Microplastics as Bioaccumulation Without Borders(Part 1): Emerging Science, Who Is Most at Risk,and Health Consequences

By Sara Szal MD | July 2, 2025 |

In recent years, microplastics have evolved from an environmental concern to a direct human health issue, with mounting evidence suggesting systemic exposure and biological harm. A recent publication on microplastics sparked concerns when researchers found widespread microplastic contamination across a range of commercially sold beverages in France, including bottled water (even in glass containers), soft drinks, and juices.1 Microplastics are ubiquitous contaminants—defined as plastic particles less than 5 mm in size—and are now routinely detected in human tissues, including the bloodstream, placenta, lungs, gastrointestinal tract, and reproductive organs.2

The primary pathways for the entry of microplastics into the body? Simple acts like eating, breathing, and contacting the skin distribute microplastics to various organs. While the clinical implications of these findings are still emerging, early studies indicate that microplastics may exert biologically active effects through mechanisms such as oxidative stress, chronic inflammation, immune dysregulation, and cellular toxicity.3

Microplastics may act as vectors for persistent organic pollutants and pathogens raises concerns about synergistic toxicity and long-term health risks.4 Children may be uniquely susceptible due to increased exposure and immature detoxification systems.5 However, despite the urgency of public concern, the current evidence base is fragmented—largely derived from animal models and in vitro studies—and significant knowledge gaps persist around dose-response relationships, chronic low-level exposure, and interindividual susceptibility.6 This review critically examines the current state of the science on microplastic exposure and human health, with a focus on known biological pathways, population-level risk, and the pressing need for mechanistic and longitudinal human data.

Unpacking the Health Puzzle: What Science Is Revealing

Early research, mainly from animal and lab studies, suggests microplastics can enter our bodies, spread to organs, and potentially cause oxidative stress, inflammation, immune imbalances, and DNA damage. They might also act as carriers for other environmental toxins, like POPs and heavy metals, further disrupting our endocrine and immune systems, potentially linking to cancer and reproductive toxicity.7

However, direct human evidence of these adverse health effects is still limited. Our understanding largely comes from extrapolating animal and in vitro data. A major challenge is the lack of standardized methods to quantify microplastics in human samples, hindering accurate risk assessment. We still don’t know the long-term health consequences, precise dose-response relationships, or the cumulative impact of chronic low-level exposure in

Current reviews stress the urgent need for more research, better analytical techniques, and regulatory action to address the growing environmental and potential health risks of microplastics.8

While microplastics are a global contaminant with demonstrated biological effects in experimental models, their direct impact on human health remains largely uncharacterized. Key gaps include human epidemiological data, standardized detection methods, and understanding long-term health outcomes.

Populations at Risk?

Certain individuals and groups are inherently more susceptible to microplastic exposure due to a blend of lifestyle, environmental factors, and unique physiological characteristics:

  • Pregnancy Microplastics have been detected in human placenta, amniotic fluid, and meconium, confirming maternal and fetal exposure during pregnancy. The most consistent human findings are associations between higher placental microplastic content and increased risk of intrauterine growth restriction (IUGR), reduced gestational age, lower birthweight, and lower 1-minute Apgar scores. Consumption of food in plastic containers and certain lifestyle factors (e.g., bottled water, takeaway food) are associated with higher placental microplastic burden.9 Animal and lab studies demonstrate that microplastics can impair placental development, alter hormone production, and increase embryo resorption, leading to poor pregnancy outcomes such as fetal growth restriction, preterm birth, and abnormal placental function.10 However, direct evidence in humans linking microplastics to adverse pregnancy outcomes remains limited and of low quality, with most data extrapolated from animal models. There are significant gaps in understanding the effects of chronic low-level exposure, long-term outcomes, and precise dose-response relationships. Current reviews emphasize the urgent need for high-quality epidemiological studies and standardized detection methods to clarify these risks.11
  • Newborns and Children This group is at the forefront of concern given their frequent hand-to-mouth exploration, higher ventilation rates relative to their body size, and still-developing biological barriers make them more vulnerable to both ingesting and inhaling microplastics. Indoor environments, where children spend a significant amount of time, can harbor higher concentrations of airborne and dust-borne microplastics, making them major exposure sources. Infant feeding bottles and formula preparation have been shown to release microplastics, contributing to their exposure. Infants and children also tend to have a higher estimated daily intake per body weight compared to adults. All factors potentially aggregate to increase risk.12
  • Individuals with Occupational and Environmental Exposure People whose professions involve direct contact with plastics, such as those in plastic manufacturing, waste management, or textile industries, face increased risk. Similarly, living in urban or industrialized areas with elevated ambient microplastic levels can lead to higher exposure. Adults with occupational exposure (e.g., in plastic manufacturing or waste management) or those in urban/industrial areas may experience higher respiratory and systemic exposure. For these adults, respiratory symptoms predominate, with evidence of chronic airway inflammation and, in some cases, reduced lung function.13
  • People with Certain Dietary Habits Populations with a high consumption of seafood, bottled water, or foods packaged in plastic are likely to have higher exposure levels.14

