Biofouled Micro- and Nanoplastics as Reactive Platforms for Potentially Toxic Element Transformation.

Area of Science:

• Environmental Science
• Environmental Chemistry
• Ecotoxicology

Background:

• Micro- and nanoplastics (MNPs) are recognized as physical pollutants.
• MNPs become dynamic chemical platforms when colonized by biofilms (plastisphere) and organic matter (eco-corona).
• This biofouling transforms inert particles into mobile microreactors.

Purpose of the Study:

• To highlight the role of biofouled MNPs as active pollutant platforms.
• To outline research priorities for understanding MNP reactivity and toxicity.
• To advocate for integrating speciation-focused monitoring into environmental policy.

Main Methods:

• This perspective synthesizes existing research on MNP biofouling and contaminant transformation.
• It analyzes current monitoring and risk assessment frameworks for MNPs.
• It proposes future research directions and policy recommendations.

Main Results:

• Biofouling on MNPs introduces redox-active and photoreactive components.
• These components can drive significant contaminant transformations, altering speciation, mobility, and toxicity.
• Current risk assessments often overlook these processes by focusing on particle counts/mass and total metal loads rather than speciation.

Conclusions:

• MNPs should be recognized as active pollutant platforms due to biofouling.
• Further research is needed to quantify biofouled MNP reactivity and the toxicity of resulting complexes.
• Policy and monitoring must evolve to include speciation-focused assessments of MNP-associated contaminants.