Few acronyms raise as much consternation these days as PFAS. The acronym stands for poly- and perfluoroalkyl substances, and they’ve become a major nuisance to clean-water and drinking water utilities.

These organic compounds, used in fire-suppression and flame retardant products and various household items, are suspected of posing the risk of cancer and assorted other health problems. Because they’ve been so widely used, they are present almost everywhere in the environment.

How much risk do they present? To whom? In what amounts or concentrations? Under what circumstances? Those are essential questions, and as of now, researchers have not found clear-cut answers. And so, out of an abundance of caution, state governments are setting various advisory and regulatory standards, often at extremely low levels. This is creating great concern for drinking water plants and for wastewater facilities and their biosolids programs.

For the past three years, the North East Biosolids and Residuals Association has followed PFAS issues and has compiled information about impacts on wastewater treatment and biosolids in its region and nationally. Ned Beecher, special projects manager for the association, and Janine Burke-Wells, executive director, talked about their observations in an interview with Treatment Plant Operator.

Where have regulators tended to focus attention in relation to PFAS?

Beecher: In PFAS regulation, which is mostly at the state level, the focus has been on setting limits in drinking water, groundwater and, in a couple of cases, even surface water. In May 2016, the U.S. EPA set a public health advisory — not a regulatory number — of 70 parts per trillion. That became a de facto regulatory limit in some states. Now some states are setting ppt limits in the twenties or teens, and even single-digit ppt limits. PFAS are the only drinking water contaminants widely used in commerce that are being regulated down to ppt.

Why does the concern extend to biosolids?

Beecher: Some of these chemicals are quite mobile in soil and groundwater — traces of PFAS can leach from soils and rural home septic systems. They can leach in tiny amounts, but given the low state standards, they can reach those levels, and that’s what is causing the concern. Is the application of biosolids and even recycled wastewater impacting groundwater and drinking water at levels in the low ppts? The answer is yes in some instances. But so are other activities and home septic systems.

What levels of PFAS are typically seen in biosolids?

Beecher: The general practice is to look at PFAS levels in biosolids and soils in parts per billion, a thousand times more than ppt. We’re finding PFAS in biosolids in the single digits to low tens of ppb for the two most common PFAS chemicals, which are perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS). In soils where biosolids have been applied for years, we see that single-digits ppb have accumulated over time. These are from biosolids that don’t have major industrial inputs.

What are the sources of these measurements?

Beecher: Different state agencies have done the studies. Michigan, Maine and New Hampshire have done the most testing of biosolids, but there is also academic research that has been done over the last 20 years. I haven’t seen a biosolids test where no PFAS is detected, even from small rural community systems in rural areas with purely domestic sources. In addition, some testing of septage in Maine shows the presence of PFAS. These substances are everywhere — coming from our carpets; our clothing; and everyday cleaning, personal care and other products.

What PFAS levels have been found in soils?

Burke-Wells: The Vermont Department of Environmental Conservation contracted with the University of Vermont and the Sanborn, Head & Associates engineering firm to test shallow soil samples all across the state with random distribution. They found background samples on average ranged from less than 1 to 5 ppb. No sample came back free of PFAS. 

So in most cases biosolids are being applied with PFAS at levels not much higher than the background levels in the soil?

Burke-Wells: That’s correct.

What levels of PFAS are typically found in wastewater?

Beecher: Levels in effluent are in the single digits to the tens of ppt. There is no incoming or outgoing wastewater that I have seen that does not show PFAS at some level.

Burke-Wells: They’re finding PFAS in rainwater too. In Massachusetts, a national atmospheric deposition study found 5 ppt PFAS in rain.

What basic types of PFAS are causing the most concern?

Beecher: PFAS are basically chains of carbon atoms with fluorine atoms attached to the carbons. The length of the carbon chain determines behavior. The longer chains are those with seven or eight carbons; six or fewer carbons are considered short chains. The most commonly used were PFOA and PFOS, which are long chains with eight carbons. They have been the most concerning. They were phased out in the U.S. and Canada from 2002-15. Associated with the phaseout, blood levels of those two in people in the U.S. have gone down 70%, and levels have gone down in biosolids and wastewater as well.

How do PFOA and PFOS behave in the soil?

