Microplastics in aquatic environment: Methods for identification and tools for impact assessment

Despite the fact that plastic is the most common component of marine waste, microplastics (MPs) are understudied due to the difficulty in determining their distribution and quantity. The threat caused by microplastics throughout the food chain include ingestion by marine organisms, the presence of toxic materials used in the manufacture of the plastics, and the transport of persistent organic pollutants (POPs) by the microplastic particles. The different methods of extraction, detection and identification of microplastics and their environmental implications are discussed in this paper. The detection methods used for identification of microplastics (FT-IR and Raman spectrometry) and structural characterization methods such as Scanning Electron microscope and pyrolysis GC-MS are compared. Attenuated Total Reflection Mid-Infrared Spectroscopy, another analytical method used for the detection and quantification of micro plastics in biological samples is also discussed. Bioinformatics tools are applied in recent studies for the analysis of MPs, including a newly developed protocol that combines context microscopy and fingerprinting spectroscopy with automated relocalization (nanoGPS) and detection (ParticleFinder) of the same MPs in separate instruments. Programs like TUM-ParticleTyper are being developed for automated detection of MPs, their quantification and characterization. Global and targeted ‘omics’ analysis provides information on the molecular effect of acute and chronic exposure of MPs in different marine organisms. Overall, this paper outlines the role of biotechnological and bioengineering techniques in mapping the pollution caused by MPs in the marine ecosystem.