PFAS in San Francisco Bay
What is PFAS?
PFAS are a group of thousands of manufactured chemicals produced since the 1940’s that have been used in a wide variety of consumer products, from textiles, clothing, and furniture to adhesives, fire-fighting foam, and metal-plating. Some lesser known uses include ammunition, climbing rope, guitar strings, and artificial turf. With this wide range of products, a large majority of Americans have been exposed to PFAS. One major example of use was perfluorooctanoic acid, or PFOA, more commonly known as teflon. Teflon was used in nonstick cooking pans, but it has not been manufactured in the United States after 2015 and was removed from consumer products in the early 2000s. Another main type of PFAS was found in a common household item called Scotchgard, which was a spray meant to protect furniture from oil, water, and dirt. The type of PFAS used here was called PFOS, and it stopped being manufactured in the United States after 2002 and was removed from consumer products in the early 2000s.
More technically speaking, PFAS stands for per- and polyfluoroalkyl substances, and are characterized by their carbon-fluorine bonds. They can be either short chain 4-6 fluorinated carbons, or long chain 7-8 fluorinated carbons. They are both hydrophilic and hydrophobic, making them great surfactants. A surfactant is a “substance such as a detergent that, when added to a liquid, reduces its surface tension, thereby increasing its spreading and wetting properties (Encyclopedia Britannica).” This makes it great at making products resistant to oil, stains, grease, and water. Along with this, PFAS are thermally stable, non-reactive, and have strong carbon to fluorine bonds, making them favorable for use in consumer products. Carbon to fluorine bonds are very strong, which makes them persistent and hard to break down in the environment. Because of its resistance to breaking down, scientists have been unable to determine an environmental half-life. This means scientists don’t know the time required for half of the chemical to break down. This has important implications regarding its residence time in the environment and the possibility of exposure to animals and humans.
Certain PFAS compounds that have already been phased out of use in consumer products and banned from production, such as PFOA and PFOS, have been replaced with GenX chemicals. Scientists have slightly changed the structure of the chemical so that it has similar properties but is technically a new chemical. This makes it possible for use in current and future products by working around current bans.
Why are PFAS concerning?
PFAS and similar chemicals have been found in the blood of 97% of Americans, based on a report by the Centers for Disease Control and Prevention’s (CDC) National Health and Nutrition Examination Survey (NHANES). PFAS are also able to bioaccumulate in which they accumulate in the body and remain for a long time. PFAS will stay in the body and build up over time with concentrations becoming higher and higher. Along with this there are a number of adverse effects to humans linked to PFAS exposure, such as reproductive defects, developmental delays in children, increased risk of some cancers, depressed immune system, hormone interference, and increased cholesterol (EPA).
It has been found that concentrations of PFAS in San Francisco Bay sediments are similar to other urban landscapes nationally. However, in the Bay PFAS have been found to be prominent in fish, particularly sport fish such as bass, halibut, and salmon. Any person or other animal that consumes these fish will be exposed to PFAS and their potential health effects. There are also some of the highest concentrations of PFAS globally found in cormorant eggs in the San Francisco Bay Area. This may lead to hatching issues for the bird species and could potentially lead to population decline rates.
Sources of PFAS to the Environment
Some of the major sources of PFAS were discussed in a digital forum called PFAS in San Francisco Bay. During session two of the forum, Wendy Linck from the State Water Resources Control Board discussed PFAS site investigation in the Bay Area. She described some of the major sources of PFAS locally: decommissioned or current military and navy bases, airports/bulk fuel terminals or refineries, landfills, and wastewater treatment plants (WWTPs) or publicly owned treatment works (POTWs). The first main source of PFAS are old military or naval bases that are out of commission. This is because of the equipment, machinery, and resources at these sites that may contain PFAS. They may have been left behind when the bases were abandoned or repurposed.
