FOREVER CHEMICALS
Garden produce grown near Fayetteville works fluorochemical plant contains GenX, other PFAs
North Carolina State University
Residential garden produce grown near the Fayetteville Works fluorochemical plant can expose those who consume it to per- and polyfluoroalkyl substances (PFAS), according to a new study conducted by researchers from North Carolina State University, East Carolina University and the Colorado School of Mines.
“It is often assumed that contaminated drinking water is the main pathway through which we are exposed to PFAS,” says Detlef Knappe, professor of civil, construction, and environmental engineering at NC State and a lead investigator of the study. “An important goal of our study was to determine whether people who live in PFAS-impacted communities are also exposed to PFAS through home-grown produce.”
The researchers collected 53 produce samples from five residential gardens located near the fluorochemical manufacturer Fayetteville Works in Fayetteville, N.C. Samples were analyzed for 43 PFAS. The targeted PFAS included GenX and 12 other per- and polyfluoroalkyl ether acids (PFEAs) that are uniquely associated with the Chemours-owned facility.
The summed PFAS concentrations detected in as-received produce reached up to 38 nanograms per gram (ng/g), with PFEAs from the manufacturer overwhelmingly dominating the PFAS profile.
Among different types of produce studied, which included fruits, vegetables, and nuts, researchers found that water-rich produce, like berries and figs, exhibited the highest PFAS levels. When comparing frozen produce harvested in the area over time, researchers observed a general decreasing trend in PFAS levels from 2013 to 2019, though with some variations. While the exact cause of this decline is unclear, researchers suspect that interventions implemented to reduce air emissions at the nearby fluorochemical manufacturer might have played a role.
Next, the researchers looked at how PFAS exposure through consuming contaminated produce compared to exposure through drinking water. Specifically, researchers determined how much produce would give the same exposure to GenX as drinking water with 10 ng/L of GenX, the highest level allowed by the U.S. Environmental Protection Agency (EPA).
“The comparison was made based solely on GenX because it was the only one of the detected PFEAs for which toxicity information was available,” says Pingping Meng, assistant professor of chemistry at ECU and lead author of this study.
For the site with the highest average GenX concentration in the studied produce (0.19 ng/g), the researchers found that for children, daily exposure to GenX from drinking water containing 10 ng/L GenX is similar to eating about 17 g (0.6 ounces, or about 10 blueberries) and adults eating about 68 g (2.4 ounces) of produce. These produce quantities are about nine times lower for children and four times lower for adults than the typical intake of fruits and vegetables.
To assess the long-term risk of consuming GenX-contaminated produce in impacted communities, researchers also calculated the chronic-exposure daily limit, which is the maximum amount of produce that an individual could safely consume daily.
For children aged 3 to 6 years, the daily limit for chronic exposure was 289 grams daily (about 10 ounces, or one and two-thirds cups of blueberries), which is higher than the typical value of 186 grams per day. However, the researchers note that the risk from consuming this amount of produce is likely underestimated because the calculation didn't consider other PFAS in the produce.
“We may be underestimating the risk because we are not considering the potentially additive effects of PFEA mixtures, particularly for PFEAs that were detected at concentrations higher than GenX but for which health-based reference doses are lacking,” Meng says. “Research is urgently needed to better understand the toxicity of the dominant PFEAs that we detected in the produce.”
“Our results show that people who live near Fayetteville Works and consumed locally grown fruits and vegetables were exposed to numerous PFEAs through their diet,” adds Knappe. “These findings highlight that diet, in addition to drinking water, can be an important human exposure pathway.”
The study, “Residential Garden Produce Harvested Near a Fluorochemical Manufacturer in North Carolina Can be an Important Fluoroether Exposure Pathway” appears in the Journal of Agricultural and Food Chemistry and was supported by the U.S. EPA [Grant R839482: U.S. National Investigation of Transport and Exposure from Drinking Water and Diet (PFAS UNITEDD)] and the North Carolina Collaboratory. NC State co-authors include Nadia Sheppard, Sarangi Joseph and Owen Duckworth. Christopher Higgins of the Colorado School of Mines also contributed to the work.
-30-
Note to editors: An abstract follows.
