The article just below mentions two major sources: - failing septic systems, and spilled wastewater. Lots of household products like food packaging and carpet

The article just below mentions two major sources: - failing septic systems, and spilled wastewater. Lots of household products like food packaging and carpets are coated with oil- and water-repellent PFAs. When you wash these products, the PFAs end in the waste water. - airports and military bases use a fire-fighting foam that is made from a PFA. Also, Kennedy space center uses fire-fighting foams (although it's far from Miami, but then again Florida is one big aquifer).