Other factors that can elevate vulnerability include younger age groups, individuals with pre-existing respiratory or gastrointestinal conditions, and socioeconomic status, which can influence living conditions and food sources.

What Are the Health Consequences?

When people have high exposure to microplastics, these tiny particles are suspected of negatively affecting the digestive, reproductive, and respiratory systems. This risk appears to be greatest for infants, newborns, children, and those with significant workplace or environmental exposure.

In these vulnerable groups, microplastics have been linked to:

  • Digestive Issues: Symptoms like abdominal pain, changes in bowel habits, and signs of chronic inflammation in the gut.
  • Reproductive Problems: Concerns such as reduced sperm quality and potential disruption of reproductive hormones.
  • Breathing Difficulties: Effects including cough, wheezing, shortness of breath, lung inflammation, and cellular stress (oxidative stress).

Summary

Chronic low-level exposure to microplastics is associated with systemic inflammation and oxidative stress. It could also worsen pre-existing conditions like asthma or inflammatory bowel disease. Besides the specific system-related symptoms, general discomforts like fatigue and dizziness are also reported.

What’s clear: Microplastics are consistently detected in human tissues and fluids. Lab studies and some limited human data suggest associations with inflammation, oxidative stress, immune problems, and reproductive and respiratory dysfunction.

What we still need to learn: We lack sufficient long-term or widespread population data to definitively link microplastic exposure to specific human diseases. We don’t fully understand the dose-response relationship (how much exposure leads to what effects), the long-term health impacts, or how factors like particle size, plastic type, and exposure to other attached pollutants influence these effects.

Citations:

