Wheat fields and rain clouds are seen at a farm in Keenesburg in 2020. (Lance Cheung/USDA/Public Domain Mark 1.0)
New information published by the Environmental Protection Agency this month revealed that dangerous amounts of the toxic chemical PFOS are spread across Colorado lands as fertilizer.
The EPA’s new draft risk analysis details the health threat posed by PFOS and PFOA pollution in biosolids, or treated sewage sludge often used to fertilize land. Both PFOS and PFOA belong to a class of chemicals called PFAS, or per- and polyfluoroalkyl substances, and are linked to cancer and liver, immune system, cardiovascular, and developmental problems. According to the EPA analysis, PFOS and PFOA contamination in biosolids at a level of just 1 part per billion is unsafe for populations heavily exposed to biosolids, such as people living on or near farms or people that rely primarily on farm products. The levels of PFOS recorded in Colorado’s biosolids exceed safe levels for exposed populations, sometimes by nearly 50 times.
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PFAS are a component of many consumer goods because they are water- and stain-proof and resistant to breaking down. This latter quality, which allows PFAS to persist in the environment, earned them the nickname “forever chemicals.”
PFAS coat rain jackets and nonstick pans, line paper straws, act as an extinguishing agent in some firefighting foams, and are prevalent in many personal care products, from dental floss to shampoo. PFAS are also used for certain industrial activities. So it’s no surprise that PFAS leak into municipal wastewater. Because very few wastewater treatment plants are equipped to filter out PFAS, biosolids (the solid byproduct of wastewater treatment) are often contaminated. As a result, PFAS-contaminated biosolids fertilize reclamation sites, golf courses, home gardens and, most of all, agricultural lands and pastures. Biosolids act as an unintentional Trojan horse, sneaking PFAS across Colorado’s lands disguised as beneficial fertilizer.
In 2023, the Colorado Department of Public Health and Environment began requiring wastewater treatment plants and other biosolids producers to test for and report PFOS contaminant levels. The 2023 biosolids test results are publicly available: Less than 2% of them fall within the EPA’s acceptable risk threshold of below 1 ppb. Ninety-eight percent of publicly available Colorado biosolids samples have levels of PFOS considered dangerous for people living on or near farms and people primarily eating farm products. The health threat to the general population is implied; in Colorado, most of the crops grown using biosolids are for animal feed, posing a risk to consumers of meat, milk and eggs.
Colorado’s biosolids samples reveal widespread PFOS contamination throughout Colorado. Samples exceeding the EPA’s 1 ppb risk threshold came from Grand County, San Miguel County, El Paso County, Larimer County and more. The Robert W. Hite Treatment Facility, which serves 2.2 million people in the Denver area, recorded PFOS levels between 8 and 49 ppb. The Upper Thompson Sanitation District in Estes Park reported 42 ppb of PFOS in its biosolids. Yet in Colorado, biosolids producers are not asked to investigate or control PFOS pollution unless levels greater than 50 ppb are detected.
The new federal administration has indicated that EPA research and regulation of PFAS has an uncertain future. The burden, therefore, falls on state governments to protect residents from the toxic forever chemicals. Maine is a national leader in this sphere — over the past decade, high levels of PFAS have been found in milk from Maine dairy farms that apply biosolids to pastures. In response, Maine’s Department of Environmental Protection published a map showing where biosolids have been applied and initiated a PFAS testing program. Maine’s state legislature banned the sale of consumer products with PFAS and prohibited the application of PFAS-contaminated biosolids on land. In total, Maine has invested more than $200 million to respond to PFAS contamination — including research, health monitoring, and payouts to farmers with polluted land.
Required reporting of PFOS in biosolids is a positive step towards addressing Colorado’s PFAS problem. So are the state laws that limit the sale of consumer products and firefighting foams containing PFAS. But no Colorado laws address PFAS contamination in biosolids.
The new EPA draft risk analysis demonstrates that more must be done to protect farms and the people reliant on them. Enough information is available to Colorado legislators and agencies to justify implementing regulations and programs to mitigate PFAS pollution via biosolids. Colorado must invest in research and technology to remove PFAS from biosolids and soils. The state should also fund programs that promote PFAS testing on agricultural land and support affected farms and individuals.
At a minimum, Colorado should prevent further contamination of farmlands and food by banning the application of PFAS-contaminated biosolids to agricultural lands. PFAS contamination in biosolids is threatening the long-term health of Colorado’s agricultural lands — urgent action is warranted.
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