Isolation of microplastics in biota-rich seawater samples and marine organisms

TLDR

Microplastic litter is a pervasive pollutant in aquatic systems worldwide, and marine organisms ingest these particles, causing adverse health effects. The study aims to develop accurate methods for quantifying microplastics in productive marine waters and within marine organisms. An optimized enzymatic digestion protocol that removes over 97 % of biological material from plankton‑rich seawater and zooplankton samples while preserving microplastics was evaluated, enabling their detection. Applying this method to western English Channel samples yielded 0.27 microplastics m⁻³ and confirmed that enzymatic digestion facilitates detection of microplastic debris in seawater and marine biota.

Abstract

Abstract Microplastic litter is a pervasive pollutant present in aquatic systems across the globe. A range of marine organisms have the capacity to ingest microplastics, resulting in adverse health effects. Developing methods to accurately quantify microplastics in productive marine waters and those internalized by marine organisms, is of growing importance. Here we investigate the efficacy of using acid, alkaline and enzymatic digestion techniques in mineralizing biological material from marine surface trawls to reveal any microplastics present. Our optimized enzymatic protocol can digest >97% (by weight) of the material present in plankton-rich seawater samples without destroying any microplastic debris present. In applying the method to replicate marine samples from the western English Channel, we identified 0.27 microplastics m −3 . The protocol was further used to extract microplastics ingested by marine zooplankton under laboratory conditions. Our findings illustrate that enzymatic digestion can aid the detection of microplastic debris within seawater samples and marine biota.