti-doping applications. It can also for example provide a picture of a population’s alcohol, sweetener and coffee consumption, or of its exposure to pesticides.
What is wastewater epidemiology?
Wastewater epidemiology collects data on human consumption and use of substances by conducting chemical analyses of the residues or transformation products of the substances in the wastewater. So-called 24-hour composite samples are collected from the influent entering a wastewater treatment plant using a special sampling procedure. The samples are then analysed for biomarkers, which are substances that – following the consumption of a substance – are excreted by people and end up in wastewater. The day’s load of such a substance is calculated by multiplying the measured concentration by the total volume of wastewater that flows into the plant over 24 hours. The load is then divided by the number of people connected to the sewer system. The data obtained on the level of use per person make it possible to compare the situation in different cities. The method has up until now been used primarily for inventories and to establish geographic and temporal trends for the use of narcotics.
A number of new applications of wastewater analyses have very recently been tested and published. Examples among many include comparisons of alcohol, nicotine and caffeine consumption in different countries, the determination of human exposure to pesticides in eight European cities, and a measurement for the level of oxidative stress, which moreover is correlated with tobacco use.
Detecting illicit use, doping and drug labs
KWR is closely involved in these developments and has even devised and tested three new applications. The first is used to demonstrate that pharmaceuticals that are only available with a prescription are also purchased by illegal means (internet) and used.
The second relates to doping among amateur athletes. Wastewater samples are collected before and during several sports events, such as bodybuilding competitions, in the cities where they take place. Significant increases in the concentrations of dangerous slimming agents/diuretics can be detected in the wastewater during the course of the events.
The third application is useful to forensic research: when (illegal) drug laboratories discharge their waste a range of compounds end up in the sewer, creating a profile – actually a kind of fingerprint – of the synthesis process used to produce the drugs (mostly amphetamine or ecstasy). KWR research has demonstrated that such fingerprints are indeed perceptible in the wastewater and can assist in tracing the laboratories.
The expectation is that wastewater, which after all contains a treasure of chemical information and therefore constitutes a mirror of the society, will be increasingly used in the future, for example to determine the health and hygiene status of cities.