Human Waste Decomposition: Fungi Break Down Pharmaceuticals

Human waste doesn’t just contain organic material—it also carries trace pharmaceuticals and synthetic chemicals that our bodies don’t fully break down.

When this waste enters the environment—whether through wastewater systems or in the backcountry—those compounds don’t simply disappear.

Research shows that these contaminants can:

• Persist in soil and organic matter

• Leach into groundwater

• Be taken up by plants, including crops

This is especially concerning because many of these compounds—like antidepressants and other medications—are biologically active by design. Even at low concentrations, they can interact with living systems in ways we don’t fully understand.

The challenge is that current waste treatment systems aren’t built to remove them. While they reduce pathogens and nutrients, they often leave behind these more complex molecules.

That means:

• Treated waste can still carry environmentally active chemicals

• Those chemicals can accumulate over time

• And they may pose long-term risks to ecosystems and human health

In the backcountry, where there is no treatment system at all, the pathway is even more direct: what’s left behind can enter the environment almost immediately.

So if these compounds persist—and current systems aren’t designed to remove them—the obvious question becomes:

What actually can break them down? This is where fungi start to stand out. Unlike traditional treatment methods that struggle with complex, tightly bound chemicals, certain fungi have evolved to break down some of the most stubborn organic compounds found in nature. And as new research shows, that ability extends to pharmaceuticals in human waste.

A 2026 study in ACS Environmental Au explored whether fungi could help solve this problem by breaking down pharmaceuticals in biosolids (treated human waste).

Researchers tested two species of white-rot fungi, known for their ability to decompose tough organic materials.

Key findings:

• 48–99% removal of pharmaceutical compounds

• Some drugs degraded almost completely (>90%)

• Identification of 40+ transformation products, showing active chemical breakdown

• Most byproducts were less toxic than the original compounds

This process—called mycoremediation—demonstrates how fungi can go beyond basic human waste decomposition and actually neutralize harmful contaminants.

At PACT Outdoors, we’ve been exploring how fungi—especially King Stropharia—can improve backcountry sanitation and human waste management. While this research studied different species in the same class of fungi, it reinforces a shared principle:

Fungi can break down not just waste, but the invisible contaminants inside it.

Research in backcountry sanitation and human waste decomposition have shown that bacterial pathogens in human waste like E. coli can persist in the soil for at least a year, and can contaminate nearby waterways. 

We’ve demonstrated through research conducted with Colorado Mountain College that white rot fungi like King Stropharia can rapidly destroy bacterial coliforms in human waste while accelerating the decomposition of the poop itself. It’s mycoremediation at the micro-level.

Wood rotting or white rot fungi are nature’s great upcyclers. They convert dead or dying matter into bioavailable nutrients for plants and soil microbes. This essential process is taking place within every square inch of biological rich, active soil on earth.

This supports the use of fungal systems to:

• Enhance human waste decomposition in nature

• Reduce environmental contamination in outdoor spaces

• Provide low-impact sanitation solutions where infrastructure doesn’t exist

Finding yet another set of complex synthetic compounds, in this case from pharmaceuticals, in human waste that our current treatment processes do not break down gives even more promise to the role that fungi can play in waste treatment whether at the municipal scale or in backcountry environments. 

Backcountry waste isn’t just a hygiene issue—it’s an environmental chemistry problem.

Even small amounts of improperly managed waste can introduce:

• Persistent pharmaceutical residues

• Long-term soil and water impacts

• Disruption to sensitive ecosystems

Fungal-based solutions offer a promising alternative:

• Natural and low-energy

• Effective in real outdoor conditions

Capable of breaking down complex contaminants.