Sampling, Sorting, and Characterizing Microplastics in Aquatic Environments with High Suspended Sediment Loads and...

Area of Science:

• Environmental Science
• Analytical Chemistry
• Ecotoxicology

Background:

• Oceanic microplastic pollution is well-documented, but freshwater microplastic quantification remains limited.
• Traditional surface sampling methods (drift nets) are ineffective in high-sediment environments and miss smaller microplastic particles (<300 µm).

Purpose of the Study:

• To develop and validate a novel protocol for microplastic sampling and quantification in freshwater systems, particularly those with high suspended sediment loads.
• To enable the capture and analysis of microplastic particles and fibers smaller than 300 µm.

Main Methods:

• Water samples collected using a peristaltic pump and stored in low-density polyethylene (PE) containers.
• Filtration via a custom device with nylon mesh sieves and mixed cellulose ester membrane filters.
• Microplastic identification and polymer typing using stereomicroscopy and micro-attenuated total reflectance Fourier transform infrared spectroscopy (micro ATR-FTIR).

Main Results:

• The protocol effectively collects microplastics in environments with high suspended loads and debris.
• Quantification of microplastic particles and fibers <300 µm is achieved.
• High recovery rates: 100% for particulates and 92% for fibers.

Conclusions:

• This validated protocol provides a robust method for microplastic analysis in challenging freshwater environments like high-velocity rivers.
• The method is adaptable for various sample volumes and particle sizes, facilitating broader microplastic research.