Featured this month

Microplastics: From Everyday Exposure to Human Health

Plastic is an essential part of our everyday lives used widely in food packaging and clothing to medical products and household items. However, as larger plastic products break down, they can form tiny particles known as microplastics, generally defined as plastic particles smaller than 5 mm.¹ Because of their widespread use and persistence in the environment, microplastics have become increasingly difficult to avoid. They have been detected in food, drinking water, household dust, and the air we breathe, raising concerns about how much exposure humans experience in their daily lives. More recently, researchers have reported the presence of microplastics in human biological samples, including blood, lungs, placenta, and brain tissue.² These findings have increased interest in understanding whether microplastics can enter and remain within the human body and, more importantly, whether their presence has consequences for human health. Although research in this area is rapidly developing, there is still uncertainty about the extent to which microplastic exposure contributes to disease. In this article, we explore how humans are exposed to microplastics, where they have been detected in the body, and what current research suggests about their potential effects on human health. Humans are continuously exposed to microplastics through daily activities, with ingestion and inhalation serving as the central and most widely recognized routes of entry, while potential exposure via dermal contact is also being investigated.³ One primary method of exposure is ingestion, which predominantly occurs through a person's diet and hydration. Specifically, the consumption of plastic-bottled drinking water, along with other commercial beverages and food items, constitutes a major contributor to human exposure.⁴ Microplastics infiltrate the human food supply through multiple mechanisms; larger plastic debris in marine and agricultural environments degrades into microscopic fragments that are inadvertently consumed by aquatic life or taken up by crops, eventually passing up the food chain. Furthermore, particles routinely shed directly from plastic food packaging during processing, storage, and heating. In addition to dietary ingestion, respiration acts as a secondary but significant exposure pathway. Airborne particles, household dust, and enclosed indoor environments act as prominent sources of inhaled microplastics.⁴ These suspended airborne plastics largely originate from the mechanical abrasion and degradation of synthetic textiles, such as clothing, carpets, couches, and pillows, which constantly shed microscopic polymer fibers that remain airborne in the spaces where people live and work. Once microplastics enter the body via the gut or lungs, they do not merely pass through the gastrointestinal or respiratory tracts; rather, they may translocate across epithelial barriers and enter systemic circulation. Evidence outlines the scientific mechanism by which these particles cross biological defenses to infiltrate deeper human tissues.⁵ The bloodstream acts as a primary transport network, as demonstrated when a study successfully detected plastic particles (≥700 nm) in the whole blood of healthy volunteers.⁶ Within the respiratory system, μFTIR spectroscopy has identified plastic particles in human lung tissue, with the highest particulate burden detected in lower-lung samples, a finding that strongly supports the mechanism of deep inhalation and subsequent long-term pulmonary deposition.⁷ Furthermore, circulating microplastics can breach highly selective physiological checkpoints. Raman microspectroscopy has detected 5–10 μm fragments in placentas from physiological pregnancies, locating particles on the maternal side, the fetal side, and within the chorioamniotic membranes.⁸ This systemic dissemination may facilitate progressive bioaccumulation across vital organs, as demonstrated by studies detecting microplastics in postmortem human brain, liver, and kidney tissues.⁹ Notably, brain samples demonstrated a greater accumulation of microplastics compared to other organs; furthermore, a reported dementia cohort exhibited an even higher cerebral microplastic burden, although current cross-sectional data cannot yet establish causality. Knowing where microplastics end up in the body is only part of the puzzle; we also need to look at how they disrupt cellular processes. Once internalized within tissues, microplastics and nanoplastics (MNPs) stimulate the excessive production of reactive oxygen species (ROS), overwhelming endogenous antioxidant defenses and triggering chronic oxidative stress. This persistent oxidative damage disrupts cell membranes, damages DNA, and stimulates pro-inflammatory signaling pathways—elevating cytokines such as IL-6, IL-18, and TNF-\alpha—which perpetuates localized and systemic inflammation.¹⁰ Beyond physical particle toxicity, microplastics act as vectors for endocrine-disrupting chemicals (EDCs), including bisphenols, phthalates, and per- and polyfluoroalkyl substances (PFAS). These leachates interfere with nuclear hormone receptor signaling, directly impairing metabolic homeostasis and normal endocrine function. The systemic distribution of MNPs raises major concerns regarding multi-organ pathology. In cardiovascular systems, particles can deposit within vascular tissues; notably, recent observational clinical evidence revealed micro- and nanoplastics embedded in human carotid atheromas, demonstrating a strong association with an increased risk of myocardial infarction, stroke, and all-cause mortality, though this cohort study established correlation rather than direct causation.