PFAS—have you heard of them? Do you know what they are, or is it more of a term thrown around without much context?
PFAS are per- and polyfluoroalkyl substances. PFAS is a class of chemicals found in various industrial and consumer goods. For instance, you may find them in food packaging, textiles, cosmetics, and frequently in aqueous film-forming foams (AFFFs) used to extinguish fires. PFAS chemicals are known for repelling grease, water, and stains, making them widely used in various applications. These chemicals are stable and persistent, earning them the nickname “forever chemicals” because they do not readily biodegrade, or break down easily in the environment.
Numerous researchers suggested PFAS are abundant in aquatic systems and toxic to a range of aquatic organisms, with additional concerns of bioaccumulation of PFAS. PFAS accumulate in sediments and aquatic organisms, which pose health risks to wildlife and humans through the food chain. Research suggests linkages of PFAS to disruption of endocrine function, reproduction, and development in aquatic organisms. Research suggests similar linkages of PFAS to humans, like increased cancer risk, immune system suppression, endocrine and reproductive disruption, and child developmental concerns.
The United States Geological Survey (USGS) estimated at least 45% of the United States’ tap water has one or more PFAS chemicals (Smalling et al. 2023). At least one PFAS was identified in 60% of public wells and 20% of domestic wells supplying drinking water in the eastern United States (McMahon et al. 2022).
Have PFAS been found in Okaloosa County drinking water and surface waters?
Measured PFAS in Florida and Okaloosa County Drinking Waters
Figure 1. Map with measured total PFAS samples across a gradient of low concentrations (green dots) to medium concentrations (yellow dots) to higher concentrations (red dots). Shaded map colors are the predicted total PFAS using estimated values of PFAS concentrations from low (green) to high (red). Data, figure, and result interpolation from Sinkway et al. 2024.
A team of researchers completed a comprehensive statewide assessment of PFAS in Florida drinking water (Sinkway et al. 2024). The team collected 448 drinking water samples across all 67 Florida counties. The drinking water samples were analyzed for 31 PFAS, where 19 PFAS were found in at least one drinking water sample. The top five most frequently detected PFAS were 6:2 fluorotelomer sulfonate (6:2 FTS) (in 84% of the samples analyzed), Perfluorooctanoic acid (PFOA) (65%), linear perfluorooctane sulfonate (PFOS) (65%), branched PFOS (64%), and perfluorobutane sulfonic acid (PFBS).
A total of 107 taps had PFOA or PFOS concentrations above 4 ng/L (ppt), where the maximum total PFAS concentration in a tap was 219 ng/L (Click on link for higher resolution–Figure 1). The maximum contaminant level for PFOA and PFOS is 4 ng/L, legally enforced by the United States Environmental Protection Agency National Primary Drinking Water Regulation as of May 14, 2025 (USEPA, 2025). Overall, 8% of the drinking water samples analyzed exceeded 4 ng/L for PFOA and 16% for PFOS. The average total PFAS in city water was 15.6 ng/L, and in well water was 4.5 ng/L.
Table 1. Top average 12 Florida counties with highest and lowest total PFAS concentrations (ng/L). Data, figure, and result interpolation from Sinkway et al. 2024.
Okaloosa County had the 11th highest total PFAS (ng/L) concentration among the 67 Florida counties (Click on link for higher resolution–Table 1). Among the eight drinking water samples collected, the maximum PFAS concentration measured was 140 ng/L, and the lowest was 18 mg/L. Okaloosa County had one drinking water sample that exceeded the 4 ng/L standard for PFOA. There were no drinking water samples that exceeded 4 ng/L for PFOS.
Measured PFAS in Florida and Okaloosa County Surface Waters
A team of researchers completed a comprehensive statewide assessment of PFAS in Florida surface waters (Camacho et al. 2024). A network of citizen scientists collected 2,323 surface water samples across the 67 Florida counties. These surface water samples were analyzed for 50 PFAS, with 33 PFAS being detected in at least one surface water sample. The top five most frequently detected PFAS were perfluorooctanoic acid (PFOA) (94% of the samples), perfluorobutane sulfonic acid (PFBS) (65%), perfluorohexanoic acid (PFHxA) (61%), perfluorononanoic acid (PFNA) (54%), and perfluorooctane sulfonate (PFOS) (53%).
