text: Biosolids contains synthetic organic compounds, radionuclides and heavy metals. The United States Environmental Protection Agency (EPA) has set numeric limits for arsenic, cadmium, copper, lead, mercury, molybdenum, nickel, selenium, and zinc but has not regulated dioxin levels.
  Contaminants from pharmaceuticals and personal care products and some steroids and hormones may also be present in biosolids.  Substantial levels of persistent, bioaccumulative and toxic (PBT) polybrominated diphenyl ethers were detected in biosolids in 2001.
  The United States Geological Survey analyzed in 2014 nine different consumer products containing biosolids as a main ingredient for 87 organic chemicals found in cleaners, personal care products, pharmaceuticals, and other products. These analysis detected 55 of the 87 organic chemicals measured in at least one of the nine biosolid samples, with as many as 45 chemicals found in a single sample.
  In 2014, the City of Charlotte, North Carolina, discovered extreme levels of polychlorinated biphenyls (PCBs) in their biosolids after being alerted by that illegal PCB dumping was taking place at regional waste water treatment plants across the state.
  Biosolids land application in South Carolina was halted in 2013 after an emergency regulation was enacted by the South Carolina Department of Health and Environmental Control (SCDHEC) that outlawed any PCB contaminated biosolids from being land applied regardless if Class A or Class B. Very soon thereafter, SCDHEC expanded PCB fish consumption advisories for nearly every waterway bordering biosolids land application fields.
  In 2019, the state of Maine found that 95% of sewage sludge produced in the state contained unsafe levels of Per- and polyfluoroalkyl substances (PFAS) chemicals. Several farms that had spread biosolids as fertilizer were found to have PFAS contaminated soil, groundwater, animals and crops. Hundreds of other farms were potentially similarly contaminated. The state subsequently imposed additional rules restricting biosolids spreading. In 2023, Arturo A. Keller at the Bren School of Environmental Science & Management within the University of California, Santa Barbara began working on solutions to eliminate these PFAS, including creating bio-char fertilizers from the bio-solids.
  Biosolids used as a fertilizer have resulted in PFAS contamination of beef raised in Michigan.  
  In October 2021 EPA announced the PFAS Strategic Roadmap which includes risk assessment for PFAS (PFOA and PFOS) in biosolids.