Doubling of research projects looking at drug residues in the wastewater system

KWR’s research looking at drug residues in the water environment started more than fifteen years ago, when drinking water utilities began to ask whether these substances constitute a difficulty for the sector. “Residues of illicit drugs enter the wastewater system in urine,” explains Ter Laak. “They then pass on into surface water and other places. It was unclear whether this was a threat to drinking water sources. It soon emerged that the risk was limited.”

Mirror of society

For the drinking water sector, it was not necessary to continue this research. However, KWR did continue to play an important role in the European consortium that uses wastewater research to map out drug use. The results provide a ‘mirror of society’, with relevant information about the lifestyle and health of residents in a given area. Ter Laak: “We are now working for a range of municipal authorities in our country, usually five or six of them every year. But in the past year, we have conducted surveys for eleven municipalities and one water authority. As an independent research institute, KWR can deliver a lot of added value because we draw on years of experience. We know what it means when you find a given amount of a given substance in wastewater. In addition, we see the difference between illicit drugs that have been discharged directly and those that have been used. It is important not to confuse the two.”

Tree with branches

Another strength of KWR is its thorough knowledge of the water system. The wastewater system holds no secrets for the researchers and so they can help municipal authorities to study drug residues in certain parts of a city or area if required. They work with wastewater experts from municipal authorities and water authorities to identify exactly which parts of the wastewater system need to be isolated to acquire the desired data. Ter Laak explains this by drawing a comparison: “You can think of a wastewater treatment plant as the trunk of a tree. With all the different branches and leaves. The leaves are the houses in a district or town that are connected to the wastewater system. When you want to look not at the trunk of the tree but at a particular branch, you need to know how to get there. This is actually quite complex because the wastewater system is no respecter of urban boundaries. You really do have to bend over backwards sometimes to position sampling equipment in a strategic location. We work very closely with the municipal and water authorities, as well as their laboratories, to get that done.”

Vulnerable districts

Ter Laak believes that the increase in the complexity of wastewater sampling is due to the policy background. “Illegal practices such as drug trafficking are on the rise. Municipal authorities therefore want to know about drug use in – for example – vulnerable districts where these activities take place. We have often been able to use our data to disprove suspicions about how the two are related. In places where there are suspicions that there is a lot of drug trafficking, you don’t necessarily find a lot of drug traces in the wastewater.”

Sensitive information

Ter Laak stresses the confidential nature of his research. This is sensitive information. It is very important for municipal authorities to be careful in how they communicate the results of wastewater research. In order to answer questions properly, the researcher often presents his results at the relevant municipal authority. “During those meetings, the Trimbos Institute is also brought in by the authority,” he says. “That brings together our data about use and knowledge about the users. That adds meaning to the data, something which is very useful for administrators.”

Patterns of drug use

A number of patterns emerge from the mountain of data from the wastewater research looking at drug use. The research focuses on a wide range of illicit narcotics from cocaine to cannabis and from MDMA (XTC) to methamphetamine (crystal meth). Last year, alcohol consumption based upon the metabolite ethyl sulphate was also included at the request of two municipal authorities. “Drug use in cities is often higher in relative terms than in the periphery,” says Ter Laak. “And use in large to medium-sized cities is fairly similar throughout the country. Cocaine and cannabis products account for the lion’s share of consumption, followed by amphetamine (speed), ketamine or MDMA. There is a weekly pattern that peaks at the weekend for some drugs, such as MDMA. We haven’t got the results for alcohol consumption yet, but similar patterns have been observed in the past for alcohol.”

Expectation for the future

When asked about the future of this research into ‘the mirror of society’, Ter Laak says that he expects the trend of the intensification and increasing complexity of the surveys to continue. “Drug use is an increasing social problem. Administrators and the health care sector want a clearer understanding and basis for action. By combining expertise and data, we can learn more from the data so that we can arrive at more generic conclusions about the patterns of drug use that we see emerging in our country. And I hope the national government will provide guidance about our surveys so that we can bring together fragmented knowledge from municipal authorities better to establish a national picture. As KWR, our ambition is to be at the forefront of innovation and quality assurance, and that includes this type of research. Just as we work with the drinking water laboratories for the drinking water utilities, we believe that we can play the same role in this wastewater research as well.”

European ring test

KWR is the only organisation in the Netherlands that is a member of the European SCORE network (Sewage analysis core group Europe), which organises a ring test each year on behalf of the European Union’s Drugs Agency. On the basis of this involvement and a high score in the test, KWR meets the standard for an international validation of wastewater research looking at drug use.

Do you wish to keep up to date with the results of the wastewater research into drug use in Europe? Then keep an eye on our newsletter. New European results are expected in March.