Notre Dame researchers have found the presence of per- and polyfluoroalkyl substances (PFAS) in fluorinated high-density polyethylene (HDPE) plastic containers, which may be used for food packaging as well as the packaging of pesticides and other consumer goods, and demonstrated the risk of human exposure to PFAS from foods that come into contact with HDPE packaging. PFAS, a class of fluorine compounds often referred to as “forever chemicals” for their indefinite persistence and accumulation in the environment and human body, have been associated with a number of negative health consequences.
The Notre Dame team conducted the present study following a U.S. Environmental Protection Agency (EPA) report demonstrating that HDPE containers contribute to high levels of PFAS in pesticides. The present research is the first measurement of the ability of PFAS to leach from HDPE containers into food, as well as the effect of temperature on the leaching process.
Results showed significant concentrations of PFAS in HDPE containers, and demonstrated the ability of PFAS to migrate from the packaging into food, resulting in a direct route of significant exposure to toxic PFAS.
HDPE packaging is not explicitly intended for food storage, but there is nothing preventing them from being used for food storage at the moment, according to the study’s authors. Although not all HDPE plastic is fluorinated, it is often impossible for consumers to know whether a container has been fluorinated. Additionally, if pesticides used on agricultural crops are stored in HDPE containers, PFAS will migrate into foods intended for human consumption. The disposal of HDPE containers also leads to further PFAS contamination of the environment, and subsequently, food.
For the study, researchers tested HDPE containers that were treated with fluorine to create a thin layer of a fluoropolymer as a means to impart chemical resistance and improve container performance over long storage periods. While such materials generally stay within the container wall, the manufacturing process can generate smaller PFAS molecules that are not polymers. The Notre Dame team measured the ability of the non-polymer PFAS to migrate from the container to samples of different foods and solvents.
The researchers found that HDPE packaging contained parts-per-billion (ppb) levels of PFAS that could migrate into both solvents and food matrices in as little as one week. Additionally, PFAS concentrations were measured in olive oil, ketchup, and mayonnaise that had been in contact with the fluorinated containers for seven days at various temperatures. Based on the levels of PFAS found in the various food samples, the researchers estimate that ingesting food stored in the fluorinated HDPE containers is a significant risk of exposure to PFAS.