Million tonnes of waste plastic pollute the world's oceans. And estimates suggest million tonnes are added every year. In many places, bags, bottles or fishing nets are easily visible with the naked eye. This plastic waste is worn down by the sun, tides and wind and leads to a less-visible environmental problem: microplastics.
There are now deposits of these tiny plastic particles, each of them smaller than 5 millimetres, all around the world. Many people fear that microplastics will enter the food chain, damage marine animals, or that pollutants will accumulate on the particles. However, there are gaps in our knowledge about the quantity of microplastics in the environment, where they come from and how exactly they arise.
An interdisciplinary team of experts at BAM is working to close these gaps, under the leadership of Dr. Ulrike Braun from the Mechanics of Polymers Division. Experts on the ageing of plastics, pollutant trace analysis and sample preparation are jointly researching the topic of microplastics.
"New and fast method of measuring for a large-scale sample"
BAM is currently developing a new and so-far unique method for measuring the amount of microplastics in the environment. What is special about it is that it uses the decomposition products of microplastics to do so. Environmental samples, for example from filtered water, are heated and the resultant gases are analysed. This enables the quantity and type of the contained microplastics to be determined.
"We believe that this method is faster than the usual investigations using microscopes and spectroscopy," says Dr. Ulrike Braun. "The method should be able to be automated and large quantities processed through samples." The quick analysis of comprehensive samples is an important factor in light of the global distribution of microplastics in the water. The scientists use a model of microplastics particles in defined environmental samples from different plastics created by BAM itself for testing and optimising. They then compare these with real samples from the environment.
More knowledge to avoid microplastics
Dr. Braun describes BAM's objectives: "More knowledge about the creation and spread of microplastics enables law makers to make better risk assessments, for example, from which they can derive a limit for microplastics or standardise the tests and taking of samples. In this way, the question of the origin of microplastics can be answered, and politicians and society can take the next step of developing strategies for avoidance."