Maryland's new law setting limits on PFAS in sewage sludge spread across farmland is drawing criticism from environmental and public health advocates who say the thresholds are set high enough that most wastewater plants in the state already meet them.
The legislation, enacted as Senate Bill 719 and House Bill 925, prohibits land application of biosolids containing a combined concentration of regulated PFAS at or above 50 parts per billion, with that prohibition taking effect October 1, 2028. Material testing at 25 parts per billion or higher may still be applied, but only under alternate management measures with source tracking and a state-approved mitigation plan.
Peter Blair, policy and advocacy director at the national nonprofit Just Zero, told Spotlight on Maryland that lawmakers have "essentially greenlit contamination." The dispute is worth understanding precisely, because it turns less on whether PFAS in sludge is a problem than on whether this particular number changes anything.
How Sludge Becomes a Farm Field Problem
Biosolids are the solid material left after municipal wastewater treatment. Because PFAS compounds resist breakdown and bind to organic matter, they concentrate in that solid fraction rather than passing through with treated water.
Land application then moves the material onto farmland as fertilizer, which is where the exposure pathway opens. PFAS in applied biosolids can persist in soil, move into forage crops and food crops, accumulate in livestock that graze on treated fields, and migrate into groundwater that supplies private drinking wells. Once the compounds are in soil, they are extremely difficult to remove.
The regional dimension is significant. Biosolids produced at the Blue Plains Advanced Wastewater Treatment Plant in Washington, D.C., are used on Maryland farms, and Maryland has about 250 permitted agricultural sites that can accept sewage sludge. Virginia enacted its own tiered PFAS framework this year.
PFAS exposure has been associated in human studies with changes in thyroid hormones, liver enzymes, cholesterol, immune response and certain cancers. The compounds are commonly called chemicals forever because they do not readily degrade in the environment or in the body.
Where the Numbers Came From, and Where They Diverge
Maryland did not start from zero. The state already requires wastewater treatment plants that distribute biosolids for land application to sample for PFOS and PFOA, put a hold on new land application permits in 2023, and enacted a 2024 law directing regulators to identify major industrial PFAS sources upstream and develop mitigation measures.
The state's environmental agency supported the bill. In testimony to a Senate committee, the Maryland Department of the Environment described the measure as expanding on the framework in its 2024 guidance, said the requirements for ongoing sampling and 12-month averaging would ground decisions in measurable data, and argued the bill would help the state avoid higher future costs from landfilling sludge and managing contaminated farmland. More than 500 biosolids samples were evaluated in 2025.
The statute also permits commingling, meaning generators may blend material to bring concentrations below the threshold. Critics view that as a workaround rather than a reduction. "The idea that the state's even encouraging the idea that you can dilute this toxic material is very concerning," Blair said.
The bill was sponsored by state Senators Katie Fry Hester and Brian Feldman. It arrives while the Environmental Protection Agency continues evaluating PFAS in biosolids and has not finalized federal limits, which is part of why states have moved on their own.
The Criticism That Cuts Deepest
The most substantive objection is not about the number itself. It is that the law regulates the endpoint rather than the source.
Critics argue that Maryland has placed the compliance burden on publicly operated wastewater treatment plants, which do not manufacture PFAS and cannot easily remove it from influent, while industrial dischargers who put the compounds into the sewer system face less direct pressure. Under that reading, the statute shifts cost to ratepayers and farmers without reducing the volume of PFAS entering the system.
A related objection is practical. If most Maryland facilities already produce biosolids below 50 parts per billion, the prohibition changes little while allowing the state to claim it has acted. Supporters counter that the law does reach upstream, since it empowers pretreatment authorities to set local limits for PFOA and PFOS under the Clean Water Act, and that an enforceable floor creates a legal baseline that can be tightened later.
Industry groups took a third position. The Maryland Association of Municipal Wastewater Agencies said a broad consensus was reached and that the legislation places Maryland among the most proactive states on this component of the PFAS problem.
What Maryland Residents Can Reasonably Do
Households near farmland where biosolids are applied, particularly those on private wells, have limited but real options. Private well water is not covered by federal drinking water standards, and testing is the only way to know what is in it. Certified laboratories can test for PFAS, and county health departments can usually point residents to accredited options.
People on public water systems can review their utility's annual water quality report, which now includes PFAS monitoring data under federal drinking water rules. Filtration certified for PFAS reduction is available for households that want an additional step, though it is not a substitute for knowing what is in the water.
No health agency has advised Maryland residents to avoid local produce or meat because of this issue, and there is no basis for doing so. The exposure question concerns cumulative environmental contamination over years, not acute risk from a specific food.
Implementation details remain unsettled. The prohibition does not take effect until October 2028, giving regulators time to issue guidance and potentially revisit thresholds, and the General Assembly could amend the framework in future sessions. MedicalDaily will report on the Maryland Department of the Environment's implementation guidance.
Frequently Asked Questions
What are biosolids? The solid material left over after municipal wastewater treatment. It is commonly applied to farmland as fertilizer.
What does Maryland's new law do? It prohibits land application of biosolids with a combined regulated PFAS concentration at or above 50 parts per billion starting October 1, 2028, and imposes monitoring and mitigation requirements at 25 parts per billion.
Why are advocates critical? They argue the threshold is high enough that most treatment plants already comply, and that permitting commingling lets generators dilute material rather than reduce contamination.
Did the state environmental agency support it? Yes. The Maryland Department of the Environment testified in support, describing the bill as building on its 2024 guidance framework.
How could PFAS in sludge reach people? Through soil, crops, forage eaten by livestock, and groundwater that supplies private drinking wells.
Should I stop buying Maryland produce or meat? No agency has recommended that. The concern involves long-term environmental accumulation rather than acute risk from a specific food item.
How do I check my own water? Public water customers can review their utility's annual water quality report. Private well owners must arrange testing through a certified laboratory, and county health departments can provide referrals.
