Forever chemicals and our food, water supply
By Stacy Gittleman
Although what we now refer to as “forever chemicals” or PFAS have been around since the 1940s, scientists, researchers, and government officials are only now beginning their quest to understand the far-reaching impact of forever chemicals on our water and food supply.
PFAS (per- and polyfluoroalkyl substances) are a class of over 9,000 manmade chemicals that were once touted as a modern miracle. Brought to the commercial market by 3M and DuPont, and best known for their use in nonstick Teflon pots and pans, PFAS chemicals also make shoes waterproof and carpet and furniture upholstery stainproof. Consumers can also thank PFAS chemicals for long-wearing mascara, lipstick, and sunscreen as well as the leak-proof wrappers and cardboard boxes that keep fast food grease from leaking onto their laps. The heat-resistant qualities of PFAS have been deployed in military, airline and firefighting applications.
These “forever chemicals” represent the strongest carbon-flourine bonds on the planet. The most pervasive and harmful of these compounds include perfluorooctanoic acid (PFOA) and perfluorooctanesulfonic acid (PFOS), and were eventually linked to kidney, liver, and thyroid cancers, as well as many other ailments. PFOS was phased out of production and use in 2002, and U.S. manufacturers eliminated PFOA emissions and product content by 2015.
Scientists and researchers have determined that nearly every organism on earth – including every human being – contains some traces of these ubiquitous chemicals. In addition to cancers, they are also blamed for elevated cholesterol levels and they may compromise immune response to diseases such as COVID-19, according to the Agency for Toxic Substances and Disease Registry. Although levels of these longer-stranded PFAS compounds have been dropping significantly in our bodies in the last 20 years, these chemicals continue to stick around and do not decompose in nature. And manufacturers like 3M and DuPont have replaced PFOA/PFOS with shorter-chained, replacement chemicals known as GenX chemicals.
The few regulations that do exist – on a state-by-state basis – focus on levels in our drinking water.
Scientists measure PFAS exposure in water in nanograms per liter. One nanogram equals one part per trillion (ppt). In layman’s terms, that one part per trillion can be visualized as one drop of water in 20 Olympic-sized swimming pools. In biosolids, it is measured in parts per billion (ppb).
The EPA has set PFOA and PFOS limits in drinking water to these most pervasive chemicals at 70 ppt.
In recent news, biosolids, which are processed human waste used for soil enrichment by the agriculture industry, are the source where elevated levels of PFAS are showing up.
In May 2021, The Sierra Club partnered with The Ecology Club of Michigan and released a study that tested nine different commercially available fertilizers made with biosolids and found high levels of PFAS in them. Even in those sold in big box hardware stores as “natural” or “organic," these fertilizers contained 14 to 20 of the 33 tested PFAS chemicals, with total concentrations ranging from 38 to 233 ppb.
Of great concern is these forever chemicals were not being filtered out at the source – industrial sites – before entering wastewater treatment plants and then into our waterways.
However, the fertilizers tested were not produced in Michigan, which maintains some of the nation’s strictest testing and monitoring to rid the most prevalent strains of legacy PFAS compounds from the waste stream thanks to its industrial pre-treatment program. As a reference point, Michigan's Department of Environment, Great Lakes & Energy (EGLE)’s March 2021 interim strategy for the application of biosolids states that biosolids exceeding 150 ppb of PFOS are deemed industrially impacted and cannot be land applied. It said the ideal level for PFOS in biosolids should be at 20 ppb.
Steven Brown, a retired chemist who serves on the Sierra Club’s Michigan Chapter PFAS response team, said the traditional way to think about chemical contaminants is that they break down and dilute in time in the ecosystem.
