WHAT IS THE STUDY ABOUT?
Kitchen sponges are considered a potential, yet largely understudied, source of microplastics in households. The study investigated how many microplastic particles are released from kitchen sponges during use and what environmental impacts result. The aim was to quantify the actual release under realistic usage conditions and to assess the environmental impacts using a life cycle assessment (LCA).
HOW DID YOU CONDUCT YOUR STUDY?
The study combined citizen science—where members of the public actively conduct experiments—with laboratory tests. Volunteer households in Germany and North America used one of three different sponge types in their daily routines and documented their usage. The sponges were weighed before and after use to determine material loss and microplastic release. In addition, laboratory experiments were carried out using an automated test device (“SpongeBot”) that simulates the mechanical stress applied to sponges during dishwashing.
WHAT ARE THE MAIN FINDINGS?
All investigated sponges lose material during use and thereby release microplastics. The annual release ranges from approximately 0.68 to 4.21 grams of microplastics per person per year, depending on the sponge type. Sponges with a lower plastic content release significantly less microplastic. Overall, however, the analysis showed that it is not the microplastic release itself, but primarily the water consumption during manual dishwashing that contributes most to the environmental impact.
WHAT ROLE DID CITIZEN SCIENCE PLAY IN YOUR STUDY?
Citizen science played a central role, as volunteer participants used the sponges under real-life conditions. This allowed for the capture of realistic usage patterns and typical dishwashing habits. These data enabled a much more realistic estimation of microplastic release compared to purely laboratory-based studies.
WHICH FACTOR CAUSES THE GREATEST ENVIRONMENTAL IMPACT DURING MANUAL DISHWASHING?
Although the amount per person appears low, when extrapolated to Germany, significant quantities can be reached, for example, up to 355 tonnes of microplastics per year if a specific sponge type is used in every household. While a large proportion of these particles is retained in wastewater treatment plants, several tonnes still enter aquatic environments or soils annually. At the same time, the environmental assessment shows that around 85 to 97 percent of the total environmental impact of dishwashing is attributable to water consumption, while microplastic emissions contribute a much smaller share to overall ecosystem damage.
WHAT CAN CONSUMERS DO TO REDUCE ENVIRONMENTAL IMPACT?
The study identifies several ways to reduce environmental impact:
- Use less water when washing dishes, as this has the greatest effect.
- Choose sponges with lower plastic content to reduce microplastic release.
- Use sponges for a longer time, as a longer lifespan reduces overall resource consumption.
WHO WAS INVOLVED IN THE STUDY?
Institute of Organismic Biology (BIOB), University of Bonn; Fraunhofer Institute for Environmental, Safety and Energy Technology UMSICHT; Leiden University.
WHAT IS THE SOURCE?
Leandra Hamann, Christina Galafton, Peter T. Rühr, Alexander Blanke, Nils Thonemann: From sink to sea: Microplastic release from kitchen sponges and potential environmental effects, Environmental Advances, Volume 23, 2026, 100693, ISSN 2666-7657, https://doi.org/10.1016/j.envadv.2026.100693
WHERE CAN I FIND OUT MORE?
Leandra Hamann, Bonn Institute of Organismic Biology, University of Bonn, hamannleandra@gmail.com (currently at the University of Alberta)
