The prior installments in this series defined biosolids and described their production and use nationally and in New York State in Part 1 and described the broader federal regulatory history of biosolids and current regulatory processes in Part 2. Part 3, below, further outlines the prominent cases of contamination over the last few decades through which we’ve come to learn about PFAS as contaminants in general and in biosolids in particular. It then explores why, despite these cases and the available research, regulatory processes have not resulted in new federal rules in over 30 years.

Parkersburg, West Virginia

As discussed in our earlier 2022 report on PFAS regulations related to drinking water, as well as in prior research, while PFAS have been in production and use since the 1940s in the United States, information on their environmental and public health impacts has been slower to come to public light. Scholar of environmental health and medicine Philippe Grandjean has noted that PFAS “constitute a clear example how narrow reliance on published toxicity studies can be misleading and result in insufficient and delayed protection of public health.” Grandjean has chronicled the unpublished studies by industry since the 1970s concerning the risks posed by PFAS, characterizing this secrecy as “the late emergence of early evidence” (see table below).

PFAS Exposure and Health Risks

Year	Exposure evidence
1968	Organic fluoride compounds discovered in human blood
1976	Organofluorines determined in blood from production workers
1981	PFOA found in umbilical cord blood when female worker gives birth
1993	Transfer of PFOS into milk observed in goats
1998	PFOS found in blood from the general population
2003	PFAS in blood from Red Cross blood donors
2004	PFAS detected in human milk
2014	Breastfeeding shown to be major source of PFAS exposure in infants
	Immunotoxicity
1978	Immunotoxicity and other adverse effects in monkeys exposed to PFOA, and mortality in monkeys exposed to PFOS
1992	Leukocyte cell count changes in PFOA production workers
2008	Mouse study shows immunotoxicity at serum PFAS concentrations similar to elevated human exposures
2012	Immunotoxicity reported in PFAS-exposed children
2013	Benchmark Dose calculations suggest that guidelines are far from protective
2017	PFAS exposure during infancy associated with subsequent immune deficiency

SOURCE: https://pubmed.ncbi.nlm.nih.gov/30060739/.

Such studies only became known to the Environmental Protection Agency (EPA) in 2001 as the result of a lawsuit brought against Dupont, a chemical company, on behalf of a family farm in Parkersburg, West Virginia (the Mid-Ohio River Valley), whose land and cattle had been impacted from contamination by PFOA (perfluorooctanoic acid—a particular and more common chemical in the large universe of PFAS compounds). That lawsuit and the class action suit that followed on behalf of workers and residents in and around DuPont’s Washington Works Plant not only resulted in the discovery of earlier industry studies, and a large class action settlement but also the establishment of an independent group of experts known as the C8 Science Panel (populated by scientists agreed to by both DuPont and the plaintiffs). The panel used settlement funds from the case to carry out a series of studies on PFOA’s health impacts beginning in 2005 and published in 2009. The studies, which included an incredibly large cohort of over 69,000 people, further concluded that there were “probable links” between PFOA exposure and six adverse health outcomes: diagnosed high cholesterol, ulcerative colitis, thyroid disease, testicular cancer, kidney cancer, and pregnancy-induced hypertension.

Decatur, Georgia

While the C8 Science Panel studies primarily considered the impacts of exposures related to drinking water, regulatory knowledge of PFAS in biosolids also developed around the same time. Between 2008 and 2009, the Environmental Protection Agency (EPA) and the Agency for Toxic Substances and Disease Registry (ATSDR) sampled and analyzed soil, groundwater, surface water, and drinking water in Decatur, Georgia, from six agricultural fields where biosolids had been applied. The sampling was part of a broader federal Exposure Investigation following notification by a manufacturing facility that they had “unknowingly discharged PFAS into the Decatur Utilities wastewater treatment plant” in 2007. The sources of PFAS discharged by the treatment plant were identified in that case as: 3M; Daikin America, Inc.; Toray Fluorofibers America, Inc.; and the Morgan County Landfill Leachate. The biosolids produced from the treatment plant’s wastewater—those impacted by the discharge of PFAS from these sources—were then applied to an estimated 5,000 acres of agricultural land over the course of about 12 years.

The Exposure Investigation ultimately found a range of concentrations of PFAS (testing for PFOA and PFOS, perfluorooctyl sulfonate) in samples collected at those sites where biosolids were applied. No standards existed at the time for PFAS in soil. Still, these samples on sites in Decatur tested orders of magnitude higher than some more recently developed guidance and screening levels. For example, New York State issued draft revisions to soil cleanup guidance values for certain PFAS in 2024 for different site uses (see table). For the protection of groundwater, the draft revisions set a level of .0010 ppm for PFOS, and .0008 ppm for PFOA. Comparatively, soil samples in Decatur ranged from .589 – 1.296 ppm for PFOS and .055 – 2.531 ppm for PFOA.

