Not only cosmetics: microplastics has many causers

How does microplastic get into the environment? And what quantities are they? The Fraunhofer Institute for Environmental Technology has ventured on the complex topic. The conclusion of the researchers: There are more sources than you think.

Oberhausen (dpa) – With every step pedestrians give microplastic into the environment. According toresearchers from the Fraunhofer Institute for Environmental, Safety and Energy Technology in Oberhausen, around 100 grams of abrasion from the soles of the shoes should be in Germany per capita per year.

This places footwear in seventh place on the list of the largest microplastic sources found in the study of environmental scientists.

So far, personal care products and cosmetics have been at the center of the public debate about microparticles made of plastic, which by definition measure a maximum of five millimeters. But there are many more polluters: for the first 51 sources of so-called primary microplastics , the authors of the study ” Plastics in the environment” have determined the emissions. Clients were chemical companies, cosmetics manufacturers, water associations, waste disposal companies and universities.

A total of 330,000 tonnes of microplastic come together each year in Germany – a good four kilograms per capita. With 19 grams shower baths and Co. are only in 17th place on the negative list. At the top of the microplastic polluter is the abrasion of car tires. About a third of the microplastic emissions account for it, according to the study.

And one more thing about the numbers from Oberhausen is remarkable. Macro plastic – that plastic bags and other carelessly discarded plastic products – provide in Germany for over a quarter of the total 446,000 tons of plastic emissions per year. Microplastic represents 74 percent of them. “What is obvious to everyone, therefore, is about a three-fold larger amount, which is sometimes visible only under the microscope,” says the study.

In the field of microplastics , the researchers distinguish between two categories: on the one hand, particles that are already added to a product during manufacture, such as rubbing bodies in cosmetics . In the case of the second type, the microparticles only form when used, for example synthetic fibers released during washing. “The distinction is important for the responsibility for the prevention of microplastics ,” says study author J├╝rgen Bertling .

How do the researchers get their numbers? Data from experiments or measurements are few. Using the example of shoe sole abrasion, co-author Leandra Hamann explains the procedure: “We assumed the total number of shoes sold per year in Germany .” The average shoe size, the sole area and about five separate paired shoes per head and year were further included in the calculations.

The numbers of scientists are, as they themselves admit, in comparison to other studies “more in the upper range”, as one has taken into account more sources. The scientists have evaluated previous studies and downscaled production and consumption data on the emissions of microplastics .

The Federal Environment Agency is not surprised that microplastics plays a subordinate role in cosmetics . Its own experts have come to the same conclusion, says spokesman Felix Poetschke . “It’s also the easiest to avoid.” The tire abrasion amount is also moving in the previously calculated frame.

Obtaining data on the targeted use of microparticles is extremely difficult for research. For example, a 2015 study by the Federal Environment Agency on the sources of microplastics states that there has been little willingness on the part of industry to provide concrete information on the quantities and types of materials that have been deliberately used. For this study too, the numbers were therefore estimated using “plausible calculation methods”.

The knowledge about origin, distribution and consequences of plastic in the environment is still very fragmented. That is why the Federal Ministry of Research has launched a major research program: 18 projects with around 100 partners from science, business, associations and municipalities are to paint an overall picture of how plastics are produced, used, traded and disposed of.

Tire abrasion is also the focus of a project coordinated by the Technical University of Berlin. It is to determine the entry of microplastic from tire abrasion in the drainage water of the streets, as Daniel Venghaus of the Department of Urban Water Management of the TU Berlin says.

A proposal on how to reduce the amount of tire wear has already been developed by Fraunhofer researcher Bertling . Motorists should pay attention to longevity when buying tires. “That’s why the EU tire label should be added,” he says. So far, there is only information on fuel consumption, braking distance on wet roads and rolling noise. About durability and abrasion of a tire say the label nothing.

And Bertling warns of a general plastic bashing. If you want to increase the very low recycling rates, you have to improve the bad image of plastics : “Only if plastic has a real value for producers and consumers, the recycling will increase.”