PFAS Exposure Assessment Community Update – Online Information Session

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The Centers for Disease Control (CDC) and the Agency for Toxic Substances and Disease Registry (ATSDR) hosted two online information sessions on September 3 and September 19, 2020, to provide an update on the ongoing per- and polyfluoroalkyl substances (PFAS) exposure assessment work. Agency scientists provided an update on the work across all eight exposure assessment sites, including an overview of the PFAS test results from the first four sites, discussed next steps, and answer community questions. The questions below were submitted by participants during the online information sessions.

Drinking Water Contamination
1. Is there more water contamination in Westfield?

Local authorities in Westfield have taken action to reduce levels of PFAS in drinking water. Based on the information ATSDR has reviewed, the public drinking water supply meets all applicable federal and state guidelines for PFAS. ATSDR does not recommend community members use alternative sources of water.

2. Who mitigated the Delaware wells in 2014?

In 2014, two drinking water systems serving the New Castle area, Artesian Water and Municipal Services Commission (MSC) of the City of New Castle, were found to contain PFAS levels exceeding the Environmental Protection Agency’s (EPA) health advisory.

After receiving the PFAS test results, both water systems were upgraded to reduce PFAS exposures, including installation of granular activated carbon (GAC) filtration systems. In 2017, the Delaware Department of Natural Resources and Environmental Control reported that the GAC filtration systems had reduced levels of two specific PFAS, perfluorooctane sulfonic acid (PFOS) and perfluorooctanoic acid (PFOA), below the EPA health advisory.

3. Is it possible to estimate what the levels of PFAS were in the blood before the Delaware well mitigation in 2014?

There are tools and methods that can be used to estimate past PFAS blood levels, but these tools work best when the past PFAS exposure is characterized (that is, the drinking water concentrations that occurred in the past, as well as information about other past PFAS exposures, are known). Estimation of past PFAS blood levels is outside the scope of ATSDR’s PFAS Exposure Assessment work.

Health Effects
1. What is treatment for PFAS exposure?

Currently, there is no medically-approved treatment for PFAS exposure. The only intervention is to identify how exposure is happening and eliminating the source. Health risks associated with PFAS are not specific to PFAS exposures only. These health risks are also influenced by many other environmental, social, or genetic factors and occur in individuals without PFAS exposures. In addition, some of the testing for PFAS-related health concerns have risks and are not generally performed on patients showing no signs or symptoms of illness.

Care of a patient exposed to PFAS may be determined based on the patient’s overall risk factors, family health and environmental exposure histories, patient signs and symptoms, and physical examination. ATSDR recommends health care providers use appropriate clinical judgement to determine the uses of diagnostic tests and screenings associated with PFAS health risks. For more information, see ATSDR’s PFAS Guidance for Clinicians document at: pdf icon[PDF – 471 KB]

2. A few people in my area have a medical condition. Could this be due to PFAS exposure?

What we know is that research has shown PFAS may lead to the following:

  • Increased cholesterol levels
  • Decreased vaccine response in children
  • Changes in liver enzymes
  • Increased risk of high blood pressure or pre-eclampsia in pregnant women
  • Small decreases in infant birth weights
  • Increased risk of kidney or testicular cancer

The literature continues to evolve and the body of science about PFAS exposure and health effects is growing rapidly. However, at this time knowledge about PFAS does not allow scientists or medical providers to predict if your PFAS exposure is connected to current or future illness. By participating in the exposure assessment, you’re helping contribute to the scientific understanding of PFAS levels in our bodies. While the exposure assessment will not tell us the impact of PFAS on human health, our ongoing Multi-site Health Studies will build our knowledge to help fill this data gap.

The goal of health studies is to learn more about the relationship between PFAS exposure and health outcomes. They will provide a better scientific understanding about the relationships between drinking water PFAS exposure and certain health outcomes and will help people understand their risk for health effects. Understanding the relationship between drinking water PFAS exposure and health outcomes will allow communities and governmental agencies to make better decisions about how to protect public health.

You can learn more about our Multi-site health studies on our Website:

3. Will binding agents like Questran or activated charcoal help the body excrete PFAS?

No. There is no scientific evidence that PFAS can be “flushed” from the body with binding agents or charcoal. These should only be taken as directed by a health care provider.

4. How long does it take PFAS consumed through food and water to leave the body?

Some PFAS remain in the body for a long time. However, biological half-life varies by chemical species. The half-life of a chemical is the amount of time it takes for 50% of it to be metabolized and/or eliminated from the body after the exposure has stopped. A few examples of PFAS half-lives in humans are:

  • PFBA: 72 to 81 hours
  • PFOA: 2.1 to 10.1 years
  • PFOS: 3.3 to 27 years
  • PFHxS: 4.7 to 35 years
1. Given PFAS entered the water system in Spokane County after use by a federal agency, is the federal government going to provide assistance, especially medical care, for those impacted?