NYS Department of Environmental Conservation Draft Revisions to Soil Cleanup Guidance 2024

Guidance Values for Anticipated Site Use	PFOA (ppm)	PFOS (ppm)
Unrestricted	0.00066	0.00088
Residential	0.0066	0.0088
Restricted Residential	0.033	0.044
Commercial	0.5	0.44
Industrial	0.6	0.44
Protection Of Groundwater	0.0008	0.0010

SOURCE: https://dec.ny.gov/sites/default/files/2024-06/draftcp51revised.pdf.

In addition to the soil samples, the EPA collected 51 samples of groundwater wells, ponds, and streams in or adjacent to the agricultural fields to which biosolids had been applied in Decatur. Likewise, no standards existed at the time for PFAS in groundwater or drinking water (although the EPA had a Provisional Health Advisory level for PFOA in drinking water of 400 ppt). The investigation noted that of the six private drinking water wells that had been sampled, two had levels of PFOA that exceeded 400 ppt for PFOA – at 2,200 ppt and 600 ppt. It is unknown how many would have exceeded the EPA’s current drinking water standards for PFOA or PFOS of 4 ppt each, or if other PFAS were present at levels above current standards (see table below). Of the thirteen wells used for nondrinking water (livestock, gardens, etc.), the samples ranged from non-detect to 150 ppt for PFOS and 6,410 ppt for PFOA; of the 32 ponds and one stream sampled, they ranged from non-detect to 80 ppt for PFOS and 11,000 ppt for PFOA. The Exposure Investigation by ATSDR also demonstrated elevated serum (blood) levels of PFOS and PFOA in the 153 people whose blood was sampled (when compared with nationwide health data).¹

Federal PFAS Drinking Water Standards (2024)

Compound</strong`>	Final MCLG</strong`>	Final MCL (enforceable levels)a
PFOA	Zero	4.0 parts per trillion (ppt) (also expressed as ng/L)
PFOS	Zero	4.0 ppt
PFHxS	10 ppt	10 ppt
PFNA	10 ppt	10 ppt
HFPO-DA (commonly known as GenX Chemicals)	10 ppt	10 ppt
Mixtures containing two or more of PFHxS, PFNA, HFPO-DA, and PFBS	1 (unitless) Hazard Index	1 (unitless) Hazard Index

^a Compliance with MCLs is determined by running annual averages at the sampling point.

SOURCE: https://www.epa.gov/sdwa/and-polyfluoroalkyl-substances-pfas.

More broadly, however, this case study reflected (through EPA and ATSDR’s own research) that there was the potential for PFAS-contaminated wastewater in treatment plants to then enter biosolids produced from the plant, for those PFAS-contaminated biosolids to then impact environmental media, including soil, groundwater, and drinking water on and adjacent to where the biosolids were spread, and for those contaminated media to then (directly or indirectly) impact the PFAS blood levels of people who lived there.

Arundel, Maine

Alongside analysis pointing to the need for further efforts to ensure the EPA’s Biosolids Rule effectively protects public health from potential contaminants, a case of PFAS contamination linked to biosolids gained broader attention. Between 2016-18, the Maine Department of Environmental Protection investigated a case of PFAS contamination on and around a dairy farm. The case was initially discovered as a result of the EPA’s testing of drinking water systems under the Unregulated Contaminants Monitoring Rule (UCMR 3) from 2013–15, in which PFOA and PFOS were detected in Kennebunk River well water. Further testing determined that the source of PFAS was the nearby Stoneridge Farm in Arundel, Maine. The farm’s owner, Fred Stone, had spread biosolids on his property under a state permit. Further testing showed that water near the property’s domestic well had elevated PFAS levels, with a combined PFOA/PFOS level of 140 ppt, and that the soil, hay, livestock, and the farm’s milk were contaminated. Residential drinking water samples reflected levels of 13 ppt of PFOA and 43 ppt of PFOS, while soil on the property had levels of up to 4,790 ppt of PFOA and up to 151,000 ppt of PFOS (along with other PFAS). The farm’s milk—its primary product—was found to have 1,420 ppt of PFOS.

As a result, Stone was unable to sell his milk to the USDA and Oakhurst dairy, initially costing him hundreds of dollars a day in milk he had to ‘dump,’ as well as the cost of a new herd of unexposed cows, hay grown elsewhere, and a $20,000 water filtration system. But even so, the milk began showing levels of PFAS once again. The multiple linked pathways through which PFAS impacted the farm complicated the identification and litigation of responsible parties, given that the wastewater treatment plant that produced the biosolids did not originate the PFAS—a larger issue in related regulations that will be discussed in Part 4.

