Thousands of chemical substances seep into the environment every day. Scientific exchange about harmful substances is one of the objectives of NORMAN, a European network of reference laboratories, research centres and affiliated organisations. Eawag is a significant Swiss partner which is actively engaged in this.

Detective work in the laboratory: using high-tech analysis equipment, the Eawag researchers discover previously unknown target substances. (Photos: Kellenberger Kaminski Photographie)

The NORMAN network, with a good 70 members, celebrated its tenth anniversary in Brussels at the end of October 2016. Juliane Hollender was there. "Through Eawag, Switzerland is a fully involved and valued partner of this  European institution," explained the head of the Environmental Chemistry Department of Eawag and professor at ETH Zurich. She specialises in discovering unknown harmful substances applying new analytical techniques. Within NORMAN, she also leads a working group on what is known as non-target screening and, together with her team, organised a conference on this topic in Ascona in 2016, attracting 120 participants from over 20 countries.

The undesired micro-impurities are residues of pharmaceuticals in rivers and lakes, for example.  Diclofenac, which is the basis for many painkillers and anti-inflammatories, made headlines right around the world. This active agent is only partially broken down in modern sewage treatment plants. While the concentrations of Diclofenac barely pose any risk to people, they may lead to kidney damage in fish. "Among other things, 100 of Switzerland's 700 sewage treatment plants are set to be updated over the next twenty years, among other things," explained Juliane Hollender, "in particular in places where there are large populations. This may bring about a substantial reduction in the concentration of pharmaceutical residue."

In addition to known active substances, such as Diclofenac, as yet unidentified pharmaceuticals are also getting into rivers and lakes.  While previously scientists had to know precisely what they were looking for and required a reference substance, non-target substances can also be identified nowadays, thanks to high resolution mass spectrometry. State-of-the-art devices can determine molecule masses with extreme precision and even separate molecules with a low mass difference.  Software reads substance signals from the mass spectrometry data and calculates the chemical composition of the substance concerned. A comparison with databases can then reveal what substance it is. For instance, a researcher from the Eawag identified the presence of the antidepressant Moclobemide in the Rhine.

Public database for greater transparency

One of these databases was created by the NORMAN network in 2012 with the purpose of recording, processing and evaluating mass spectra of substances and, thus, the exchange of information between teams of researchers in the different countries, and ultimately to be better placed to meet the requirements of a risk assessment. The public sector also benefits from it. Scientist and former Marie Curie Fellow Emma Schymanski played a significant role in the setting up and operation of this NORMAN MassBank: "We supplied a large volume of mass spectra for it, and it can now be accessed right around the world," the Eawag scientist, who works in Juliane Hollender's group, said. "We have substances in Switzerland, for example, which can rarely be found on the market anywhere else, if at all, while there are similar substances in Germany or in the Netherlands," Emma Schymanski explained. However, as the Rhine flows through all three countries, it is important to share these specific national details. In contrast to the databases provided by device manufacturers, the NORMAN MassBank is accessible to the public and can include spectra from all devices.

The environmental chemists Dr Emma Schymanski, Prof. Juliane Hollender and laboratory assistant Birgit Beck (from left) take a water sample to test for micro-impurities such as pesticides or pharmaceutical residue.

It irks the environmental chemists that  the composition of many chemical products is bound by trade secrecy - despite the fact that toxicology tests whose results are even held in the authorities' archives are required to have new products licensed.  As Emma Schymanski explained with regret, "we can't get anywhere near those secret details. That data would enable us to gauge which substances could become a problem."

The researcher is involved through the NORMAN network in a large EU project called "Solutions" which is aiming to find solutions for harmful substances in the environment and is committed to sharing the research results in an international forum. 18 institutions from 12 European countries analysed the same water sample from the Danube in a training experiment. The participants discussed their findings during a workshop at the Eawag and created the new NORMAN Suspect List Exchange platform, which enables lists of suspect substances to be shared across Europe.

Reducing the risk of pesticides

The environmental chemists are not only searching for pharmaceutical drugs in water;  as Juliane Hollender pointed, "pesticides frequently pose an even greater risk to the environment. Even though they frequently occur in lower concentrations than pharmaceutical residue in lakes and rivers, they can have a greater effect as they have been developed to be damaging to organisms."  Three years ago, the Eawag researchers conducted searches in various rivers and lakes for all the pesticides that are licensed in Switzerland.  "We were surprised at how many we found," explained the environmental chemist. On average, each water sample contained 40 different pesticides.

The scientist is convinced that "this study has opened the discussion around the problem". For instance, the Federal Office for Agriculture (FOAG) started a consultation process on a "National Action Plan on Pesticides" in 2016. It is hoped that this will reduce the risk and ensure that pesticides are used more sustainably. However, the Eawag research team's ingenious analytical methods also revealed the presence of pesticides which should not even occur here. "My post-doctoral researcher recently discovered a harmful substance which is sprayed on citrus fruit and which is only permitted with restrictions in Switzerland," explained Juliane Hollender.

Sweeteners in the drinking water

According to the environmental chemists' measurements, artificial sweeteners account for the highest concentrations of organic micro-impurities in water. They leave our bodies and the sewage treatment plants practically unchanged and, therefore, accumulate in the rivers. 50 to 100 kilograms of Acesulfame, one of the most common sugar substitutes, pass through the Rhine monitoring station at Weil near Basel every day. "While we cannot rule out the possibility that this could be a problem for certain organisms," said Juliane Hollender, "we should not over-dramatise this issue, even though there are sometimes very low concentrations of sweeteners in our drinking water as well." Acesulfame can even be useful for researchers. Used as a tracer, the sweetener indicates the passage of waste water into groundwater.

Even though the analyses largely run automatically, they also require a great deal of detective work.  "They would not work without expertise," explained Juliane Hollender. "The NORMAN network also acts as a springboard for us to find partners for EU projects", - an undertaking which has become increasingly difficult due to the political situation since the mass immigration initiative was adopted. "I originally became involved in Eawag with an EU fellowship," explained Emma Schymanski. "However, EU funding is more difficult to come by nowadays which lowers our opportunities as scientists in an international context." Juliane Hollender stresses the fact that this is also why it is so important to be involved in the European NORMAN network.