“But these chemicals are impossible to destroy,” explained Brown. “There was never enough testing to understand what these chemicals do to the body as they build up over time. There needs to be action and regulation at the federal level. Congresspeople like Debbie Dingell (D-Dearborn) and Elissa Slotkin ((D-Rochester, Rochester Hills, northern Oakland, parts of Livingston and Ingham counties)) are working to ban all PFAS because no one really knows where and how manufacturers are using them. After all, manufacturers do not have to list them in consumer products."
rown said the Michigan PFAS Action Response Team (MPART) – a multi-agency environmental task force launched in the Governor Rick Snyder administration and signed into law in 2018 by Governor Gretchen Whitmer – puts the state in leader status to stopping PFAS contamination at their sources – industrial, military and airport sites – and monitoring levels in waters coming out of wastewater treatment plants and the biosolid sludge they produce.
"However, I am concerned that in the Republican-led Michigan legislature there will be blowback to prevent bills from being passed to further regulate or provide funding for cleanup activity, " Brown said.
Hailed as a sustainable alternative to sending treated sewerage to incinerators, landfills, or dumping in waterways, biosolids are nutrient-rich organic materials leftover when human waste is treated at a wastewater treatment plant. According to the EPA, there are 16,000 wastewater treatment plants annually producing seven million tons of biosolids. Data on PFAS levels in these biosolids is extremely limited.
Brown said the Sierra Club study of biosolids serves as an entry point to raise awareness to the consumer. “You may want to ask what’s in that fertilizer before you put it in your garden – and it does not matter if the product is organic or not. The problem is that these PFAS chemicals have stuck around so long that everywhere you test for it, it is found.”
Michigan’s Biosolids Program is regulated by Michigan Environment, Great Lakes and Energy’s (EGLE) Water Resources Division. In Michigan, there are approximately 400 municipal wastewater treatment plants, and 95 are required by their National Pollutant Discharge Elimination System permits under the Clean Water Act to have an Industrial Pre-Treatment Plan because of their proximity to industrialized sites emitting contaminants.
Two hundred of Michigan’s wastewater treatment plants process sewage sludge into biosolids intended for land application into two classes, according to state and federal regulations. Class A - Exceptional Quality, where biosolids are treated to meet tight restrictions on pathogens, metals, and traces of pestilence that can transmit diseases. Most wastewater treatment plants in the state produce class B biosolids, meaning they are treated to a point where they are safe to use as a fertilizer or soil amendment, with the use of site restrictions. There are significant restrictions on when and where these biosolids can be spread to protect ground and surface waters.
According to a February 2020 report from the Michigan Biosolids Team, 89,000 tons of biosolids created from municipal waste sludge have been applied to 21,000 acres of farmland since 2015. This represents a fraction of Michigan’s total farmland area of nearly 10 million acres. When used, it saves farmers $12 million annually in fertilizer costs, and wastewater facilities nearly $8 million annually in disposal costs.
According to the Environmental Working Group, Michigan is the country's most PFAS contaminated state, with 192 hotspot sites as of 2018. The reason why Michigan holds this high level classification, however, is because of MPART’s efforts, beginning in the fall of 2018, to assess PFAS levels at 42 wastewater treatment plants, to understand how these chemicals travel in the waste stream.
And wherever the state tests for PFAS, they are found.
As recently as June of this year, Oakland County discovered the groundwater below the Oakland County International Airport property at levels exceeding state recommended maximum contaminant levels after the state installed several permanent detection wells on the site. The elevated levels are most likely due to the use of firefighting foams used to extinguish several fires between 1996 and 2019, according to media reports.
In 2018, the Michigan Water Resources Division began to evaluate PFAS levels of water and materials flowing into and from 42 municipal wastewater treatment plants, as well as associated residuals known as sludge, or biosolids. Initial findings from the study found that PFAS were frequently detected in municipal wastewater, residuals, and at land application sites where biosolids were applied.
