‘Forever chemicals’ are being found everywhere. What about in Tacoma’s TAGRO fertilizer?
There’s growing concern about the dangers associated with a class of chemicals so long lasting in the environment that they carry the nickname, “forever chemicals.” The chemicals, which number in the thousands, can be found in a variety of household sources and can make their way into municipal sewage systems.
Including Tacoma’s.
The city, like others, treats and processes its sewage sludge into fertilizer for homes and agricultural use. Because the chemicals, collectively called PFAS, can’t be removed from the sludge, called biosolids, the industry is coming under increased scrutiny, bans and lawsuits. Tacoma, one of the first cities in the nation to create a biosolid fertilizer program called TAGRO, has long marketed its products as safe.
But, are they?
What are PFAS?
PFAS (which stands for per- and polyfluoroalkyl substances) have no safe levels, according to the Environmental Protection Agency (EPA). They are suspected of increasing certain cancer rates and causing birth defects.
In Tacoma, the PFAS found in wastewater mostly enter from residential sources, according to the city. They’re used in nonstick cookware, waterproof clothing, computer equipment, stain-resistant carpeting and numerous other products.
Some manufacturers have voluntarily phased out their use. They are no longer used, for instance, in grease-resistant food packaging like microwave popcorn bags.
Everywhere chemicals
Those who study the presence of human-made or human-placed chemicals and compounds have a common through line: If you go looking for something, you’ll probably find it.
Whether it’s artificial sweeteners in mountain streams, caffeine in Puget Sound or PFAS in wastewater, the essence of people is spread everywhere on the landscape, according to Joel Baker, a University of Washington Tacoma professor and researcher who studies environmental contamination.
“We can detect insanely small concentrations of stuff in the water,” Baker said. “So if you look hard enough, you find things ... a lot of this stuff is so ubiquitous.
“The question is, does it matter that it’s there?”
Scrutiny
A recent New York Times story revisited the issue of PFAS, looking at a lawsuit against a major manufacturer of biosolids and claims of deaths of livestock which grazed on fields where the product was used. In 2022, the state of Maine banned the use of sludge on agricultural land after inspectors found high levels of contamination.
For years, the EPA has championed the use of biosolids as both a way to reduce sludge transported to landfills and as a way for home gardeners and agriculture to reap the benefits of a nutrient-rich and cheap fertilizer.
Now, the EPA is taking another look at PFAS in both drinking water and biosolids. In April, it issued new regulations for the chemicals in municipal water supplies.
The renewed spotlight on PFAS comes in part from the increasing ability to detect the chemicals in the environment. Tacoma is at the forefront of that detection ability, say the city officials who supervise it.
Water supply
PFAS, which are human-made, are found in most municipal water supplies.
Here’s where Tacoma’s story takes a turn for the better. The city’s water supply is virtually PFAS-free. That’s because the city gets the bulk of its water from the Green River watershed.
“I think all of us just have to take a deep breath and realize that these things are present at low concentrations,” Baker said.
Even if completely banned today, it would probably take decades for the chemicals to work their way out of residential use, he said.
In the home, where most PFAS reside, consumers can look for products that carry PFAS-free labeling. Driven by consumer concern, some manufacturers are producing PFAS-free products from clothing to wall-to-wall carpeting.
“There might be some trade-offs, so maybe your carpet is not quite as stain resistant,” Baker said.
TAGRO’s History
TAGRO first began as a liquid supplement that was sprayed on hay fields.
“We could double the production of a farmer’s hay field,” said Dan Eberhardt, the city’s biosolids supervisor.
In 1991, the city switched to a solid fertilizer by mixing in sawdust, bark and sand. The program was pioneering.
“There’s probably not a month or so that goes by that we don’t get a call from somebody saying, ‘How did you guys do that?’” Eberhardt said.
Today, all the solid matter produced by the wastewater treatment plant becomes TAGRO. Liquid effluent, cleaned and purified, is piped into Commencement Bay. Without TAGRO, the city would have to rely on an alternative disposal method that could include dumping in landfills, incineration or even barging the material out to sea.