¹⁰ Regarding reproductive health, while foreign particles and chemical leachates are increasingly detected in mammalian reproductive tissues, evidence linking them to compromised gametogenesis and adverse reproductive outcomes stems primarily from animal and in vitro models, meaning their direct clinical manifestation in humans remains under ongoing evaluation.¹¹ In neurological contexts, particles capable of crossing the blood-brain barrier can induce microglial activation, astrogliosis, and localized neuroinflammation in preclinical models, which may contribute to neurodegenerative and cognitive deficits. Despite these findings, a critical gap remains between preclinical evidence and definitive human risk assessment. Most current mechanistic data stem from high-dose in vitro assays and animal models exposed to uniform, pristine spheres—conditions that poorly reflect the polydisperse, aged, and chemically complex particles typical of real-world environmental exposure. Epidemiological evidence is further limited by the lack of standardized biomonitoring methodologies, uncharacterized background contamination, and difficulties in proving direct causation over chronic low-dose lifespans.⁵ Consequently, while current data substantiate the biological plausibility of harm, robust longitudinal human studies are essential to establish clear dose-response relationships and long-term clinical risks. Growing evidence shows that microplastics can enter the human body and reach multiple organs, raising concerns about their potential effects on human health. Current research suggests that microplastics may contribute to oxidative stress, inflammation, and endocrine disruption, while emerging studies are investigating their potential effects on cardiovascular, reproductive, and neurological health.¹² However, the long-term health consequences of microplastic exposure remain unclear. Although microplastics have been detected in human tissues and several potential biological effects have been identified, it is not yet clear whether exposure directly contributes to the development of disease or what levels of exposure may pose significant health risks. Long-term human studies are therefore needed to better understand the health effects of chronic microplastic exposure. Until more evidence is available, reducing unnecessary plastic exposure may be a reasonable precaution while research in this field continues to develop. 1. Kumar M, Chaudhary V, Kumar R, Chaudhary V, Srivastav AL. 2025. Microplastics, their effects on ecosystems, and general strategies for mitigation of microplastics: A review of recent developments, challenges, and future prospects. Environmental Pollution and Management. 2. Zhang R, Zhou YI, Zhao X, Chen Q, Li X, Chen Y, Xi J, Yang R, Xie BO, Yang Y, Zhai T, Meng Y, Chen L, Yan Z, Qi YA, Xiang F, Zheng W, Jiang S, Cao T, Wang Y, et al. 2026. Identification and analysis of microplastics in main organs of human fetus. 3. Prata, J. C., da Costa, J. P., Lopes, I., Duarte, A. C., & Rocha-Santos, T. (2020). Environmental exposure to microplastics: An overview on possible human health effects. Science of The Total Environment, 702(134455). ScienceDirect. 4. Zuri, G., Angeliki Karanasiou, & Lacorte, S. (2023). Microplastics: human exposure assessment through air, water, and food. Environment International, 179, 108150–108150. 5. Zarus, G. M., Muianga, C., Hunter, C., & Pappas, R. S. (2020). A Review of Data for Quantifying Human Exposures to Micro and Nanoplastics and Potential Health Risks. Science of The Total Environment, 756, 144010. 6. Leslie, H. A., J. M. van Velzen, M., Brandsma, S. H., Vethaak, D., Garcia-Vallejo, J. J., & Lamoree, M. H. (2022). Discovery and quantification of plastic particle pollution in human blood. Environment International, 163(107199), 107199. 7. Jenner, L. C., Rotchell, J. M., Bennett, R. T., Cowen, M., Tentzeris, V., & Sadofsky, L. R. (2022). Detection of Microplastics in Human Lung Tissue Using μFTIR Spectroscopy. Science of The Total Environment, 831, 154907. 8. Ragusa, A., Svelato, A., Santacroce, C., Catalano, P., Notarstefano, V., Carnevali, O., Papa, F., Rongioletti, M. C. A., Baiocco, F., Draghi, S., D’Amore, E., Rinaldo, D., Matta, M., & Giorgini, E. (2021). Plasticenta: First evidence of microplastics in human placenta. Environment International, 146(106274), 106274. 9. Nihart, A. J., Garcia, M. A., El Hayek, E., Liu, R., Olewine, M., Kingston, J. D., Castillo, E. F., Gullapalli, R. R., Howard, T., Bleske, B., Scott, J., Gonzalez-Estrella, J., Gross, J. M., Spilde, M., Adolphi, N. L., Gallego, D. F., Jarrell, H. S., Dvorscak, G., Zuluaga-Ruiz, M. E., … Campen, M. J. (2025). Bioaccumulation of microplastics in decedent human brains. Nature Medicine, 31(31). 10. Raffaele Marfella, Prattichizzo F, Celestino Sardu, Fulgenzi G, Graciotti L, Spadoni T, Nunzia D’Onofrio, Scisciola L, Rosalba La Grotta, Chiara Frigé, et al. 2024. Microplastics and Nanoplastics in Atheromas and Cardiovascular Events. The New England Journal of Medicine. 390(10):900–910. 11. D’Angelo S, Meccariello R. 2021. Microplastics: A Threat for Male Fertility. International Journal of Environmental Research and Public Health. 18(5):2392. 12. Kadac-Czapska K, Ośko J, Knez E, Grembecka M. 2024. Microplastics and oxidative stress—current problems and prospects. Int J Mol Sci. 25(10):5537.