The Water Resources Division identified six wastewater treatment plants with high PFOS concentrations in their wastewater treatment plant discharge and biosolids/sludge, and temporarily restricted land application from those facilities until sources of PFOS are controlled and concentrations in the residuals decrease. As part of this initiative, The Water Resources Division also screened 22 sites for 24 PFAS compounds where this sludge was applied – such as farmland – to further understand and measure the presence of PFAS and how it impacted the environment.
Concentrations in residuals were similar or lower than concentrations identified in previous studies in the United States and other countries with industrial sources. EGLE spokesperson Scott Dean said Michigan’s approach for addressing PFAS in municipal wastewater and biosolids is to control significant industrial sources of PFAS before they are discharged to wastewater treatment plants.
Dean said MPART’s industrial pre-treatment plan has been successful with municipal wastewater treatment plants in pinpointing sources of PFAS (specifically PFOS and PFOA) in effluent before they reach the wastewater treatment plant.
“These efforts are resulting in significant reductions in their discharges, in some cases by as much as 99 percent,” said Dean. “In 2021, we are taking additional actions, such as requiring PFAS testing of biosolids for land applications that occur after July 1, 2021. MPART will also implement a municipal permitting strategy, which will establish effluent limits for PFOS/PFOA in municipal permits issued after October 1, 2021.”
In June of 2020, EGLE concluded that the average concentration in biosolids/sludge of PFOS was 195 parts per billion while the median concentration was only 13 ppb. Only seven samples of biosolids from six wastewater treatment plants were above the average concentrations of 195 ppb.
Dean said these six facilities identified highly elevated discharges of PFOS to their collection system from industrial sources. “As we identify and address facilities with elevated PFOS concentrations, we expect to find lower concentrations in biosolids on average in Michigan moving forward.”
Brown said the Sierra Club was pleased that Michigan’s most severely impacted water treatment plants, through granulated charcoal activation filtration systems, were able to reduce the levels of longer-chain PFAS in their effluent by over 90 percent within two years. But he asserted that the shorter-chain chemicals are still slipping through because water treatment plants are not equipped to remove them.
“What is more concerning are the shorter-chained PFAS chemicals that manufacturers are still producing and using that replaced PFOS and PFOA. That’s the stuff no one is regulating,” Brown said.
Science and researchers are only beginning to understand how PFAS gets into the food stream, and just how much of these chemicals are absorbed in crops.
On June 30, the Food and Drug Administration (FDA) released their latest Total Diet Study, that samples and measures commercially sold foods across the United States for nutrients and contaminants, including PFAS. The FDA analyzed 94 samples of a variety of food products collected in 2020 from general food supplies and found only one sample of cod to have detectable levels of two types of PFAS – perfluorooctane sulfonate (PFOS) and perfluorononanoic acid (PFNA). The FDA has determined that the PFAS levels found in a cod sample did not present a human health concern.
According to an FDA spokesperson, the food samples analyzed are from retail locations analysis and therefore information about specific source farms – and if and when they applied PFAS-laced biosolids to their land – is limited. These foods are in the general food supply and are chosen to be representative of the major components of the average U.S. diet, based on national food consumption survey data. The sampling plan, implemented in 2018, is based on population distributions in all 50 states; all areas are included in the sampling plan, but densely populated areas are more likely to be included as sampling sites.
Specifically, the sampling plan includes two types of sample collections, one for foods that are distributed nationally, and one for foods with chemical concentrations that may vary regionally and seasonally, such as fresh produce, meats, and dairy products. Foods with nutrient or contaminant concentrations that are less likely to vary by location or by time of year are categorized as “national” foods. Foods with nutrient or contaminant concentrations that may vary by location or by time of year are categorized as “regional” foods. The food samples recently tested for PFAS were from a regional collection.
“The FDA’s work in this space is critically important to advance science and fill knowledge gaps about these chemicals and their occurrence in food. We’re committed to using all tools available to help ensure the food we consume is safe and doesn’t risk anyone’s health,” Health and Human Services Secretary Xavier Becerra stated in an FDA press release.
