What the Heck are Anthropogenic Cellulose Microfibers?

Understanding Textile Pollution

Discussions around sustainable fashion and textile pollution often focus on synthetic fibers like polyester and nylon, which shed microplastics into the environment. However, recent research has highlighted another category of fibers that behave similarly: anthropogenic cellulose microfibers. These are natural fibers, such as cotton and bamboo rayon, that have undergone extensive chemical treatments, altering their biodegradability and impact on ecosystems.

How Do Anthropogenic Cellulose Microfibers Form?

Natural fibers, in their raw form, are biodegradable and break down in the environment. However, through conventional textile processing, they are often treated with a range of synthetic chemicals to improve durability, colorfastness, and other performance factors. These treatments fundamentally change the fibers' properties, making them more persistent in the environment and introducing chemical residues that can affect human and ecological health.

When washed, these chemically altered fibers behave much like synthetic microplastics, breaking down into microscopic fragments that enter waterways. Unlike untreated natural fibers, which degrade quickly, these microfibers remain in the environment, carrying traces of the chemicals used in their processing.

Comparing Conventional Cotton and Bamboo Rayon Processing

To understand how anthropogenic cellulose microfibers form, it is important to examine the full production process of two commonly used fibers: conventional cotton and bamboo rayon. Both undergo extensive chemical treatments, but the processes differ significantly.

Conventional Cotton Production and Chemical Use

Production Step	Synthetic Chemicals Used	Purpose of Chemicals
Cultivation	Pesticides, Herbicides, Fertilizers	Increase yield, prevent pest damage
Harvesting	Defoliants	Remove leaves for easier machine harvesting
Ginning	Cleaning Agents	Clean and prepare fibers for spinning
Spinning	Sizing Agents (PVA, Acrylics)	Improve fiber handling, prevent breakage
Weaving/Knitting	Lubricants, Anti-static Agents	Ensure smooth fabric production, prevent static
Pre-Treatment (Scouring, Bleaching)	Detergents, Caustic Soda, Hydrogen Peroxide	Remove natural oils, waxes, and impurities
Dyeing	Synthetic Dyes, Fixatives	Achieve desired color, improve color fastness
Finishing (Softening, Wrinkle Resistance, Water Repellency)	Formaldehyde, Silicone Softeners, Fluorochemicals, Resin Finishes	Enhance fabric softness, wrinkle resistance, water resistance

Bamboo Rayon Production and Chemical Use

Production Step	Synthetic Chemicals Used	Purpose of Chemicals
Harvesting Bamboo	None (bamboo is naturally pest-resistant)	Not needed for bamboo growth
Pulping	Sodium Hydroxide (Caustic Soda)	Break down bamboo into cellulose pulp
Chemical Processing (Viscose Method)	Carbon Disulfide, Sodium Hydroxide	Dissolve pulp into viscose solution for fiber extrusion
Fiber Regeneration	Sulfuric Acid	Regenerate fiber from viscose solution
Spinning	Lubricants, Anti-static Agents	Aid in spinning fibers into yarns
Weaving/Knitting	Lubricants, Anti-static Agents	Facilitate fabric formation
Dyeing	Synthetic Dyes, Fixatives	Color fabrics and improve fastness
Finishing	Formaldehyde, Silicone Softeners, Anti-wrinkle Agents	Enhance softness, durability, wrinkle resistance

Organic Certifications and Their Limits

Organic textile certifications, such as GOTS (Global Organic Textile Standard) and OEKO-TEX, play a significant role in reducing the presence of synthetic chemicals in textiles. These standards regulate pesticide use, restrict hazardous chemical treatments, and enforce fair labor practices. However, while organic certifications eliminate many harmful substances, they still permit the use of synthetic dyes, often labeled as "low-impact dyes."

Low-impact dyes are promoted as a more sustainable alternative to traditional synthetic dyes due to their higher absorption rates, reducing water pollution. However, they still contain petrochemical-derived compounds and require fixatives to adhere to fibers. As a result, even certified organic textiles may contribute to anthropogenic cellulose microfiber pollution when washed, as these chemically treated fibers do not break down as easily as untreated natural fibers.

The Role of Dyes in Anthropogenic Cellulose Microfiber Pollution

Dyes play a critical role in how fibers interact with the environment. Synthetic dyes, including low-impact dyes, require chemical binders and fixatives that alter the fiber’s structure and longevity. This can lead to increased microfiber shedding and environmental persistence.

An alternative approach is the use of plant-based dyes, such as those utilized by AIZOME. These natural dyes do not contain petrochemical derivatives or synthetic fixatives, eliminating concerns about chemical pollution. In fact, emerging research suggests that plant-dyed textiles may even offer functional benefits beyond aesthetics. AIZOME’s plant-dyed textiles have demonstrated antibacterial properties, as evidenced by laboratory testing (see antibacterial study).

By using medicinal plant dyes, textile manufacturers can reduce the environmental burden of dyeing while potentially enhancing the well-being of the wearer. Unlike synthetic dyes, which introduce chemicals into the environment through laundering, plant-based dyes decompose naturally without leaving behind toxic residues, offering a true alternative to the current system of mass textile dyeing.

Why Does This Matter?

Studies have shown that microfibers—both synthetic and chemically altered natural fibers—are found in marine ecosystems, drinking water, and even the air we breathe. The long-term impact on human health is still being studied, but early research suggests potential risks related to chemical exposure and bioaccumulation in food chains.

Despite growing regulations addressing synthetic microplastic pollution, anthropogenic cellulose microfibers remain largely unregulated. As the industry seeks sustainable alternatives, it is essential to consider the full life cycle of natural fibers and the role chemical treatments play in their environmental persistence.

What Can Be Done?

Material Transparency: Advocating for greater disclosure of textile treatments can help consumers and businesses make informed choices about fiber selection.
Sustainable Alternatives: Choosing untreated or minimally processed natural fibers reduces the release of persistent microfibers into the environment.
Responsible Manufacturing: Innovations in plant-based dyeing and mechanical finishing (rather than chemical treatments) offer ways to maintain fabric performance without synthetic additives.

Moving Forward

As the conversation around textile pollution evolves, expanding the focus beyond synthetic microplastics to include chemically altered natural fibers is a critical step. Understanding the chemical processes that create anthropogenic cellulose microfibers allows us to push for more sustainable practices, reducing environmental impact while maintaining textile quality and performance.