WHAT IS PFAS AND WHY IS IT IN THE NEWS?

The City of Ames has proactively undertaken a sampling initiative looking at our finished drinking water and our inventory of 22 wells to determine the prevalence of a class of chemicals known as per-and polyfluoroalkyl substances, commonly referred to by the acronym “PFAS.”  This is a huge class of manmade compounds that includes more than 12,000 individual chemicals. 

PFAS compounds have been extensively used for more than 70 years in applications such as: non-stick coatings; stain-resistant carpeting; water-repelling clothing and fabrics; paper packaging for food; metal plating operations; and aqueous fire-fighting foam.  There is emerging scientific data indicating that in high enough concentrations, PFAS can pose a health risk.

 

NEW PFAS REGULATIONS

In 2016, the US EPA issued a lifetime Health Advisory (HA) for two specific PFAS compounds: PFOA and PFOS.  The summed concentration of those two compounds in drinking water consumed over a lifetime should not exceed 70 parts per trillion (ppt).  On June 15, 2022, the US EPA released new “interim” health advisory levels for these two chemicals that were in the parts per quadrillion range, and issued new “final” health advisories for two additional chemicals, PFBS and HFPA.   EPA’s Health Advisories are non-regulatory, non-enforceable numbers.  They do not carry the same obligations as a formal Primary Drinking Water Standard.

 

On March 14, 2023, EPA proposed “final” National Primary Drinking Water Standards for PFOA and PFOS.  They also issued a new combined standard for four additional compounds: PFNA, PFHxS, PFBS, and HFPO-DA.  This is the first time in over 25 years that EPA has issued a new Primary Drinking Water Standard.  In anticipation of these new federal regulations, the Ames Water Plant has been testing for these and many other PFAS compounds for over a year.  Because the health risks from PFAS compounds comes from a prolonged exposure over time, the proposed standards are based on a “running annual average.”  Ames drinking water fully meets the new proposed standards.

 

NOTE: “Running Annual Averages” for the past four quarters are all below the new regulatory standard (see the table below)

Compound	Ames Results	Maximum Contaminant Level (MCL)
Perfluorooctanoic acid (PFOA)	0.0 ppt	<4.0 ppt
Perfluorooctanesulfonic acid (PFOS)	0.0 ppt	<4.0 ppt
Perfluorohexanesulfonic acid (PFHxS)	0.00	<1.0 (unitless ratio)
Perfluorononanoic acid (PFNA)
Perfluorobutanesulfonic acid (PFBS)
Hexafluoropropylene dimer acid (HFPO-DA)

Comparison of Ames water from the past four quarters to the proposed Maximum Contaminant Levels released by the EPA on March 14, 2023.

 

In sampling that was concluded in March 2022, Well #17 was identified as having elevated concentrations for some PFAS compounds.  The Water Plant subsequently stopped using Well #17.  Since that time, all sample results have been below the Maximum Contaminant Level established by the proposed regulation.  

 

Click here to be taken to the US EPA’s PFAS webpage. 

 

MORE ABOUT PFAS

The recently established Health Advisory levels announced by the US EPA applies to four specific PFAS compounds.  Because these chemicals have been used in an array of consumer products, most people have been exposed to them.  In fact, researchers have found PFOA and PFOS in the blood of nearly all the people they tested.

In 2006, eight major companies voluntarily agreed to begin to phase out their global production of PFOA and PFOA-related chemicals.  As the production of the chemicals dropped, research studies show that the levels of PFOA and PFOS found in blood have been decreasing.  However, they continue to be used in some specialized applications.

The US EPA Health Advisory includes the following statements. 

“Drinking water health advisories provide information on contaminants that can cause human health effects and are known or anticipated to occur in drinking water. EPA's health advisories are non-enforceable and non-regulatory and provide technical information to drinking water system operators, as well as federal, state, Tribal, and local officials on health effects, analytical methodologies, and treatment technologies associated with drinking water contamination.”

“EPA’s lifetime health advisories identify levels to protect all people, including sensitive populations and life stages, from adverse health effects resulting from a lifetime of exposure to these PFAS in drinking water. They also take into account other potential sources of exposure to these PFAS beyond drinking water (for example, food, air, consumer products, etc.), which provides an additional layer of protection.”

