Urban stormwater particles from tire wear were the most prevalent microplastic a new study has found. The study showed that in stormwater runoff during rain approximately 19 out of every 20 microplastics collected were tire wear particles with anywhere from 2 to 59 particles per liter of water. Tire rubber contains up to 2500 chemicals with the contaminants that leach from tires considered more toxic to bacteria and microalgae than other plastic polymers.