7 May 2026, by S. Otto, M. Eberhard

Photo: UHH/Otto

Biology students from the “Data Science 1” course collecting trash along the Outer Alster.

About 240 first-year students from the Department of Biology collected trash along the Outer Alster—6,370 items. This resulted in a pilot study that combines teaching, research, and environmental engagement.

As part of the “Data Science 1” module, around 240 first-year students in the “Biology” and “Marine Ecosystem and Fisheries Science” degree programs had the opportunity to experience how scientific data collection works—from planning and fieldwork to statistical analysis.

Twelve groups, two weeks, one mission

Over a two-week period in November 2025, twelve practice groups, accompanied by their instructors, fanned out to the Outer Alster and the adjacent waters from the Mundsburg Canal to the Kuhmühlenteich. Equipped with gloves, tongs, trash bags, and a standardized survey form, they systematically documented every single piece of trash—from cigarette filters to plastic bottles. Location coordinates were recorded via a smartphone app, and every find was photographed. The project was designed as a pilot study in cooperation with the project “Lebendige Alster” (NABU/BUND Hamburg).

Initial results: Plastic dominates

A total of 6,370 items of trash were recorded and categorized. The analysis paints a striking picture: Plastic accounts for around 67 percent of all trash—a finding now substantiated by local data. Cigarette filters are by far the most common single item, making up just under 30 percent. “A result that is likely to fuel the discussion about ashtrays at public gathering places and on park benches,” says Dr. Saskia Otto, research associate in the Department of Biology and lecturer for the Data Science module. “At the EU level, a ban on plastic filters is currently being actively discussed; a revision of the Single-Use Plastics Directive and the Tobacco Products Directive is planned for 2026/2027. Local data like this could help substantiate the need for action.”

About two-thirds of all items found are single-use products; some of these fall under the EU bans on single-use plastics in effect since 2021 and were nevertheless found along the waterfront. And: The density of litter varied considerably between areas—by a factor of 3.4 between the least polluted section (in the southeast along the Kennedy Bridge) and the most polluted section (in the northeast of the Alster, along Bellevue Street). About 30 percent of all collection sites were located in so-called problem hotspots—areas with above-average amounts of litter and, at the same time, few trash cans nearby. In the canal area, as many as half of all findings were affected by this. However, it cannot simply be concluded from this that more trash cans would solve the problem: In the canal area, trash likely accumulates less due to active littering than due to wind drift and water inflow into hard-to-reach embankments. Targeted cleanup campaigns, such as those already carried out by the “Lebendige Alster” project, make more sense there. In more accessible recreational areas of the western Outer Alster, however, improved infrastructure could have a direct impact.

More Than Just a Course Project

For the students, the case study was far more than a required assignment. They became familiar with the entire data science workflow: collecting, digitizing, cleaning, visualizing, and interpreting data—all while addressing a socially relevant topic. “Many students initially approach the Data Science module with great respect and fear being overwhelmed by formulas and complicated mathematical terms,” reports Dr. Monika Eberhard, a research associate in the Department of Biology and also a lecturer for the Data Science module. “This project has not only helped many students overcome their fear of working with datasets, but also shows them how relevant data science is to Biology and environmental protection.”

The complete results are now available as an interactive online report and have been made available to the “Lebendige Alster” project as well as the Hamburg City Cleaning Department. Plans for a repeat of the project in the upcoming winter semester are already underway.

The raw data has been published as open access on Zenodo, the results report is available at this link. (german) 

(This content has been translated automatically.)