“Residential garden produce harvested near a fluorochemical manufacturer in North Carolina can be an important fluoroether exposure pathway”
Authors: Pingping Meng, East Carolina University; Nadia Sheppard, Sarangi Joseph, Owen W. Duckworth, Detlef R. U. Knappe, North Carolina State University; Christopher P. Higgins, Colorado School of Mines
Published: Nov. 20, 2024 in the Journal of Agricultural and Food Chemistry
Abstract:
Dietary intake can be an important exposure route to per- and polyfluoroalkyl substances (PFASs). Little is known about the bioaccumulation of emerging per- and polyfluoroalkyl ether acids (PFEAs) in garden produce from PFAS-impacted communities and the associated dietary exposure risk. In this study, fifty-three produce samples were collected from five residential gardens near a fluorochemical manufacturer. Summed PFAS concentrations ranged from 0.0026 to 38 ng/g wet weight of produce, and water-rich produce exhibited the highest PFAS levels. The PFAS signature was dominated by PFEAs, and hexafluoropropylene oxide-dimer acid (commonly known as GenX) was detected in 72% of samples. Based on average measured GenX concentrations, chronic-exposure daily limits were as low as 289 g produce/day for children (3-6 yr). This analysis does not consider other PFEAs that were present at higher concentrations, but for which reference doses were not available. This study revealed that consuming residential garden produce grown in PFAS-impacted communities can be an important exposure pathway.
Journal
Journal of Agricultural and Food Chemistry
Method of Research
Experimental study
Subject of Research
Not applicable
Article Title
Residential garden produce harvested near a fluorochemical manufacturer in North Carolina can be an important fluoroether exposure pathway
Article Publication Date
20-Nov-2024
Chemistry paper discusses new approach to breakdown PFAS, forever chemicals
Researchers have found a new approach for breaking down a group of human-made chemicals that can carry health risks from long-term exposure
image:
Garret Miyake
view moreCredit: Colorado State University College of Natural Sciences/John Cline
Researchers at Colorado State University have found a new approach for breaking down PFAS – a group of human-made “forever” chemicals commonly used for their water-resistant properties that can carry health risks from long-term exposure.
The carbon-fluorine bond found in PFAS (perfluoroalkyl and polyfluoroalkyl substances) compounds is particularly challenging to break apart. That durability has led to widespread use of these manufactured chemicals in medical, industrial and commercial settings. However, that inherent stability has also made them difficult to dispose of, and over time, they have made their way into water, air and soil across the world according to the Environmental Protection Agency. The EPA says exposure to these lingering compounds can lead to health problems, including cancer or reproductive issues.
In a paper published today in Nature, CSU researchers showcase an effective LED light-based photocatalytic system that can be used at room temperature to break down those key carbon-fluorine bonds. The system is an improvement over traditional chemical manufacturing processes that typically require high temperatures to achieve similar results.
Work at CSU was led by Professor Garret Miyake in the Department of Chemistry. His team partnered with fellow CSU chemistry Professor Robert Paton as well as Professor Niels Damrauer at the University of Colorado Boulder on the paper.
Miyake said complimentary expertise across those teams led to this high-impact interdisciplinary research finding.
“Our approach is a fundamental advancement in organic synthesis that achieves activation of these challenging carbon-fluorine bonds across a variety of situations,” he said. “Our method is more sustainable and efficient and can be used to address stubborn compounds in plastics, for example, in addition to the obvious uses around PFAS.”
Most people in the world have been exposed to PFAS by touching or eating materials containing them. A common source of exposure is drinking water, but the compounds can also be found in non-stick consumer products, food packaging, and common manufacturing processes. Research led by the EPA shows that even low-level exposure can result in developmental effects like low birth weight or reduced immune response, among many other health issues.
Postdoctoral researcher Mihai Popescu served as an author on the paper and contributed to the mechanistic understanding of the research using computational chemistry. He said the next challenge will be in taking the technology and preparing it for application in the field across many instances.
“We need to make this technology more practical so it can be used in water or soil – places where PFAS are found,” said Popescu. “We need the chemistry we are showcasing here to be useful in those conditions and that is where a lot of work remains.”
Miyake currently serves as director of the National Science Foundation funded Center for Sustainable Photoredox Catalysis (SuPRCat) on campus. That center launched in 2023 with a goal of developing chemical manufacturing processes that harness light energy and utilizing readily available materials as catalysts.
Miyake noted that similar research projects to the one discussed in the paper are happening every day through the center. Postdoctoral researcher Xin Liu – who lead the synthetic development of this work and is also a member of SuPRCat – said the work holds many possibilities.
“This paper deals specifically with forever chemicals, but our approach in SuPRCat to using LED lights presents a host of possibilities towards achieving these reactions in a more sustainable and efficient way,” said Liu. “From dealing with plastics that don’t degrade quickly to improving the manufacturing process of needed fertilizers, this is a key area and something CSU is well positioned to lead on.”
