Some commercial bottled waters have been found to have twice as much micro and nanoplastics as tap water. Photo: MART PRODUCTION/Pexels
I have written about the prevalence of plastic compounds in our food and environment several times before, but at the time, the hard evidence for actual harm to human health caused by them was not extensively researched.
But now, several scientific studies have conclusively proved that microplastics and nanoplastics (MNPLs) both have significant negative impacts on our well-being, and they may in fact constitute one of the biggest threats to our health in the not-too-distant future, especially as our food and environment become more and more congested and infested with MNPLs.
Not a credit card
But first, some good news. There have been sensationalist claims that many humans are ingesting as much as five grams of plastics a week, the weight of a credit card. This was based on a World Wildlife Fund (WWF) 2019 study conducted by the University of Newcastle, Australia, which suggested that, on average, human beings are each ingesting around 21 grams of plastic a month, or just over 250 grams a year.
This study is now proven to be inaccurate as the assumptions used by the WWF were deeply flawed, and the amount of plastics going into humans is very, very much less. An Austrian review in 2022 found that statistically, a human would probably take 23,000 years to acquire five grams of plastics in the body, based on their analysis of environmental plastics at the time at chosen points in the world.
The issue with this newer study is that concentrations of plastics around us are getting higher all the time, and the distributions/concentrations are also highly uneven across various countries, so the period for many humans to acquire five grams of plastics in their bodies is certainly much lower than 23,000 years and getting lower every year. But it is not one week.
Size matters
At this point, it may be helpful to note that there is a very strong link between the size of the MNPLs and negative health outcomes; basically, the smaller the plastic particles ingested, the more damage is likely to be caused in the body. To understand why, here are the differences between microplastics (MPL) and nanoplastics (NPL). Note that most NPLs are originally derived from MPLs after erosion or weathering effects.
Paper cups are lined with a plastic coating that can degrade into microplastics, so avoid these as much as possible. — NGQAH/Pexels
Size: Microplastics range in size from 5 millimeters to 100 nanometers, while nanoplastics are even smaller, ranging from 0.001 to 0.1 micrometers (1 to 100 nanometers). Nanoplastics are effectively a thousand times or more smaller than microplastics.
Degradation: Microplastics arise from the breakdown of larger plastic debris, clothing fabrics, cosmetics, industrial processes involving fossil fuels, etc. Nanoplastics are formed from the further continued degradation of microplastics, or they can also be directly released into the environment, such as from microbeads in personal care products.
Surface Ratio: Due to their extremely small sizes, nanoplastics have a much higher surface area-to-volume ratio compared to microplastics. This allows them to be more reactive, absorbing and carrying higher concentrations of pollutants like heavy metals, pesticides, and other toxins. Nanoplastics can also penetrate cells and tissues much more easily than microplastics and have already been observed to cross biological barriers like the blood-brain barrier.
Complex Reactivity: Nanoplastics exhibit more complex environmental behaviours than microplastics. Their extremely small sizes allow them to be transported over long distances through the air to pollute even very remote locations. Their extremely tiny mass allows them to bind/interact more strongly with other pollutants, natural organic matter, and sunlight, compared to microplastics.
Getting into the body
MNPLs can enter the human body through various routes, including food, inhalation, and dermal contact. Once inside the body, they can interact with biological systems, leading to a range of adverse health effects.
The health impacts of MNPLs, and especially NPLs, are now reasonably well-established via various scientific/medical studies over the last few years. In a recent May 2024 report, MNPLs were detected in every sample taken from the testicles of postmortem men and dogs, with the human testes having almost three times the concentration of MNPLs than the dogs (330 mcg/gram vs 123 mcg/gram for dogs). This has led to reports that endemic lower sperm counts in many countries may be potentially due to the high levels of MNPLs in men.
MNPLs can enter the human body through the consumption of contaminated food and water. Studies have detected these particles in seafood, table salt, bottled water, beer, etc. Ingested MNPLs often act as carriers for toxic chemicals and pathogens, further exacerbating their harmful effects. They accumulate in the gastrointestinal tract, potentially causing physical damage and inflammation in the guts. Moreover, NPLs can also cross the intestinal barrier and directly enter the bloodstream, where they can spread to contaminate other organs and tissues.
