Concepts – Per- and Polyfluoroalkyl substances (PFAS)
Updated: Dec 6, 2018
Why the concern?
PFAS are of particular concern because some of these chemicals are very resistant to degradation in the environment, migrate easily in groundwater, bioaccumulate in the food chain, are ecologically toxic, and possibly carcinogenic to humans. There is limited knowledge regarding microbial degradation of these compounds; thus, the compounds mostly remain in the environment for very long periods of time. They are found worldwide in groundwater, surface water, soil, and air, as well as in fauna, flora, food, breast milk, and human blood serum. The mobility of these chemicals in the environment is influenced by many factors including the site’s hydrogeology, the specific PFAS compound chemical characteristics, and their affinity to sorb to sediments or soils.
PFAS are a group of over 3,000 synthetic fluorine-containing chemicals used in many industrial, commercial, and firefighting applications, and are present in many household products. These constituents have been used widely throughout the world since the 1950s. However, in 2009, the U.S. Environmental Protection Agency (USEPA) published provisional health advisories warning that at least some of these substances may pose a threat to human health and the environment; particularly, perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA). In November 2016, the USEPA published a Health Advisories Fact Sheet establishing the lifetime health advisory (LHA) level at 70 parts per trillion (ppt) in drinking water (PFOS or PFOA or a combination of both). In January 2018, the Michigan Department of Environmental Quality (MDEQ) developed drinking water criteria for the combined levels of PFOS and PFOA that match the LHA of 70 ppt. In some other states and internationally, acceptable levels of PFOA and PFOS have been established at concentrations lower than the 70 ppt suggested by USEPA, and are expected to be reduced in the future. Besides PFOS and PFOA, other PFAS are being investigated by USEPA including perfluorononanoic acid (PFNA), perfluorohexanesulfonic acid (PFHxS), perfluoroheptanoic acid (PFHpA), and perfluorobutanesulfonic acid (PFBS), which are also listed in EPA’s Third Unregulated Contaminant Monitoring Rule (UCMR3). Another related chemical of rising concern is GenX, a PFOA replacement. The list of regulated PFAS and related contaminant chemicals is expected to increase over the next few years.
What can be done? To properly assess and mitigate PFAS sources, industries that use or have used these compounds need to review how and where PFAS-containing materials are/were used in their process, how these materials and waste products were managed, and the possibility these materials used historically may still be present. Industries that discontinued using these compounds many years ago are reportedly still finding significant quantities in process vessels and piping. For these industries, steps should be taken to eliminate or reduce the PFAS by replacing PFAS products with more environmentally friendly alternatives, and cleaning or replacing impacted equipment and materials.
In 2018, the MDEQ began requiring water resource recovery facilities (WRRFs) with industrial pretreatment programs (IPPs) to evaluate their influent water for PFAS constituents; with PFOS and PFOA being of particular concern. Consequently, WRRFs with a detectable level of PFAS in their influent are faced with the need to implement sampling strategies to identify potential PFAS sources. This effort has focused on targeting contributing industries typically known for using PFAS — electroplaters, leather and fabric treaters or tanneries, paper and packaging manufacturers, manufacturers of parts with polytetrafluoroethylene (PTFE) coatings, landfills, centralized waste treaters, and airports or other facilities where AFFF firefighting foam was used. Dischargers of wastewater exceeding 12 ppt of PFOS (currently known to be the most toxic PFAS constituents) or 12,000 ppt of PFOA, will be required by the WRRF and MDEQ to identify and mitigate PFAS sources within their facilities. FTCH’s PFAS Technical Support Team has been actively working with facilities to proactively develop and implement source evaluation strategies including chemical review and inventory, and sampling and analysis. Please contact our team for more information.
For additional guidance on PFAS, contact our task force Fernanda Wilson, PhD | (616)464-3752 | Environmental Engineering Lead Dan Greene, CPG | (616)464-3761 | Hydrogeological Science Lead John Willemin, PE | (616)464-3801 | Water Engineering Lead Dave Filipiak, CHMM | (616)464-3743 | Wastewater Engineering Lead
Concepts is a series of articles published by FTCH on relevant engineering topics