But these findings do not override state restrictions on eating fish caught recreationally in Michigan’s waterways with elevated PFAS levels. For example, in 2018, EGLE declared that all fish in the Huron River, starting where North Wixom Road crosses into Oakland County and extending downstream to the mouth of the Huron River as it enters Lake Erie in Wayne County, were unfit for human consumption due to elevated PFOS levels. The state has yet to reverse this advisory.
In a 2018 study, the FDA tested for 16 forever chemicals on produce grown at a farm in Fayetteville, North Carolina, near a PFAS production plant. The study also included one head of romaine lettuce grown from another source that did not have any detectable levels of PFAS. The two chemicals that were the most detected were PFOA and PFOS. In parts per trillion, the highest concentration of chemicals was PFOA found in cabbage (67.5) and kale (179). Most other chemical compounds in produce such as tomatoes, blueberries and corn demonstrated barely detectable levels of contaminants.
Despite these studies, there are still no federal standards for PFAS levels in the nation's food. While it is possible to test animal products such as meat, dairy, and eggs, MPART states there are very few laboratories that can do this. Science is only beginning to understand how PFAS is transferred from the animal to the product, and currently, there are no federal food safety standards for PFAS levels in food.
Water managers attest that the solution in getting PFAS out of our food chain lies at stopping contamination at the industrial source.
Founded in 2016, the Great Lakes Water Authority (GLWA) is one of the largest utilities of its kind in the United States, serving 126 municipalities in seven southeast Michigan counties, including Detroit.
“As a leader in the water sector, GLWA continues to monitor the emerging pollutants in our wastewater and is committed to protecting public health,” said Majid Khan, GLWA wastewater operations director. “Our approach to the PFAS challenge is to reduce these chemicals from entering the wastewater system from its industrial users by working directly with them to either eliminate the use of PFAS compounds in their products or to have them incorporate treatment processes to remove PFAS compounds from their wastewater stream.”
Because PFAS compounds are untreatable at the wastewater treatment plant phase, Khan said controlling the concentration levels of these chemicals in biosolids is most effective by enforcing MPART guidelines.
Khan said GLWA has implemented strategies to control, reduce and eliminate PFAS from the point source’s wastewater discharge. The point source program was implemented in 2018 and the minimization program was implemented in January 2020. By successfully implementing these two programs, GLWA by December 2020 identified 49 sources of PFOS. GLWA also observed reductions in source contributions between 2019 and 2020 as it pinpointed the sources of PFAS in its waste steam collection system.
Khan said with periodic testing, levels of the most prevalent PFAS have been dropping. According to EGLE, tests conducted in November 2018 of GLWA’s biosolids pellets were at 9.4 ppb for PFOS. A sample collected in May 2021 detected PFOS at 4.9 ppb.
According to John Norton, GLWA Director of Energy, Research and Innovation, the water authority has ongoing research projects with Michigan State University focusing on biosolids. Another research project with MSU commenced in July of 2021 to understand the uptake of PFAS by food crops grown on dried biosolid amended soils.
In September 2020, Oakland County opened its $32 million biosolids treatment facility in Pontiac, and stopped sending biosolids to landfills, tallying up to an annual savings of $1.8 million.
Oakland County Water Resources Commissioner Jim Nash attributes the state’s stringent industrial pre-treatment plan for curbing PFAS levels in the industrial waste stream.
“Michigan cannot sell biosolids to farmers growing crops for human consumption with PFAS levels over 20 ppb and most states do not test for PFAS levels in wastewater released by industrial sites into waterways,” said Nash.
Even with PFAS levels measuring in at 18 ppb, Nash said Oakland County has yet to sell any of its biosolid production and is in talks with EGLE this summer to market it for ornamental applications, such as landscaping and golf courses.
When it comes to PFAS levels in drinking water, Nash pointed to Maine as leading the country with the most stringent proposed PFAS regulations in limiting th