Per- and Poly-Fluoro-Alkyl-Substances (PFAS) is a class of chemicals that have evolved to become a global environmental and health contaminant. 

This article will identify and discuss PFAS , provide a brief background, discuss the health risks of PFAS, how the process of contamination occurs, and list common sources of PFAS.  Of special concern to gardeners and agriculturists is the presence of PFAS in various fertilizers. Considerations for avoidance of commercial products are listed.  References are numbered and hyperlinked (X) throughout the article for further reading.

Background: Per- and Poly-Fluoro-Alkyl-Substances (PFAS) is a class of chemicals that have evolved to become a global environmental and health contaminant.  Considered inert at their introduction in the 1940’s, persistent research has proven that PFAS are highly toxic and persist –  seemingly forever  – in water resources, soil, and animal tissue and organs with malignant effects.  In the US alone, as early as 1998, a study by 3M, manufacturer of PFAS varieties,  verified that PFAS were in the blood stream of the general US population. ⁽⁷⁾

This is a global crisis as PFAS contamination is now worldwide due to the extensive use of household and industrial products. ⁽¹⁾ Now labeled as “forever chemicals”, just how to reduce and eliminate them from tissue and blood has yet to be discovered. The first PFAS were “long chain”, 8-Carbon atoms. More recent PFAS have six carbons atoms (Gen X or “short chain” PFAS)  Research indicates that the short chain PFAS which were hoped to be less residual, are actually more toxic. ⁽¹⁾

Sources of PFAS: PFAS are found in a vast assortment of common products. Contamination of air occurs from emissions from manufacturing sites, ⁽⁶⁾ and from heating cookware to boiling point temperature (100 °C or 212 °F) a common cooking temperature. PFAS leach into food and water stored in PFAS-infused plastic containers and water bottles.  Other sources of absorption through skin or off-gassing are: “products designed to repel soil, grease, and water, for carpet and furniture treatments, food wraps, sprays for leather, shoes and other clothing, paints and cleaning products, shampoo and floor wax, where PFCs are used as surfactants.” Scotchguard (3M) applications ⁽³⁾ , Class B firefighting foams (note: exempt is Class A foam for wildland fires) ⁽⁸⁾, and various mosquito treatments.

Health Impacts: Once PFAS are absorbed by animal tissue or are respired through aerosol they enter the blood, or plant cells, reside in soil, or in water, they persist for an indefinite amount of time. This is significant because we are continually exposed to PFAS  through consumer products, water, air, and environmental locations. If a PFAS-free world could suddenly be created, it would still take an estimated 44 years to excrete half the mass of PFAS accumulated in a living organism. ⁽⁵⁾  The persistency of toxic absorption undermines mitigation, assuring negative health impacts.

Research on pregnant women indicated that PFAS pass through the umbilical cord and is stored in fetal tissue. ⁽²⁾ In studies the 3M Company submitted to the government (2001), they found  PFAS in the blood of 96 percent of 598 children tested in 23 states and the District of Columbia. [Extract | Full Document]  ⁽³⁾  A peer-reviewed study in 2021 found that PFAS were in mothers’ breast milk in the US at levels higher than a previous 2005 study, including newer varieties of PFAS being present.  Lastly, water supplies in many areas of the US carry PFAS either influent (to homes) or effluent (from homes, industry) or both.  Both pharmaceuticals and personal care products (PPCPs) and PFAS are not filtered by most municipal water treatment plants in the effluent cycle. PFAS reside in the biosolids/manure from the waste plant at that point. If the biosolids become a primary ingredient in a fertilizer, PFAS are present. Forever.

PFAS have been linked to cancer, immune system harm, kidney and testicular cancer, high cholesterol, high blood pressure,  low birth weights, obesity, reduced fertility in both men and women, thyroid disease, brain damage, low birth weights,  hormone suppression, pre-eclampsia in pregnant women, birth defects, and other health issues. ^{(7) (3)}

PFAS and Fertilizer: Sewage sludges (biosolids) are treated various ways to kill pathogens and then spread on farmland, forests, parks, golf courses, pastures, and wildlands in some cases. As just discussed, the problem with this ‘re-cycling’ of manure resources is that sewage sludge also contains PFAS, PPCPs (pharmaceutical and personal care products) and we don’t know how to eliminate these chemical groups once introduced. The sludge treatments applied to land contaminate the ground and surface water through the natural percolation, the soil, the plants. the wildlife who survive on what’s left of their habitat.  Here’s how to be part of the solution, every good intention matters. Reference Sierra Club Graph.

Be Part of the Solution: Check the label. Biosolid fertilizers are often presented as ‘natural’ and ‘organic’ , a comforting but inaccurate description. Look on the label for the “Guaranteed Analysis” section where you ‘ll find the source of the fertilizer. If purchasing compost or topsoil, check product information for terms like “biosolids,” “residuals,” or “municipal waste,” which could indicate it is made from sewage. ⁽¹¹⁾ Of course,  there are products which bypass the PFAS/PPCP problem which will be clear in the analysis section. In closing, here’s some gardening strategies which are sustainable and avoid purchasing products entirely:

1. Start your own compost  bin or barrel or other method (check references for the method that suits your situation),
2. Have a worm bin and engage the ready help of Red Wigglers (Eisenia fetida) or one of 7000 species of Eisenia. Youtube has so many options for organizing a worm farm! 
3. If allowed by zone, consider having a blend of rabbit or small poultry species which can provide a variety of rich N increasing amends.  Manure of Guinea fowl, ducks, pigeons (4.2 N), chicken ( 1.1 N), and rabbit (2.4 N)varies.
4. Between seasons grow green manure crops in your garden or containers to amend:    Alfalfa (Lucerne), Crimson Clover, Fenugreek, Lupins, Red Clover, Sweet Clover, White Clover, Yellow Trefoil, Field Beans, Forage Pea, many more.
5. Every positive action to keep your garden and food, your air, water, soil,  free of forever chemicals not only decreases your accumulative levels, it helps a corner of the world. And corners, half acres, acres, sections, they all add up to one round earth.

Submitted by A. West