by Sarah Craighead Dedmon

A new Maine law will, effective July 24, ban the spreading of municipal sewer sludge and the production of PFAS-containing sludge-derived materials, including many commercial compost mixes which contain perfluoroalkyl and polyfluoroalkyl substances, collectively known as PFAS.

Locally, the only commercial compost known to be made with sludge-derived materials is sold by the company Mark Wright in Columbia under the name Mark’s Mix. Mark Wright is, as of 2021, owned by Casella Waste Systems.

Leading up to LD 1911, An Act To Prohibit the Contamination of Clean Soils with So-called Forever Chemicals, the state of Maine regulated sewage-derived composts, requiring producers to conduct testing and requiring distributors to provide a fact sheet to their customers detailing safe-use instructions.

Clark James is the Director of Logistics for Casella and says Casella has complied with those regulations.

“The risk assessment that we conducted in concert with the Maine DEP (Department of Environmental Protection), and which they approved, allowed us to continue marketing the compost, and we had to provide some instructions for users not to reuse it a certain number of times or consecutively on the same plot of land,” said James. “It’s the most highly regulated of all the composts out there, and others don’t have to go through the rigid screening criteria that we do on the front and on the back end.”

James says Casella will eventually be offering a line of new organic compost products.

Casella Director of Compliance Jeff McBurnie, who served on governor Janet Mills’ PFAS Task Force, said sludge materials typically departed Casella facilities compliant with state screening guidelines, and users, such as Mark Wright, were then guided to mix the sludge with other substances, such as wood chips, or peat, to dilute the compost under the state’s safe PFAS thresholds, which vary according to the specific type of chemical — PFBS, PFOS, or PFOA. 

Though Mark’s Mix has been built on Casella-produced sludge materials, it is also mixed with other substances, which likely diluted the PFAS concentrations further. 

Mark Wright/Casella’s local office did not respond to requests for specific testing or composition data concerning their product.

Tested

Testing for PFAS in soil and water is costly, and at this time, not conducted within the state of Maine. Homeowners may order their own soil and water tests via laboratories like Alpha Analytical in Massachusetts, where tests range between $300 and $400 each. 

One Washington County homeowner this spring sent soil and water samples to Alpha after learning that their lawn had been spread with more than 20 cubic yards of Mark’s Mix. 

Testing showed that their well water had no trace of PFAS. 

Speaking to Alpha directly, this newspaper confirmed that their soil test results showed traces below the state’s previous legal limits of PFOS, PFBS, and PFOA, three compounds historically regulated in Maine’s sludge products. (These legal limits become obsolete when LD 1911 takes effect July 24.)

Their PFOS level measured 1.53 ng/g (nanograms per gram), against Maine’s “Soil Beneficial Use” screening level of 5.2 ng/g. 

PFBS measured 1.53 ng/g, Maine’s screening level is 1,900 ng/g.

PFOA measured .90 ng/g, Maine’s screening level is 2.5 ng/g.

Of 28 total PFAS compounds included in the test, Alpha’s test results confirmed the presence of seven.

David Madore, deputy commissioner of Maine DEP, says that on a national level, there is little scientific data on how to effectively treat PFAS-contaminated soil.

“Research and development on this issue is ongoing,” said Madore. “If vegetable beds have already been prepared and homeowners are certain the product was sludge-derived, they should contact Maine CDC if they have any questions about exposure or risk to health.”

What are PFAS?

PFAS chemicals, short for perfluoroalkyl and polyfluoroalkyl chemicals, were originally invented in the 1940s by Dupont and marketed as Teflon.

Today they’re called “Forever Chemicals” because PFAS can last for centuries in soil and years in the human body. But they might also be called “Everywhere Chemicals” because even today, hundreds of PFAS-type chemicals remain approved for use in products such as fast-food wrappings, non-stick cookware coatings, stain-resistant furniture, and carpet treatments, firefighting foam, clothing labeled stain and water repellent, and microwave popcorn bags.

Exposure to PFAS has been linked to reproductive issues, developmental delays, and birth defects in children; increased risk of some cancers, including prostate, kidney, and testicular cancers; increased cholesterol levels, and reduced function of the immune system.