Inhalation of airborne MNPLs is another significant exposure route. These particles can be released into the air from various sources, including industrial emissions, road dust, the degradation of synthetic textiles, etc. Inhaled microplastics can accumulate in the respiratory tract, leading to inflammation, oxidative stress, and respiratory diseases. Recent animal studies have shown that inhalation exposure to MNPLS, especially polystyrene microplastics, caused lung inflammation.
Although less studied, dermal contact with MNPLs is also a known exposure route. These particles can be present in personal care products, such as exfoliating scrubs and toothpaste, leading to direct skin contact. While the skin should act as a barrier, there is strong evidence that NPLs can penetrate the skin and enter systemic circulation within the body directly.
Toxicology
The toxicological effects of MNPLs are multifaceted, involving physical, chemical, and biological interactions. Notably, they can cause changes in cell structures such as the mitochondria, leading to impaired energy production and increased oxidative stress. This can result in cellular dysfunction and apoptosis (programmed cell death).
Also within cells are other structures called lysosomes and the endoplasmic reticulum (ER). Lysosomes can be induced by NPLs to release enzymes which can cause cell damage and inflammation, and the normal folding of proteins (which is controlled by the ER) is disrupted in the presence of NPLs.
Like unhealthy free radicals, NPLS can also generate oxidative stress which may swamp the body’s antioxidant defences, resulting in damage to lipids, proteins, and DNA. Persistent oxidative stress is a well-known precursor to chronic health issues such as inflammation and dysregulation of the immune system. Inflammation is caused by the body responding to MPLs and NPLs as pathogens, by activating immune cells and releasing pro-inflammatory cytokines.
Chronic inflammation is associated with various serious diseases, including cardiovascular diseases, neurodegenerative disorders, and cancer. Continuous exposure to NPLs can further lead to immune system dysregulation, potentially causing allergies, autoimmune diseases and hypersensitivity reactions.
MNPLs are known to interfere with metabolic processes and endocrine function, by disrupting metabolic processes, leading to metabolic disorders such as obesity and diabetes. Additionally, NPLs can act as endocrine (hormone) disruptors, interfering with hormone signalling pathways and potentially causing effects such as infertility, mental and other disorders, and even cancer.
Avoid takeaway packaging that comes in plastic containers. — Photos: MART PRODUCTION/Pexels
A recent USA study found that 58% of a group of 257 older people had detectable levels of MNPLs in their neck arteries, mostly polyethylene and polyvinyl chloride. Within three years, the mortality rate of people with MNPLs was 450% higher than those without MNPLs, with the cause of death being mostly cardiovascular events.
Cutting down on plastics
For their health, people and their families should consider reducing their exposure to MNPLs. It may not always be easy or straightforward, but the evidence strongly suggests that the effort is worthwhile. Some suggestions are as follows:
• Cut down on drinking water sold in single-use plastic bottles. Use reusable water bottles made of glass or stainless steel instead. Some commercially bottled waters have been found to contain more than twice as much MNPLs as tap water
• Avoid using takeaway cups. Paper cups are lined with a plastic coating that can degrade into microplastics. Invest in a reusable coffee cup made of recycled material, stainless steel, ceramics, or glass
• Avoid single-use plastic bags, cutlery, straws, etc, by carrying reusable alternatives
• Buy plastic-free cosmetics and household products, especially those containing microbeads made of plastic. Look for “natural ingredients only” on labels
• Choose food with minimal plastic packaging or packaged in foil or glass instead of plastic
• Dry clothes on a clothesline instead of using an electric tumble dryer, as an electric dryer can release millions of MNPLs such as microfibers into the air each session
• Wash synthetic fabrics like polyester, acrylic, rayon, etc, less frequently, as they shed microfibers into the water when rinsing
• Dust, clean, and vacuum regularly to remove microplastics from household dust using cleaning machines with High-Efficiency Particulate Air (HEPA) filters
• Use glass, ceramic or paper containers instead of plastic when microwaving food to avoid MNPLs and other chemicals leaching into food
• Recycle as much household plastic waste as possible. Sadly, much less than 8% of plastics are actually recycled worldwide, but it is better than nothing
• Reduce overall plastic consumption by choosing products made from sustainable, natural materials wherever possible.
And this might sound odd, but cutting down on using cars and other vehicles to reduce wear and tear on the tyres can help cut down on MNPL pollution. Statistically, every person can generate up to a current maximum of 4.7 kg of MNPLs from tyres per year. This is a significant amount of MNPL pollution, equivalent to the plastics needed to make up to 940 credit cards a year per person.
The views expressed here are entirely the writer’s own.