The contamination from the biosolids not only impacted the farm, the people and animals who lived on it, and the wastewater treatment facility but also the drinking water system. The Kennebunk, Kennebunkport, and Wells Water District installed a granulated activated carbon (GAC) filter that was estimated to cost about $1.5 million, with annual operating costs in the tens of thousands, in addition to hundreds of thousands of dollars for local systems to test for PFAS and landfill sludge that would otherwise have been land applied. As a result of this case, the Maine Department of Environmental Protection announced in 2019 that all sludge would have to be tested for PFAS before being applied to agricultural land and Governor Janet Mills implemented a task force concerning regulation and remediation, which has since precipitated further actions that will be discussed in Part 4.

This case drew broader national attention to the issue of PFAS contamination in biosolids and its potential impacts on farmers, their surrounding communities, and our broader waste, water, and food systems. It further (along with other cases that followed) started to precipitate state and federal actions, regulations, and legislative proposals to address PFAS in biosolids—though there is still no new regulation of PFAS under the Biosolids Rule as of now.

The Biosolids Biennial Review (BBR) and PFAS

As noted in Part 1 of our series, the EPA is required to conduct a Biosolids Biennial Review (and produce a Biosolids Biennial Report based on that review) that is meant to identify new pollutants in biosolids that may “adversely affect public health or the environment” under the Clean Water Act. This process is also meant to identify related data and research that can then inform risk assessments of those pollutants and act as the potential basis for further regulatory action. This data and research includes: (1) occurrence and concentration of pollutants in biosolids (necessitating the analytic capability to detect them in biosolids and determine their concentrations therein); (2) human and ecological health toxicity data (as defined by referenced dose, reference concentration, cancer slope factor, lethal dose, and lethal concentration, or chronic endpoints); and, (3) environmental fate and transport (that demonstrates how it moves through particular pathways to result in exposures) for those pollutants. However, the EPA is not required to produce any of the data or research needed to complete this work, so the BBR is in effect a review of recent available literature.

In the 2013 Biosolids Biennial Review, covering the period from July 2011 through December 2013, for the first time the EPA identified 13 perfluoroalkyl substances (PFAS), including PFOS and PFOA, as biosolids pollutants. This identification was based on a study that analyzed 94 unused samples taken by the EPA for the 2001 National Sewage Sludge Survey. The study represented the broadest sample of biosolids from wastewater treatment plants in the United States, including samples from 32 states and the District of Columbia, with respect to the detection of PFAS in biosolids (previous studies had detected PFAS in biosolids in smaller samples or particular locations). This study demonstrated the availability of broadly representative occurrence and concentration data, as well as the EPA’s awareness of that data’s analysis in 2013.

However, the 2013 BBR did not include other seemingly relevant and important research demonstrating the fate and transport of PFAS related to biosolids (including in New York State), nor was it made public until 2018 (see listed studies below). As noted in Part 2, the EPA relies on existing research in the Biosolids Biennial Review and follows a specific and narrow set of search parameters that requires all criteria to be met—including for a study to have been conducted in the US or Canada in the previous two years. This temporal restriction appears to be the case even if a contaminant is being considered for the first time (as with PFAS in the 2013 BBR). While it makes sense to try to identify a targeted list of research, the downside of such a narrow approach to doing so is that it may not include all relevant studies.

Despite the importance of the unincluded studies with respect to understanding PFAS in biosolids, the fact that they are widely cited in related literature, and that the EPA had a direct role in some of this work, none of the studies below were referenced in the 2013 BBR. With the exception of some of the C8 Science Panel studies, none of them would have fallen within the temporal boundaries of the literature review, which only went back to July 2011 (Sepulvado, for example, was published in March 2011). The 2013 BBR, published in May of 2018, ultimately concluded that it had “not identified any additional toxic pollutants for potential regulation.”

The 2015 BBR, covering the period from January 2014 through December 2015 and likewise published in May of 2018, concluded the same, though it identified later studies from some of the same authors noted above (namely, Venkatesan and Halden [2014]). Both reviews noted that the available data for these chemicals “were not sufficient at this time to evaluate risk using current biosolids modeling tools.”

Since then, the EPA has published three further BBRs, in 2019 (covering 2016–17), in 2020 (covering 2018–19), and in 2022 (covering 2020–21). The 2019 report identified two new PFAS including concentration data for them in biosolids. The 2020 report identified eight new PFAS in biosolids, including concentration data for two of them (leaving 12 total PFAS without concentration data). And, the 2022 report included three new PFAS, all of which had identified concentration data. While many of the PFAS identified by and between the 2013 and 2022 reports also had one or multiple other pieces of the necessary data and research to support further risk assessment, none of them were identified through this process as having all the necessary types of data and research to support further regulatory action.

