A sugar cube in a pond
Researchers at the Toxicology Centre drain a small amount of wastewater just before it is treated at a wastewater treatment plant. Every 10 to 15 minutes, a small amount drops into a bottle. After 24 hours, the researchers can extract a sample from it that is representative of the whole day.
Then they measure the ultra-small number of metabolic products in that bottle. The ratio is comparable to the ratio of a sugar cube in a pond. They compare that result to the amount of wastewater and the local population. Thus, they arrive at a number of metabolic products per day per 1,000 people.
By taking samples at different times and from different places, researchers can infer certain trends. Does alcohol consumption increase on holidays? Are drugs also taken during the week? Is there more corona in urban or rural areas?
More cocaine in Western Europe
‘We can even make international comparisons’, Tim Boogaerts says, toxicology researcher in pharmaceutical sciences. ‘Every year, we take samples of wastewater in more than 100 European cities for a week. We then analyse those for metabolic products of, for example, cocaine and ecstasy.’ This provides an interesting, international picture of the distribution of illicit substances.
We now know that cocaine and ecstasy use is higher in Western Europe than in Eastern European cities. Another interesting finding: the use of stimulants is increasing every year in Belgium. ‘Of course, you have to note here that we only take samples from Brussels and Antwerp’, Boogaerts says.
Mirror of society
‘Besides measuring the use of classic drugs, wastewater analysis can also be used to detect new trends in drug markets’, Boogaerts continues. ‘In recent years, for example, we have seen a huge increase in the use of ketamine, a narcotic.’
According to Boogaerts, the technology will still be widely used in the future: ‘For many substances, such as pesticides or PFAS, we do not currently have sufficient research methods to measure their presence in wastewater. We are currently working on fine-tuning these methods. In the coming years, we will dive into the sewers to measure these substances as well.’
In short: wastewater analysis is an interesting research method, which can be used in many studies in addition to interviews or surveys, etc. In just one move, you can collect data on a large population AND you know for sure that the data are reliable. So wastewater is an honest mirror of our society.