This week’s Wednesday Nite @ The Lab talk featured University of Wisconsin civil and environmental engineering professor Christy Remucal, who discussed the impact of PFAS in Wisconsin’s water supply and what is being done to address them.
Remucal started out the event by defining PFAS as Per-and Polyfluoroalkyl substances and PFOS Perfluorooctane sulfonic acid. PFAS is a catch-all term used to describe the general class of over 5,000 chemicals, which have a number of applications including being involved in consumer products, industry and firefighting foams.
PFOS is one specific species of PFAS listed as a persistent organic pollutant by the Stockholm Convention in 2009.
PFAS can have a number of significant health effects and are a topic of public concern, Remucal explained. Potential health impacts can include thyroid disease, decreased fertility, pregnancy complications, decreased immune response, decreased cholesterol and cancer.
Remucal said a major issue with PFAS is the health effects can be linked to very low concentrations of the chemicals. PFOS can have detrimental health effects at around 20 nanograms per liter, which is substantially less than other dangerous chemical amounts such as arsenic at around 10 micrograms per liter — a 500-fold difference.
The chemicals can enter bodies of water in a variety of ways. Remucal said one avenue is the transportation of wastewater to treatment plants from industrial processes and landfills. Another way PFAS can enter water is through water treatment plants transporting biosolids to farmlands, which can then runoff into ground water.
Part of the danger of PFAS and PFOS is the nature of their chemical makeups. PFOS is a hydrophilic molecule, which allows it to readily dissolve in water. It also is lipophilic, which means PFOS will accumulate in biota and sediments, leading to significant build up of the chemical. PFOS contains a number of carbon-fluorine bonds which resist degradation, further adding to the build up of the dangerous chemical.
Action has been taken to curb these dangerous chemicals’ infiltration. Remucal said existing PFAS regulations both nationally and in Wisconsin provide some protection. The EPA health advisory level for PFOS is 70 nanograms per liter, while the Wisconsin groundwater standard and surface water criteria are 20 nanograms per liter and eight nanograms per liter, respectively.
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Remucal said there are many implications for regulations in the field. One area of focus is on sites with high chemical concentrations, which raised the question of what could be done if the goal was to prevent PFAS from entering the Great Lakes.
To conclude her talk, Remucal went over the existing technologies that can remove PFAS from the water. These include Granular activated carbon, reverse osmosis and point-of-use filters.
The weekly labs take place every Wednesday at 7 p.m. More information about the upcoming Wednesday Nite @ The Lab can be found at science.wisc.edu.