Yet, some have identified that these later reviews—using the same processes—may have also resulted in the exclusion of relevant data and research. In 2024, the legal assistance and environmental advocacy group Public Employees for Environmental Responsibility (PEER) filed a lawsuit against the EPA on behalf of a group of farmers concerning the regulation of PFAS in biosolids. The group argued that as with the earlier BBRs, which appear to have excluded relevant research, “scientific studies show that there are additional PFAS in biosolids which EPA did not identify in the agency’s most recently published Biosolids Biennial Report.” Once more, they contended that other excluded research would support further regulatory action, “additional scientific studies show that sufficient scientific information is available to promulgate regulations for at least 12 PFAS previously identified in biosolids.”

The OIG Report(s)

This relatively slow, delayed, and narrow approach of the Biosolids Program in attending to contaminants is not, however, specific to PFAS. At least three times, in 2000, 2002, and 2018, the EPA’s Office of Inspector General published reports on the Biosolids Program, in addition to reports by other federal entities. The most recent report in November of 2018 found that “the EPA’s controls over the land application of sewage sludge (biosolids) were incomplete or had weaknesses and may not fully protect human health and the environment.” Moreover, the report noted that while few pollutants in biosolids had been regulated for land application under the rule, between 1989 and 2015 the EPA had identified an additional 343 pollutants in different studies that were found in biosolids. Thus, while a total of 352 pollutants were identified in biosolids by the EPA, just 10 pollutants have been regulated under the rule, with nine regulated for land application. No additional pollutants have been regulated in over 30 years, since the Biosolids Rule was finalized in the early 1990s.

These unregulated pollutants identified in biosolids included: pharmaceuticals, steroids and hormones, and flame retardants. The report further found that 61 of those pollutants had been designated as one or more of the following: acutely hazardous (4) or hazardous (28) under the Resource Use Recovery Act; EPA priority pollutants (35); or hazardous drugs by the National Institute for Occupational Safety and Health (NIOSH).

…[W]hile a total of 352 pollutants were identified in biosolids by the EPA, just 10 pollutants have been regulated under the rule, with nine regulated for land application. No additional pollutants have been regulated in over 30 years…

While these unregulated biosolids pollutants in the OIG’s report were identified over a long period of time by the EPA (1989–15), the EPA’s biosolids biennial reviews (BBR) only included this longer list in the 2015 BBR, published in 2018. The OIG’s report also noted repeatedly that the staff and resources for biosolids at the EPA have declined over time. It found that there were only two full-time employees (FTE) staff in the Biosolids Center of Excellence, while the EPA’s Office of Science and Technology had 1.5 FTE staff working on biosolids and no funds to support outside research.

The Center of Excellence has been responsible for overseeing compliance monitoring and enforcement of biosolids regulations since 2013, including the review of reports by major permit holders and inspections. The OIG’s 2018 report noted that the inspections for biosolids may not be recorded properly or may be insufficient. The EPA has a goal (though not a requirement) under the Clean Water Act’s National Pollutant Discharge Elimination System’s (NPDES) Compliance and Monitoring Strategy of an on-site inspection for each publicly owned treatment works (POTW) every five years—or 20 percent of facilities inspected annually. However, EPA data reflected that only one in four “major facilities” has been inspected over 5.5 years. According to the OIG, the Center’s staff “explained that inspections were de-emphasized due to other, higher-priority water issues. The main focus for the Center’s two full-time-equivalent employees is reviewing annual reports filed by permittees while also reviewing inspection reports referred to them for compliance.”

As noted above, the OIG’s report did emphasize that EPA is not required to obtain the new or additional data necessary for completing risk assessments of biosolids contaminants. But, among other things, the OIG’s report included recommendations and corrective actions to “(a) identify unregulated pollutants found in biosolids, (b) disclose biosolids data gaps, and (c) include descriptions of areas where more research is needed.” These particular recommendations were not agreed to by the EPA at that time, however, and no such action was taken. The EPA maintained that while the 343 additional pollutants had been identified in biosolids, and given the agency’s existing assessment or modeling tools, it did not have the data necessary to complete the risk assessment for any of them.

These review and assessment processes and their implementation have continued to result in the absence of any regulations for PFAS in biosolids or any other new contaminants in the over 30 years since the Biosolids Rule was finalized. The next installment of this series, Part 4, will consider those more recent efforts to address PFAS in biosolids through policy and regulation at the state and federal levels.

ABOUT THE AUTHOR

Laura Rabinow is deputy director of research at the Rockefeller Institute

---

[1] This comparison was specifically to the 2009–10 NHANES data. For PFOS there was a geometric mean of 16.3 ppb and for PFOA it was 39.8 ppb.