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  3. Chartres, N., et al. “Effects of Microplastic Exposure on Human Digestive, Reproductive, and Respiratory Health: A Rapid Systematic Review.” Environmental Science & Technology 58, no. 52 (2024): 22843–22864. https://doi.org/10.1021/acs.est.3c09524; Kumar, R., et al. “Micro(nano)plastics Pollution and Human Health: How Plastics Can Induce Carcinogenesis to Humans?” Chemosphere 298 (2022): 134267. https://doi.org/10.1016/j.chemosphere.2022.134267; Prata, J. C., et al. “Environmental Exposure to Microplastics: An Overview on Possible Human Health Effects.” Science of the Total Environment 702 (2020): 134455. https://doi.org/10.1016/j.scitotenv.2019.134455; Winiarska, E., et al. “The Potential Impact of Nano- and Microplastics on Human Health: Understanding Human Health Risks.” Environmental Research 251, part 2 (2024): 118535. https://doi.org/10.1016/j.envres.2024.118535. ↩︎
  4. Kumar, R., et al. “Micro(nano)plastics Pollution and Human Health: How Plastics Can Induce Carcinogenesis to Humans?” Chemosphere 298 (2022): 134267. https://doi.org/10.1016/j.chemosphere.2022.134267; Prata, J. C., et al. “Environmental Exposure to Microplastics: An Overview on Possible Human Health Effects.” Science of the Total Environment 702 (2020): 134455. https://doi.org/10.1016/j.scitotenv.2019.134455. ↩︎
  5. Luo, Q., et al. “Microplastics as an Emerging Threat to Human Health: An Overview of Potential Health Impacts.” Journal of Environmental Management 387 (2025): 125915. https://doi.org/10.1016/j.jenvman.2025.125915. ↩︎
  6. Rahman, A., et al. “Potential Human Health Risks Due to Environmental Exposure to Nano- and Microplastics and Knowledge Gaps: A Scoping Review.” Science of the Total Environment 757 (2021): 143872. https://doi.org/10.1016/j.scitotenv.2020.143872; Blackburn, K., and D. Green. “The Potential Effects of Microplastics on Human Health: What Is Known and What Is Unknown.” Ambio 51, no. 3 (2022): 518–530. https://doi.org/10.1007/s13280-021-01589-9. ↩︎
  7. Rahman, A., et al. “Potential Human Health Risks Due to Environmental Exposure to Nano- and Microplastics and Knowledge Gaps: A Scoping Review.” Science of the Total Environment 757 (2021): 143872. https://doi.org/10.1016/j.scitotenv.2020.143872; Prata, J. C., et al. “Environmental Exposure to Microplastics: An Overview on Possible Human Health Effects.” Science of the Total Environment 702 (2020): 134455. https://doi.org/10.1016/j.scitotenv.2019.134455; Xu, J. L., et al. “A Review of Potential Human Health Impacts of Micro- and Nanoplastics Exposure.” Science of the Total Environment 851, part 1 (2022): 158111. https://doi.org/10.1016/j.scitotenv.2022.158111; Bocker, R., and E. K. Silva. “Microplastics in Our Diet: A Growing Concern for Human Health.” Science of the Total Environment 968 (2025): 178882. https://doi.org/10.1016/j.scitotenv.2025.178882; Kumar, R., et al. “Micro(nano)plastics Pollution and Human Health: How Plastics Can Induce Carcinogenesis to Humans?” Chemosphere 298 (2022): 134267. https://doi.org/10.1016/j.chemosphere.2022.134267; Xu, J. L., et al. “A Review of Potential Human Health Impacts of Micro- And Nanoplastics Exposure.” The Science of the Total Environment 851, no. 1 (2022): 158111; Luo, Q., et al. “Microplastics as an Emerging Threat to Human Health: An Overview of Potential Health Impacts.” Journal of Environmental Management 387 (2025): 125915. https://doi.org/10.1016/j.jenvman.2025.125915; Chakraborty, S., et al. “Evaluation of the Health Impacts and Deregulation of Signaling Pathways in Humans Induced by Microplastics.” Chemosphere 369 (2024): 143881. https://doi.org/10.1016/j.chemosphere.2024.143881. ↩︎
  8. Zuri, G., et al. “Human Biomonitoring of Microplastics and Health Implications: A Review.” Environmental Research 237, no. 1 (2023): 116966; Zuri, G., et al. “Microplastics: Human Exposure Assessment Through Air, Water, and Food.” Environment International 179 (2023): 108150. Ziani, K., et al. “Microplastics: A Real Global Threat for Environment and Food Safety: A State of the Art Review.” Nutrients 15, no. 3 (2023): 617.
    Li, Y., et al. “Microplastics in the Human Body: A Comprehensive Review of Exposure, Distribution, Migration Mechanisms, and Toxicity.” Science of the Total Environment 946 (2024): 174215. https://doi.org/10.1016/j.scitotenv.2024.174215; Chartres, N., et al. “Effects of Microplastic Exposure on Human Digestive, Reproductive, and Respiratory Health: A Rapid Systematic Review.” Environmental Science & Technology 58, no. 52 (2024): 22843–22864. https://doi.org/10.1021/acs.est.3c09524; Zhao, B., et al. “The Potential Toxicity of Microplastics on Human Health.” Science of the Total Environment 912 (February 20, 2024): 168946. https://doi.org/10.1016/j.scitotenv.2023.168946. ↩︎
  9. Ali-Hassanzadeh, M., et al. “The Effects of Exposure to Microplastics on Female Reproductive Health and Pregnancy Outcomes: A Systematic Review and Meta-Analysis.” Reproductive Toxicology 135 (2025): 108932. https://doi.org/10.1016/j.reprotox.2025.108932; Hunt, K., et al. “Exposure to Microplastics and Human Reproductive Outcomes: A Systematic Review.” BJOG: An International Journal of Obstetrics and Gynaecology 131, no. 5 (2024): 675–683. https://doi.org/10.1111/1471-0528.17756. ↩︎
  10. Cheng, Y., et al. “Gestational Exposure to Micro- and Nanoplastics Leads to Poor Pregnancy Outcomes by Impairing Placental Trophoblast Syncytialization.” Environmental Pollution (2025): 126520. https://doi.org/10.1016/j.envpol.2025.126520; Hanrahan, J., et al. “Maternal Exposure to Polyethylene Micro- and Nanoplastics Impairs Umbilical Blood Flow but Not Fetal Growth in Pregnant Mice.” Scientific Reports 14, no. 1 (2024): 399. https://doi.org/10.1038/s41598-023-50781-2; Song, X., et al. “Effects of Micro(nano)plastics on the Reproductive System: A Review.” Chemosphere 336 (2023): 139138. https://doi.org/10.1016/j.chemosphere.2023.139138. ↩︎
