Yes, tire dust is one of the most toxic substances, but known by few. It kills any fish eggs laid in rivers and creeks underneath bridges. There should be tons of research to create a replacement that is more benign and that decomposes to harmless elements. It's difficult, tires have to endure a lot of stress, function in a wide temperature range, resist light damage, have good dry and wet traction, ride well, be low cost... just a ton of challenges. But I don't see any research for substitutes. At the very least, more freight should go by rail, steel on steel creating some rust dust by tracks is far less toxic.

Aluminum is a great substitute for many plastic applications. And yes, transparent aluminum is now a reality, not just science fiction circa 1986; aluminum oxynitride, "ALON", a hard ceramic of aluminum, oxygen, and nitrogen.