
For many years, farmers across the United States have been encouraged by the Federal Government to spread sewage from homes and factories on farmland as fertilizer. This sludge, obtained from wastewater treatment plants, was rich in nutrients, and it helped keep the sewage out of landfills.
But research now shows that this black sludge (called “biosolids”) can contain heavy concentrations of chemicals that can increase the risk of certain types of cancer and cause birth defects and developmental delays in children.
Known as “forever chemicals” (PFAS), these toxic contaminants are now being detected on farmland across the United States.
Read more —
Tabuchi, Hiroko. (August 31, 2024). Something’s Poisoning America’s Land. Farmers Fear ‘Forever’ Chemicals. New York Times.
Further information:
*United States Environmental Protection Agency. Per- and Polyfluoroalkyl Substances (PFAS) in Biosolids.
*Johnson, G. R. (2022). PFAS in soil and groundwater following historical land application of biosolids. Water Research, 211, 118035. [Cited by]
“The land application of digested sewage sludge (biosolids) is widely employed across the globe. Studies show that biosolids contain significant amounts of inorganic and organic materials, as well as emerging pollutants, including per- and polyfluorinated alkyl substances (PFAS). With the wide range of pollutants commonly reported in biosolids, the potential risks associated with long-term land application operations are concerning. In this study, PFAS in surface soils, deeper soils into the vadose zone, and immediately-underlying groundwater was measured at an agricultural station with a long record of biosolids applications plus irrigation using treated wastewater. Twelve PFAS homologues were detected in every near surface soil sampled 0–30 cm depth below ground surface with multiple PFAS (especially short-chain) distributed through the soil profile. Average measured concentrations of PFAS in these soils suggest the soil burden PFOS>PFDA>PFOA for all substations sampled, independent of the historical loading rates and patterns of agricultural operations on those substations. Measured concentrations of PFOA and PFOS in the soil profile (0–90 cm) suggest these compounds have migrated to deeper soil depths (up to 9 m below the surface) with quantifiable concentrations in the soil and the immediate underlying groundwater located approximately 17 m below. Estimates of the total mass of PFAS in surface soils were effectively made using PFAS levels reported in sludges from the USEPA NSSS combined with long-term loading rates on record at the substations. With the land application of biosolids in the USA regulated by the USEPA, additional and updated risk assessments and surveys to include emerging pollutants such as PFAS are needed to protect public health and the environment.”
“Summary —
- PFAS levels are correlated to sludge loadings regardless of those patterns, crops, or down time.
- The impact of PFAS from treated wastewater as irrigation is negligible.
- PFOS and PFOA were detected in groundwater at 1 to 2 orders of magnitude higher than soils.”
*Lindstrom, A. B., Strynar, M. J., Delinsky, A. D., Nakayama, S. F., McMillan, L., Libelo, E. L., Neill, M., & Thomas, L. (2011). Application of WWTP biosolids and resulting perfluorinated compound contamination of surface and well water in Decatur, Alabama, USA. Environmental Science & Technology, 45(19), 8015-8021. [Cited by]
“Perfluorinated chemicals (PFCs) such as perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS) have been produced and used in a wide range of industrial and consumer products for many decades. Their resistance to degradation has led to their widespread distribution in the environment, but little is known about how humans become exposed. Recent studies have demonstrated that the application of PFC contaminated biosolids can have important effects on local environments, ultimately leading to demonstrable human exposures. This manuscript describes a situation in Decatur, Alabama where PFC contaminated biosolids from a local municipal wastewater treatment facility that had received waste from local fluorochemical facilities were used as a soil amendment in local agricultural fields for as many as twelve years. Ten target PFCs were measured in surface and groundwater samples. Results show that surface and well water in the vicinity of these fields had elevated PFC concentrations, with 22% of the samples exceeding the U.S. Environmental Protection Agency’s Provisional Health Advisory level for PFOA in drinking water of 400 ng/L. Water/soil concentration ratios as high as 0.34 for perfluorohexanoic acid, 0.17 for perfluoroheptanoic acid, and 0.04 for PFOA verify decreasing mobility from soils with increasing chain length while indicating that relatively high transport from soils to surface and well water is possible.”
*Jha, G., Kankarla, V., McLennon, E., Pal, S., Sihi, D., Dari, B., Diaz, D., & Nocco, M. (2021). Per- and Polyfluoroalkyl Substances (PFAS) in Integrated Crop-Livestock Systems: Environmental Exposure and Human Health Risks. International Journal of Environmental Research and Public Health. [PDF] [Cited by]
“Per- and polyfluoroalkyl substances (PFAS) are highly persistent synthetic organic contaminants that can cause serious human health concerns such as obesity, liver damage, kidney cancer, hypertension, immunotoxicity and other human health issues. Integrated crop–livestock systems combine agricultural crop production with milk and/or meat production and processing. Key sources of PFAS in these systems include firefighting foams near military bases, wastewater sludge and industrial discharge. Per- and polyfluoroalkyl substances regularly move from soils to nearby surface water and/or groundwater because of their high mobility and persistence. Irrigating crops or managing livestock for milk and meat production using adjacent waters can be detrimental to human health. The presence of PFAS in both groundwater and milk have been reported in dairy production states (e.g., Wisconsin and New Mexico) across the United States. Although there is a limit of 70 parts per trillion of PFAS in drinking water by the U.S. EPA, there are not yet regional screening guidelines for conducting risk assessments of livestock watering as well as the soil and plant matrix. This systematic review includes (i) the sources, impacts and challenges of PFAS in integrated crop–livestock systems, (ii) safety measures and protocols for sampling soil, water and plants for determining PFAS concentration in exposed integrated crop–livestock systems and (iii) the assessment, measurement and evaluation of human health risks related to PFAS exposure.”
See also —
Questions? Please let me know (engelk@grinnell.edu).