A research team from the University of Sfax and the University of Almeria has published a review paper examining the analysis and fate of microplastics (MPs) in wastewater, sludge, and landfills.
A team from the University of Sfax and the University of Almeria has published a review paper exploring the analysis and fate of microplastics (MPs) in wastewater, sludge, and landfills, highlighting the importance of environmentally friendly analytical methods for detecting MP pollution (1). The study was published in the journal Advances in Sample Preparation.
Microplastics are tiny plastic particles less than 5 millimeters in size. The increasing prevalence of these plastics in aquatic environments has prompted ongoing research into effective detection and analysis methods. Microplastics (MPs) originate from various sources, including the degradation of larger plastic debris through wind, sunlight, and friction, as well as the direct release of primary microplastics like microbeads from consumer products. Monitoring their presence in wastewater, sludge, and freshwater systems remains a complex scientific and practical challenge due to their diverse origins and behaviors.
Wastewater treatment plants (WWTPs) are a significant conduit for MPs entering the environment, with effluents and sludge serving as reservoirs of these particles. Sludge, often applied as fertilizer in agriculture, can concentrate MPs, raising concerns about potential impacts on soil and food safety.
The team confirms that one of the key difficulties in analyzing MPs within these matrices is their complex composition. Sludge and wastewater contain organic matter, microorganisms, and biofilms that can bind or conceal MPs, complicating detection. Techniques such as Fourier transform infrared spectroscopy (FT-IR), Raman spectroscopy, and pyrolysis-GC–MS (py-GC–MS) are proven to be effective in identifying MPs, alongside treatment methods including density separation, enzymatic digestion, and oxidation. However, these techniques may unintentionally alter or damage the particles, especially nanoplastics (particles smaller than 1 micrometer).
Recent efforts aim to improve detection accuracy while also prioritizing environmental sustainability. Advanced analytical methods such as FT-IR and Raman spectroscopy have been employed for polymer identification, with recent research emphasizing the need for environmentally friendly procedures. For instance, some studies have utilized visual counting methods that eliminate chemicals, achieving high sustainability scores due to low reagent use and minimal energy consumption.
Innovative sampling techniques, including passive collection methods and visual assessments of flood-damaged areas, have provided ecological insights while reducing environmental impact. These approaches facilitate broader spatial coverage but may lack the resolution to detect smaller MPs and nanoplastics.
Moving forward, the development of low-impact, scalable, and standardized analytical protocols is essential for consistent monitoring and comparison across regions. Combining multiple analytical techniques—such as automated Raman spectroscopy with spectroscopic mapping—may enhance detection sensitivity and speed.
Further research is needed to understand the interactions of MPs with other environmental contaminants, including heavy metals and pharmaceuticals, and to evaluate their implications for soil and aquatic health. Emphasizing sustainable and harmonized methodologies will support more comprehensive environmental assessments and inform effective policy measures, according to the research team.
Overall, progress has been made in developing techniques for detecting and analyzing microplastics in environmental systems. However, to tackle this global problem, policymakers, industry stakeholders, and the scientific community must be involved. Ongoing challenges emphasize the need for methodological standardization and sustainable practices, which are vital for accurately assessing the scope of plastic pollution and implementing effective mitigation strategies.
(1) Mallek, M.; Barcelo, D. Sustainable Analytical Approaches for Microplastics in Wastewater, Sludge, and Landfills: Challenges, Fate, and Green Chemistry Perspectives. Adv. Samp. Prep. 2025, 14, 100178. DOI: 10.1016/j.sampre.2025.100178
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