By Jerri-Lynn Scofield, who has worked as a securities lawyer and a derivatives trader. She is currently writing a book about textile artisans.
The Environmental Protection Agency (EPA) released two reports last month, Persistent Chemical Contaminants and Plastic Contamination, documenting the presence of PFAS and plastics contamination in compost.
According to the EPA’s website:
Per- and polyfluoroalkyl substances (PFAS) are a group of man-made chemicals that includes PFOA, PFOS, GenX, and many other chemicals. PFAS have been manufactured and used in a variety of industries around the globe, including in the United States since the 1940s. PFOA and PFOS have been the most extensively produced and studied of these chemicals. Both chemicals are very persistent in the environment and in the human body – meaning they don’t break down and they can accumulate over time. There is evidence that exposure to PFAS can lead to adverse human health effects.
How Do PFAS and Plastics Get Into Compost?
It won’t come as any surprise that such PFAS and plastics are found in compost. What I found most worrying is the source: food waste. Yes, that’s right, PFAS get into compost via the food supply. According to the EPA’s Persistent Chemical Contaminants report:
This issue paper demonstrates that food waste streams are a source of per- and polyfluoroalkyl substances (PFAS) contamination in composts and digestates, with PFAS detected in food waste, food contact materials, and composts produced from food waste. While data on PFAS in food waste is limited, one study reported concentrations of three PFAS in the range of 0.11–1 μg/kg in samples collected from grocery stores, hospitals, schools, restaurants, retirement communicates, and residences. The presence of PFAS in food waste is further supported by multiple studies reporting PFAS in food (i.e., precursor of food waste) from non-contaminated areas, with concentrations generally <10 μg/kg. Seafood, followed by meat, may be important contributors to PFAS in food items, possibly due to bioaccumulation. Compared to PFAS concentrations in food contact materials, which ranged from <1 to 485 μg/kg, the limited data show that food contact materials may contribute more to overall PFAS levels in food waste streams.
Composts made from a variety of mixed feedstocks, such as food waste, green waste (leaves and grass), and manure, showed total PFAS levels ranging from 2.3 to 75 μg/kg. Comparison of composts made with and without food waste showed that food waste compost had higher PFAS levels than green waste compost. Comparing results across three studies, which originated from the same research group, PFAS concentrations in decreasing order were: biosolids-based products (i.e., treated biosolids, composted biosolids) > food waste compost > green waste compost ≈ other organic composts. An additional study on composts in Europe also showed that kitchenwaste compost had higher PFAS concentrations than green waste compost. Furthermore, the limited data also showed that PFAS concentrations were higher in composts with compostable food packaging and that compostable food contact materials have higher PFAS concentrations that non-compostable samples. No data on digestates were identified that would enable the determination of whether food waste digestates would have higher, similar, or lower PFAS concentrations compared with digestates produced from other feedstocks [executive summary, p.ii].
Likewise for plastics, including microplastics. According to the EPA’s Plastic Contamination report:
The primary source of plastic contamination in food waste streams collected for processing at compost and anaerobic digestion facilities appears to be food packaging and containers, most likely from residential, commercial, and institutional sources. Food itself is also a source of microplastic particles. The level of plastic contamination present in food waste streams is not well characterized in the scientific literature. A recent analysis found approximately 300,000 pieces of microplastics per kilogram of food waste collected from grocery stores in the United States. In addition, limited data from Washington State and Oregon reports plastic contamination rates up to 2.8 percent (by weight) in mixed waste streams including food waste that were destined for composting or anaerobic digestion. Plastic contamination rates in purely food waste streams may be higher, as available evidence indicates plastic contamination levels in food waste streams may be higher than that of other organics waste streams, such as yard waste[executive summary p. ii]
In order to keep this post at a manageable length, I’ll concentrate on the EPA’s Persisistent Chemical Contaminants report. Waste Dive reports in Compost groups say EPA’s new PFAS report misses the mark that makers of compost have criticised the EPA’s framing of the PFAS issue, arguing the EPA should be focusing on targeting the manufacturers of PFAS and makers of plastic rather than discussing the presence of PFAS in compost. This is an excellent point and any policy that targets manufacturers of PFAS and makers of plastics would have the added benefit of reducing the presence of these substances in the food supply:
Organics and compost trade groups say the report unfairly scrutinizes their sector and mischaracterizes some of the data in the report. More should be done to target PFAS manufacturers and manufacturers of packaging and products known to contain the chemicals instead, said Frank Franciosi, executive director of the US Composting Council.
“This issue is created by the companies that created these forever chemicals. Food has some PFAS in it, but the report also shows that it can show up anywhere, so how do we control that? It’s not something we have an easy answer for,” Franciosi said. “Our position is, let’s follow the stream of where the [PFAS] started and go upstream first. We need to fix upstream problems while we also get some more science behind this.”
One source of the problematic substances in compost may be compostable food packaging – although there is disagreement between the EPA report and makers of such packaging on this point. Per Waste Dive:
Composters that handle food waste think the main source of PFAS in their facilities is packaging waste, and the EPA report highlights one study showing that PFAS concentrations were higher in composts that included compostable food packaging than those without. However, the EPA acknowledges there’s “limited data” on the topic.
