Extraction, characterisation and remediation of microplastics from organic solid matrices

Plastics are an essential commodity due to their superior engineering properties, durability and low cost for utilization in various commercial products. However, the degradation of plastics due to several environmental stresses has led to the formation of microplastics (MPs). MPs have risen to the top of environmental concerns due to their affinity to pollute the environment and to pass it to the food chain, threatening human health. In this context, attempts have been made to extract and characterise MPs from aqueous and solid matrices. A problem that not only hampers research but also regulatory decisions is the variety of methods used for the extraction and characterisation of MPs, especially in organic solid matrices (OSMs) with organic matter >5%, making the comparison of results difficult. This paper aims to address this by critically assessing the methodologies used for the extraction and qualitative and quantitative characterisation of MPs in OSMs. Further, the current impediments in the accurate characterisation of MPs in OSMs are identified, along with recommendations for future research. Finally, recent efforts by various countries to legislate against certain sources of MPs, as well as issues and novel techniques to remediate MPs from the soil, and wastewater have been highlighted.