PFAS Exposure Assessment: Spokane County, Washington

Background

In 2019, the Centers for Disease Control and Prevention (CDC) and the Agency for Toxic Substances and Disease Registry (ATSDR) conducted an exposure assessment (EA) from the City of Airway Heights, Spokane County, Washington, near Fairchild Air Force Base. CDC/ATSDR sent the individual test results to participants and released summary results to the community in May 2020. The PFAS exposure assessment report was released in March 2022.

Why the Airway Heights site was selected

Airway Heights was one of several sites nationwide identified with PFAS drinking water contamination from use of products such as aqueous film forming foam (AFFF). When selecting EA sites, ATSDR considered the:

• Extent of PFOA and PFOS contamination in drinking water supplies.
• Amount to time the exposure may have occurred.
• Number of potentially affected residents.

As early as the 1970s, the Fairchild Air Force Base used AFFF containing PFAS for firefighter training. Over time, the PFAS from the AFFF entered the ground. It then moved into the groundwater to offsite locations and affected nearby municipal wells.

PFAS were first detected in Airway Heights municipal wells in May 2017. Airway Heights authorities immediately removed the contaminated drinking water wells from service and provided residents bottled water until drinking water could be obtained from the uncontaminated City of Spokane water supply. By June 2017, the city declared the water safe to drink. Since 2017, Airway Heights has reactivated some of its drinking water wells with treatment systems to remove PFAS.

ATSDR has determined that the City of Airway Heights public drinking water supply currently meets or is below the U.S. Environmental Protection Agency's (EPA) 2016 health advisory (HA) for PFAS in drinking water. This is based on information reviewed by ATSDR. At this time, ATSDR does not recommend that residents who get drinking water from the City of Airway Heights' public water supply use alternative sources of water.

Sampling area

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Timeline

How testing was conducted

ATSDR invited Airway Heights residents who met certain eligibility criteria to participate in the EA. Participants had to have:

• Used drinking water from the City of Airway Heights Water Department and lived west of Hayford Road for at least 1 year before June 8, 2017.
• Been older than 3 years at the time of sample collection.
• Not been anemic or had a bleeding disorder that would prevent giving a blood sample.

Households with private wells were not eligible for participation. Measuring PFAS in the blood of people from selected households allows us to estimate exposure from consumption of public drinking water for the entire community in the affected area. This included those who were not tested.

Results

In May 2022, CDC/ATSDR released a summary of the biological and environmental test results. The full report was released March 10, 2022. A summary of the report's findings is below.

In November 2019, ATSDR collected samples and other information from participants and analyzed samples and data from the following:

• 333 people, including
  • 286 adults
  • 47 children
• 168 households
• Questionnaires completed by participants
• Blood and urine samples provided by participants
• Samples of tap water and dust from some homes

ATSDR sent individual results to each participant in May 2020. The community summary results were published.

This PFAS EA provides evidence that past exposures to PFAS in drinking water have impacted the levels of PFAS in people's bodies. PFAS are eliminated from the body over a long period of time. This allowed ATSDR to measure PFAS even though exposures through drinking water were mitigated, or lowered, years ago.

Although the exposure contribution from PFAS in drinking water in Airway Heights has been reduced, there are actions community members and city officials can take to further reduce exposures to PFAS and protect public health.

Based on the recent PFAS drinking water test results from the Airway Heights municipal water system, ATSDR does not recommend an alternate source of drinking water at this time.

Other testing

Only two PFAS (PFBA and PFHxS) were detected in urine.

All tap water samples collected during the EA in 2019 met or were below EPA's health advisory for PFAS in drinking water.

PFAS contamination in house dust was similar to that reported in other studies (with and without PFAS contamination).

Key takeaways

• Levels of some PFAS in the blood of Airway Heights residents were up to 56 times higher than national levels.
• Elevated PFAS blood levels may be linked with past drinking water contamination.
• Some demographic and lifestyle characteristics were linked with higher PFAS blood levels.

All tap water samples collected during the EA in 2019 met or were below EPA's health advisory and Washington State public health guidelines for PFAS in drinking water.

Future direction

Average blood levels of PFAS

The average blood levels of five PFAS (PFHxS, PFOS, PFOA, PFNA, and PFDA) in Airway Heights EA participants were higher than average levels nationwide.

Of the seven PFAS tested at the Spokane County EA site, at least one PFAS was detected in all participants. And all seven PFAS were detected in more than 60% of the blood samples collected:

• PFHxS
• PFOS
• PFOA
• PFNA
• PFDA
• PFUnA
• MeFOSAA

Since 1999, the National Health and Nutrition Examination Survey (NHANES) has measured PFAS levels in blood in the U.S. population, and PFAS levels are shown to be age dependent.

ATSDR adjusted blood levels of EA participants at the Spokane County EA site for age to enable meaningful comparison to the NHANES dataset. After adjusting for the effects of age, PFHxS, PFOA, PFOS, PFNA and PFDA were all elevated compared to levels nationwide. Age-adjusted averages are more representative the Spokane County EA site community.

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Information to protect our communities

Elevated blood levels

Elevated blood levels of three PFAS in the Airway Heights EA participants may be linked with past contamination of the city's drinking water.

