Many surface waters in Lower Saxony are heavily polluted with nitrate. Together with researchers from the Universities of Oldenburg and Osnabrück, citizens can now find out for themselves how high the levels are - knee-deep in the nearest stream or from home with the "Nitrogen Box".
It can be found in salami and even in lettuce leaves: Nitrate is a vital nitrogen compound that helps nature in the right doses. However, too much nitrate can be harmful to humans and the environment. Too much nitrate in nature, for example, not only over-fertilises water and soil, but also impairs biodiversity. But why does nitrate act as a fertiliser? How does the nutrient get into the groundwater? And how polluted are our waters actually?
These questions are the focus of a project at the universities of Oldenburg and Osnabrück. The special thing about this project: Citizens themselves become nitrate researchers. They use simple methods to measure nitrate levels in surface waters such as streams or wells. The Oldenburg researchers are also providing some participants with an experiment box so that they can familiarise themselves with the topic even more closely.
However, the project not only brings scientists and citizens together: Schools from the north-west are also involved in the project. For two years, sixth form students have been working intensively on the nitrogen problem and the associated research projects in seminar subjects. As "mentors", they supervise small groups of interested people during the nitrate measurements and explain the test method to them.
Both sides benefit
"The issue of nitrate affects everyone in our region," says Oldenburg chemistry didactics expert Prof Dr Verena Pietzner, who is leading the project together with Prof Dr Marco Beeken from the University of Osnabrück. In many areas of northern Germany, the surface water is contaminated with nitrate, which can have an impact on the groundwater. And a so-called citizen science project on nitrate is a good opportunity to bring the problem to households. Ultimately, both sides benefit: Participants provide additional data for research and, in addition to learning scientific working methods, they also learn what is going on in the environment on their doorstep.
The approach of bringing non-scientists together with researchers is not yet very common in chemistry. But Pietzner is very keen: "In the 19th century, people went to scientific evening events like they go to the theatre today. It would be nice to revive this curiosity about science."
The soil in the returnable bottle
The curiosity of the more than 600 amateur scientists who have already registered with the project partners in Osnabrück is cause for optimism. The researchers in Osnabrück are responsible for the first part of the project, which the German Federal Environmental Foundation is supporting both technically and financially until March 2020. They are equipping citizens with small test strips that indicate the nitrate content in the respective surface waters. The amateur scientists upload the data obtained online.
In Oldenburg, Pietzner and her doctoral student Mientje Lüsse have developed an experiment box in the second part of the project. 15 different experiments for young and old invite you to tinker and try things out. A brochure contains instructions and background information. The material for the experiments is either included in the experiment kit or can be found in every household. With just a PET bottle, some sand, gravel and a coffee filter, for example, a simplified model of the soil can be constructed. If you now add a nitrate or ammonium solution, it becomes clear how a plant-free soil filters out ammonium, but not the nitrate. In reality, this allows it to seep into our groundwater. Plants, on the other hand, are able to absorb nitrate from the soil, which is why it is important to green the soil as much as possible.
Experimentation as food for thought
The accompanying booklet also contains tips on how every private individual can reduce their personal nitrate emissions. "Small things can make a big difference: for example, only buying as much as you use or eating less meat," explains Lüsse. Like her colleagues in Osnabrück, the doctoral student is also in close contact with the schools involved. The sixth form students put the experiment boxes through their paces. Among other things, they check the comprehensibility of the information and the handling of the experiments. The scientists integrate the students' feedback before releasing the experiment kit to the public. A good 100 amateur scientists will then receive the box at the beginning of this year.
In late summer and autumn, Pietzner and Lüsse will interview the participants about their experiences with the experiment kit. "We hope that citizens and schoolchildren alike will be inspired to think through the experiments. And we want to find out whether this leads to a change in attitudes towards environmental issues," says Lüsse. Organised by the pupils, the project concludes with several exhibitions. There, both the Osnabrück and Oldenburg scientists will present their results. Until then, some amateur scientists are still trudging through streams and using deposit bottles for their experiments.
