A moral compass for using sewage water to study drugs use

And it’s not only in the digital world that we leave tracks: we all leave chemical tracks in our environment as well. Studying a city’s sewage water tells you a lot about its inhabitants. Sewage water reflects society. It contains information about, for example, the prevalence of diseases, for example with fragments of the coronavirus, or the presence of antibiotic resistance in a particular area. It can also be used to learn more about the use and application of household chemicals such as detergents, disinfectants, personal care products or cosmetics, and the monitoring of the use of illegal drugs in sewage water won’t have escaped your notice. Sewage water is a seemingly inexhaustible source of information for experts from various disciplines such as chemists, engineers, pharmacologists, sociologists, doctors, epidemiologists, statisticians and data analysts. But how do we handle this information?

Sewage water research to monitor drugs use

The drugs we use leave their traces in our waste water. This makes it possible to map the extent of use, and trends, in individual villages, towns or regions. This is a fantastic tool for assessing the use of illegal drugs on its merits, and to check whether local or national drugs policies are having an effect on use patterns. Drugs use is surrounded by shame and secrecy. Which is why, as with the surveillance of our conduct on the Internet, it’s fair to ask whether Big Brother is also in our drains.

However, there is one important difference. Unlike our activities on the Internet, our waste water doesn’t contain IP addresses or personal data. Our waste water is mixed up with waste water from many other people. So studies of sewage water will not compromise our individual privacy as long we don’t study the drains from individual homes or buildings. To protect the privacy of individuals and generate robust results, the international sewage water research community (SCORE network) has proposed that waste water from communities with fewer than 10,000 inhabitants should not be reported separately.

However, the privacy of individuals will still not be compromised if we report on communities smaller than 10,000 inhabitants. Moreover, these substances have a major impact on people’s health and socio-economic position, which means that more detailed information about geographical distribution and temporal variation in use can be useful for governments and civil society organisations. Nonetheless, information of this kind can lead to stigmatisation, regardless of the size of the community. That was seen some years ago when there were reports about relatively high levels of cocaine use in Volendam. Precisely because drugs use is a delicate topic for individuals and communities, it continues to represent a dilemma for the sewage water researcher.

Sewage water reflects society. For example, we can map out drugs use for individual regions, municipalities or local areas. But how do you decide what to investigate, and what to leave to one side? These are moral questions that are involved when studying all our sewage water, yours and mine.

Sewage water research for the public good

In the sewage water studies looking at drugs use, we should consider not only the size of the community studied but also how the information is used. Smaller communities can be studied as long as the privacy of individuals is not at stake and the information serves a public interest. Examples include research for government organisations working on public health, prevention or the legal aspects (such as the undermining of public institutions) of drug use and the related production, processing and trade.

This is one researcher who will, in principle (and as a matter of principle), not work on studies that serve commercial interests rather than public interests. As a researcher at KWR, with drinking water companies as shareholders, and at the University of Amsterdam, I serve the public interest. That is my moral compass for sewage water research, where there is a close relationship between value for society and the value judgment of society.