Journal
Nature
Article Title
Photocatalytic C‒F bond activation in small molecules and polyfluoroalkyl substances
Article Publication Date
20-Nov-2024
Study tracks PFAS, microplastics through landfills and wastewater treatment plants
Contaminants end up in biosolids, which are sprayed on croplands as fertilizer
University of Illinois at Urbana-Champaign, News Bureau
image:
Microplastics and PFAS flow into wastewater treatment plants from landfill leachate, left, and from storm and sanitary sewers. Both contaminants accumulate in biosolid waste, most of which is carted out and spread on agricultural fields. On the right, a sample of the microplastics recovered from wastewater treatment plants in Illinois.
view moreCredit: Photo by Fred Zwicky
CHAMPAIGN, Ill. — Scientists analyzed the liquid waste, or leachate, released by four Illinois landfills and the inflows and outflows of associated wastewater treatment plants to determine the fate of two contaminants: microplastics and per- and polyfluoroalkyl substances, or PFAS.
The good news from the study is that landfills retain most of the plastic waste that is dumped there, and wastewater treatment plants remove 99% of the microplastics and a some of the PFAS from the wastewater and landfill leachate they take in. The bad news is that both microplastics and PFAS accumulate in the biosolids that settle to the bottom of wastewater treatment plants. These biosolids must be disposed of in other ways.
The findings are reported in the journal Science of the Total Environment.
According to the industry-funded National Biosolids Data Project, 70% of the biosolids from Illinois wastewater treatment plants are used as fertilizers on agricultural land, and 30% are buried in landfills. This means that most of the microplastics and PFAS that flow into wastewater treatment plants are going right back into the environment, said John Scott, a research scientist at the Illinois Sustainable Technology Center at the University of Illinois Urbana-Champaign who led the study with fellow ISTC research scientist Andres Prada.
“The wastewater treatment plants are just taking the contaminants from one media and putting it into another,” Scott said.
Several hundred million tons of plastics are produced each year globally, and an estimated 79% of this material ends up in landfills or “becomes fugitive in the environment,” the researchers wrote in their report. Both microplastics and the endocrine-disrupting chemicals known as PFAS are now ubiquitous: detected in soil, water and in the human body, they said.
The new study is unusual in that it calculated the mass of microplastics in landfill leachate and wastewater influent and effluent. Most studies simply count the number of microplastic particles per volume of liquid, an unreliable measure because the particles will keep breaking into smaller bits, Prada said. To get the mass, the team measured the total surface area of the plastic particles and incorporated a standard measure of thickness and density based on the most common microplastic waste types: polyethylene and polypropylene.
“Landfills and wastewater treatment plants are usually studied separately, but in reality, those are combined systems,” Prada said. “Regulations require that landfills send their liquid waste to the treatment plants.”
And many studies look at only one contaminant at a time, he said.
“We wanted to put everything together, look at both systems and give results for both contaminants,” Prada said.
The analysis revealed that while landfills do a good job of retaining microplastics, their leachate contains high levels of PFAS.
“We were surprised how high the PFAS levels were in landfill leachate, while the microplastics were lower than expected,” Prada said.
While plastics degrade more slowly in landfills due to the compression of waste and the lack of solar radiation once they’re buried, the plastics will continue to break down into smaller particles, which will eventually flow out with the leachate, Scott said.
Wastewater treatment plants are designed to take in thousands of gallons of wastewater from sanitary and storm sewer systems, and that water also carries a significant load of microplastics and PFAS. While the concentration of PFAS in water flowing through these systems is lower than that found in landfill leachate, the massive volume of water coming in from sewers brings in a higher overall load of both contaminants, the team reported.
Wastewater treatment plants can take in 10,000 gallons of wastewater per minute but only about 30,000 gallons of landfill leachate per day, Prada said.
The problem of microplastics and PFAS in biosolids is not easy to solve, the researchers said. Spreading PFAS and microplastics across cropland is not a good practice, Scott said. “But what else are we to do with it? If we landfill it, we’re just going around and around in the circle of moving it from landfill to wastewater treatment plant and back to the landfill.”
Trying to treat the biosolids before disposal is a very expensive prospect, Scott said. The best practice would be to prevent the problem of plastic and PFAS pollution further upstream, he said.
“It’s time to tell people to start moving away from these things, stop producing these things,” Scott said. “Let’s turn them off at the tap before this gets any worse.”
This research was funded by the Hazardous Waste Research Fund, which is administered by the ISTC, a part of the Prairie Research Institute at the U. of I.
The paper “Microplastics and per- and polyfluoroalkyl substances (PFAS) in landfill-wastewater treatment systems: A field study” is available online or from the U. of I. News Bureau.
DOI: 10.1016/j.scitotenv.2024.176751
Journal
Science of The Total Environment
Subject of Research
Not applicable
Article Title
Microplastics and per- and polyfluoroalkyl substances (PFAS) in landfill-wastewater treatment systems: A field study
No comments:
Post a Comment