TAGRO products
Three TAGRO products are currently produced. The regular TAGRO mix makes up 40 percent of the production volume. A topsoil mix accounts for 36 percent and the remaining 22 percent is potting soil.
Slightly more than 98 percent of TAGRO by weight is used by residential customers. The rest, 1.4 percent, goes to agricultural use.
The use of biosolids as a fertilizer is a net win, Baker said, because they have to go somewhere, and they reduce the need for chemical fertilizers in both home and agricultural use.
“But you always need to have your radar up a little bit,” he said, referring to testing.
Urban waters
At the city’s Center for Urban Waters, Baker and other UW researchers study PFAS and numerous other contaminants in the environment. It’s also where testing of both Tacoma’s water supply and effluent takes place.
The environmental laboratory there tests industrial discharge, landfills and Thea Foss Superfund sites. It also tests soil moved due to industrial activity.
The lab periodically tests TAGRO for PFAS and heavy metals. All routinely fall in acceptable levels, according to government guidelines.
One area not tested: the agricultural lands that have been the recipient of TAGRO products, according to Tiffany Ryan, an environmental services manager.
Testing for PFAS
In 2019, before the EPA mandated testing for PFAS, Tacoma began its own testing program.
“We could see the writing on the wall,” Ryan said.
The city recently purchased a $400,000 machine that is technically known as a liquid chromatography triple quadrupole mass spectrometry device. Its users just call it an LC triple quad. The device, about the size of a large copy machine, uses liquid chromatography to separate and analyze chemical compounds.
“It’s like a Ferrari that we have in our laboratory right now,” Ryan said.
The futuristic-looking collection of tubes, tanks, buttons, vials and screens can find PFAS in minute amounts. What once took weeks and required sending the samples out of state can now be done in a day or two.
The machine is also being used to test for 6PPD, a chemical additive that helps vehicle tires last longer. It’s now being studied as an environmental hazard that can harm salmon.
“We are doing the good work to beneficially reuse a waste stream that otherwise would go to other sources that we would not be beneficial,” said Kurt Fremont, an environmental services manager.
Outside testing
In 2019, the city hired Canadian residuals consulting firm Sylvis to test TAGRO products. Residuals refers to the waste or byproducts produced by municipal wastewater plants, pulp mills, food waste and other processes.
It its findings, Sylvis characterized TAGRO’s PFAS levels as “very low.”
“They fall below all science-based benchmarks, and most additional indicator guidelines or regulatory benchmarks for soils that are currently available for comparison,” the company’s report stated.
While noting that research and regulatory levels for PFAS continues to evolve, “PFAS concentrations observed are not likely to pose any acute or chronic environmental or health concerns for TAGRO users with regards to the use of TAGRO products; health risks have not been observed at the low concentrations of PFAS which are present in TAGRO products.”
Oversight
While the number of chemicals that qualify as PFAS are in the thousands, only eight are regulated. Tacoma tests for those and 32 others, according to Ryan.
Of those total, 33 are below detectable levels in Tacoma’s sludge before it’s processed and mixed into TAGRO, according to Ryan.
While most of Tacoma’s wastewater PFAS come from residential sources like toilet paper, dental floss and lipstick, it doesn’t mean the city is ignoring commercial sources, which have their own pretreatment protocols.
About 40 Tacoma industrial customers get their wastewater pre-treated and are monitored by the business operations and environmental services departments.
“Based on the industry, we have an idea of who’s most likely (to produce PFAS), and we’re partnering with other municipalities as well, who have had really good success in identifying who their sources of PFAS are,” Ryan said.
The state Department of Ecology closely monitors the city’s biosolids program including onsite inspections. An annual report is filed with the EPA, according to Fremont.
Not forever?
It’s clear the people who manage TAGRO are proud of their product.
“We have class A, exceptional quality biosolids, which is really hard to meet,” Eberhardt said. “Most other municipalities have what they call class B, so they’re not allowed to distribute that to the general public. It all has to go to agricultural land.”
But, those same managers say they want to stay ahead of any new regulations and concerns that could affect their industry. They are already looking at experimental processes to destroy PFAS before they leave the wastewater plant.
The hope is that forever chemicals just might not be forever, after all.