Three researchers from Oldenburg, Germany, wanted to use spider webs to gain an overview of microplastics in the air. To do this, they took samples on roads with different traffic intensities – the more cars there were on the road, the more they got stuck in the fine wires.
According to a statement, the particles mainly include plastic PET, presumably from textiles, as well as wear and tear from car tires and polyvinyl chloride (PVC). The amount of microplastics depended on the location.
Spider webs are a simple and inexpensive way to monitor air pollution from microplastics in the city and identify particularly polluted areas, the researchers write in the journal Science of the Total Environment.
“Fall for everything that floats in the sky”
“Spiders are found all over the world, including in cities. Their sticky webs are an ideal trap for anything that floats through the air,” said study leader Barbara Scholz-Böttcher, a microplastics expert at the university’s Institute of Marine Chemistry and Biology. Several studies have shown that pollutants such as heavy metals get into the webs. “Until now, however, no one has examined cobwebs for microplastics,” says the geochemist.
No net without plastic
To find out whether microplastics can be detected in spider webs and whether there are certain distribution patterns, nets have been collected in the upper area of semi-covered bus stops. “All cobwebs were contaminated with microplastics,” reports Isabel Goßmann, who was involved in the research as part of her PhD.
In some cases, the plastic content even made up a good tenth of the total weight of a net. Nearly 90 percent of the plastic consisted of PET, PVC and car tires. The share of tire wear fluctuated strongly – depending on the traffic.
Microplastics are quickly released into the air
“Our results also indicate that road marking wear is another major source of microplastics along roads,” explains Scholz-Böttcher. The researchers also found evidence that the tiny plastic particles accumulate surprisingly quickly in the cobwebs.
According to Scholz-Böttcher, the method offers a simple alternative to time-consuming measurements to relatively assess the microplastic content of the immediate ambient air.