Compost is supposed to enrich your garden soil for a healthy summer bounty: tomatoes, peppers, green beans and melons. But some compost used on gardens and farms in North Carolina — and nationwide — contains perfluorinated compounds, or PFAS.
The state’s compost rules are up for re-adoption, but they don’t require compost — or the materials used to make it, known as feedstock — to be tested for these harmful contaminants. Exposure to PFAS has been linked to a variety of health disorders: a depressed immune response, thyroid disease, high cholesterol, high blood pressure during pregnancy — known as preeclampsia — hormonal disruption, developmental problems, and even cancer. Yet there is no state or federal standard for PFAS in compost and its feedstock.
However, the public can influence the final rule language, which must be approved by the Environmental Management Commission. A public hearing on the proposed compost rules is scheduled for Tuesday, July 16, at 6 p.m., at the NC Department of Environmental Quality, 217 W. Jones St. The public can also comment in writing. Contact Jessica Montie at firstname.lastname@example.org, 919-707-8247. The comment period ends Aug. 16.
Prompted by a Policy Watch investigation, earlier this year the NC Department of Environmental Quality tested compost from McGill Environmental, a large composting facility in Sampson County. Results showed that the compost contained 20 types of PFAS. The cumulative total for all 20 was 136.8 parts per trillion; four of the compounds had concentrations of at least 10 ppt. The state has advised that people shouldn’t drink water containing more than 10 ppt of any single PFAS.
One likely source of the PFAS in compost is sludge — wastewater residuals — which McGill receives from municipal and industrial treatment plants. The sludge is mixed with other materials, like peanut shells, animal waste and untreated wood, to make the compost. It’s likely that compost at other facilities also contains PFAS if it is made with sludge.
The question of PFAS in compost arose after Policy Watch published a two-part investigation in April about a different harmful compound. Policy Watch found sludge containing 1,4-Dioxane, a likely carcinogen, was being shipped from DAK Americas, a plastics plant in Fayetteville, to McGill Environmental. The compost itself didn’t contain the compound. 1,4-Dioxane clings to water; as the compost dried the compound could have evaporated. But McGill workers could be exposed to 1,4-Dioxane either by touching contaminated material or inhaling its vapors.
In May, Michael Scott, director of the Division of Waste Management, confirmed Policy Watch’s findings to the Environmental Management Commission. At that meeting, EMC members discussed the problem of 1,4-Dioxane and PFAS in compost but decided to wait until after the public comment period to consider adding testing requirements to the proposed rules. The EMC is expected to finalize the rules this fall.