Wastewater-based epidemiology, or WBE for short, is the practice of analysing sewage samples from a community to determine levels of certain chemicals, pathogens or other substances in the wastewater. It has been employed by nations around the globe for a number of decades, though its use in the ongoing coronavirus pandemic has earned it greater mainstream attention than it has enjoyed prior.
Nonetheless, its widespread use has not prevented those without any background in scientific research from knowing very little about its applications. With that in mind, here are three of the most common uses of WBE, along with some information about how exactly it is employed and the potential benefits it can bring in each discipline.
The most famous application of WBE is its role in determining the propagation of a virus or disease among a certain segment of the population. Specifically, high-throughput wastewater has grown to play a key role in coronavirus surveillance, since it is capable of monitoring a far larger number of people in comparison to individual polymerase chain reaction (PCR) tests. In fact, the very same PCR technology is used in most WBE techniques, meaning that it essentially performs the same role as individual diagnostics – but for a whole group of people.
It also does so in a non-invasive and without patients even developing symptoms. This gives the authorities a jump on the disease and allows them to impose restrictions or divert resources to contain its spread. Of course, the same is applicable to a wide variety of illnesses and afflictions, not just COVID-19. Indeed, WBE techniques have been used to determine widespread infection of polioviruses, bacteria and other pathogens for several decades now.
At the same time, WBE is capable of detecting the presence of far more than just harmful bacteria and pathogens responsible for diseases and viruses. It can also quantify the concentrations of certain chemicals, giving the scientific community an approximation of their prevalence in the local population and their ability to endure in both the human body and the environment.
For instance, so-called “forever chemicals” (or per- and polyfluoroalkyl substances, or PFAS) have been an increasing topic of concern for environmentalists, thanks to their incredibly long half-life and the way in which they can travel extremely long distances undamaged. For those interested, the article PFAS: Keeping Up with Trends, Detection Methods and Regulatory Measures has more information on this emerging topic and how it relates to WBE.
Another application of WBE is the quantification of certain types of drugs, medications and narcotics in the sewage of a community. This allows us to understand more about how pharmaceuticals can persist in the environment and their potential effects on the natural world. It also gives a snapshot of the extent of legal and illegal drug use and abuse.
It should be stressed that WBE is not capable of identifying individual drug users and is not intended as a tool for pointing blame or proving criminal complicity. It can, however, paint a picture of how widespread drug use and abuse is in a society, allowing the authorities to take relevant action to address the issue where necessary.