Evaporating MCCP Toxins Are Going Airborne

CLIFF NOTES

• CU Boulder found MCCPs in air in rural Oklahoma.
• It was the first airborne MCCP detection in the Western Hemisphere.
• The team saw odd isotope patterns during 24/7 testing for a month.
• Biosolid (sewage sludge) fertilizer on fields may be the source.
• Scientists want to track levels over time and study impacts.

Air monitoring in an agricultural region of Oklahoma found toxic airborne MCCPs for the first time in the Western Hemisphere. University of Colorado Boulder researchers were studying particle formation, not MCCPs. The team suspects sewage sludge fertilizer used on nearby fields may be releasing these chemicals into the air, revealing a hidden path for contamination.

What happened in Oklahoma?

A University of Colorado Boulder research team ran a month-long air study in an agricultural region of Oklahoma. The project aimed to track how tiny airborne particles form and change. Instead, the instruments picked up Medium Chain Chlorinated Paraffins (MCCPs) in the air.

The study reports the first airborne detection of MCCPs in the Western Hemisphere. The findings were published in ACS Environmental Au.

“It’s very exciting as a scientist to find something unexpected like this that we weren’t looking for,” said Daniel Katz, a CU Boulder chemistry PhD student and lead author. “We’re starting to learn more about this toxic, organic pollutant that we know is out there, and which we need to understand better.”

What are MCCPs, and why do they matter?

MCCPs are toxic organic pollutants used in industrial applications. The article cites their use in metalworking fluids and in making PVC and textiles.

Scientists have detected MCCPs before in places such as Antarctica and Asia. But the article says researchers had struggled to measure them in air over the Western Hemisphere until this work.

MCCPs are now being evaluated for possible regulation under the Stockholm Convention, an international agreement focused on protecting human health from persistent and widespread chemicals.

Where did the airborne MCCPs likely come from?

The researchers point to biosolid fertilizer—also called sewage sludge—as a likely source.

MCCPs often appear in wastewater and can end up in biosolid fertilizer produced during wastewater treatment. The team believes the MCCPs detected in Oklahoma likely came from nearby fields where biosolids had been applied.

“When sewage sludges are spread across the fields, those toxic compounds could be released into the air,” Katz said. “We can’t show directly that that’s happening, but we think it’s a reasonable way that they could be winding up in the air. Sewage sludge fertilizers have been shown to release similar compounds.”

Could regulation have pushed industry toward MCCPs?

The article connects MCCPs to a closely related group: Short Chain Chlorinated Paraffins (SCCPs).

SCCPs are already regulated under the Stockholm Convention and by the U.S. Environmental Protection Agency since 2009, following evidence they can travel long distances, persist in the environment, and pose human health risks.

Researchers suspect that as SCCPs were limited, industries may have substituted MCCPs in some uses, increasing MCCP presence.

“We always have these unintended consequences of regulation, where you regulate something, and then there’s still a need for the products that those were in,” said Ellie Browne, a CU Boulder chemistry professor, CIRES Fellow, and co-author. “So they get replaced by something.”

How did scientists detect MCCPs in the air?

The team ran continuous monitoring at the Oklahoma site for a full month. They used a nitrate chemical ionization mass spectrometer, which can identify specific compounds in air.

Katz saw unusual isotopic patterns in the data that did not fit known compounds. Further work linked those patterns to chlorinated paraffins associated with MCCPs.

How does this connect to PFAS and “forever chemicals”?

Katz said MCCPs share similarities with PFAS, often called “forever chemicals” because they break down very slowly.

The article notes that PFAS concerns in soil helped drive the Oklahoma Senate to ban biosolid fertilizer. In that context, the MCCP finding adds another reason researchers want a closer look at what can be carried from land into air.

What researchers say comes next

With a method now proven to detect MCCPs in air, researchers want to measure how levels change over time. They plan to track seasonal variation and study what happens to these chemicals once they are airborne.

“We identified them, but we still don’t know exactly what they do when they are in the atmosphere, and they need to be investigated further,” Katz said. “I think it’s important that we continue to have governmental agencies that are capable of evaluating the science and regulating these chemicals as necessary for public health and safety.”

How reverse osmosis and whole-home water conditioners relate

Airborne pollutants can settle onto soil and surface water, then move into wells or municipal sources. When persistent chemicals show up in the environment—whether PFAS, chlorinated compounds, or related contaminants—water treatment becomes a practical last line of defense. Reverse osmosis systems can reduce many dissolved contaminants at the tap, while whole-home water conditioners can improve water quality throughout the house and help protect plumbing and appliances.