ATSDR is assisting communities by conducting investigations to better understand PFAS exposure. ATSDR does not provide medical care. ATSDR and its partners have provided education to local medical providers about clinical care considerations for people who have had PFAS exposure.

2. In Hampden County, how broadly are you providing education to physician practices? For example, all Baystate providers? (Residents in Westfield don’t necessarily have Westfield physicians.)

We mailed out information and guidance to clinicians as broadly as possible and hosted a webinar for clinicians that was advertised in Baystate. The clinician information and guidance is also available on the ATSDR PFAS Website: pdf icon[PDF – 471 KB]

1. What are some of the recent EPA changes related to safety limits and use of PFAS? How will these affect people who have already been exposed?

For EPA related questions, please contact the agency at: icon. For more information, please see the EPA website: icon.

2. Why did the PFOS levels [in blood] in the general population go down?

Since 2002, production and use of PFOS and PFOA in the United States have declined. As the use of some PFAS has declined, some blood PFAS levels have gone down as well.

From 1999 to 2014, blood PFOS levels have declined by more than 80% in the general U.S. population.

From 1999 to 2014, blood PFOA levels have declined by more than 60% in the general U.S. population.

3. PFAS levels [in blood] are decreasing in the general population because PFAS are being phased out. How do you account for other countries still using PFAS (such as China) in products sent to the U.S.? And what about the EPA continuing to approve additional, new PFAS?

In 2020, EPA announced a supplemental proposal called a ‘significant new use rule (SNUR).’ It aims to ensure that new uses of certain persistent PFAS in surface coatings cannot be manufactured or imported into the United States without review under the Toxic Substances Control Act (TSCA).

You can get more information about the proposal at the EPA Website: icon

New kinds of PFAS have replaced historical PFAS such as PFOA and PFOS. CDC has developed new laboratory methods to detect these alternative PFAS in people’s bodies (blood and urine). Recent investigations indicate that some of these alternatives, such as GenX, are not as readily found in people’s bodies compared to historical PFAS. Scientist believe that the chemical structure of these alternative chemicals may allow them to be more easily eliminated from people’s bodies. To learn more about CDC’s work on alternative PFAS see:

Pritchett JR, Rinsky JL, Dittman B, Christensen A, Langley R, Moore Z, Fleischauer AT, Koehler K, Calafat AM, Rogers R, Esters L, Jenkins R, Collins F, Conner D, Breysse P. Notes from the Field: Targeted Biomonitoring for GenX and Other Per- and Polyfluoroalkyl Substances Following Detection of Drinking Water Contamination – North Carolina, 2018.external icon MMWR Morb Mortal Wkly Rep. 2019 Jul 26;68(29):647-648. doi: 10.15585/mmwr.mm6829a4. No abstract available. PMID: 31344024. PMCID: PMC6660104external icon

Calafat AM, Kato K, Hubbard K, Jia T, Botelho JC, Wong LY. Legacy and alternative per- and polyfluoroalkyl substances in the U.S. general population: Paired serum-urine data from the 2013-2014 National Health and Nutrition Examination Survey.external icon Environ Int. 2019 Oct;131:105048. doi: 10.1016/j.envint.2019.105048. Epub 2019 Jul 31. PMID: 31376596

4. Has food that’s been grown in gardens and farms been studied for contamination?

Studies have shown that PFAS can accumulate in plants grown in PFAS-contaminated soil or irrigated with PFAS-contaminated water. However, accumulation depends on multiple factors including the type of plant, concentration of PFAS in soil and water, and type of PFAS.

An individual’s PFAS exposure from eating plants grown in soil or irrigated with water with PFAS depends on how much and how often they eat the contaminated plants. Research is still ongoing to determine how people may be exposed to PFAS from plants grown in PFAS-contaminated areas and whether this kind of exposure poses a health risk.

You can lower your risk of exposure by following safe gardening practices such as:

  • Washing produce before consumption to remove soil/dust particles containing PFAS
  • Increasing natural matter in the soil which can lower plants’ ability to accumulate PFAS. Sources of natural matter include composts and manure.
  • Irrigating crops with rainwater
  • Using raised garden beds with clean soil
1. Since these [blood] samples were taken several years after the water was mitigated, is it possible to calculate backwards what the levels in the blood would have been before water mitigation?

There are tools and methods that can be used to estimate past PFAS blood levels, but these tools work best when the past PFAS exposure is well characterized (that is, the drinking water concentrations that occurred in the past, as well information about other past PFAS exposures, are known). Estimation of past PFAS blood levels is outside the scope of ATSDR’s PFAS Exposure Assessment work.

Project Design
1. Were National Guard members or firefighters eligible to participate in the study?

People who were exposed to PFAS while working as firefighters or serving in the military were eligible to participate if their household was randomly selected.

