A recent article published in Environmental Science and Technology Letters evaluated the contribution of per- and polyfluoroalkyl substances (PFAS) to wastewater from toilet paper. While multiple PFAS compounds were reported in the samples, the study found that 6:2 fluorotelomer phosphate diester (6:2 diPAP) was the most prevalent PFAS detected in toilet paper and wastewater sludge. Of particular interest, the study concluded that toilet paper should be considered a potentially significant source of PFAS entering wastewater treatment systems.
BBJ believes these findings are not simply of academic interest. Instead, they may have implications across a variety of client sectors.
What are PFAS compounds?
PFAS are a family of man-made chemicals that have been widely used in industrial, commercial, and consumer applications since the 1950s. They are resistant to heat, water, and oil, making them useful in non-stick cookware, stain-resistant fabrics, firefighting foam, and many others.
However, PFAS have been found to persist in the environment, accumulate in living organisms, and potentially cause adverse health effects in humans, such as increased cholesterol levels, decreased fertility, and a higher risk of certain types of cancer. Due to their persistence and potential health impacts, there has been increasing regulatory attention and public concern over PFAS in recent years. Perfluorooctane sulfonic acid (PFOS) and perfluorooctanoic acid (PFOA) are the most commonly known as they received the earliest attention.
What is 6:2 diPAP? And why is it in toilet paper?
Diesters of polyfluoroalkyl phosphates (diPAPs) are commonly used during paper production as they improve the pulping process. In addition, they are extensively utilized in the “impregnation“ of paper and cardboard products. They are an additive that makes those products more resistant to water, grease, or stains and, therefore, more robust and durable. As such, these compounds have apparent benefits in thin paper products such as toilet paper. However, diPAPs are released into waste streams during the production and use of impregnated consumer paper products.
In addition to 6:2 diPAP, it’s worth noting that other PFAS compounds were identified in the toilet paper samples analyzed, including perfluorohexanoic acid (PFHxA), perfluorooctanoic acid (PFOA), perfluorodecanoic acid (PFDA), and addition to other fluorotelomer diesters.
What is the concern?
6:2 diPAP is in a family of compounds called “fluorotelomers.” As BBJ blogged in 2019, fluorotelomers are precursors to forming better-known and environmentally persistent perfluoroalkyl acids (PFAAs), the chemicals most closely related to PFOS and PFOA. In other words, in the proper environmental conditions, fluorotelomers such as 6:2 diPAP can undergo chemical reactions to be transformed into more commonly regulated compounds such as PFHxA, PFOA, or PFDA.
While lists for regulated PFAS compounds vary from state to state, they generally include PFOS, PFOA, and select PFAAs. BBJ still believes that as the knowledge base around PFAS chemistry grows, the next group of compounds to be added to the growing lists of regulated PFAS compounds may be fluorotelomers.
Why is this relevant?
Toilet paper, of course, is ubiquitous and has regular usage, and this evidence suggests that it may be a significant contributor of fluorotelomers into the wastewater stream. Regulators focus on a subset of the vast family of PFAS compounds, including PFOS and PFOA, and the most similar PFAA compounds. But it should be noted that 6:2 diPAP is a chemical precursor to those chemicals currently of interest to regulators.
Fluorotelomers may be somewhat flying under the radar now. However, their prevalence in typical waste streams and their proclivity toward transforming into the more highly regulated PFAS may represent a future risk for the regulated community. Consequently, clients evaluating PFAS-related risks may need to contemplate risks for compounds beyond simply PFOS and PFOA.