Grant to Study Occurrence of PFAS in Biosolids and Swine Sludge

hog barns and waste lagoon

North Carolina’s Attorney General has awarded a three-year, $242,000 grant to NC State’s Department of Crop and Soil Sciences to study the potential presence and fate of per- and polyfluoroalkyl substances (PFAS) in biosolids and swine sludge.

map of cape fear river watershed in North Carolina
Cape Fear River Basin in SE North Carolina. Map from

“We are seeking to identify whether PFAS are prevalent in swine sludges and biosolids of the Cape Fear Watershed,” said Steph Kulesza, project leader and an assistant professor in crop and soil sciences. “It’s not a given that we will or won’t find PFAS. We are conducting unbiased research to evaluate their presence and determine potential mechanisms of movement.” 

Kulesza is leading a multidisciplinary team of NC State researchers including collaborators Owen Duckworth and Aziz Amoozegar, professors in crop and soil sciences, and Detlef Knappe, a professor in civil, construction, and environmental engineering. The team will conduct lab, greenhouse, and field research to complete the study.

The grant from the Environmental Enhancement Program seeks to identify the presence of PFAS in swine sludge and biosolids in five southeastern NC counties, as well as the potential for PFAS leaching into agricultural soils through sludge and biosolid application on cropland. This is the first study in NC to evaluate the presence of PFAS in swine manure.

Swine sludge is commonly applied to row crop fields as a source of nitrogen, phosphorus, potassium and trace minerals. Sludge must be spread in accordance with a Certified Animal Waste Management Plan and is typically used on a multi-year rotating basis with field ‘rest’ periods. Because swine sludge has a high water content, and heavy weight, it usually isn’t transported far from swine farms which could geographically constrain any impact from PFAS contamination.

PFAS Prevalence

In 2016, NC State and EPA scientists reported the presence of high concentrations of PFAS in North Carolina’s Cape Fear River and its watershed, and in the drinking water supply of more than 200,000 North Carolinians living downstream of the Chemours fluorochemical manufacturing plant. 

PFAS are used to manufacture a wide range of products, from Teflon and firefighting foams to food packaging, for their water, stain, and grease resistance. There are almost 5,000 registered PFAS, and testing for them requires complex sample processing and sophisticated instrumentation. These notorious compounds, often called “forever chemicals”, are an environmental and human health challenge, in part, because they persist in the environment for an extended time. 

infographic showing movement of PFAS into ground water
Infographic by the PFAS Testing Network

“Our goal is to identify if PFAS is present in swine manure and if so, to determine the fate of these compounds once applied to soil – whether they migrate to groundwater through leaching, are taken up by plants, or accumulate and persist in soils,” Kulesza said. “Once we understand the prevalence and fate after application, we can provide guidance to growers on whether this is an issue of concern and how it can impact feed sources or sludge application moving forward.”

Our goal is to identify if PFAS is present in swine manure and if so, to determine the fate of these compounds once applied to soil

Researchers see this investigation as a precautionary move. “If we don’t find PFAS in swine sludge or biosolids in this region, we need to make sure we identify ways to protect this industry from potential contamination moving forward,” Kulesza said.

The project includes a significant Extension outreach component for growers. The team plans to develop fact sheets, educational videos, and presentations to agents and growers on their research findings through field days and events. Depending on study outcomes, future research could address treatment or mitigation options. 

“Understanding the current prevalence of PFAS and how swine sludges and biosolids impact their leaching and uptake, we will be able to make better decisions regarding how these materials are handled in the future,” Kulesza said. “It’s all about protecting NC’s citizens, swine industry and environment.”

Looking for More Inquiry?

Ebook cover for soil science degreeCrop and Soil Sciences’ research impacts farmers, students, and NC citizens. Follow how our discoveries affect agriculture and environmental science by joining our weekly newsfeed.

If you are a student interested in nutrient management or soil science, investigate our undergraduate and graduate degree programs, including a deep dive with our soil degree ebook. Then join us for a guided email tour of our department and university.  Protecting NC agriculture through investigation is just part of how we are growing the future.