Microplastics in Different Environmental Matrices: Co-Contaminants and its Monitoring Techniques

Microplastics (MPs) are tiny plastic particles ranging from 1 to 5000 μm in size and are of particular concern nowadays because of their ecological risk & health concerns. MPs are prevalent environmental contaminants and have been reported in various ecosystems such as soil, air, water, and road dust. However, a thorough understanding of their distribution across various environmental matrices remains elusive. Therefore, this review aims to fill this knowledge gap by examining the abundance of MPs and different techniques utilized for their identification and characterization including sampling, extraction, identification, characterization, and quantification methods. MPs possess a large surface area and exhibit hydrophobic properties, providing a substrate for environmental pollutants such as Polyaromatic hydrocarbons (PAHs) and organochlorine pesticides (OCPs). The primary mechanisms through which pollutants attached to MPs are hydrophobic interactions, electrostatic attraction, hydrogen bonding, halogen bonding, and π-π interactions. Therefore, a better understanding of these interactions is crucial for determining the fate and transport of MPs and co-contaminants in the environment. Researchers commonly deploy techniques such as stereomicroscopy and spectroscopy for the characterization and quantification of MPs. However, size and chemical properties of MPs pose a challenge in their quantification, thereby necessitating the development of standardized analytical methods. Use of bio-indicators for MPs biomonitoring has gained popularity in recent years as an affordable option over conventional techniques however research in this area is limited. With this intention, the present review is designed to provide information about the status of the field and advance our knowledge of MPs in various environmental matrices.