Low levels of 16 types of “forever chemicals” — PFAS — found in New Hanover County compost

Low levels of 16 types of “forever chemicals” — PFAS — found in New Hanover County compost

- in Environment, Top Story
(Screenshot from New Hanover County composting video)

Since PFAS are unregulated, no public notification is required.

Food packaging could be a source of toxic perfluorinated compounds detected in compost produced by New Hanover County. 

According to county sampling data from this fall, the individual levels of 16 types of PFAS in the compounds were low, ranging from less than 1 part per trillion to just over 3 ppt.

There is no EPA or state recommended health goal or an enforceable maximum contaminant level for PFAS in compost. In drinking water, the state has adopted the EPA’s recommended goal of no more than 10 ppt for a single compound or a combined total of 70 ppt.

The compost was produced at the southeastern North Carolina county’s food waste composting program, which is intended to divert that material from the landfill. According to county officials, the program accepts all food scraps, as well as coffee grounds, filters, tea bags, plates, flatware, straws or cups marked “BPI Certified Compostable.” The facility also accepts ground yard waste, and soiled animal bedding.

It does not accept sludge from wastewater treatment plants, a common source of PFAS. Although some of the compounds, such as PFOA and PFOS, have been discontinued, they persist in the environment for decades, if not hundreds of years — earning them the nickname “forever chemicals.”

CompoundConcentration (parts per trillion)CompoundConcentration (parts per trillion) 
PFHxA3.23PFTeDA0.26
PFHpA0.25PFOS0.26
PFOA0.32PFNS0.10
PFNA0.134:2 FTS0.11
PFDA0.226:2 FTS0.42
PFUnA0.158:2 FTS0.13
PFDoA0.21N-MeFOSAA0.15
PFTrDA0.17N-EtFOSAA0.15
TOTAL 6.24

The county uses the compost to fortify soil at county parks and gardens, including Airlie Gardens and the arboretum. Although the county does not sell the compost, it does occasionally offer the material to community organizations and non-profits interested in using it for research, education, or community gardens. In addition to drinking water, the compounds are also found in waterproof clothing, flame retardants used on furniture and carpeting, non-stick cookware, and personal care items like dental floss.

New Hanover County spokeswoman Kate Oelslager said that it’s difficult to discern the source of the PFAS contamination in the compost because the compounds are so prevalent. “We’re looking at compostable containers to see if they are a potential source.”

The U.S. Composting Council recommends that consumers buy compost or compostable materials that have been certified by the Biodegradable Products Institute. As of March 31, all companies seeking BPI certification must have submitted tests verifying that the products contain no more than 100 parts per million of fluorine, which is present in PFAS. That threshold, though, doesn’t guarantee that no PFAS will be present in the compost.

Although New Hanover County asks customers to compost only BPI-certified materials, it’s difficult to enforce that recommendation. Oelslager said workers “visually inspect” the feedstock entering the compost facility and remove non-compostable materials.

New Hanover County voluntarily tested its compost after PFAS were found in source material and finished product at a commercial facility, McGill, in Sampson County. Earlier this year Policy Watch reported on 1,4-Dioxane contamination in feedstock entering McGill, prompting state environmental officials to sample the compost. Although no 1,4-Dioxane — a likely carcinogen — was detected in compost, 20 types of PFAS were found, and at much high levels than those in the New Hanover County material. McGill, though, accepts wastewater sludge from several industrial and municipal plants.

The problem with contaminated compost compelled the Environmental Management Commission to approve new rules this fall authorizing the NC Department of Environmental Quality (DEQ) to require facilities to test their feedstock and finished compost for PFAS and 1,4-Dioxane. The rules went into effect Nov. 1.

However, without regulations governing PFAS in compost, there is no public notification requirement. (The county has posted information about drinking water and PFAS, as well as the ongoing testing of landfill leachate.)

People could be exposed to PFAS in the compost by swallowing contaminated soil or dust, according to federal health officials, which could occur while gardening with contaminated compost. Produce grown in soil contaminated with PFAS can take up the chemicals. An FDA study released earlier this year revealed that PFAS had been detected in sweet potatoes, leafy greens, pineapples seafood, meat, milk, and even chocolate cake.

A study published in Environmental Health Perspectives in October showed that people who cook at home with food purchased from groceries are less likely to be exposed to PFAS through food than those who eat fast food, pizza and other take-out items.

PFAS have been linked to thyroid and liver disorders, including tumors; low birth weight; high blood pressure during pregnancy; increased breast density; and decreased immune response, which means vaccines might not be as effective in some people.

PFOA, a compound found in the New Hanover County compost, can be transmitted both through the placenta and breast milk. Based on mouse studies, researchers have determined that the longer a child is breast-fed, the greater the amount of the compound PFOA is in the body. Suzanne Fenton, a scientist at the National Institute of Environmental Health Sciences, told the state’s Science Advisory Board last week  that exposure to PFOA in early life can result in increased breast density later on — a primary risk factor for breast cancer. “This is a persistent, low-dose effect,” Fenton said. “And it’s irreversible.”

Prenatal exposure to PFOA has also been linked to obesity in early adulthood.

“It’s a lingering national problem,” Fenton said. ‘Even though PFOA is no longer manufactured, many areas will still need to be sampled.”

It’s still unclear how the different types of perfluorinated compounds — there are roughly 5,000 — could interact when mixed.  “What about the mixtures, the crosstalk?” said board member and N.C. State scientist Detlef Knappe. “Where do we even start?”