In the lab, PFAS water tests drop from six hours to 30 minutes

Maria Guerra de Navarro, a postdoctoral associate at FIU's Institute of Environment, is pictured collecting water samples. Her team at Florida International University has now built a laboratory method that returns PFAS results in 30 minutes, where testing used to take over six hours. PFAS are a family of so-called forever chemicals: they are nearly indestructible, found almost everywhere in the U.S., and linked to endocrine disruption, immune system impairment and cancer.

The stakes are local for South Florida. Drinking water there comes from the shallow Biscayne Aquifer, which is exposed to surface runoff from landfills, airports and military air bases, as well as to rainwater. Neither wastewater treatment plants nor drinking water facilities currently treat for PFAS, so contamination moves through the entire water cycle. Utilities are investing in activated carbon, reverse osmosis and nanofiltration membranes, but these systems concentrate the chemicals into a waste stream instead of destroying them. In Miami-Dade County, groundwater wells are monitored for PFAS every four months.

The new method automates sample cleanup using online solid-phase extraction, paired with high-precision testing tools that measure tiny traces of the chemicals. Because it uses smaller samples and less solvent, it reduces the risk of human handling errors. It detects 39 of the 40 EPA-listed PFAS. The team deliberately left out one compound, because tracking it would have raised the detection limits for PFOS and PFAS, the most regulated chemicals. Natalia Quinete, associate professor at FIU, called that trade-off an unacceptable compromise. The team has also shown that the method can analyze small and large PFAS molecules at the same time, and it is now working on smaller ones, which are frequently found in drinking water as larger molecules break down.

For a water utility, the change would be a shorter wait between a sample and a result, but the method is not yet usable in that role. It must first be certified through extensive validation studies across multiple independent laboratories, and the sources give no date for that. Guerra de Navarro said the EPA should consider incorporating this type of technology into a standard method, given the national demand for PFAS monitoring under new drinking water rules. The team has already characterized PFAS in tap water across several areas of Miami-Dade County and is now analyzing human serum samples. A simpler test for total PFAS, which could process 20 samples in a day with less expensive equipment, is in development, with real-time field assessment as the longer-term goal.