Beecher: They tend to bind strongly in the soil, so leaching to groundwater doesn’t happen very much. Even with industrially contaminated biosolids, those two and the other longer-chain PFAS tend to stay in the soil. Product manufacturers are replacing PFOA and PFOS with shorter-chain versions, and we’re seeing more of them in wastewater and biosolids. They are not as well studied, but they are considered probably less concerning because they don’t stay in the human body as long. However, they are more mobile in water and soil.

What have been the impacts of PFAS on biosolids in the New England region?

Beecher: Maine imposed a moratorium on biosolids use last March and required testing of all biosolids products. That included compost products that were ready for spring distribution. They used a screening value for PFAS that we argued was inappropriate: 2.5 ppb for PFOA and 5.2 ppb for PFOS. There are background levels in soils in Vermont that exceed those numbers. At the time, they were not aware that all biosolids would fail those tests.

What happened when the biosolids were tested?

Beecher: In Maine, we had one or two compost products out of 50 samples that did not exceed the screening values. Biosolids producers had to do calculations based on application rates to limit the amount of PFAS they would contribute to soil. In the end, those calculations allowed all the composts and other Class A products to be used last year and going forward for now.

What happened with Class B biosolids for land application?

Beecher: The liquid land application program in the Town of Presque Isle, Maine, was shut down. They had to bring in dewatering presses to create semisolid material that went to landfill. Their costs for biosolids management have skyrocketed. The Lewiston-Auburn Water Pollution Control Authority in Maine, which has a great sustainable program, got slammed hard. It could not apply on about two-thirds of the fields it used to apply on. The disruptions are significant and costly.

Have there been disruptions in other New England states?

Beecher: Last fall New Hampshire imposed enforceable drinking water standards and became the first state to go as low as teens of ppt. Its standards are between 11 and 18 for four individual PFAS. A biosolids program or even a wastewater management program may be affecting groundwater and drinking water at those levels because the standard is so low.

What are some potential consequences of this level of regulation?

Beecher: Six facilities in New Hampshire discharge effluent to groundwater through sand filter beds. All of those facilities have become noncompliant. The state has given them exemptions because they are discharging PFAS above the groundwater standard. But how does that play out over the long term? If PFAS turns up in neighbors’ wells above the state’s levels, is that wastewater facility now liable for putting in a charcoal treatment system for those homeowners and keeping that going in perpetuity? Those are the kinds of questions that have come up.

Has there been any pushback against these limits?

Beecher: The Plymouth Village Water & Sewer District and a biosolids management company, along with 3M, filed a lawsuit against the state that put the new drinking water standards on hold; it’s going to the New Hampshire Supreme Court for review. The concept is that the state did not conduct a cost-benefit analysis before imposing the regulations.

What is happening with PFAS around the rest of the U.S.?

Beecher: More than half the states use the EPA’s 70 ppt as the screening standard. Michigan has focused a good deal on wastewater and biosolids. It established a surface water screening value some years back for PFOS, which biomagnifies into fish. Michigan set its surface water standard at 11 ppt. Many places exceed that level, as do many wastewater effluents. Biosolids programs have also been affected. Many facilities have been required to stop land-applying biosolids, and those are going to landfill. In Wisconsin, the city of Marinette biosolids program has been stopped because of PFAS concerns related to a major industrial source.

Are there any notable situations on the drinking water side?

Beecher: California instituted public drinking water notification levels of 5.1 ppt and 6.2 ppt for PFOA and PFOS. A drinking water system that has PFAS above one of those numbers needs to notify the community. In practice, they are telling people that their wells are polluted, and so they’re going to have to take action.

What is the solution for PFAS treatment in water systems?

Beecher: What makes sense and is effective is granulated activated carbon filtration of drinking water. For example, a water system serving 34,250 people in Maine put in a carbon treatment system for about $5 million. They did that proactively because a well of concern was at 50 ppt for PFOS, and Maine is using the 70 ppt screening value. They thought that was concerning enough to warrant treatment.

Where do you see efforts being focused on PFAS in the near future?

Beecher: Nationwide, the effort has been and will continue to be focused on treating drinking water. A lot of money will be spent on that. Then you have the effects on wastewater, biosolids and solid waste management. How much money will society spend in trying to manage those?

Burke-Wells: There are some legitimate PFAS hot spots that we need to focus on, such as firefighting and manufacturing facilities that have polluted their areas. The resources should go to those places, at least initially. Until the science catches up and defines what should be regulated, clearly those are big problems that need to get addressed.