Disclaimer: I'm not a scientist. And as we have seen time and time again, science is always developing as we discover more information about the world around us. In this article, I've tried my best to share links to studies and respected authorities on the topic as opposed to just sharing my opinion.
PFAS (which is short for polyfluoroalkyl substances) isn’t a self-explanatory acronym. Because of that, you’ll often hear the term “Forever Chemicals” as a stand-in for PFAS, as that’s a more descriptive name.
The Harvard School of Public Health states that PFAS doesn't readily break down in the environment - in fact, that's why it's been used, as it's water-resistant, grease-resistant, and heat-resistant.
The NIH explains that PFAS is so persistent is because on an atomic level, the bonds between the carbon and fluorine are exceptionally strong.
I couldn't find an exact number for how long PFAS remains in the environment, and the NIH confirms that it stays present for an "unknown amount of time."
PFAS can be absorbed by plants, according to a study conducted in 2018.
The Minnesota Department of Health shares that research studies haven't been conducted yet that tell us just how much PFAS is brought up into the plant. Understanding this topic is in development.
However, there is some good news: the FDA has tested 800 different fresh and processed foods available in the United States since 2019. They found NO PFAS in over 97% of the foods tested.
While PFAS is called a "forever chemical," scientists are looking into different ways to either reduce the plant intake of PFAS or to remove PFAS entirely.
The study from 2018 referenced above noted that plants absorbed less PFAS when the soil they were grown in has been amended with soil organic matter such as compost, cover crop residue, and other mulches.
Grist highlights the Micmac Nation, who found hemp plants to have a role in the remediation of PFAS from the soil. They found that the hemp especially worked to remove smaller molecules of PFAS (which are often found in water). The length of time and number of plantings isn't something that scientists can fully standardize, however. And then there is the question of where to store the removed hemp plants after harvest.
News Center Maine reports that corn has been shown to remediate PFAS is corn - and the PFAS actually ends up in the stalk, not the edible ear.
In order to remove larger molecules of PFAS from soil, graduate students from UMN are working on making synthetic nanoparticles from carbon and silica that could soak up the more persistent larger PFAS molecules.
So while these chemicals may be "forever," there might also be effective and accessible ways to reduce levels and rates of absorption.
Cardboard is accessible and free for many people. Being able to do lasagna and sheet mulching with cardboard is what helps people to transform their lawns into gardens.
Since certain cardboards are coated with PFAS to protect them from water damage, these types of coated cardboards should not be used in the garden. It's easy to spot these and lots of cardboard is available without this coating.
But what about uncoated cardboard? When this coating is not present, it is hard to know for sure if it has PFAS in it. This is because some cardboard these days is recycled, and there could be PFAS in the original contents of the end recycled product.
In September of 2023, this study out of Norway found that recycled papers and cardboard contained some PFAS.
Justin Boucher, operations manager for Food Packaging Forum, notes that companies who make cardboard might not know if the recycled material has PFAS in it. He says, “if you're allowed to use recycled pulp in food contact, paper, and board packaging, and you don't have total control or oversight over what material was recycled, you don't always know what chemicals were present.”
If you're looking to start a new garden and want to avoid cardboard for any reason, there are some alternatives to using cardboard in lasagna gardening and permaculture. Thick layers of wood chips, organic straw, autumn leaves, weed-free spray-free grass clippings, and spent organic hay can be applied in its place.
Some of these items, like wood chips, can be obtained for free through services like chipdrop. Grass clippings and autumn leaves can be acquired from your own yard, or you may be able to collect these items from neighbors.
My hope is that as awareness builds about the environmental and human health issues associated with PFAS, that more funding will go towards studies to find a solution to this ecological issue. There is already promising research being done, and promising findings from farmers and scientists around the globe.