  11. Chartres, N., et al. “Effects of Microplastic Exposure on Human Digestive, Reproductive, and Respiratory Health: A Rapid Systematic Review.” Environmental Science & Technology 58, no. 52 (2024): 22843–22864. https://doi.org/10.1021/acs.est.3c09524; Dusza, H. M., et al. “Experimental Human Placental Models for Studying Uptake, Transport and Toxicity of Micro- and Nanoplastics.” Science of the Total Environment 860 (2023): 160403. https://doi.org/10.1016/j.scitotenv.2022.160403; Zurub, R. E., et al. “Microplastics Exposure: Implications for Human Fertility, Pregnancy and Child Health.” Frontiers in Endocrinology 14 (2023): 1330396. https://doi.org/10.3389/fendo.2023.1330396; Paul, I., et al. “Beyond the Cradle – Amidst Microplastics and the Ongoing Peril During Pregnancy and Neonatal Stages: A Holistic Review.” Journal of Hazardous Materials 469 (2024): 133963. ↩︎
  12. Liu, S., et al. “Detection of Various Microplastics in Placentas, Meconium, Infant Feces, Breastmilk and Infant Formula: A Pilot Prospective Study.” Science of the Total Environment 854 (2023): 158699. https://doi.org/10.1016/j.scitotenv.2022.158699; Liu, S., et al. “The Association Between Microplastics and Microbiota in Placentas and Meconium: The First Evidence in Humans.” Environmental Science & Technology 57, no. 46 (2023): 17774–17785. https://doi.org/10.1021/acs.est.2c04706; Kadac-Czapska, K., et al. “Isolation and Identification of Microplastics in Infant Formulas—A Potential Health Risk for Children.” Food Chemistry 440 (2024): 138246. https://doi.org/10.1016/j.foodchem.2023.138246; Zhang, Q., et al. “Microplastics in Infant Milk Powder.” Environmental Pollution 323 (2023): 121225. https://doi.org/10.1016/j.envpol.2023.121225; Luo, Q., et al. “Microplastics as an Emerging Threat to Human Health: An Overview of Potential Health Impacts.” Journal of Environmental Management 387 (2025): 125915. https://doi.org/10.1016/j.jenvman.2025.125915; Sripada, K., et al. “A Children’s Health Perspective on Nano- and Microplastics.” Environmental Health Perspectives 130, no. 1 (2022): 015001. https://doi.org/10.1289/EHP9086. ↩︎
  13. Vattanasit, U., et al. “Airborne Microplastics: A Narrative Review of Potential Effects on the Human Respiratory System.” Science of the Total Environment 904 (2023): 166745. https://doi.org/10.1016/j.scitotenv.2023.166745; Amato-Lourenço, L. F., et al. “An Emerging Class of Air Pollutants: Potential Effects of Microplastics to Respiratory Human Health?” Science of the Total Environment 749 (2020): 141676. https://doi.org/10.1016/j.scitotenv.2020.141676; Prata, J. C., et al. “Environmental Exposure to Microplastics: An Overview on Possible Human Health Effects.” Science of the Total Environment 702 (2020): 134455. https://doi.org/10.1016/j.scitotenv.2019.134455; Prata, J. C. “Airborne Microplastics: Consequences to Human Health?” Environmental Pollution 234 (2018): 115–126. https://doi.org/10.1016/j.envpol.2017.11.043; Chen, C. Y., et al. “Regional and Population-Scale Trends in Human Inhalation Exposure to Airborne Microplastics: Implications for Health Risk Assessment.” Environmental Pollution 371 (2025): 125950. https://doi.org/10.1016/j.envpol.2025.125950; Amato-Lourenço, L. F., et al. “Presence of Airborne Microplastics in Human Lung Tissue.” Journal of Hazardous Materials 416 (2021): 126124. https://doi.org/10.1016/j.jhazmat.2021.126124; Qiu, L., et al. “Evidence of Microplastics in Bronchoalveolar Lavage Fluid Among Never-Smokers: A Prospective Case Series.” Environmental Science & Technology 57, no. 6 (2023): 2435–2444. https://doi.org/10.1021/acs.est.2c06880; Chartres, N., et al. “Effects of Microplastic Exposure on Human Digestive, Reproductive, and Respiratory Health: A Rapid Systematic Review.” Environmental Science & Technology 58, no. 52 (2024): 22843–22864. https://doi.org/10.1021/acs.est.3c09524; González-Acedo, A., et al. “Evidence from in Vitro and in Vivo Studies on the Potential Health Repercussions of Micro- and Nanoplastics.” Chemosphere 280 (2021): 130826. https://doi.org/10.1016/j.chemosphere.2021.130826; Lu, K., et al. “Detrimental Effects of Microplastic Exposure on Normal and Asthmatic Pulmonary Physiology.” Journal of Hazardous Materials 416 (2021): 126069. https://doi.org/10.1016/j.jhazmat.2021.126069. ↩︎
  14. [xiv] Barboza, L. G. A., et al. “Marine Microplastic Debris: An Emerging Issue for Food Security, Food Safety and Human Health.” Marine Pollution Bulletin 133 (2018): 336–348. https://doi.org/10.1016/j.marpolbul.2018.05.047; Mason, Sherri A., et al. “Synthetic Polymer Contamination in Bottled Water.” Frontiers in Chemistry 6 (2018): 407. https://doi.org/10.3389/fchem.2018.00407; Cox, K. D., et al. “Human Consumption of Microplastics.” Environmental Science & Technology 53, no. 12 (2019): 7068–7074. https://doi.org/10.1021/acs.est.9b01517; Zhang, Qiwen, et al. “A Review of Microplastics in Table Salt, Drinking Water, and Air: Direct Human Exposure.” Environmental Science and Pollution Research 29, no. 15 (2022): 21849–21865. https://doi.org/10.1007/s11356-021-17364-9.
    Additional citations:
    Arif, Y., et al. “Microplastics and Nanoplastics: Source, Behavior, Remediation, and Multi-Level Environmental Impact.” Journal of Environmental Management 356 (2024): 120618.
    Chakraborty, S., et al. “Evaluation of the Health Impacts and Deregulation of Signaling Pathways in Humans Induced by Microplastics.” Chemosphere 369 (2024): 143881.
    Jung, Y. S., et al. “Characterization and Regulation of Microplastic Pollution for Protecting Planetary and Human Health.” Environmental Pollution 315 (2022): 120442.
    Ma, Y. B., et al. “Recent Advances in Micro (Nano) Plastics in the Environment: Distribution, Health Risks, Challenges and Future Prospects.” Aquatic Toxicology 261 (2023): 106597.
    Mamun, A. A., “Microplastics in Human Food Chains: Food Becoming a Threat to Health Safety.” The Science of the Total Environment 858, no. 1 (2023): 159834.
    Méndez Rodríguez, K. B., et al. “Microplastics: Challenges of Assessment in Biological Samples and Their Implication for in Vitro and in Vivo Effects.” Environmental Science and Pollution Research International 30, no. 57 (2023): 119733–119749.
    Osman, A. I., et al. “Microplastic Sources, Formation, Toxicity and Remediation: A Review.” Environmental Chemistry Letters (2023): 1–41.
    Tran, T. V., et al. “A Review on the Occurrence, Analytical Methods, and Impact of Microplastics in the Environment.” Environmental Toxicology and Pharmacology 102 (2023): 104248. ↩︎

