What exactly is PFOS, and why should we be concerned about it?
PFOS is a synthetic, highly persistent chemical widely used in various products, including fire-fighting foams, non-stick coatings, and stain-resistant fabrics. PFOS exposure can pose health risks such as developmental, liver, and immune system issues, as well as potential hormonal disruptions. The US EPA’s health advisory limit for PFOS in drinking water is 70 parts per trillion (ppt) to protect against associated health risks.
In this article, we’ll shed light on the nature and uses of Perfluorooctanesulfonic acid (PFOS), a synthetic and highly persistent chemical that has found its way into various everyday products. We’ll delve into the health risks associated with PFOS exposure, as well as its impact on drinking water quality.
Armed with this knowledge, you’ll be better equipped to understand the importance of keeping an eye on PFOS levels and taking necessary precautions to safeguard your health and that of your loved ones.
Read my comprehensive article on What is PFAS for an in-depth look at this class of toxic chemicals.
What Is PFOS?
Perfluorooctanesulfonic acid, commonly known as PFOS, is a synthetic chemical compound that has been widely used in various industrial and consumer products. Due to its unique properties, such as water and oil repellency, temperature resistance, and chemical stability, PFOS has found applications in many everyday items.
Check out my list of PFAS chemicals.
What products contain PFOS
PFOS has been used in a wide range of products, including firefighting foams, stain-resistant carpets, non-stick cookware, water-resistant clothing, and food packaging materials. Manufacturers have found PFOS particularly useful due to its ability to repel both water and oil, making it an ideal ingredient for creating durable, stain-resistant surfaces.
The following products contain PFOS:
- Fire-fighting foams (Aqueous Film Forming Foams or AFFF)
- Non-stick cookware (such as Teflon)
- Stain-resistant carpets and upholstery
- Water-repellent clothing and footwear
- Food packaging materials (like microwave popcorn bags)
- Some cleaning products and stain removers
- Industrial surfactants and emulsifiers
- Certain adhesives and sealants
- Electronics manufacturing (in some cases, for etching and coating processes)
However, because of its persistence in the environment and potential health risks, many countries, including the United States, have phased out or restricted the use of PFOS in certain applications.
Chemical properties of PFOS
PFOS is a man-made chemical compound that belongs to a family of chemicals known as perfluoroalkyl substances (PFAS). These substances have a strong carbon-fluorine bond, making them resistant to degradation and allowing them to persist in the environment for long periods.
Perfluorooctanesulfonic acid (PFOS) is a toxic, persistent environmental pollutant. Here is a summary of its chemical properties:
| Property | Value |
| Chemical Synonym | PFOS |
| CAS Number | 1763-23-1 |
| Molecular Mass | 500.13 g/mol |
| Chemical Formula | C8HF17O3S |
| Main Hazards | Toxic, persistent environmental pollutant |
What are the health risks of PFOS
PFOS exposure has been linked to various health problems, including:
- Cancer: Some studies have suggested a possible link between PFOS exposure and certain types of cancer, such as kidney and testicular cancer. However, more research is needed to establish a definitive link.
- Thyroid disorders: PFOS can interfere with the normal functioning of the thyroid gland, leading to hormonal imbalances and potential health problems.
- Liver damage: Prolonged exposure to PFOS has been associated with liver damage in animal studies. Although similar effects have not been conclusively proven in humans, concerns about liver toxicity remain.
- Immune system dysfunction: PFOS may weaken the immune system, making individuals more susceptible to infections and other illnesses.
- Reproductive and developmental issues: PFOS has been shown to cause reproductive and developmental problems in laboratory animals, raising concerns about the potential effects on human fertility and child development.
It is important to note that the health risks associated with PFOS exposure can vary depending on the level and duration of exposure, as well as individual susceptibility. To minimize your risk, it is essential to take steps to reduce your exposure to PFOS, especially in drinking water sources.
What is the Drinking Water Standard for PFOS?
Ensuring safe and clean drinking water is a top priority for public health authorities. As the potential health risks associated with PFOS exposure have become more apparent, various states and countries have established drinking water standards to protect their residents from harmful PFOS concentrations. In this section, we will discuss the drinking water limits for PFOS set by the U.S. Environmental Protection Agency (EPA) and specific state regulations in California, Massachusetts, and New Jersey.
