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Eliminating PFAS From Our Pipes

APTIM scientists and the Environmental Protection Agency answer questions about a recent study.

Over the past couple months, one four-letter acronym has taken the hazardous materials and public health spheres by storm: PFAS. There currently seems to be a lot more unknowns than knowns when it comes to the extent and nature of perfluoroalkyl and polyfluoroalkyl substances (PFAS), or “forever chemicals.” At APTIM, our team of scientists and engineers aim to discover and share these unknowns through research on how to safely manage PFAS in the environment.

Most recently, our technical staff members Sue Witt, Nicole Sojda, and Don Schupp published a scientific journal article co-authored with the Environmental Protection Agency (EPA), an APTIM client, in the Journal of Environmental Engineering. The paper, entitled “Flushing Home Plumbing Pipes Contaminated with Aqueous Film-Forming Foam Containing Per- and Polyfluoroalkyl Substances,” was a collaborative effort aimed to improve understanding of how PFAS behave in plumbing systems.

The experts share a behind-the-scenes of these scientific revelations below.

What inspired the team to begin working on this experiment?

One source of PFAS that is relatively well understood is fire extinguishing foam, often referred to as aqueous film forming foam (AFFF). This foam is commonly dispersed using built-in pumps in fire trucks, fueled by water pressure from nearby fire hydrants. If the correct valving is not put in place, however, backflow of the foam into the water distribution system could occur and contaminate the system as well as piping from nearby homes.

Our team at APTIM and our client partners at the U.S. EPA found this potential health hazard to be a threat worthy of investigation for the protection of our nation’s people and natural resources. APTIM has held a contract for facility and research services support at the EPA’s Test & Evaluation Facility in Cincinnati, Ohio, since 1989, where we have collaborated on similar projects, including another publication that won the 2020 Publications Award for the most notable contribution to the public water supply profession.

What are the significant results of the study, and what do they mean for first responders and the average property owner?

Based on the results of the study, our team concluded that it is possible that PFAS will flush out of home plumbing systems, but multiple rounds of flushing may be needed. Flushing conditions may also need to be optimized for efficiency based on water flow rate, frequency of flushing, number of flushes, stagnation time, etc. These specific conditions may vary greatly between sites.

For homeowners and first responders, our results confirm that flushing can decrease levels of PFAS in plumbing pipes, but they may increase during periods of stagnation. Therefore, sampling for contaminant levels should be conducted after prolonged stagnation, and water consumption should resume only once post-stagnation PFAS levels are consistently below any applicable health advisory levels. Site-specific flushing programs should also be developed to ensure health and safety.

What do you hope to be the outcome of this research?

In conjunction with publishing our findings, we recognize and encourage the effort required to reduce the chances of AFFF entering water distribution systems. These efforts might include properly training first responders on operating the AFFF systems and their connection to the water supply.

For the purposes of continuing research, our results justify the need to test PFAS concentrations in a more complex piping system typical of an actual home. Findings from that experiment could provide a more accurate depiction of how PFAS concentrations oscillate in a real-world environment.

Learn more about PFAS services at APTIM here.

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