Figure 2. Map A contains all surface water sampled sites with detected PFAS, where the dots’ color represents the total PFAS concentration measured. Map B shows predicted PFAS levels based on measured total PFAS concentrations in surface water samples. Note that these values do not represent predicted PFAS concentrations on land. Data, figure, and result interpolation from Camacho et al. 2024.
There were 915 (39%) surface water samples with PFOA concentrations above 4 ng/L and 920 (40%) samples with PFOS above 4 ng/L (Click on link for higher resolution–Figure 2). All counties had at least one sample with PFOA, 96% had PFNA, 93% had PFBS, 91% had PFOS, and 82% of counties had PFHxA. The average PFAS detected among counties ranged from 2 ng/L of PFNA to 10 ng/L of PFOS. The maximum PFAS detected among counties ranged from 81 ng/L of PFOA to 1135 ng/L of PFOS. Figure 2
Okaloosa County ranked 27th among Florida counties due to 10 (20%) surface water samples with PFOA above 4 ng/L. Okaloosa County ranked 9th for the number of samples (38 total samples or 78% of the samples) above 4 ng/L for PFOS. A total of 49 surface water samples were collected in Okaloosa County. The average total PFAS concentration detected in a surface water sample was 31 ng/L, while the maximum total PFAS concentration detected in a sample was 185 ng/L.
Dr. Bowden, with the University of Florida’s College of Veterinary Medicine and Chemistry Department, led the PFAS research shared here. Dr. Bowden has extensive information on the Bowden Lab website (https://www.bowdenlaboratory.com/dr-bowden.html), including an interactive map of all the PFAS surface water samples collected in Florida. Select Okaloosa County under the filter section to see the surface water samples and learn more about the PFAS information for each sample collected in Okaloosa County (https://www.bowdenlaboratory.com/florida-surface-water.html).Figure 2Table 1
What does this mean for Okaloosa County?
PFAS have been detected in drinking water and surface waters in Okaloosa County. Although not the highest concentrations or most frequent identified in Florida, there were drinking and surface water samples above USEPA’s 4 ng/L contaminant level standard. Understanding what PFAS are and joining in educational conversations about PFAS helps our community. Efforts that support continued sampling and extended monitoring also increase our understanding of PFAS concentrations in Okaloosa County’s drinking and surface waters. If you want to learn more about PFAS or join community scientists’ efforts to expand PFAS water monitoring, please contact Dana Stephens at the UF/IFAS Okaloosa County Extension Office.
References
Camacho, C.G., et al. 2024. Statewide surveillance and mapping of PFAS in Florida surface waters. American Chemical Society, 4: 434-4355. https://doi.org/10.1021/acsestwater
McMahon, P.B., Tokranov, A.K., and Bexfield, L.M. 2022. Perfluoroalkyl and polyfluoroalkyl substances in groundwater used as a source of drinking water in the Eastern United States. Environmental Science and Technology 56(4): 2279-2288. https://doi.org/10.1021/acs.est.1c04795
Skinkway, T.D., et al. 2024. Crowdsourcing citizens for statewide mapping of per- and polyfluoroalkyl substances (PFAS) in Florida drinking water. Science of the Total Environment, 926: 1-9. https://doi.org/10.1016/j.scitotenv.2024.171932
Flooding due to heavy rains can cause septic systems to fail. Image: B. White NASA. Public Domain
About 30% of households in Florida rely on septic systems to treat and dispose of household wastewater. This includes all water from bathrooms and kitchens, and laundry machines.
Conventional septic systems are made up of a septic tank (a watertight container buried in the ground) and a drain field, or leach field. The septic tank’s job is to separate out solids (which settle on the bottom as sludge), from oils and grease, which float to the top and form a scum layer. Bacteria break down the solids (the organic matter) in the tank. The liquid wastewater or effluent, which is in the middle layer of the tank, flows out through pipes into the drain field and underlying soil, where most of the treatment takes placeDuring floods or heavy rains, the soil around the septic tank and in the drainfield become saturated, or water-logged, and the effluent from the septic tank can’t properly drain though the soil. Special care needs to be taken with your septic system during and after a flood or heavy rains.
Diagram of a conventional septic system. Courtesy of the Leon County Public Works Department.
