Detection and characterization of MPs in the human stool: an observational study in Bushehr, Iran

Plastic particles smaller than 5 mm, known as microplastics (MPs), are considered emerging contaminants that may pose health risks to humans. The present observational-descriptive study aimed to detect and characterize MPs in stool samples of 30 adult individuals with endocrine disorders in Bushehr, Iran. The presence, morphology, polymer types, and elemental composition of MPs in human stool samples were analyzed using Micro-Raman spectroscopy, scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDX). All stool samples contained MPs, with a mean concentration of 6.22 items/g. The most frequently identified MPs were within the size range of 500–1000 μm, and fibers accounted for 97.9% of the observed shapes. White/transparent and black/gray were the most common colors detected. Raman analysis identified six types of polymers, with polypropylene (PP) being the most prevalent (36.36%). EDX results revealed major elements such as carbon and oxygen, followed by trace elements like Na, Mg, Si, Cl, K, Ca, Fe, and I. Overall, the findings indicate widespread exposure to MPs, likely via ingestion, and highlight their roles as vectors for environmental pollutants due to their ability to adsorb heavy metals and undergo surface modification through environmental weathering.