Pieces of artificial grass can make up a large portion of the plastic found in the seawater close to a major city, a study in Spain has revealed.
Liam de Haan at the University of Barcelona and his colleagues analysed 217 water samples collected off the coast of Barcelona, in north-east Spain, and 200 from the Guadalquivir river in Seville, in the south-west of the country, collected between 2014 and 2021.
They focused their analysis on plastic pieces larger than 5 millimetres, excluding smaller particles, known as microplastics, because it is harder to determine where they come from, says de Haan.
Fibres that make up artificial grass are usually very thin, long and curled, and green in colour, he says, making them easy to identify.
In Barcelona, fibres from artificial grass accounted for 15 per cent of plastic pieces larger than 5 millimetres in the samples from within 1 kilometre of the shore. “We were really surprised that nobody had reported this before,” says de Haan.
The concentration of artificial grass fibres floating in the sea was as high as 213,200 fibres per square kilometre in some places. Barcelona’s large population – around 1.7 million – and the large number of artificial sports pitches in the city probably account for why the figure is so high, says de Haan.
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In the Guadalquivir river in Seville, the average concentration of plastic pollution from artificial grass was on average 50 times lower than in the seawater off Barcelona.
This difference could be down to the fact that the river simply flushes plastic into the ocean, whereas plastic can accumulate more in the sea, says de Haan. Seville also has a far smaller population than Barcelona, at just over 700,000 people.
Read more:
Scientists warn of 'alarming' rise in ocean microplastic pollution
De Haan says the issue is likely to be global. “I think it’s pretty implausible that this is only happening in Spain,” he says. Since we don’t know how much artificial grass breaks down into microplastics and nanoplastics, and how much this contributes to plastic pollution in water bodies, the problem could be even bigger, he adds.
Journal reference:
Environmental Pollution DOI: 10.1016/j.envpol.2023.122094