An Elm Dirt company·Kansas City, MissouriCDFA Certified Organic
Elm Dirt, Together We GrowRemediation

Contaminant group

PFAS

For PFAS, the so-called forever chemicals, the established field tool today is holding them in place with carbon amendments and measuring leaching over time, which is the approach we take.

What biology does
Binds
Shows up at
East Palestine, Ohio
Diagram: PFAS, microbial action, outcomeCarbon chains wrapped in fluorine, held together by the carbon-fluorine bond, one of the strongest in chemistry. Some bacteria partially transform precursor compounds, though complete microbial breakdown is not established. Breakdown: emerging research. Microbial breakdown of PFAS is an active research field. Field work today centers on holding PFAS in place. Binding: in the research. Carbon-rich amendments such as biochar bind PFAS and cut how much leaches toward water.01 CONTAMINANT02 MICROBIAL ACTION03 OUTCOMEFFFFFF PFASCarbon chains wrapped influorine, held together by thecarbon-fluorine bond, one of thestrongest in chemistry.Microbial actionSome bacteria partially transformprecursor compounds, thoughcomplete microbial breakdown isnot established.CO2H2OEMERGING RESEARCHBreakdownMicrobial breakdown ofPFAS is an activeresearch field. Fieldwork today centers onholding PFAS in place.IN THE RESEARCHBindingCarbon-rich amendmentssuch as biochar bind PFASand cut how much leachestoward water.Diagram: PFAS, microbial action, outcomeCarbon chains wrapped in fluorine, held together by the carbon-fluorine bond, one of the strongest in chemistry. Some bacteria partially transform precursor compounds, though complete microbial breakdown is not established. Breakdown: emerging research. Microbial breakdown of PFAS is an active research field. Field work today centers on holding PFAS in place. Binding: in the research. Carbon-rich amendments such as biochar bind PFAS and cut how much leaches toward water.01 CONTAMINANTFFFFFFPFASCarbon chains wrapped in fluorine,held together by the carbon-fluorinebond, one of the strongest inchemistry.02 MICROBIAL ACTION Microbial actionSome bacteria partially transformprecursor compounds, though completemicrobial breakdown is notestablished.03 OUTCOMECO2H2OEMERGING RESEARCHBreakdownMicrobial breakdown of PFASis an active research field.Field work today centers onholding PFAS in place.IN THE RESEARCHBindingCarbon-rich amendments suchas biochar bind PFAS and cuthow much leaches towardwater.
Fig. 1How biology acts on PFAS, as described in the peer-reviewed literature. Rates depend on soil, moisture, oxygen and temperature, and are confirmed by lab testing over months.
On this page (7 sections)
  1. What Elm Dirt does about PFAS
  2. What it is
  3. Where it comes from
  4. Why it matters
  5. Where the science is
  6. What to expect
  7. Studies

What Elm Dirt does about PFAS

Marketing runs further ahead of the science on PFAS than on any other contaminant, so here is exactly what we do: we bind PFAS and measure it, and we do not claim to destroy it. Microbial PFAS breakdown is emerging research, and the established field tool today is holding PFAS in place with carbon amendments while tracking leaching and concentrations over time.

Biochar is our holding tool, and in soil from a firefighting training facility, carbon amendment cut PFAS leaching sharply, with results depending on the material [1]. Longer-chain PFAS bind more strongly than shorter-chain ones [2].

Soil structure, roots and plant cover keep contaminated soil from washing into the water, the pathway that counts most on a PFAS site. That part is ordinary soil-building, which is our core work.

Because sorption keeps PFAS in the soil, a total-concentration test will still find it, so we measure leaching alongside the totals. Leaching into water is the number that tracks risk, and an independent lab measures both.

Where groundwater is the main concern, engineered methods lead: containment, sorbent treatment, soil removal and water treatment come first, and our work supports the soil around them.

What it is

PFAS, per- and polyfluoroalkyl substances, are thousands of widely used, long-lasting chemicals whose components break down very slowly [3]. Each is built on a carbon chain wrapped in fluorine.

The carbon-fluorine bond is the strongest single bond in organic chemistry. It gives PFAS their resistance to water, oil, heat and stains, and almost nothing in nature can break it.

Where it comes from

  • Firefighting foam is the classic source of concentrated soil and groundwater contamination, above all the aqueous film-forming foam used at airports, refineries, military sites and fire training grounds.
  • Manufacturing and industrial discharge
  • Consumer products: non-stick cookware, stain-resistant textiles and carpet, grease-resistant food packaging
  • Land-applied biosolids and landfill leachate
  • Firefighting at a derailment or chemical fire, adding PFAS to the combustion products

EPA notes PFAS turn up in water, air, fish and soil across the country and the globe, and in the blood of people and animals worldwide [3].

Why it matters

PFAS do not meaningfully degrade in the environment, and some travel easily with groundwater. EPA states that exposure to some PFAS may be linked to harmful health effects in humans and animals [3]. Drinking-water limits are set in parts per trillion, so very small soil residues can matter wherever there is a path to groundwater.

For a landowner, the realistic goal today is keeping PFAS out of water and showing it with measurements. That expectation belongs at the start of the conversation.

Where the science is

A 2022 review of microbial degradation of polyfluorinated and perfluorinated substances lays out which transformations have been found and why progress is slow [4]. A specialized iron-reducing bacterium has defluorinated PFOA and PFOS in laboratory incubations [5]. That organism is not in our products, and neither is any other known defluorinator.

Binding has measured results under field-relevant conditions: in soil from a Norwegian firefighting training facility, activated carbon cut PFAS leaching by 94 to 99.9 percent, while compost-type and clay amendments cut it by roughly 28 to 40 percent [1]. The amendment matters, and biochar results vary with the feedstock it was made from [2].

What to expect

Bound PFAS is still in the soil, and changed conditions can change how much of it moves. A PFAS program is therefore a long-term monitoring program, with leaching tests next to totals, and we set expectations before anyone writes a plan. Reading the results takes months to a year or more.

Our soil-restoration pilot in East Palestine, Ohio handles PFAS this way, through binding and monitoring.

Studies

  1. Hale SE, et al. (2017). Sorbent amendment as a remediation strategy to reduce PFAS mobility and leaching in a contaminated sandy soil from a Norwegian firefighting training facility. Chemosphere 171:9–18. doi:10.1016/j.chemosphere.2016.12.057
  2. Fabregat-Palau J, Vidal M, Rigol A (2022). Examining sorption of perfluoroalkyl substances (PFAS) in biochars and other carbon-rich materials. Chemosphere 302:134733. doi:10.1016/j.chemosphere.2022.134733
  3. US Environmental Protection Agency. PFAS Explained. epa.gov/pfas/pfas-explained
  4. Wackett LP (2022). Nothing lasts forever: understanding microbial biodegradation of polyfluorinated compounds and perfluorinated alkyl substances. Microbial Biotechnology 15(3):773–792. doi:10.1111/1751-7915.13928
  5. Huang S, Jaffé PR (2019). Defluorination of perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS) by Acidimicrobium sp. strain A6. Environmental Science & Technology 53(19):11410–11419. doi:10.1021/acs.est.9b04047

Working on a site with PFAS?

Send the location and any sampling results, and we'll tell you whether biology has a role there.

Start with your site details