Microplastics and nanoplastics are found in the air, water, and food, leading to concerns about how they enter our bodies and the potential health risks they pose
Plastic pollution is a widespread environmental issue with extensive consequences. An emerging aspect of this problem is the increasing presence of microplastics and nanoplastics in our environment, which may impact human health. These small plastic particles, measuring less than 5 millimetres in size, are found in the air, water, and food, leading to concerns about how they enter our bodies and the potential health risks they pose.
Exposure routes
Research has identified three major routes through which microplastics and nanoplastics can enter the human body: Ingestion, inhalation and dermal contact.
- Ingestion
Ingestion, or oral consumption, is a primary route for exposure to microplastics and nanoplastics. These particles have been detected in various food and water sources, including drinking water, seafood, salt, bottled water, and even tea and coffee. Studies have found microplastics in fish, mussels, salts from lakes and oceans, as well as in commercial salts and bottled water.
Polyethylene terephthalate (PET) and polypropylene (PP) are among the most commonly reported polymers in bottled water. Additionally, tap water has been found to contain microplastics in both developed and developing countries. Even seemingly innocuous items like teabags, coffee, and food products have been found to contain microplastics, illustrating the pervasive nature of this contamination
- Inhalation
Inhalation, or breathing, is another significant route of exposure to MPs and NPs. These particles have been detected in the ambient air, with outdoor and indoor concentrations varying depending on location and environmental factors.
Sources of airborne microplastics include synthetic textiles, industrial emissions, solid waste dumping sites, and agricultural activities. Sea breeze and sea spray near coastal areas also contribute to atmospheric microplastic pollution.
Inhalation of microplastics may lead to their accumulation in the respiratory tract and potential translocation across the blood-brain barrier, raising concerns about respiratory and neurological health effects.
- Dermal Contact
Dermal contact, or skin exposure, is another route through which individuals may be exposed to microplastics and nanoplastics. Consumer products such as face creams, face washes, and cosmetics can contain microplastics, increasing the risk of dermal exposure.
While absorption through the skin is unlikely due to the physicochemical properties of microplastics, deposition on the skin and potential absorption of nanoparticles raise concerns about skin exposure. Studies have suggested that microfibers and particles from cosmetics and toothpaste may be absorbed by the skin, indicating a need for further investigation into their potential health effects.
Potential health risks
Research on the potential health risks associated with exposure to microplastics and nanoplastics is ongoing, with findings indicating a range of adverse effects on human health. Here are some key areas of concern:
- Gastrointestinal and urinary tract system
Exposure to microplastics and nanoplastics via ingestion can lead to their translocation through the gastrointestinal tract and potential accumulation in tissues. Studies have shown that these particles may cause oxidative stress, inflammation, and histological changes in the intestines of animals.
Furthermore, exposure to microplastics has been associated with immune system dysregulation and metabolic disorders, raising concerns about their long-term health effects.
- Respiratory tract system
Inhalation of microplastics and nanoplastics can lead to their accumulation in the respiratory tract, potentially causing irritation, inflammation, and oxidative stress. Research suggests that exposure to these particles may worsen respiratory symptoms and contribute to the development of respiratory disorders.
Additionally, the size and concentration of microplastics can affect their toxicological impact on lung cells, emphasising the need for further research into respiratory health risks.
- Blood and immune system
Exposure to microplastics and nanoplastics has been shown to affect immune cell function and cytokine production in animal studies. Changes in serum levels and immune cell activity have been observed following exposure to these particles, suggesting potential systemic effects.
Furthermore, the presence of microplastics in lymph nodes and blood circulation raises concerns about their long-term impact on immune function and overall health.
- Brain and nervous system
Studies have suggested that microplastics and nanoplastics may have neurotoxic effects, leading to oxidative stress, cytotoxicity, and changes in neurotransmitter levels.
Exposure to these particles has been linked to cellular damage and inflammation in brain tissue, raising concerns about their potential role in the development of neurological disorders. Moreover, the ability of nanoparticles to cross the blood-brain barrier underscores the need for further research into their neurotoxic effects.
- Embryos and placental barrier
The presence of microplastics in the placenta and foetal tissues raises concerns about their potential impact on foetal development and pregnancy outcomes. Studies have shown that microplastics can cross the placental barrier and accumulate in foetal tissues, potentially leading to developmental abnormalities and embryotoxicity.
Additionally, exposure to microplastics during pregnancy may have long-term implications for the health of both the mother and the developing foetus, highlighting the need for further research in this area.
Source: Sangkham et al., (2022). Potential pathways and routes of exposure to MPs/NPs and potential toxic effects on humans. A review on microplastics and nanoplastics in the environment: Their occurrence, exposure routes, toxic studies, and potential effects on human health. Marine Pollution Bulletin Volume 181, August 2022, 113832
The presence of microplastics and nanoplastics in our environment, along with their potential impact on human health, is a matter of increasing concern. Although ongoing research is providing more information on the health effects of these particles, evidence suggests that exposure to microplastics and nanoplastics could pose significant risks to various organ systems and physiological processes within the human body.
It is crucial to continue efforts to understand the sources, pathways, and health implications of microplastics and nanoplastics to develop effective mitigation strategies and protect public health.
Addressing this issue requires a comprehensive approach that includes reducing plastic waste at its source, improving waste management practices, and finding innovative solutions for the removal of microplastics from the environment.
By raising awareness, implementing robust policies, and adopting sustainable practices, we can mitigate the threats posed by microplastic contamination and ensure the well-being of future generations.
