PFAS in Soils

Several of my clients have asked about the levels of PFAS in normal soils. It's a very good question. What is the background level of PFAS on an average farm or even backyard? Sally Brown, a respected researcher from the University of Washington, wrote an article¹ that summarized some recent studies.  In one of the studies, 30,000 samples of soil were taken at 5700 background sites worldwide. Almost all of the samples contained PFAS. These background soils averaged 2.7 parts per billion PFAS. Studies of background soils in the United States showed an average range of 1.7 to 55.2 parts per billion PFAS. Background was defined as soils in yards, gardens, agriculture, school yards, parks, and commercial property. None of these sites had known sources of PFAS such as firefighting foam. 

A paper entitled; “PFAS Concentrations in soils: Background levels versus contaminated sites”² provides more detail. Measurements were taken at sites called “secondary source soils”. These 9 sites were either adjacent to sites that were known to have been contaminated with PFAS, had been irrigated with surface water/ground water/treated wastewater, or were sites where biosolids and other amendments were applied. The results varied widely.  The PFOA average maximum level was 38 ppb. For PFOS, the average maximum result was 680 ppb. One site in Germany that received amendments derived from industrial waste had a maximum PFOS level of 5500 ppb. Another site in Washington State that received PFAS industrial waste-impacted municipal biosolids had a maximum PFOA level of 2531 ppb. Compare that to two sites that received regular municipal biosolids, one in the US and one in Canada. The US site has a max PFOA of 38 ppb and PFOS of 483. The Canadian site had a max PFOA of 0.8 ppb and PFOS of 0.4 ppb. This stands in contrast to a study³ done in 2012 that found maximum concentrations of PFOA of 1.5 ppb and PFOS of 5.4 ppb in Antarctica.

It appears that PFAS are in the soils almost everywhere on planet Earth. The study² concluded that soil is a significant reservoir for PFAS. The level of contamination depends on a sites exposure to contaminated industrial sources. While some of the most commonly occurring PFAS are no longer manufactured in the United States, they are still manufactured in other countries and imported in products and for use in the manufacture of products here.

Before burdening the water sector and everybody who drinks water or flushes with expensive monitoring and treatment, the government should ban the manufacture and importation of non-essential PFAS.

Status of Pre Draft Changes to the Biosolids Land Application Permits

Did you know that PADEP plans to propose extensive changes to the Biosolids Land Application permits? The changes would affect recycling of Exceptional Quality and Non Exceptional Quality biosolids as well as septage.

Did you know that PA Congress asked the Legislative Budget and Finance Committee (LBFC) to study the impact of the pre draft changes? And they asked DEP not to move forward with the changes until the study was complete in July, 2023.

On March 30, 2023, DEP made a presentation to the Solid Waste Advisory Committee titled; “New DEP-Initiated General Permit: Anaerobic Digestion at Sewage Treatment Facilities”.  In this presentation to the Solid Waste Advisory Committee, PADEP described how the permitting system would be changed. In fact, the DEP is starting to write a new land application permit for wastewater residuals produced by WRRFs that accept trucked in waste directly to the digesters.* Residuals from these plants would no longer be covered by the existing biosolids land application general permits. The residuals from these plants would no longer be defined as biosolids. They would be defined and regulated as “Industrial Residuals.” Obviously, this will make it more difficult to recycle this product as a fertilizer and soil conditioner.

On a brighter note, the LBFC, asked USEPA to weigh in on the requirement in the pre draft permits that the Phosphorus Index be conducted on all fields receiving biosolids. Fortunately, our sources at EPA said they were not recommending or requiring the P Index be a condition in the permits. But that may not influence the future wording in the draft permits. DEP seems to be moving forward to implement the conditions in the Pre Draft Permits despite feedback describing the negative consequences.

*Pardon me if I am stating the obvious but approximately 15 WRRFs in PA accept High Strength Organic Waste into the digesters to boost production of heat and power. An additional benefit is that it provides an opportunity for local businesses to recycle a material that has value rather than disposing in a landfill.

1 Sally Brown, 2023, Mid-Atlantic Biosolids Association April 2023 - Sally Brown Research Library & Commentary

2 Mark L. Brusseau, R Hunter Anderson, Bo Guo, 2020, PFAS Concentrations in soils: Background levels versus contaminated sites

3 Llorca,M.,Farré,M.,Tavano,M.,Alonso,B.,Koremblit,G.,Barceló,D., 2012, Fate of a broad spectrum of perfluorinated compounds in soils and biota from Tierra del Fuego and Antarctica. Environ. Pollut. 163, 158–166