2. Were the urine, tap water, and dust samples collected [in Spokane] before or after the wells were mitigated?

Yes – Samples were collected after mitigation of the municipal wells and connections to the City of Spokane water supply. The primary mitigation was connecting to the City of Spokane Water System.  Treatment systems were added to wells used during summer when there is increased water use. All drinking water meets Washington and EPA standards.

3. Do you expect more updated NHANES data? It is my understanding the NHANES data you used as a comparison is from 2015/2016?

The comparisons for the exposure assessments were calculated using the most recent NHANES data available at the time. It is appropriate to compare the exposure assessment results to the most similar time period available from NHANES at the time of analysis. In this case, with the lag time in NHANES reporting, the most recent data we had for conducting our analyses was 2015/2016. Comparison information will not be updated with newer NHANES data at this time. We do expect NHANES to continue monitoring concentrations of some PFAS in the general US population.

4. Does ATSDR have plans to follow up with a survey in the future to determine changes in blood levels over time?

At this point in time, ATSDR does not have plans to follow blood levels over time.

5. Did you analyze for Total Oxidizable Precursors as well as these specific PFAS compounds?

We did not analyze Total Oxidation Precursors. We measured a targeted list of PFAS in blood, urine, water, and dust. These PFAS are identified in our exposure assessment protocol.

6. Are you saving these blood, urine, and dust samples for possible future analysis?

Participants were given the option to agree to sign the exposure assessment consent forms giving permission to save blood and urine samples for other PFAS-related tests. ATSDR is saving the samples for participants that gave permission. Personal information will be protected. If your blood and urine are analyzed in the future, we will send you the results.

7. Have you analyzed PFOA and PFOS levels together? The health advisory from EPA discusses drinking water levels of 70 parts per trillion for them separately and together.

Although analysis of PFOA and PFOS in biological samples was done separately, concentrations of PFOA and PFOS in drinking water were combined to compare the results to the EPA health advisory.

8. Did participants fill out a health survey and share their health symptoms with ATSDR so you can make connections between levels of PFAS in the blood and health effects?

No, participants were not asked to complete a health survey. An exposure assessment does not look at what types of health problems the exposure might cause. The Multi-site Health study will investigate specific health outcomes including kidney function, thyroid disease, and diabetes.

9. My physician said that once you excrete the toxic chemicals, the damage has been done to your endocrine systems and organs. Why didn’t the CDC/ATSDR study the organ damage/medical issues in the exposed areas?

The purpose of an exposure assessment is to try to find out more about how PFAS exposures can affect PFAS blood levels. People are tested to see whether they have been exposed. Using this information, public health professionals provide guidance to help people reduce or stop exposure. We didn’t study organ damage and medical issues in the exposure assessment because this was outside the scope of the investigation. The Multi-site Health study will investigate specific health outcomes including kidney function, thyroid disease, and diabetes.

1. Were all the tests analyzed at the same lab?

Different types of tests were analyzed at different labs. All blood and urine samples were analyzed at the CDC’s National Center for Environmental Health laboratory. All water samples were analyzed by Eurofins. All dust samples were analyzed by SGS AXYS. More information about the laboratory analyses is available in the exposure assessment protocol.

2. Do you feel the number of participants you tested are enough to represent the community?

Yes. Yes, ATSDR conducted sample size calculations to identify how many people we need to enroll to provide an estimation of PFAS levels in the community and detect if there are differences in PFAS blood levels between the community and the rest of the U.S. population. ATSDR is able to draw conclusions from the available test results even if the target goal of recruiting approximately 400 participants is not met.

1. When will the demographic data be released?

Demographic data will be in the final reports.

1. Will you overlay results in each community with known cancer clusters?

The purpose of an exposure assessment is to try to find out more about how PFAS exposures can affect PFAS blood levels. It does not look at what types of health problems the exposure might cause. ATSDR does not plan to assess if there is a spatial relationship between PFAS blood levels and cancer cases in the exposure assessment communities. Investigating cancer clusters is outside of the scope of the PFAS exposure assessments.

We are pursuing other ways to address community members’ concerns about the possible risk of PFAS exposure and cancer.

We are working on a study that will look at rates of certain health outcomes, including many adult and pediatric cancers, in communities that have been exposed to PFAS through drinking water.

This study will analyze previously collected data. This gives CDC/ATSDR an advantage because the study can proceed more quickly, as we don’t have to gather the data from individuals.

Due to the design of the study, the results will give information about the differences between communities that do and do not have drinking water PFAS exposures. While this type of study cannot tell us about the relationships between health outcomes and exposure at the individual level, it will serve as a crucial first step that can help scientists pinpoint which health outcomes need further study.

2. Why is there a delay in analyzing and/or reporting the dust samples results? Will communities have to wait for the final report to get their results?

Dust samples can take more time to analyze because the method to measure PFAS in dust is new. All households that participated in indoor dust sampling will receive their individual results as soon as possible. Overall dust sample results for each community will be shared in the final reports.

Page last reviewed: January 22, 2021