Our research group focuses on the sustainable management of solid waste, and I have specifically been studying how PFAS can impact certain waste streams and what that means from an environmental impact or management perspective.
WT: It has been well documented in scientific research that PFAS are found in wastewater slurry. What have been the recognized sources of this contamination?
Thompson: PFAS have been identified in several industrial applications and consumer products. The use of consumer products such as cosmetics or waterproof clothing are sources which have been identified but the ubiquitous nature of PFAS makes it difficult to identify all potential inputs to wastewater systems.
WT: According to your most recent publication this month, you have looked at an understudied source of PFAS contamination. What was that source and why did you embark upon this study?
Thompson: We recently published (February 2023) a study on PFAS in biosolids which points to 6:2 diPAP as one of the major PFAS (not all studies look for this) in wastewater residuals. We explored where this chemical is commonly used – and one product is paper. Hence the look at toilet paper.
WT: The latest (March 2023) study in the Townsend lab tested PFAS levels in 21 different toilet paper samples from across the globe and you found PFAS in all 21 samples. What did you look at in your study? What were the conclusions?
Thompson: We estimated the release of one particularly dominant PFAS (6:2 diPAP) by performing a mass balance using reported values on the concentration in sludge, per capita toilet paper use, and per capita sludge generation from different countries. The results did not show much difference in PFAS concentration between the toilet paper samples.
WT: Do these findings have public health implications since the byproducts of wastewater sludge are processed and sold as agricultural additives?
Tompson: Studies have shown that exposure to some PFAS may be linked to harmful effects in humans. However, in this study, we did not evaluate health risks but rather the load of PFAS being sent to wastewater treatment plants
WT: What are your recommendations?
Thompson: PFAS are ubiquitous in modern consumer products. Toilet paper is a large enough contributor to wastewater that it should be considered. Our hope is that by understanding potential PFAS sources, decision-makers are better equipped to address the challenge of PFAS.