Tons of microplastic from tire abrasion

Videos about microplastic in cosmetics and clothes are going viral, sensitizing people about the topic. Those two examples are not the main contributors to the problem however. That pole position is held by cars and, more specifically, their tires. As a new study from the Fraunhofer institute showed, the most microplastic is released from this source. Next to the abrasion from car tires, the study also lists other surprising sources of microplastic emissions, such as sports fields, compost, construction waste, building facades, medications, pyrotechnics, and shoe soles.

Do we need to clean our streets more?

According to the study, cars, motor trucks, motorcycles, bicycles and skateboards emit a total of 1228.5 grams of microplastic, when calculated together. The lion’s share of that is made up by abrasion of car tires, with 998.0 grams per person and year. This should not come as a surprise, as car tires wear out during their lifespan, growing smaller in total circumference, says Ralf Bertling, engineer and contributor to the microplastic study. “The tire abrades, which is actually a good thing. If this weren’t the case, we would lose grip in a curve and be unable to stay on the street.”
But the firm grip on the asphalt comes at a cost – whether it be braking marks or normal abrasion, the plastic is washed from the street by rainfall onto the river bank or into the sewer system. Finally, it ends up in soil or water. This begs the question: Is there a need to clean our streets more or better? “Removing plastic from streets would conform to the precautionary principle. However, increased efforts to clean the asphalt would lead to more CO2-emissions as well”, a research assistant of the Fraunhofer institute says.

What about microplastic sources like cosmetics and clothes?

The total amount of emitted microplastic per person and year for all clothing amount to 142.8 grams. This is an average value, falling into the same category as sources of microplastic which are not yet discussed as often, such as sport fields, which rank right behind clothes with a value of 131.8 grams. In this case, the abrasion gets into the environment by rain or wind drift.
Much larger contributors to total emissions are waste disposal (302.0 grams), asphalt (228 grams) or construction (117.1 grams). The much-maligned cosmetic manufacture is only a „featherweight“, with its 19 grams. More deserving of such a bad rep are paints and varnishes with 65 grams, or house facades with abrasions of 37 grams.

Where else does microplastic come from?

The very detailed allocation in the study differentiates between many emitters of microplastic: abrasion from tires and shoes, microplastic from cosmetics all the way to sweepers and facades – it seems as if manufacture isn’t a big contributor when looking at construction plastics, conveyer belts, cogwheels, wear protection, friction bearings and gliding rails separately.

“Our goal was to reach the highest possible completeness of possible sources”, says environmental scientist Bertling. The manufacturing business still seems to take a back seat when looking at the whole picture though: only 14 percent of the total microplastic volume stem from the producing industry. Private consumption accounts for 24 percent and the remaining 62 percent are distributed among the traffic, infrastructure and building sectors. This indirectly falls on the consumers, because it is them driving cars, not the industries. The outcome is really dependent on the point of view that is taken, when analyzing the lifespan and usage of any product. Because even if the driver is responsible for abrasion on streets, the tires are still produced by the manufacturer.

Whose responsibility is it?

With whom does the responsibility lie then? The industry, politicians or the consumers? “Every single one of them, whether you’re a business leader or politician - we are all citizens living in a country, on the same planet, so we can all work on it”, says Bertling. He specifies, by saying: „We can help by not taking the car on the weekends, or by reducing our plastic waste and if we do produce waste, by disposing of it properly.” While the knowledge on effects and consequences of microplastic in soils in regards to humans still limited, it always helps being critical, says the environmental scientist. He points out the impact of public debate: “Microplastic from cosmetics has already been reduced significantly by manufacturers.”

Source: https://www.mdr.de/wissen/mehr-mikroplastik-durch-reifenabrieb-als-durch-kosmetik-und-kleidung-100.html

Original article (DE): https://www.umsicht.fraunhofer.de/content/dam/umsicht/de/dokumente/publikationen/2018/kunststoffe-id-umwelt-konsortialstudie-mikroplastik.pdf