Additional citations:

  • Arif, Y., et al. “Microplastics and Nanoplastics: Source, Behavior, Remediation, and Multi-Level Environmental Impact.” Journal of Environmental Management 356 (2024): 120618.
  • Chakraborty, S., et al. “Evaluation of the Health Impacts and Deregulation of Signaling Pathways in Humans Induced by Microplastics.” Chemosphere 369 (2024): 143881.
  • Jung, Y. S., et al. “Characterization and Regulation of Microplastic Pollution for Protecting Planetary and Human Health.” Environmental Pollution 315 (2022): 120442.
  • Ma, Y. B., et al. “Recent Advances in Micro (Nano) Plastics in the Environment: Distribution, Health Risks, Challenges and Future Prospects.” Aquatic Toxicology 261 (2023): 106597.
  • Mamun, A. A., “Microplastics in Human Food Chains: Food Becoming a Threat to Health Safety.” The Science of the Total Environment 858, no. 1 (2023): 159834.
  • Méndez Rodríguez, K. B., et al. “Microplastics: Challenges of Assessment in Biological Samples and Their Implication for in Vitro and in Vivo Effects.” Environmental Science and Pollution Research International 30, no. 57 (2023): 119733–119749.
  • Osman, A. I., et al. “Microplastic Sources, Formation, Toxicity and Remediation: A Review.” Environmental Chemistry Letters (2023): 1–41.
  • Tran, T. V., et al. “A Review on the Occurrence, Analytical Methods, and Impact of Microplastics in the Environment.” Environmental Toxicology and Pharmacology 102 (2023): 104248.
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