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Conference Paper/Proceeding/Abstract 506 views

Quantitative identification of microplastic using an automated mineralogical and infrared approach

Gareth H. Rogers, David Patrick Gold, Uche Onwukwe, Arnaud Gallois, Amy McGarry, Mark Rees, Freya Watkins, Lorna Anguilano, Jesus Ojeda Ledo Orcid Logo, Natalie Caughtry

Geological Society of London: Plastics in the Environment 2021, at: Geological Society of London, Pages: 43 - 43

Swansea University Author: Jesus Ojeda Ledo Orcid Logo

Abstract

Plastic pollution is an increasing environmental concern, with millions of tons of plastic accumulating in the world’s oceans annually. While large pieces of plastic are a well-known problem and can cause entanglement and injuries from ingestion to marine life, smaller (<5mm) particles of plastic...

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Published in: Geological Society of London: Plastics in the Environment 2021, at: Geological Society of London
Published: 2021
Online Access: https://www.geolsoc.org.uk/expired/03-rescheduled-plastics-in-the-environment-2021
URI: https://cronfa.swan.ac.uk/Record/cronfa61829
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Abstract: Plastic pollution is an increasing environmental concern, with millions of tons of plastic accumulating in the world’s oceans annually. While large pieces of plastic are a well-known problem and can cause entanglement and injuries from ingestion to marine life, smaller (<5mm) particles of plastic, known as microplastics, are less visible and may present an even bigger challenge to marine ecosystems. Microplastics are categorized in two groups; primary microplastics are originally created as small particulates, and secondary microplastics which are created through the abrasion of larger plastic over time. Microplastic particles are often present as anthropogenic grains occurring as a significant proportion of beach sand. Consequently, microplastic particles can be treated as sedimentological grains using mineralogical techniques to determine the scale of plastic pollution in the environment. Automated mineralogical tools, such as Quantitative Evaluation of Minerals by Scanning Electron Microscopy (QEMSCAN®), combined with Micro-Fourier Transform Infrared spectroscopy (μFT-IR) are able to accurately quantify the amount of microplastic in a known sample volume and also identify the composition, range of ‘grain’-sizes and morphologies (for example, fibres, hemi/spheres etc.) of the plastic particles. Using beach sand samples collected from the Conwy Estuary in North Wales, United Kingdom, we present an integrated workflow for the mass, rapid screening of samples for the presence of microplastic using QEMSCAN®, supplemented by µFT-IR to identify the composition of the plastics. Beach sand samples were mounted in a non-plastic medium and scanned using a QEMSCAN® Quanta 650F. iDiscover software was used to provide information about the 2D textural, morphometric and mineralogical composition of the scanned data, quantifying the amount microplastic present in the samples. This was followed by μFT-IR spectroscopy to identify polymers by verifying the specific spectral bands of microplastics found within the beach sand samples against a known polymer database. This workflow demonstrates how geological techniques can be redeployed to quantify anthropogenic grains within sedimentary deposits. The results of this work show the ease in which plastic grains can become incorporated into the depositional environment and, given the long degradation time of plastic particles, how they can persist in the sedimentary record.
College: Faculty of Science and Engineering
Start Page: 43
End Page: 43