Mercury methylation network on microplastics: Multipathway coupling, regulatory mechanisms, and environmental risks

Area of Science:

• Environmental Science
• Environmental Chemistry
• Microbiology

Background:

• Microplastics (MPs) are pervasive environmental contaminants.
• MPs can influence the biogeochemistry of mercury (Hg), a potent neurotoxin.
• Understanding Hg transformation in the presence of MPs is crucial for environmental risk assessment.

Purpose of the Study:

• To elucidate the mechanisms by which MPs regulate mercury (Hg) methylation.
• To propose a conceptual network illustrating the coupled interactions between MPs, Hg, and methylation processes.
• To predict environmental risks and suggest mitigation strategies related to MPs-Hg interactions.

Main Methods:

• Review and integration of existing knowledge on MPs-Hg interactions.
• Conceptual modeling of the "Microplastics-Mercury Methylation coupling network".
• Analysis of physicochemical and microbial pathways influencing Hg methylation.

Main Results:

• MPs act as carriers and alter microenvironments, influencing Hg speciation and mobility.
• The plastisphere on MPs supports Hg-methylating microorganisms, enhancing microbial methylation.
• MPs-DOM interactions can also mediate abiotic methylation pathways.

Conclusions:

• MPs play a multifaceted role in regulating Hg methylation through physicochemical, microbial, and organic matter-mediated pathways.
• The proposed coupling network highlights significant environmental risks associated with MPs-Hg interactions.
• Further research and mitigation strategies are needed to address the environmental implications of MPs contamination.