Platinum and palladium from catalytic converters accumulates in roadside dust: https://www.forbes.com/sites/timworstall/2013/07/15/the-streets-are-paved-with-g

Platinum and palladium from catalytic converters accumulates in roadside dust: https://www.forbes.com/sites/timworstall/2013/07/15/the-streets-are-paved-with-gold-and-platinum/ https://www.forbes.com/sites/timworstall/2013/07/15/the-stre...