The Biodegradable Products Institute (BPI), which certifies items including biodegradable packaging, disagrees with how the EPA characterized the study comparing composts with and without compostable food packaging.
“The study was about municipal organic waste streams that have food packaging more broadly, not specifically compostable packaging,” said Rhodes Yepsen, BPI’s executive director, in an email. “This is an important distinction, as only a fraction of food packaging is certified compostable today, and only one material type of certified compostable items (molded fiber) ever had PFAS, with other items using compostable biopolymers to provide grease and moisture barriers.”
The industry may be right – although I point out that this wouldn’t be the first time that some technofix solution to waste problems didn’t prove to be all that it was cracked up to be, as I wrote in this 2019 post, Plastic Watch: Debunking the Technofix Fairy, Biodegradable Bags Don’t Degrade:
‘Biodegradable ‘ plastic bags were still intact and capable of carrying shopping three years after being exposed to the natural environment, according to a study published this week by scientists at the UK’s International Marine Litter Research Unit, School of Biological and Marine Sciences, University of Plymouth.
The industry trade group took a step in 2020 that should reduce PFAS contamination in food waste, according to Waste Dive:
In 2020, BPI stopped certifying compostable food packaging known to contain PFAS, a move the EPA report says “should lead to decreased PFAS levels in food waste streams.” Some composters have said they will not accept compostable food packaging.
Industry sources aren’t the only critics of the EPA’s focus. Banning some chemicals outright has had a measurable impact on their concentrations in human blood. Per Waste Dive:
Sally Brown, a research professor at the University of Washington’s School of Environmental and Forest Sciences, said the report misses the mark on the important steps needed to reduce and eliminate PFAS in the environment. She argues that more needs to be done to eliminate PFAS at the source instead of starting with compost.
Some PFAS chemicals, such as PFOA, are no longer used in the United States to make certain items like fire-resistant products, and United Nations regulators voted to ban PFOA in 2019. Brown said restrictions on such PFAS chemicals have led to lower concentrations in human blood levels, “so it really does work to ban the compounds,” she said. However, other PFAS chemicals are still being used in everyday products such as cosmetics. “It’s a real question of if they’re necessary. How much would your lipstick suffer if it wasn’t in there?” she said.
What Is to Be Done?
Reports such as these make for depressing reading. The scale of our environmental problems is overwhelming, and the solutions proposed are usually so meager, not to mention long overdue – if and when they’re finally adopted in some much watered-down form. The presence of PFAS in food waste streams should be yet another reason to ban single-use plastic packaging. But even that sensible step is controversial, and as I wrote earlier this week, only evades the much more serious problem of curtailing excess plastic packaging (see Waste Watch: Russia, UK Adopt Single Use Plastics Bans).
Waste Dive summarizes the state of play for a more limited ban on PFAS in food packaging:
There are currently no standards for PFAS in finished composts or digestates, but the EPA report mentions that state and local guidelines prohibiting PFAS in food packaging have gained momentum in recent years.
Maine, Vermont, Connecticut and Minnesota passed laws this year banning or phasing out packaging containing PFAS. New York and Washington also have similar laws. When signing his state law in July, Connecticut Gov. Ned Lamont said minimizing future releases of PFAS to the environment is an important way to protect people from the health risks posed by PFAS.
At the federal level, lawmakers are also working to advance the PFAS Action Act, which would set a deadline for the EPA to designate certain PFAS as hazardous substances and place a moratorium on products containing new PFAS. Some lawmakers have urged the EPA to speed up its regulatory process to avoid a “patchwork of regulations” they say could create confusion or uneven environmental protections.
One final point: Food waste is not the only source of chemical contamination in compost – a point made before in comments on some of my previous posts. The EPA’s Persistent Chemical Contaminants report mentions “documented cases” of herbicide contamination in compost, traced to “green waste, manure, or hay”:
For persistent herbicides, food waste streams are likely not a major source of contamination for the four persistent herbicides of interest—clopyralid, aminopyralid, picloram, and aminocyclopyrachlor. No studies were identified that reported concentrations of these four persistent herbicides in food waste or feedstock mixtures containing food waste; however, clopyralid has been detected in food samples in the United States. The detection of only clopyralid in food samples is consistent with the registered use sites of the four persistent herbicides, where only clopyralid had agricultural settings (e.g., fruits, vegetables, and cereal grains) as a registered use site. No studies were identified that investigated these four persistent herbicides in commercial composts, but documented cases of compost contaminated with clopyralid, aminopyralid, picloram, and/or aminocyclopyrachlor show that the source of contamination is green waste, manure, or hay. Food waste has not been indicated in any documented incident to date. The available data on two additional chemical contaminants—polychlorinated biphenyls (PCBs) and polycyclic aromatic hydrocarbons (PAHs)—in food waste and associated composts and digestates were briefly summarized in this issue paper but were not further discussed due to the lack of recent U.S. compost or digestate data and in the case of PCBs, due to the U.S.ban on PCBs [executive summary, p.iii].