What should you do after flooding occurs?
The U.S. Environmental Protection Agency (EPA) offers these guidelines:
If your water supply comes from a private well, have it tested for bacteria (total coliform bacteria and E. coli) to make sure it’s safe for consumption, which includes drinking, brushing teeth and cooking. Contact your local County Health Department for testing information. Use an alternate water source or boil your water (bring it to a rolling boil for at least 1 minute) before using it.
Relieve pressure on the septic system by using it less or not at all until floodwaters recede and the soil has drained. For your septic system to work properly, water needs to drain freely in the drainfield. Under flooded conditions, water can’t drain properly and can back up in your system. Remember that in most homes all water sent down the pipes goes into the septic system. Clean up floodwater in the house without dumping it into the sinks or toilet.
Avoid digging around the septic tank and drainfield while the soil is water logged. Don’t drive heavy vehicles or equipment over the drainfield. By using heavy equipment or working under water-logged conditions, you can compact the soil in your drainfield, and water won’t be able to drain properly.
Don’t open or pump out the septic tank if the soil is still saturated. Silt and mud can get into the tank if it is opened and can end up in the drainfield, reducing its drainage capability. Pumping under these conditions can cause a tank to pop out of the ground.
If you suspect your system has been damage, have the tank inspected and serviced by a professional. How can you tell if your system is damaged? Signs include: settling, wastewater backs up into household drains, the soil in the drain field remains soggy and never fully drains, a foul odor persists around the tank and drain field.
Keep rainwater drainage systems away from the septic drainfield. As a preventive measure, make sure that water from roof gutters doesn’t drain into your septic drainfield – this adds an additional source of water that the drainfield has to manage.
Private well system in Florida. Image: UF/IFAS, C. Wofford
About 2.5 million Floridians rely on private wells for home consumption, which includes water for drinking, cooking, and personal hygiene. Private wells are not regulated by the EPA Clean Water Act, and well users are responsible for ensuring their water is safe to drink.
What should you have your well water tested for?
The Florida Department of Health (FDOH) recommends that well users test their well water once a year for bacteria at a minimum. Another important contaminant to test for is nitrate.
Bacteria: Labs generally test for total coliform (TC) bacteria and fecal coliforms (like E. coli).
Coliform bacteria are a large group of bacteria and most are harmless. But a positive test result indicates that if they are in your water, other pathogens that cause diseases may also be present. They are used as indicator organisms.
Fecal coliform bacteria are a subgroup of coliform bacteria found in human and other warm-blooded animal feces. E. coli are one species and some strains can cause diarrhea, food poisoning and other illnesses.
If your water sample tests positive for only total coliform bacteria or both TC and fecal coliform (E. coli), FDOH recommends your well be disinfected through shock chlorination. You can either hire a well contractor to do this or you can do it yourself. Information for how to shock chlorinate your well can be found at EDIS Private Wells 101: Bacterial Contamination and Shock Chlorination
Take a water sample at the kitchen faucet if this is where you get most of the water that your household consumes. Image: F. Alvarado
Nitrate: The U.S. EPA set the Maximum Contaminant Level (MCL) allowed for nitrate in drinking water at 10 milligrams per liter of water (mg/L). Values above this are a particular concern for infants less than 6 months old because high nitrate levels can cause a type of “blue baby syndrome” (methemoglobinemia), where nitrate interferes with the capacity of hemoglobin in the blood to carry oxygen. It is especially important to test for nitrate if you have a young infant in the home that will be drinking well water or when well water will be used to make formula to feed the infant.
If test results come back above 10 mg/L, never boil nitrate contaminated water as a form of treatment. This will not remove nitrates. Use water from a tested source (bottled water or water from a public supply source) until the problem is addressed. Nitrate in well water can come from multiple sources, including fertilizers, animal waste and/or human sewage, such as from a septic tank.
You should also have your well water tested at any time when:
The color, taste or odor of your well water changes or if you suspect that someone became sick after drinking your well water.
A new well is drilled or if you have had maintenance done on your existing well
A flood occurred and your well was affected
Remember: Bacteria and nitrate are by no means the only parameters that well water is tested for. Call your local health department to discuss what they recommend you should get the water tested for. FDOH also maintains an excellent website with many resources for private well users which includes information on potential contaminants and how to maintain your well to ensure the quality of your well water.