Airports, bulk fuel terminals, and even refineries can be a source of PFAS because of procedures that happen when a fire occurs. A fire at an airport would require the use of a foam to put the flame out rather than water, which may worsen the fire due to the presence of fuel in the area. This foam is an aqueous film forming foam that requires PFAS for production. During the discussion at the forum, the speaker communicated that there were significant concentrations (>5000 ppt) at airports found in soils, groundwater, and stormwater. There were also moderate concentrations (100 ppt to 5,000 ppt) found in municipal drinking water and wastewater. Based on the concentrations found in this study, airports could be a prominent contributor of PFAS in the San Francisco Bay Area compared to other local sources.
Within landfills, PFAS can be found in the leachate that is formed from the trash. When many household or usual products that contain PFAS are piled together in a landfill, the leachate formed can then contain PFAS which can then penetrate the groundwater or infiltrate wastewater. In this discussion, there were moderate concentrations found in the groundwater from landfills and significant concentrations in wastewater.
In POTWs or WWTPs, PFAS can occur because of the accumulation of it in feces or urine that end up in these facilities. In humans, PFAS can accumulate and be excreted as waste that may end up in other water sources. There were moderate concentrations of PFAS found in groundwater, and they were either not detected or there were low concentrations (<100 ppt) in soil, municipal drinking water, stormwater, and wastewater. Overall, there were concentrations of PFAS in the environment from all of these sources, although it was stated that further testing must be done to determine which of these sources may be the most serious and how the PFAS infiltrate different parts of the environment.
Along with certain compounds of PFAS being banned and phased out of production, one main piece of legislation concerning PFAS was Assembly Bill 1200 passed by Governor Newsom in October 2021. This bill banned all plant fiber-based food packaging containing PFAS. Although there is some legislation regarding PFAS, there is no EPA regulation of PFAS in drinking water. There are also many proposed bills and legislation that have not been passed yet and are in the process of review. The federal government is working to expand testing of PFAS in drinking water sources and setting national testing strategies. There is an EPA council on PFAS that works to understand PFAS more fully and reduce potential risks associated with it. Although certain types of PFAS have been banned and phased out of production, there must be further legislation to phase out new GenX PFAS chemicals and limit exposure to humans and the environment. Along with this, large companies and corporations must remove all products consuming PFAS from their inventory and sales. For example, Lowe’s has banned toxic PFAS chemicals in carpets and rugs it sells and advocates for other retailers to do the same (Release). These actions can also go further in ensuring that PFAS are not in any of its products, not only its carpets and rugs.
What can you do?
As a consumer, it’s important to research products and try to ensure that anything you buy is free of PFAS. As previously stated, PFAS can be found in a wide range and variety of things from cooking pans, to clothing, to carpeting. If you have questions or concerns about products you use in your home, contact the Consumer Product Safety Commission at (800) 638-2772. Along with personal research, it’s important to keep track of what may be in your drinking water supply. If your water is contaminated with PFAS, use alternative drinking sources. Similarly, avoid eating contaminated fish as it could lead to accumulation of PFAS in your body. Take extra precaution if you are part of a sensitive group that may be more likely to experience negative effects from PFAS. Some of these groups include the elderly, young children, individuals with underlying or preexisting conditions, and pregnant women.
In summary, PFAS are a large group of manmade chemicals that range extensively in consumer products. Although some forms of PFAS have been banned in the United States and from production, there are new types of PFAS being produced by changing the structure slightly. This means they may be used in products being made currently. A large majority of Americans have been exposed to PFAS already, about 97% according to one study, which may lead to adverse health effects over time. Some major health effects may be reproductive effects, developmental delays in children, increased risk of some cancers, depressed immune system, hormone interference, and increased cholesterol. Although there are some bills passed regarding PFAS, there must be more legislation regarding concentrations in drinking water and other environmental sources. Major companies must lead in banning PFAS products from their inventory and sales, and the public should be made more aware of PFAS and their potential adverse effects.
Congress.gov. (n.d.). Text – H.R.2467 – 117th Congress (2021-2022): Pfas action .
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