A new University of Bonn study found that kitchen sponges release microplastics during everyday dishwashing, but water use remains the largest contributor to the environmental impact of washing dishes.
The sponges used in kitchen dishwashing release microplastics daily, as revealed by a study conducted by scientists at the University of Bonn and published in Environmental Advances. The study indicates that an individual may release 0.68 to 4.21 grams of microplastics annually based on their usage of sponges, although the study notes that water consumption in manual dishwashing is environmentally more damaging.
The research examined three types of kitchen sponges with different plastic content under household and laboratory conditions. While all of them released microplastics as they wore down, sponges made with less plastic lost less material over time.
How was the study conducted?
Researchers combined household observations with laboratory testing. Volunteers in Germany and North America used one of the three sponge types during their normal dishwashing routines, allowing the team to record realistic patterns of use.
The sponges were weighed before and after use to measure material loss. Researchers also used an automated testing device called SpongeBot, which replicated the mechanical stress of dishwashing under controlled conditions. The results from both methods showed that every sponge released microplastics during use, although the amount differed by sponge type.
What did the environmental assessment find?
The researchers carried out a life cycle assessment covering the manufacture, use, and disposal of the sponges.
The analysis found that 85% to 97% of the total environmental impact of dishwashing was linked to water use, making it the largest contributor. By comparison, microplastic emissions accounted for a much smaller share of the overall environmental burden.
Even so, the study estimated that if every household in Germany used one of the higher-emitting sponge types, annual microplastic releases could reach 355 metric tonnes. Although wastewater treatment plants retain much of this material, some particles are still released into rivers, lakes, oceans, and agricultural soils.
What can reduce the impact?
The study identifies three measures that can lower the environmental footprint of dishwashing:
- Use less water while washing dishes.
- Choose sponges with lower plastic content.
- Use sponges for longer before replacing them to reduce material consumption.
The researchers said the combination of household data and laboratory testing provides a more realistic estimate of microplastic release from kitchen sponges during everyday use.
What's Your Reaction?
