Microplastics: A major source of phthalate esters in aquatic environments

Area of Science:

• Environmental Chemistry
• Polymer Science
• Ecotoxicology

Background:

• Phthalate esters (PAEs) are widely used plastic additives, raising concerns about their environmental contamination.
• Microplastics derived from various plastic products are a significant source of PAE release into aquatic ecosystems.

Purpose of the Study:

• To investigate the release behavior and leaching potential of PAEs from different types of microplastics.
• To identify the specific PAE congeners released and their dependence on polymer type.
• To estimate the annual PAE input into oceans from microplastic sources.

Main Methods:

• Twelve common plastic products were artificially weathered into microplastics.
• Microplastics were incubated in water for 14 days to quantify PAE leaching.
• PAE concentrations and congener profiles were analyzed using gas chromatography-mass spectrometry (GC-MS).
• Kinetic leaching models were applied to understand the release process.

Main Results:

• Significant variations in PAE leaching were observed across different plastic types, with polyvinyl chloride (PVC) showing the highest release (6660 ± 513 ng/g).
• Polypropylene (PP) and polyethylene terephthalate (PET) microplastics exhibited the lowest PAE leaching.
• The dominant PAE congeners varied by polymer type, with di-n-butyl phthalate (DBP) prevalent in PA, PP, and PET, and diethyl phthalate in PVC and rubber.
• Estimated annual PAE release into oceans ranged from 57.8 to 16,100 kg/year.

Conclusions:

• The type of plastic polymer significantly influences the migration of phthalate esters (PAEs).
• Microplastics, particularly from PVC, contribute substantially to PAE pollution in marine environments.
• Understanding PAE release kinetics and polymer-specific patterns is crucial for assessing environmental risks and developing mitigation strategies.