Investigating Plastic-Metal Interactions in Aquatic Environments Using Laser Ablation ICP-MS and Chemical Markers

Area of Science:

• Environmental Science
• Materials Science
• Analytical Chemistry

Background:

• Plastics in aquatic environments interact with metals, affecting their fate and transport.
• Biotic aging of plastics significantly influences these interactions, but the underlying mechanisms remain poorly understood.

Purpose of the Study:

• To investigate the mechanisms of metal enrichment in biotically aged plastics.
• To assess the role of biofilms in metal accumulation and transport associated with plastics.
• To evaluate the efficacy of laser ablation-inductively coupled plasma mass spectrometry (LA-ICP-MS) in studying metal-plastic interactions.

Main Methods:

• Utilized laser ablation-inductively coupled plasma mass spectrometry (LA-ICP-MS) for elemental cross-sectional distribution analysis.
• Employed copper as a marker for biofilm presence and antimony/tin for plastic identification (PET and PLA).
• Compared LA-ICP-MS with conventional acid digestion methods.

Main Results:

• Distinct metal distribution patterns were observed in biotically aged plastics, with copper enrichment localized to the biofilm.
• Physicochemical changes on the plastic surface confirmed biofilm presence.
• Copper depletion in the surrounding water indicated significant metal uptake by aged plastics, mediated by biofilms.
• LA-ICP-MS provided a more detailed understanding of metal accumulation compared to acid digestion.

Conclusions:

• Biofilms play a critical role in mediating metal accumulation on aged plastics in aquatic environments.
• LA-ICP-MS is a powerful tool for elucidating metal-plastic interactions and metal sequestration by biofilms.
• Findings underscore the importance of considering biofilm-mediated processes in environmental risk assessments of plastic pollution.