Assessing the impact of microplastics on the aquatic realm at scale: Applying newly developed microscopy, elemental analysis, and semi-automated identification techniques to Viet Nam

Microplastics are omnipresent in the aquatic environment, these particles can be ingested by marine life and act as surfaces to which pathogens and heavy metals can become attached. However, their breakdown and distribution into increasingly smaller particles can make them difficult and time-consuming to analyse. Scanning electron microscopy with backscattered electron and x-ray imaging (SEM-BEX) represents a novel way to conduct regional-scale assessment of microplastics in environmental samples and characterise their physio-chemical properties. SEM-BEX provides discrete element maps alongside backscattered electron imaging in a single detector, allowing microplastics to be characterised at higher speeds than previously possible. When combined with semi-automated and machine learning image analysis, this new SEM-BEX approach has high potential to be applied as a more rapid screening tool for initial broad-scale environmental assessment, before targeting areas of greatest environmental impact. The applications of SEM-BEX to microplastics research are shown here using case studies from the Red River and Cát Ba islands in Viet Nam, and include microplastic budget calculations for a given environment, toxicity assessments by tracing the absorption and delivery of heavy metals through environments by microplastics, and in tracking the potential ingestion of microplastics by micro-organisms. Ultimately, this shows how the transfer of microplastics from the terrestrial to marine realms can be better tracked and helps to determine the environmental impact of these microplastics.

Presentation Preference: Oral

Primary Presenter: Max Webb, Heriot-Watt University (max.webb@hw.ac.uk)

Authors:

Max Webb, Heriot-Watt University  (max.webb@hw.ac.uk)

Jim Buckman, Heriot-Watt University  (j.buckman@hw.ac.uk)

Bérénice Ratouit, University of Poitiers  (berenice.ratouit@gmail.com)

Juliane Bischoff, Heriot-Watt University  (j.bischoff@hw.ac.uk)

Huong Ngo, Phenikaa University  (huong.ngothithuy@phenikaa-uni.edu.vn)

Jennifer Scott, Heriot-Watt University  (js2092@hw.ac.uk)

Tony Gutierrez, Heriot-Watt University  (tony.gutierrez@hw.ac.uk)

Thomas Wagner, Heriot-Watt University  (t.wagner@hw.ac.uk)

Michel Kaiser, Heriot-Watt University  (m.kaiser@hw.ac.uk)

Ryan Pereira, Heriot-Watt University  (r.pereira@hw.ac.uk)