Where can you have your well water tested?
UF/IFAS Extension will be hosting a private well and water quality workshop on April 11 in Blountstown, with a Zoom option. We will cover well and septic system function and maintenance, water testing and how to prepare for hurricane season. We will also offer facilitated water testing. For more information and to register go to our Eventbrite link or you can also register by visiting the Calhoun County Extension Office, (850-674-8323). Last week’s post about the workshop provides more information as well.
In general, many county health departments accept samples for water testing. You can also submit samples to a certified commercial lab near you. Contact your county health department for information about what to have your water tested for. If they don’t offer testing, they often provide the name of certified laboratories near you. Or you can search for FDEP certified laboratories here.
If you have any questions, you can also reach out to me at albertin@ufl.edu or (850)875-7111.
Prepare an emergency drinking water supply for your household before a storm hits. Image: UF/IFAS – Tyler Jones.
Hurricane season is just around the corner. During a natural disaster, drinking water supplies can quickly become contaminated. To be prepared, store a safe drinking water supply before a storm arrives. If you are unable to store enough water before a storm, it’s important to know how to make water safe to consume in an emergency.
Before a storm: How much water should be stored?
Store enough clean water for everyone in the household to use 1 to 1.5 gallons per day for drinking and personal hygiene (small amounts for things like brushing teeth). Increase this amount if there are children, sick people, and/or nursing mothers in the home.
Store a minimum 3-day supply of drinking water. If you have the space for it, consider storing up to a two-week supply.
For example, a four-person household requiring 1.5 gallons per person per day for 3 days would need to store: 4 people × 1.5 gallons per person × 3 days = 18 gallons. Don’t forget to include additional water for pets! Store a quart to a gallon per pet per day,depending on their size.
Examples of 3 and 5 gallon food grade jugs for storing water. Image: A. Albertin
What containers can be used to store drinking water?
Store drinking water in thoroughly washed food grade safe containers that are durable and unbreakable such as food grade plastic and enamel-lined metal containers with tight-fitting lids. These materials will not transfer harmful chemicals into the water or food they contain.
Specific examples include containers previously used to store beverages, like 2-liter soft drink bottles, juice bottles or containers made specifically to hold drinking water. Avoid plastic milk jugs if possible because they are difficult to clean. If you are going to purchase a container to store water, make sure it is labeled food-grade or food-safe.
As an extra safety measure, sanitize containers with a solution of 1 teaspoon of non-scented household bleach per quart of water (4 teaspoons per gallon of water). Use bleach that contains 5%–9% sodium hypochlorite. Add the solution to the container, close tightly and shake well. Make sure that the bleach solution touches all the internal surfaces. Let the container sit for 30 seconds and pour the solution out. You can let the container air dry before use or rinse it thoroughly with clean water.
Best practices when storing drinking water
Store water away from direct sunlight, in a cool dark place if possible. Heat and light can slowly damage plastic containers and can eventually lead to leaks.
Make sure caps or lids are tightly secured.
Store smaller containers in a freezer. You can use them to help keep food cool in the refrigerator if the power goes out during a storm.
Keep water containers away from where toxic substances (such as gasoline, kerosene, or pesticides) are stored. Vapors from these substances can penetrate plastic.
When possible, use water from opened containers in one or two days if they can’t be refrigerated.
After a storm: Ensuring a safe drinking water supply
If a boil water notice has been issued in the area you live or you suspect your water supply may be contaminated, don’t consume it. Do not use it for drinking, preparing baby formula or food, making ice (if you have electricity), washing dishes, or brushing your teeth. Don’t swallow water when bathing. If you have any open cuts or wounds, do not use it for bathing. Instead, use your own clean, stored water supply or use bottled water.
If you don’t have access to clean water, you can boil, disinfect, and filter your water during an emergency to make it safe to drink. But, if your water is contaminated by fuel or toxic chemicals, boiling or disinfection won’t make it safe to drink. In these cases, it’s important to call your local health department for guidance and use bottled water instead.
Boiling water is the most effective way to destroy pathogens in water including viruses, bacteria, and parasites such as Cryptosporiduim and Giardia. If the water is cloudy or murky, let it settle and filter it through a clean cloth or coffee filter before boiling.
