Tools and Techniques to Analyse Microplastic Pollution in Aquatic and Terrestrial Ecosystems

The estimation of microplastic pollution in the terrestrial and aquatic ecosystem is carried out by quantification and identification of the contaminated environment. Microplastic estimation consists of various steps such as sampling, visualization and quantification. Generally, the planktonic net, bongo net, manta net, and neuston net have been used for water sampling. While, grab samplers, tweezers, tablespoons, trowels, shovels, spatulas, or hand picking methods have been used for soil and sediment sampling. The biological sample from the study sites comprises the direct collection of the whole organism or its colony as a sampling unit. However all samples are required to be processed further to extract the microplastic using techniques such as filtration, density extraction, digestion, and magnetic & electrostatic extraction. The digestion method is used for direct characterization such as thermal gravimetric analysis. The identification of microplastic is based on microscopic images which provide the shape, size, colour, and texture of the microplastic surface. Visual identification using microscopes is time-consuming and susceptible to human error as well as a risk of misidentification, which leads to underestimation or overestimation of microplastic pollution. Spectroscopic methods such as ATR-FTIR, µ-FTIR and Raman spectroscopy provide identification and quantification of synthetic polymer. Advance combined analytical techniques have been reported during the last few years such as portable micro-Raman, SEM-FTIR, Pyr-GC-MS, TGA-DSC, and PEE. Priority and care are essential concerning the sampling, storage and handling microplastic samples for the QA/QC for accurate analysis. The present chapter aims to provide a comprehensive overview of the current knowledge of tools and techniques used for microplastic inquiries from an environmental sample.

Keywords: Aquatic ecosystem, Biota, Density extraction, Environment, Extraction, Electrostatic separation, Filtration, FTIR, Grab sampler, Identification, Magnetic extraction, Microplastic, Planktonic Net, Pyr-GC-MS, QA/QC, Quantification, Raman spectroscopy, SEM, Sampling, Sediment, Sample processing, Terrestrial ecosystem.