EPA drinking water limit for PFOS
In the United States, the EPA has established a health advisory level for PFOS in drinking water. A health advisory is a non-enforceable, non-regulatory guideline that provides information on contaminants that may cause health effects and are known or anticipated to occur in drinking water. The EPA’s health advisory level for PFOS is set at 70 parts per trillion (ppt), which is a combined limit that also includes perfluorooctanoic acid (PFOA), another harmful PFAS chemical.
The EPA’s health advisory level is designed to provide a margin of safety for all Americans, including vulnerable populations such as pregnant women, nursing mothers, infants, and those with compromised immune systems. It is important to note that health advisories are not legally enforceable standards, but rather guidelines to help water system operators and state regulators manage PFOS contamination in drinking water.
California drinking water standard for PFOS
California has set its own drinking water standards for PFOS, known as Notification Levels (NL) and Response Levels (RL). Notification Levels are health-based advisory levels that trigger certain requirements for public water systems, while Response Levels are levels at which public water systems are recommended to take action to reduce exposure.
As of September 2021, the California State Water Resources Control Board has established a Notification Level for PFOS at 6.5 ppt and a Response Level at 40 ppt. When a public water system detects PFOS levels above the Notification Level, it is required to notify its governing body and the State Water Board. If PFOS concentrations exceed the Response Level, the public water system is recommended to take measures to reduce the PFOS levels in the affected water source.
Massachusetts drinking water standard for PFOS
Massachusetts has also set its own drinking water standards for PFOS. In October 2020, the Massachusetts Department of Environmental Protection (MassDEP) established a Maximum Contaminant Level (MCL) of 20 ppt for PFOS, as part of a combined limit with five other PFAS chemicals. The MCL is a legally enforceable standard that applies to public water systems in the state.
Public water systems in Massachusetts are required to regularly monitor their water sources for PFOS and other PFAS chemicals, and to take corrective actions if PFOS levels exceed the MCL. This may include installing treatment systems to remove PFOS from the water or finding alternative water sources that meet the state’s drinking water standards.
New Jersey drinking water standard for PFOS
New Jersey has also established its own drinking water standards for PFOS. In September 2018, the New Jersey Department of Environmental Protection (NJDEP) set a Maximum Contaminant Level for PFOS at 13 ppt. This legally enforceable standard applies to all public water systems in the state.
Public water systems in New Jersey must comply with the PFOS MCL by regularly monitoring their water sources and taking corrective actions if PFOS concentrations exceed the established limit. Similar to Massachusetts, this may involve installing treatment systems or identifying alternative water sources that meet the state’s drinking water standards.
What Filters Remove PFOS?
Given the potential health risks associated with PFOS exposure, it’s important to ensure that your drinking water is free from this harmful contaminant. One way to do this is by using a water filter that effectively removes PFOS from your tap water.
In this section, we will discuss various water filtration methods, such as reverse osmosis, carbon filters, and other popular filter types, to help you determine the best option for removing PFOS from your drinking water.
Read my article about how to remove PFAS from drinking water.
Does reverse osmosis remove PFOS?
Reverse osmosis (RO) is a highly effective water filtration method that can remove a wide range of contaminants, including PFOS. RO systems work by forcing water through a semipermeable membrane, which filters out impurities based on their size and molecular weight. Studies have shown that RO filters can remove over 90% of PFOS from drinking water, making them an excellent option for those concerned about PFOS contamination.
However, RO systems also have some drawbacks. They can be relatively expensive to purchase and maintain, and they may produce a significant amount of wastewater during the filtration process. Additionally, RO systems can remove beneficial minerals from water, which may affect its taste and nutritional value.
Do carbon filters remove PFOS?
Activated carbon filters, commonly used in pitcher-style filters and under-sink systems, can also effectively remove PFOS from drinking water. Carbon filters work by adsorbing contaminants onto the surface of the activated carbon, which has a large surface area and high affinity for many organic compounds, including PFOS.
Studies have shown that activated carbon filters, particularly those using granular activated carbon (GAC) or powdered activated carbon (PAC), can remove between 70% and 90% of PFOS from water. However, the effectiveness of carbon filters depends on various factors, such as contact time, flow rate, and the type and quality of activated carbon used. It is important to regularly replace the filter cartridges to maintain their effectiveness in removing PFOS and other contaminants.
Do Brita filters remove PFOS?
Brita filters, which typically use activated carbon and ion exchange resin as their primary filtration media, can help reduce PFOS concentrations in drinking water. While Brita filters may not be as effective as reverse osmosis or dedicated carbon filters in removing PFOS, they can still provide a degree of protection, particularly when used in conjunction with other water treatment methods.
