Dairy cows rest outside the home of Fred and Laura Stone at Stoneridge Farm in Arundel, Maine, in this Aug. 15, 2019, file photo. Credit: Robert F. Bukaty / AP

The BDN Opinion section operates independently and does not set newsroom policies or contribute to reporting or editing articles elsewhere in the newspaper or on bangordailynews.com.

Michael Haedicke is an associate professor of sociology at the University of Maine and a faculty fellow at the Senator George J. Mitchell Center for Sustainability Solutions. Jean MacRae is an associate professor of civil and environmental engineering at the University of Maine and a Mitchell Center faculty fellow. This column reflects their views and expertise and does not speak on behalf of the University of Maine or the Mitchell Center. Haedicke is a member of the Maine chapter of the national Scholars Strategy Network, which brings together scholars across the country to address public challenges and their policy implications. Members’ columns appear in the BDN every other week.

This year, many Maine communities will face increased costs for sewage disposal because of recent legislation that prohibits spreading wastewater sludge on farmland. These communities will need to send their sludge to landfills instead.

Using wastewater sludge to fertilize agricultural soil has been a longstanding practice in Maine and elsewhere, but this practice can expose people to PFAS. These “forever chemicals” persist in  the environment, accumulate in food and water, and have been linked to health problems like cancer, thyroid disease and weakened immunity.

Ending agricultural use of wastewater sludge will help limit people’s exposure to PFAS, but it doesn’t solve the problem. Storing PFAS-laden sludge in landfills is a temporary fix that raises new concerns. Ultimately, PFAS must be removed from consumer products to reduce environmental contamination.

PFAS is a blanket term for thousands of synthetic chemical compounds with carbon-fluorine bonds. The widespread use of these compounds since the mid-20th century means that most people are exposed to trace amounts in everyday life. PFAS are in non-stick cookware, waterproof and stain-resistant clothing, food packaging and even in personal care products.

PFAS end up in sewers after they pass through our bodies or are washed from our bodies and laundry. During sewage treatment, solids are separated from liquid wastewater, creating biosolids or “sludge.” PFAS stick to the solids, becoming concentrated there. Maine Department of Environmental Protection tests have demonstrated that PFAS concentrations in the sludge produced in nearly all Maine communities exceed safe levels for agricultural soil.

When sludge is applied to agricultural land, PFAS may be taken up by crops, move with runoff to the nearest water body, or seep into groundwater, causing PFAS to enter drinking water and food supplies. Moreover, as the nickname “forever chemicals” suggests, PFAS break down very slowly. Once they enter the environment, they will be there for the foreseeable future.

Maine’s new law prohibiting agricultural use of wastewater sludge is a step in the right direction for public health and environmental quality. Diverting sludge to landfills will help to contain PFAS and limit exposures.

Unfortunately, this practice creates new problems. The easiest to see is the financial burden that it places on municipalities, which may be passed on to residents in the form of higher sewage rates or property taxes. Making landfills responsible for wastewater sludge in addition to other materials will also use up their limited space more quickly.

Other problems are less obvious. For instance, when organic materials like sludge decompose in landfills, they produce methane, a potent greenhouse gas. Even with systems in place to capture and burn methane, a sizeable fraction of landfill gas escapes to the atmosphere.

Additionally, PFAS can dissolve in water that contacts solid waste, known as leachate. While modern landfills are lined to collect leachate, small amounts migrate through and can contaminate groundwater. Even when leachate is treated, and the resulting sludge is returned to the landfill, some PFAS remains in the treated liquid and is discharged into the environment.

There is no surefire way to safely contain PFAS chemicals. Instead, policymakers and citizens need to work towards reducing the use of PFAS altogether to limit the burden of forever chemicals in our bodies and our environment.

Maine has begun this process. Last year, lawmakers enacted LD 1503, which will ban the sale of most products containing intentionally added PFAS by 2030. The process will start next year with carpets, rugs and fabric treatments. Using LD 1503, we believe that regulators should make immediate efforts to remove PFAS from food contact materials and personal care products to stop the most direct routes of human — and wastewater — exposure.

When PFAS are removed from the products we consume, we might once again be able to return organic matter to agricultural soils. Getting to a safe, circular food system should be a critical priority for Maine policymakers. This means acknowledging current safety concerns but creating a system where sludge becomes a resource once again.