Report collects everything you need to know about non-target analyses

Which unwanted substances are in the groundwater? That is always a relevant question for anyone who deals with groundwater and – especially – with drinking water. Until now, each individual substance, for example a specific pesticide, has been measured separately when there has been a suspicion that the water is contaminated with that particular substance. But there are thousands of substances about which we know nothing, or only very little, and which it is therefore very difficult to test for, simply because it is hard to look for something when you don’t know what it looks like.

But when we introduce so-called non-target analysis methods in the monitoring of our water, we can begin to answer the question. And to spread the latest knowledge about the non-target analysis methods, GEUS has prepared a report for the Danish Environmental Protection Agency, which acts as a guide focusing on both opportunities and challenges associated with the method.

“At the moment, the new non-target measurement methods are developing at a rapid pace, and they make it possible for us to measure far more substances in the water, but that opens up a lot of new questions and uncertainties. We have tried to counter that with this report, which describes the methods and limitations and what can be done, so that this type of method can best contribute to the mapping and monitoring – and ultimately protection – of our groundwater and drinking water,” explains Head of Department of Geochemistry at GEUS, Claus Kjøller, who is one of the authors of the report.

Knowledge of the untrodden path

The report discusses, amongst other things, how to handle the measurement of substances no-one may ever have heard of, since a particular challenge with the non-target analysis is that there are basically no required values ​​or standardised ways to handle many of the substances that can be identified with the new methods.

Furthermore, with the report, the researchers try to show why it is not realistic to expect that it will ever be possible to know everything about what is in the water, or what is on its way to the groundwater from sources on the earth’s surface. Senior Researcher Ulla Elisabeth Bollmann, who is also part of the author group from GEUS, explains:

“Each step in a chemical analysis will exclude some types of substances, and so the final method uncovers only a part of the total chemical space,” she says and adds:

“However, with the non-target methods we are taking quite a few steps in the right direction.”