It is essential to follow the manufacturer’s recommendations for filter replacement and maintenance to ensure optimal performance in removing PFOS and other contaminants from your drinking water.
Do refrigerator filters remove PFOS?
Refrigerator filters, which often use activated carbon as their primary filtration media, can also help reduce PFOS levels in drinking water. However, the effectiveness of refrigerator filters in removing PFOS can vary widely depending on the specific filter model and design.
To determine whether your refrigerator filter is capable of removing PFOS, consult the filter’s documentation or contact the manufacturer for more information. Keep in mind that regularly replacing your refrigerator filter, as recommended by the manufacturer, is crucial for maintaining its effectiveness in removing PFOS and other contaminants from your drinking water.
FAQs About PFOS
Understanding PFOS and its potential impact on your health and the environment is essential for making informed decisions about your drinking water. In this section, we will address some frequently asked questions about PFOS to provide you with the information you need to protect yourself and your family from this harmful contaminant.
Is PFOS banned?
PFOS is not completely banned, but its use has been significantly restricted in many countries, including the United States. In 2000, the primary U.S. manufacturer of PFOS voluntarily phased out its production due to concerns about its persistence in the environment and potential health risks. In 2009, PFOS was added to the Stockholm Convention on Persistent Organic Pollutants, an international treaty aimed at reducing or eliminating the use of certain hazardous chemicals. As a result, the production and use of PFOS have been restricted in many countries, although some exemptions still exist for specific applications.
How can I test my water for PFOS?
Testing your water for PFOS can be done through a certified laboratory that specializes in PFAS analysis. You can contact your local or state health department for guidance on selecting a certified lab and collecting water samples for PFOS testing. Alternatively, some companies offer at-home test kits for PFOS and other PFAS chemicals, which may provide a convenient and cost-effective option for initial screening.
How can I reduce my exposure to PFOS?
There are several steps you can take to reduce your exposure to PFOS:
- Filter your drinking water: Use a water filter certified to remove PFOS, such as a reverse osmosis system or an activated carbon filter, to ensure that your drinking water is free from this contaminant.
- Test your water: Regularly test your water for PFOS and other contaminants to ensure that your filtration system is working effectively and that your water is safe to drink.
- Stay informed about local water quality: Keep up-to-date with information about your local water supply, as water utilities are required to provide annual water quality reports to their customers.
- Avoid products that may contain PFOS: Although the use of PFOS has been phased out in many products, it may still be present in some older items or imported goods. Be cautious when using older non-stick cookware, stain-resistant carpets, and water-resistant clothing, as these products may contain PFOS.
Can boiling water remove PFOS?
Boiling water does not remove PFOS. In fact, boiling may concentrate PFOS and other contaminants in the water, as some water will evaporate during the boiling process. To remove PFOS from your drinking water, use a certified water filtration system, such as a reverse osmosis or activated carbon filter, as previously discussed.
Read my article “Does Boiling Water Remove PFAS” to learn more.
How long does PFOS stay in the body?
PFOS can persist in the human body for a long time due to its chemical stability and resistance to degradation. Studies have shown that the half-life of PFOS in humans, which is the time it takes for the concentration of the substance to decrease by half, is approximately 5.4 years. This means that it can take several years for PFOS to be eliminated from the body, underscoring the importance of minimizing exposure to this harmful contaminant.
Learn More About PFOS
The California Office of Environmental Health Hazard Assessment details PFOS as a synthetic chemical used in products for stain, grease, soil, and water resistance.
EPA’s Technical Fact Sheet provides insights into PFOS and PFOA, highlighting their role in the larger group of PFAS substances.
The American Cancer Society discusses the characteristics and concerns surrounding PFOA and PFOS, emphasizing their classification as lab-made chemicals.
Final Take on PFOS
This article provides an in-depth look at PFOS (perfluorooctanesulfonic acid), a harmful and persistent environmental pollutant commonly found in various products and drinking water sources. It discusses the chemical properties of PFOS, its potential health risks, and the drinking water standards set by the U.S. Environmental Protection Agency and specific states.
It also covers various water filtration methods that can remove PFOS from drinking water, including reverse osmosis and carbon filters, as well as frequently asked questions about PFOS, such as its ban status, testing procedures, and ways to reduce exposure.