Biosolids have been in use since the 1940s for a wide variety of industrial/agricultural applications. It has been a highly encouraged practice by the USEPA and others to find beneficial uses for the sewage sludge collected from wastewater treatment plants and to prevent disposal at waste facilities or incineration of the material. Over half of the biosolids manufactured are land applied onto farmland as fertilizer according to USEPA. In the last few years, concerns around of PFAS in biosolids have increased greatly. Due to their presence and migration to surrounding soil, groundwater, surface water, livestock, and possible uptake in crops, this has led to severe losses for farmers, as reported in the local news in states such as Maine and Texas, as well as nationally.
In a recent update, USEPA has published its draft risk assessment for PFOA and PFOS in sewage sludge which shows that a relatively low concentration of 1 ppb of either contaminant can present a significant risk to human health. The PFAS found in biosolids can be attributed to the wastewater from industries and households received at publicly owned treatment works (POTW) facilities, and therefore, some states have begun to require testing of sewage sludge, such as New Hampshire, Vermont, Massachusetts, Michigan, and soon Minnesota, while the State of Maine has banned land application of biosolids altogether, because of PFAS concerns. This does not eliminate the potential for PFAS contamination in the environment since disposal at hazardous waste facilities can still result in leaching into surrounding soil, groundwater, and neighboring bodies of water, much like it can on farmland; however, it does minimize its potential to contaminate crops and livestock feeding on the silage. More information on state actions may be found here.
Biosolids can be challenging in the lab due to safety issues, matrix complexity and the wide variety of sewage sludges produced. SGS is a pioneer in biosolids testing for PFAS. For the last 15 years, large studies performed with the USEPA (Venkatesan and Halden, 2013), Environment Canada (Guerra et al., 2014; Lakshminarasimman et al., 2021), and the San Francisco Estuary Institute and Bay Area Clean Water Agencies (Lin et al., 2024) has allowed our scientists to develop the best practices with this challenging matrix, resulting in the best possible data quality, including TOP assay.
Many of these best practices were incorporated into USEPA Method 1633, which is based upon procedures developed at SGS. However, there is no substitute for experience, so trust your sample testing to the experts.
SGS has seven PFAS laboratories across North America and a dedicated staff of scientists ready to answer your questions and discuss your next project. Contact us at pfas@sgs.com or call +1 800 329 0204. We look forward to hearing from you soon.
References
Guerra, P., Kim, M., Kinsman, L., Ng, T., Alaee, M., Smyth, S.A., 2014. Parameters affecting the formation of perfluoroalkyl acids during wastewater treatment. J. Hazard. Mater. 272, 148–154. https://doi.org/10.1016/j.jhazmat.2014.03.016
Lakshminarasimman, N., Gewurtz, S.B., Parker, W.J., Smyth, S.A., 2021. Removal and formation of perfluoroalkyl substances in Canadian sludge treatment systems – A mass balance approach. Sci. Total Environ. 754, 142431. https://doi.org/10.1016/j.scitotenv.2020.142431
Lin, D., Mendez, M., Paterson, K., 2024. Study of Per- and Polyfluoroalkyl Substances in Bay Area POTWs Final Report.
Venkatesan, A.K., Halden, R.U., 2013. National inventory of perfluoroalkyl substances in archived U.S. biosolids from the 2001 EPA National Sewage Sludge Survey. J. Hazard. Mater. 252–253, 413–418. https://doi.org/10.1016/j.jhazmat.2013.03.016
Figure 11: Lin, D., Mendez, M., Paterson, K., 2024. Study of Per- and Polyfluoroalkyl Substances in Bay Area POTWs Final Report.