The analytical test methods required are exceedingly sensitive. That fact coupled with the wide range of PFAS uses over the past 70-plus years means that detecting PFAS compounds is nearly certain when sampling ambient rivers and streams. Previous testing in Ames in 2013 used an older test method that was less sensitive. The testing at that time returned a “not detected” result. It is only since 2021 that test methods have been approved by the US EPA to allow detection at these parts per trillion levels. There are no analytical test methods capable of detecting PFAS at the parts per quadrillion levels contained in the new Health Advisories for PFOA and PFOS.  When sampling for PFAS compounds, some of the steps that must be taken to avoid contaminating the sample include:

• A requirement that the staff doing the sampling cannot have eaten at a fast food restaurant in the prior 24 hours. Otherwise, they might have traces of PFAS on their hands from the food wrappers.
• Only certain brands of plastic baggies can be used to wrap the sample bottles, because some brands contain PFAS and will contaminate the samples.
• Shipping containers cannot use “blue ice” types of cold packs, because they contain PFAS and will contaminate the samples.
• Even when using regular wet ice, the ice and the samples must be separated by at least two layers of PFAS-free plastic. Otherwise, PFAS found in the ice could contaminate the samples.
• Filling out sample labels used in the field when sampling must use “fine point” Sharpies, because the same brand of wide-tipped markers contains enough PFAS to contaminate the samples.

 

Conceptualizing these very low concentrations can be a mind-boggling proposition.  Consider it in this way.  Trying to find a concentration of 2.2 parts per trillion, such as the PFOA level found in Ames tap water, is analogous to downloading a Netflix movie and trying to fast forward through it to find an image that lasts for just a single second; except the movie you are searching through is more than 14,800 years long!

The Health Advisory for PFOA, at 4 parts per quadrillion, translates to a single second out of 8,140,000 years!

To put these new Health Advisory levels in perspective, they can be compared against other, more familiar, contaminants.  The HA level for PFOA is 500,000 times lower than the Maximum Contaminant Level for mercury, 2,500,000 times lower than the Maximum Contaminant Level for Arsenic, and 25,000,000 times lower than the Maximum Contaminant Level for chromium.

 

FAQ

Q.  Is Ames water safe to drink?

A.  The US EPA states “We don’t fully understand yet how harmful PFAS are to people and the environment.”  They go on to say on their website that “…health effects associated with exposure to PFAS are difficult to specify for many reasons.” Click here to view the US EPA website on PFAS.

Because of that, the City of Ames cannot make a categorical statement.  We can, however, clearly confirm that Ames Water fully complies with the new Maximum Contaminant Levels as proposed by the US EPA on March 14, 2023.

 

Q.  Is drinking water the largest risk from PFAS? 

A.  Risk to human health is a function of both how dangerous a chemical is, and how much of it someone is exposed to. It is worth noting that the US EPA proposal is built on the idea that only 20% of a person’s exposure to PFAS comes from drinking water. The other 80% comes from consumer products like non-stick cookware, water and stain repelling fabrics, and food packaging. The issue with PFAS compounds goes way beyond drinking water.

 

Q.  Is there PFAS in Ames water, and if so, is the source known?

A.  Because of the widespread use of PFAS compounds over the past 70 years, these compounds are endemic. That is, they can be found almost anywhere in the environment, including ground water. The US EPA notes that PFAS have been detected worldwide in the air, soil, and water. Due to their widespread use and persistence in the environment, most people in the United States have been exposed to PFAS and have traces of PFAS compounds in their blood.

Testing in Ames has periodically detected trace amounts of a handful of PFAS chemicals in its finished water.  In early 2022, the City entered into a research agreement with Iowa State University to conduct an in-depth source water characterization study that will provide a thorough evaluation of each of the City’s 22 wells. Those results will then be put through a forensic assessment to use each of the City’s 22 wells’ unique “PFAS fingerprint” to try to identify what the original source of the PFAS may have been. There may be different sources in different locations throughout the community.

It is important to remember that water and wastewater utilities do not produce or generate PFAS chemicals.  Water systems are now being forced to deal with the traces of these chemicals used by manufacturers and everyday consumers.

 

Q.  Is bottled water safer than tap water for PFAS?

A.  The US EPA has clearly stated that they are not recommending that consumers switch to bottled water. That is true even for nursing mothers, as the EPA notes that the benefits of breastfeeding far outweighs the risks posed by PFAS at low levels.