Three PFAS (PFHxS, PFOS, and PFOA) were detected in Airway Heights drinking water in 2017. We do not know if contamination began earlier, because no earlier data are available.

By 2017, Airway Heights municipal drinking water met the EPA's HA for PFOA and PFOS. There were more than 2 years and 5 months between the reduction of exposure via contaminated drinking water and the collection of the EA blood samples.

Due to the long half-lives of PFHxS, PFOS, and PFOA in the human body, past drinking water exposures may have contributed to the EA participants' blood levels. Typically, participants who had elevated blood PFHxS levels also had elevated blood PFOS and blood PFOA levels. This suggests a common source of exposure, such as the Airway Heights public water supply prior to June 8, 2017. Other sources of exposure were not measured but could have contributed to PFAS concentrations measured in blood of the EA participants.

Long-time residents had higher PFHxS, PFOS, and PFOA blood levels. For every additional year an adult participant lived in Airway Heights, there was an increase in blood PFHxS (7.2%), PFOS (5.6%), and PFOA (3.9%) levels.

Statistical findings

PFHxS, PFOS, and PFOA levels in blood were higher in older participants. These PFAS increased by 1.1% to 1.8% for every year of participant age.

Males had 77% higher PFNA blood levels than females.

Participants who ate fast food a few times per month had lower blood PFHxS, PFOS, PFOA, PFNA, and PFDA blood levels compared to participants who ate fast food a few times per year or less. This finding differs from other studies and may be due to differences in diet and lifestyle correlated with fast food consumption.

Adult participants who identified as non-White or Hispanic had higher PFNA and PFDA blood levels than White, non-Hispanic participants:

• PFNA 37% higher
• PFDA 33% higher

Female participants' PFAS blood levels decreased with increasing number of child births. For each child, PFAS levels were:

• PFHxS 11.7% lower
• PFOS 9.3% lower
• PFOA 13.7% lower
• PFNA 8.1% lower

Participants reporting any use of stain-resistant products had 26% higher blood levels of PFDA than participants who reported never using these products.

Adults who donated blood at least once a year had lower blood levels of PFHxS (67%), PFOA (60%), and PFNA (49%) than participants who never reported donating blood.

Exposure in children

Though many exposure factors could not be evaluated due to the small number of children who participated, two associations were observed in children:

• Children who were breastfed had higher blood levels of PFNA, but current science shows the benefits of breastfeeding outweigh the risks for infants exposed to PFAS in breast milk.
• Children who drank formula prepared with tap water had higher PFHxS and PFOS blood levels than children who never drank formula prepared with tap water. For every month on formula, PFAS levels increased:
  • 2.2% PFHxS
  • 1.5% PFOS

Because of the small sample size, results should be interpreted with caution. ATSDR will gather the data from children across all exposure assessment sites and provide a detailed analysis.

What else can be done

Community members

For information on water quality, become familiar with Consumer Confidence Reports.

Private well owners living in the area affected by PFAS should consider having their wells tested for PFAS if testing has not been conducted before.

Verify a water filter's ability to reduce PFOA and PFOS. NSF International, the global health organization, developed a test method to verify a water filter's ability to reduce PFOA and PFOS to below the health advisory levels set by the EPA.

To find NSF International-approved devices, go to the bottom of the NSF Product and Service Listings page. Then check the boxes for PFOA Reduction and PFOS Reduction.

Pay attention to advisories about food consumption, such as local fish advisories.

Nursing mothers should continue breastfeeding. Based on current science, the benefits of breastfeeding outweigh the risks for infants exposed to PFAS in breast milk.

Discuss any health concerns or symptoms with your health care provider. Share results of PFAS blood testing with your health care provider and make them aware of ATSDR resources for clinicians.

Follow the advice of your health care provider and the recommendations for checkups, vaccinations, prenatal care, and health screening tests.

Follow the advice of your child's health care provider. This includes well-child checkups, vaccinations, and health screening tests. Visit MyHealthfinder for more information. Find more information on environmental exposures and children's health.

ATSDR does not have plans to conduct additional blood testing for PFAS at this time. It is not recommended that PFAS EA participants get individually retested.

What the City of Airway Heights can do

Operators of the municipal water system should continue to monitor concentrations of PFAS in drinking water delivered to the Airway Heights community. This will ensure that concentrations of PFAS remain below the EPA's health advisory for specific PFAS in drinking water.

All treatment systems to remove PFAS from the public drinking water in Airway Heights should be maintained appropriately to ensure that PFAS concentrations remain below the EPA's health advisory for PFAS in drinking water.

Results of PFAS drinking water monitoring should continue to be shared with community members through Consumer Confidence Reports.

Resources

• PFAS Exposure Assessment, Spokane County, WA: Report (3/10/2022)
• PFAS Exposure Assessment, Spokane County, WA: Report Appendix (3/10/2022)
• PFAS Exposure Assessment, Spokane County, WA: Report Consumer Summary (3/10/2022)
• PFAS Exposure Assessment, Spokane County, WA: Fact Sheet
• PFAS Exposure Assessment, Spokane County, WA: Community-Level Summary Results Fact Sheet