Once water begins boiling, continue to boil it for at least one minute.
Let the water cool and transfer it to a clean, food-grade container with a tight lid.
You can improve the taste of boiled water by aerating it (transfer water back and forth from one clean container to another) or you can add a pinch of salt for each quart of boiled water.
Disinfecting water will kill most viruses and bacteria, but it’s not as effective in killing parasites (like Giardia and Cryptosporidium) as boiling. Disinfect water by using the following amounts of household chlorine bleach (5%-9% sodium hypochlorite) and water. Do not use ‘splashless’ bleach or scented bleach. If the water is cloudy or murky, filter through a clean cloth or coffee filter before disinfecting. If water remains cloudy, double the amount of recommended chlorine bleach.
Amountof water
Amount of chlorine bleach (5-9% sodium hypochlorite)
Clear water
Cloudywater
1 quart
2 drops
4 drops
1 gallon
8 drops
16 drops
5 gallons
½ teaspoon
1 teaspoon
After mixing in the bleach, let the water stand for 30 minutes. If the water is still cloudy after 30 minutes, repeat the chlorination procedure once.
You can also use chlorine dioxide tablets, or iodine tablets to disinfect water. Follow the manufacturer’s instructions for disinfection.
Filtering water – According to the CDC, many filtration systems can remove parasites like Giardia and Cryptosporidium if the absolute pore size is 1 micron or smaller. This does not filter out viruses or many bacteria. When choosing a filter, it’s important to carefully read the manufacturer’s instructions to understand what the system is effective against. The CDC recommends adding a disinfectant to the filtered water (chlorine, iodine, or chlorine dioxide tablets) to kill most viruses and bacteria. Follow the manufacturer’s instructions for disinfection.
Private well system in Florida. Image: C. Wofford, UF/IFAS Photography
As a private well owner, you are responsible for ensuring that your water is safe to drink. What do you know about where well water comes from? Do you know how well water can become contaminated? If you want to learn about steps you can take to help ensure your drinking water is safe to consume and about what you can do to help protect groundwater quality, join us at our upcoming workshop. We will cover how private wells and septic systems work, maintenance, protecting drinking water quality, and disaster preparedness for this upcoming hurricane season.
The workshop will be offered on Thursday, April 13, 2023, from 5:00 pm – 7:30 pm at the Jackson County Agriculture Offices, 2741 Penn Ave., Marianna. You can also attend virtually viaZoom. Registration is $5.00 per person. Facilitated water screening for total coliform and E. coli bacteria is available for FREE! Please register using this Eventbrite link, or you can also register by visiting the Jackson County Extension Office, 2741 Penn Avenue, Suite 3, Marianna (850-482-9620). This workshop is being presented by UF/IFAS Extension Bay, Calhoun, Holmes, Jackson, and Washington Counties.
For lead and nitrate testing prices and additional details, visit our Eventbrite page or call the Jackson County Extension Office at 850-482-9620. Pre-registration is encouraged as seating is limited, but as mentioned previously, a virtual option is also available. For persons with disabilities requiring special accommodations, please contact the Extension Office (TDD, via Florida Relay Service, 1-800-955-8771) at least ten working days prior to the class so that proper consideration may be given to the request. UF/IFAS Extension is an Equal Opportunity Institution.
Are you a Florida homeowner connected to a private well and/or septic system? Do you know want to learn more about your water and wastewater management systems at home?
If so, please join the UF/IFAS Central and Northwest Florida water resources regional specialized agents Yilin Zhuang and Andrea Albertin, in our four free private well and septic system webinars in February and March:
Thursday, February 9 at 2:00 p.m.: Private Wells 101
Thursday, February 16 at 2:00 p.m.: Septic System 101
Thursday, February 23 at 2:00 p.m.: Private Well Care Before and After Storms
Thursday, March 2 at 2:00 p.m.: Septic System Care Before and After Storms
After completing the webinars, attendees will also receive free mail-in well water screening for total coliform bacteria and E. coli.
To register, please visit our Eventbrite page: https://2023FWON.eventbrite.com. These webinars are free, but we ask all attendees to register.
For more information, please contact Dr. Yilin Zhuang at yilinz@ufl.edu, or Dr. Andrea Albertin at albertin@ufl.edu or via telephone: (850) 875-7111.
