West Des Moines Water Works
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PFAS in Finished Water

What is PFAS?
What is PFAS? Per- and polyfluoroalkyl substances (PFAS) are a large group of manmade chemicals that are resistant to heat, and repel water, and oil. PFAS have been identified by the U.S. Environmental Protection Agency (EPA) as emerging contaminants in water and other natural resources. Four of the substances in the category in particular are concerning enough to carry health advisories from the EPA. They are perfluorooctanoic acid (PFOA), perfluorooctanesulfonic acid (PFOS), perfluorobutane sulfonic acid (PFBS) and for hexafluoropropylene oxide (HFPO or also known as GenX). (Source: Iowa Department of Natural Resources)

What is the EPA’s health advisory level, and what does it mean?
Health advisories are not enforceable like regulations. Health advisories are interim guidance before the EPA develops a formal regulation. Sometimes, the advisory is lower than current analytical methods can detect, which is the case today with the new PFAS advisory. The new interim health advisory levels were set by EPA at 0.004 parts per trillion for perfluorooctanoic acid (PFOA), and 0.02 parts per trillion for perfluorooctanoic sulfonate (PFOS). For perspective, 1.0 part per trillion is equal to one second in 35,000 years. In 2016, the EPA established the first Drinking Water Health Advisory for PFAS, at 70 parts per trillion.

Where do PFAS substances come from?
Of the more than 9,000 known PFAS compounds, 600 are currently used in the U.S. in countless products. Many are used in many industrial applications and consumer products such as carpeting, waterproof clothing, upholstery, food paper wrappings, personal care products, some firefighting foams and metal plating. PFAS have been found at low levels both in the environment and in blood samples of the general U.S. population. (Source: Iowa Department of Natural Resources and Scientific American)

Why are they referred to as forever chemicals?
Substances falling within the PFAS category are referred to as persistent in that they do not break down and can accumulate or build up in blood systems and other organs. (Source: Scientific American)

How long have we been monitoring for PFAS?
In 2014, WDMWW finished water was tested under the Unregulated Contaminant Monitoring Rule (UCMR) for 22 PFAS compounds with no detections found. The PFAS category contains a number of compounds, four of which now carry a health advisory—perfluorooactanic acid (PFOA), perfluorooctanesulfonic acid (PFOS), perfluorobutane sulfonic acid (PFBS) and for hexafluoropropylene oxide (HFPO or also known as GenX).

In 2021, WDMWW finished water produced at the A.C. Ward Municipal Water Treatment Plant, the presence of PFOA and PFOS were detected at 2.9 ppt and 2.4 ppt, respectively. A presence of 2.6 ppt of PFBS but no detection of HFPO/GenX was found in the finished water. In compliance with IDNR’s testing protocol, the Water Works increased its testing and monitoring frequency. WDMWW has begun to conduct research to determine whether the source or sources of PFAS compounds in the utility’s raw source water can be identified.

The utility has and will continue to be in regular contact with IDNR regarding the detection of PFOA and PFOS and appropriate strategies to employ, if needed. The presence of PFOA and PFOS could be new, but it may also reflect the availability of more refined and accurate testing, which now can detect levels as low as 1.9 ppt compared with earlier methods that could only detect levels as low as 17 ppt. One particular shallow well reported higher numbers than the others, and WDMWW has limited its use until we can address its issues.

How Does the New EPA Health Advisory for Four PFAS Compounds Affect WDMWW A.C. Ward Treatment Plant?

 

PFAS
Compound
 
Previous EPA Health Advisory Level
(ppt*)
 
WDMWW Finished Water
(most recent test)
 
New Interim EPA Health Advisory Level (ppt*) 
 PFOA  70 ppt
(combined with PFOS)
 Non-detectable**  0.004 ppt
 PFOS  70 ppt
(combined with PFOA)
 Non-detectable**  0.02 ppt
 Gen X  NA  Non-detectable**  0.02 ppt
 PFBS  NA  Non-detectable**  2,000 ppt

*ppt – parts per trillion
** - current detection limits are <1.9 ppt

 

Is Bottled Water Safer?
Bottled water is not held to the same requirements for testing as tap water. PFAS has been found in a number of different bottled water brands. Check out this study done by Consumer Reports.

What is West Des Moines Water Works doing about PFAS?
The utility has and will continue to be in regular contact with IDNR regarding the detection of PFOA and PFOS and appropriate strategies to employ, if needed. The presence of PFAS compounds could be new, but it may also reflect the availability of more refined and accurate testing, which now can detect levels as low as 1.9 ppt compared with earlier methods that could only detect levels as low as 17 ppt. One particular shallow well reported higher numbers than the others, and WDMWW has limited its use until we can address its issues.

Additional sampling of our wells and evaluation of options to keep PFAS out of our finished water are ongoing.

What Can A Homeowner Do If They Are Concerned about PFAS in their Drinking Water?

The US EPA has prepared a fact sheet that describes ways to minimize PFAS exposure from additional sources. Click here to view that fact sheet (https://www.epa.gov/pfas/meaningful-and-achievable-steps-you-can-take-reduce-your-risk).

More information about PFAS and the IDNR action plan is also available on the agency’s website. West Des Moines Water Works will continue to test, monitor and inform its customers of detectable PFAS levels.

 

Additional Resources:

 

EPA Health Advisory 9

 

Des Moines Water Works PFAS information (for those receiving water we purchase from DMWWW)

 

Press Release and Analytical Report 

 

EPA PFOS and PFOA Fact Sheet

 

IaDNR PFAS Action Plan