A 2021 study by Consumer Reports found PFAS in 39% of the bottled water samples they tested. Click here to view the 2021 study by Consumer Reports. 

The International Bottled Water Association’s website in March 2023 noted that “there are no US Food and Drug Administration (FDA) Standards of Quality or testing requirements for per- and polyfluoroalkyl substances (PFAS) in bottled water.”  The website did describe voluntary standards that they recommend their members adhere to, but those standards were higher than the drinking water limits placed on tap water by the US EPA. Click here to view the International Bottled Water Association's website.

 

Q.  Are there any immediate changes that the Ames Water Plant has made?

A.  Yes. The combination of individual PFAS compounds found in Well #17 was markedly different from, and higher than, the other wells. As a result, the Ames Water Plant has taken Well #17 out of service. Removing Well #17 has resulted in an immediate reduction of approximately 65% for PFOS, 50% for PFOA, and brought PFBS down to below detection.

More investigation is needed to definitively identify the source of PFAS in Well #17. The source that would be first investigated is the old fire training facility located on Haber Road. Over the many years that facility was in use, there was repeated use of AFFF foam on the site. Well #17 is located directly down-gradient based on the direction of flow in the shallow aquifer in the area, so any AFFF contamination of the groundwater would likely migrate towards Well #17.

 

Q.  Is there any additional testing planned in Ames?

A.  Yes. Staff of the Ames Water Plant have already conducted what is perhaps the most extensive source water PFAS characterization study to date in Iowa. The finished drinking water and every individual well have been tested multiple times. The City will also be testing the finished drinking water at least once every quarter to ensure that the PFAS concentrations are not changing. Those quarterly results will be provided to the Iowa DNR and will be posted to this web page. 

 

Q.  Is there a plan to perform any sort of “groundwater remediation?”

A.  There is no plan currently in place to attempt to remediate the PFAS that has been detected. It is possible that remediation may be considered in the future, depending on the results of the ISU study and additional consultation with the Iowa DNR. 

 

Q.  Can any changes be made to the treatment process to remove PFAS?

A.  Yes; there are ways to remove PFAS from drinking water. But they are very expensive. In January 2023, a study was completed to determine the cost to treat for PFAS in Ames. That study looked at three different technologies. That study concluded that the cost would be at least $36 million to construct the removal system and $1.5 million per year to operate it.  Those costs do not include any disposal costs to get rid of the PFAS compounds once they are removed from the water.

A study commissioned by the American Water Works Association estimated the cost would be between $30 and $40 per month per household to remove PFAS; that cost would double if the waste stream was determined to be hazardous. Since the average cost for a typical residential customer in Ames is around $28 per month, that means that the water portion of an Ames customer’s bill would double or triple if Ames must remove the trace levels of PFAS that have been detected. Click here to view the study commissioned by the American Water Works Association. 

 

Q.  If a customer wants to take extra precautions on their own, what recommendations would the Ames Water Plant offer?

A.  There are some home filters that customers could use. A study performed by the New Hampshire Department of Environmental Services found two classes of home filters that can be effective at removing PFAS compounds. Granular Activated Carbon (GAC) filters can be effective, as long as the customer regularly replaced the carbon filters at the interval recommended by the filter manufacturer. Reverse Osmosis (RO) systems can also be quite effective. But RO systems tend to waste two to four gallons for every gallon treated, so their use should be limited to points where water is used for drinking. The National Sanitation Foundation (NSF) maintains a listing of products that claim to remove PFOA and PFOS compounds on their website. Click here to view the National Sanitation Foundation product list.

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.

 

Q.  What about the thousands of other PFAS compounds?

A.  The science is still improving. Until June 15, 2022, only two PFAS chemicals were covered by a Health Advisory. Now there are a total of six covered by a federal Maximum Contaminant Level. It is possible that ongoing research may suggest further regulations. Ames, along with other utilities across the United States, will participate in the EPA’s Unregulated Contaminant Monitoring Rule Round 5 (UCMR5) testing in the next few years. The UCMR5 will look to characterize the prevalence of 29 individual PFAS chemicals.

 

Click here to view the Summary of Detected PFAS Compounds in Ames Tap Water –
Second Quarter 2022 to First Quarter 2023

 

Updated May 17, 2023.