I remember having to point this out to a local councillor some 15 years ago. The wanted to expand road development in our city centre from 3 lanes to 4. Whilst it didnt run past homes it was a very busy shopping area at the time. The councillor, at the time, thought that cars didnt pollute, and it was a real struggle to get the point across. Until the local sewerage system got gunked up with a grey paste every time after heavy rain. Turned out that was tyres that had worn. It kind of blocked the water from flowing and had a weird effect.

What made this oddly schadenfraude was the water, when it did come out of the storm drain, discharged into a part of the River Itchen that said councillor liked to fish in. It was probably, and probably is to this day, depleting the fish stocks. We know that microplastics have been found in fish, but we've found other chemicals related to cars have also been found.