Plastic pollution has become one of the defining environmental issues of modern life, and microplastics are known to enter the body through food, drink, and the air. Previous studies have detected them in organs and tissues such as the lungs, placenta, brain, semen and feces, raising concerns about long-term health effects. However, one important question remains largely unanswered. The question is: where do these particles go after they enter the body, and how do they affect the systems that process and excrete them? Based on these challenges, detailed studies on microplastic accumulation and toxicity in the biliary system are needed, since bile is a digestive fluid and also an important medium for material excretion in the enterohepatic circulation, and disturbances in bile balance can contribute to gallstones and other diseases.
Researchers from the Tenth Affiliated Hospital of Southern Medical University (Dongguan People’s Hospital), Sun Yat-sen University, Guilin Medical University, and partner institutions reported the study in 2016 (DOI: 10.1016/j.ese.2026.100686). Environmental science and ecotechnology Accepted as a pre-proof in the 2026 Journal on April 26, 2026, it describes how microplastics accumulate in human bile and cause cholangiocyte aging.
To answer this question, the research team collected bile from 14 patients who underwent surgery, using strict plastic-free protocols to avoid contamination. Five of the patients were without gallstones and nine were with gallstones. They used a combination of pyrolysis-gas chromatography-mass spectrometry, laser direct infrared spectroscopy, and scanning electron microscopy to identify polymer type, estimate concentration, and characterize particle size and morphology. Microplastics were detected in all samples. Six polymers were identified by Py-GC/MS, with PET accounting for 68.05% and PE accounting for 27.11%. Gallstone patients had a much heavier burden. The median bile concentration reached 25.89 μg g−1 compared to 6.98 μg g−1 in the control. Most particles were 20–50 μm in size, and microscopic examination revealed irregular rod-like, spherical shapes. The researchers then used low-dose polystyrene nanoplastics to model chronic exposure in cultured human cholangiocytes. Proteomics and cellular assays showed increased expression of senescence-associated molecules, increased SA-β-gal activity, and G1 cell cycle arrest. Mechanistically, the particles decreased ATP, increased mitochondrial reactive oxygen species, promoted Drp1-associated mitochondrial fission, and decreased mitochondrial membrane potential. Melatonin reversed much of this damage and suppressed inflammatory markers such as IL-6 and TNF-α.
“This study reconstitutes the biliary system as more than just a passive transit site,” experts might say. “This study suggests that bile may serve as a previously underappreciated storage and excretion pathway for microplastics, while also revealing that chronic exposure can age cholangiocytes through mitochondrial damage. Equally important, melatonin Our finding that blunts these effects provides a biologically plausible starting point for protective interventions, although large-scale human studies are still needed.” This interpretation is consistent with the authors’ conclusion that the biliary system may represent a new target for microplastic-related health risks.
The effects extend beyond gallstones. This study opens new doors on how plastic pollution affects digestive and liver-related health by identifying bile as a potential accumulation and excretion hub. It will also strengthen the evidence base for improved monitoring of microplastics in drinking water and food systems, more realistic chronic exposure models, and broader risk assessments for vulnerable populations. At the same time, the authors caution that because the sample size was small and drawn from a single center, the findings should be expanded in larger multicenter studies. Still, this study provides a compelling story. That means tiny plastic particles may be leaving a measurable biological footprint in one of the body’s most overlooked fluids.
sauce:
Chinese Academy of Sciences
Reference magazines:
Zhang, L. Others. (2026). Microplastics accumulate in human bile and cause cholangiocyte aging. Environmental science and ecotechnology. DOI: 10.1016/j.ese.2026.100686. https://www.sciencedirect.com/science/article/pii/S2666498426000311?via%3Dihub
