Microplastics in watershed: extraction, identification, and environmental risk assessment from the real sample

There has been an increase in plastic production and consumption in recent years, which has become a major global environmental challenge due to the persistence of plastics in nature. Microplastics (MPs) contamination signifies a serious environmental challenge, yet discrepancies among analytical methodologies and sample matrices continue to limit the harmonization and cross-comparability of reported data. This study investigates MPs’ extractions from the soil collected from the Sukhna Lake Watershed, Chandigarh, India. This research employs systematic sampling for soil collection by dividing a single sampling site into a 4 × 4 grid. Furthermore, the density separation method was employed for the extraction of MPs from the soil samples. The extracted MPs were comprehensively characterized using a fourier transform infrared spectroscopy (FTIR), field emission scanning electron microscope (FE-SEM), energy-dispersive X-ray Spectroscopy (EDS)-mapping, X-ray photoelectron spectroscopy (XPS), and inductively coupled plasma mass spectrometry (ICP-MS), which was used to elucidate the molecular structure, morphology, surface chemistry, and elemental composition of the MPs. The MPs were further solubilized in various solvents and analyzed using UV-visible spectroscopy. The results from the FTIR and FE-SEM demonstrated the presence of various types of plastics at the collecting site, including polyethylene, polypropylene, polyvinyl chloride, and polyethylene terephthalate in different morphologies. These techniques also confirmed that plastics had undergone prolonged interactions with the environment, enabling them to interact with contaminants. Furthermore, the results from XPS, ICP-MS and UV-Visible spectroscopy suggested the presence of organic and inorganic contaminants, including heavy metals, in the MPs. The combined results emphasize that the MPs present in the watershed can function as potential vectors for the accumulation and transport of potent and persistent contaminants. This research delivers new insights into MPs as environmentally aged, oxidized materials with mineral-organic surface coatings, highlighting their enhanced capacity to act as carriers of pollutants and their broader environmental implications.