Plastic In Humans: An Alarming Reality Check

It is estimated that the average person consumes between 78,000 and 211,000 microplastic particles every year through food, drink, and inhalation. This is equivalent to about 5 grams of plastic per week, or the weight of a credit card. Microplastics are present in the air we breathe, the oceans we fish, and the packaged goods, fruits, and vegetables we eat. They are even fed to animals, which eventually become food for humans. The health risks of ingesting microplastics are still being studied, but initial research suggests they can be harmful to the human body and may affect neurobiology.

Microplastics in bottled water

It is estimated that the average person consumes between 78,000 and 211,000 microplastic particles annually, with bottled water being the largest source of microplastics entering our bodies.

Bottled water has been found to contain a surprisingly high number of microplastics. Research has shown that a litre of bottled water can contain anywhere from 94 to 325 microplastic particles, with one study finding an average of about 240,000 pieces of plastic per litre. These microplastics are the result of the breakdown of plastic products over time. The plastic bottles themselves can also be a source of microplastics in bottled water. Repeatedly opening and closing the bottle, crushing it, or exposing it to heat can cause microplastic particles to break off into the water.

The presence of microplastics in bottled water is concerning, as it may pose a risk to human health. Nanoplastics, in particular, are a cause for concern as they are small enough to enter the body's cells and tissues and could potentially be misidentified as natural components in our bodies. The potential health impacts of consuming microplastics and nanoplastics are still not fully understood, but researchers believe there is cause for concern.

To avoid consuming microplastics in bottled water, it is recommended to switch to using glass or steel water bottles and to filter tap water instead. Tap water has been found to contain lower levels of microplastics, and it is more tightly regulated than bottled water. By making this switch, individuals can reduce their exposure to microplastics and help reduce plastic waste, which ends up in landfills and contributes to the microplastic pollution in our environment.

Plastic in human organs

Plastic pollution is everywhere, from Arctic snow and Alpine soils to the deepest oceans. It is, therefore, unsurprising that it is also in the human body. A growing body of scientific evidence shows that microplastics (MPs) are accumulating in critical human organs, including the brain. Microplastics are defined as plastic fragments smaller than 5mm in length. They are shed by synthetic clothing, vehicle tyres, and plastic pellet spillages. They are also created by the physical breakdown of plastic litter, which is washed into rivers and the sea by rainwater.

MPs can enter the human body through ingestion, inhalation, and dermal absorption. They have been found in human blood, the liver, kidneys, lungs, heart, placenta, breast milk, sputum, semen, testis, urine, and even the brain. A study published in the International Journal of Impotence Research detected plastic particles in the penises of four out of five men being treated for erectile dysfunction. Another study found MPs in all 23 human testicles examined, with a nearly threefold greater concentration than in the 47 canine samples.

The health hazards of MPs within the human body are not yet well understood. However, MPs may carry toxic additives, adsorb harmful chemicals, and trigger inflammatory responses. Researchers are actively working to understand the long-term consequences of internal plastic exposure, including possible links to chronic diseases such as cancer, autoimmune disorders, and neurological conditions.

The global plastics industry is dedicated to advancing the scientific understanding of microplastics, and the United Nations Environment Assembly has been working towards a global treaty to end plastic pollution. The US Environmental Protection Agency is also working on guidelines for measuring plastic particles in food and water.

Plastic in food packaging

Plastic food packaging is a common source of microplastics, which are consumed by humans and can have harmful health effects. Food packaging accounts for 50% of the plastics derived from fossil fuels. The packaging industry consumes the highest volumes of plastics and is a major source of waste plastics in the environment. This has led to growing environmental concerns and a need for sustainable alternatives.

There are several types of plastics commonly used in food packaging, including polyethylene terephthalate (PET), high-density polyethylene (HDPE), low-density polyethylene (LDPE), polypropylene (PP), polyvinyl chloride (PVC), and polystyrene (PS). These plastics are used for various food packaging applications due to their durability, flexibility, and ability to preserve freshness. For example, PET is known for its strength, lightweight build, and crystal-clear colouring, making it ideal for creating shiny and durable packaging coatings. HDPE is popular for its high impact resistance and melting point, and it is commonly used in water bottles, margarine and butter tubs. LDPE is a thermoplastic used in bread and frozen food packaging, while PP is commonly found in sour cream and cream cheese tubs, yoghurt packets, and chip bags. PVC is suitable for food products like tubing for beverage systems and blister packaging for gum due to its ability to act as a barrier to grease and oil.

The use of plastic food packaging has raised concerns due to its environmental impact and the potential health hazards associated with the consumption of microplastics. Microplastics can contaminate food products and accumulate in the environment, posing a global threat to human health and the ecosystem. Studies have shown that the consumption of microplastics can damage human systems and impair normal metabolic processes, leading to acute inflammation and cell damage.

To address these concerns, there is a growing focus on developing sustainable and eco-friendly packaging materials. Bioplastics, such as polylactic acid (PLA)-based packaging, are being explored as potential alternatives to conventional plastics. By blending agricultural waste and natural fillers, it is possible to create green composites with low costs, low greenhouse gas emissions, and improved performance for food packaging applications. The development of renewable alternatives to plastic food packaging is crucial to reducing the environmental and health impacts of microplastic consumption.

Plastic in the air

The average person unknowingly consumes tens of thousands of microplastic particles annually through inhalation, ingestion, and insalivation. While the health implications of this are not yet fully understood, it is known that microplastics enter the human body through the air we breathe.

Microplastics are small pieces of plastic less than five millimeters long. They are formed through the mechanical, chemical, and physical fragmentation of larger plastics. These can include "legacy" plastics disposed of decades ago. At every stage of a plastic item's life cycle, from production to disposal, microplastics are emitted.

Primary sources of airborne microplastics include roadways, agricultural dust, and oceans. On roadways, tires and brakes hurl microplastics into the air. In agriculture, microplastics are found in dust in part due to the use of plastics on farm fields and in part because people wash synthetic clothing, releasing plastic microfibers that end up in treated wastewater and, eventually, on farms as fertilizer. In the oceans, large globs of plastic degrade into microscopic pieces, which then float to the surface and are whipped into the air by rough waters and bursting air bubbles.

Wind currents carry microplastics to remote parts of the Earth in a matter of days. Approximately 25 metric tons of microplastics are transported thousands of kilometers per year by ocean air, sea spray, and fog. These microplastics can act as ice-nucleating particles and cloud condensation nuclei, potentially altering cloud formation processes and the Earth's radiation balance and climate.

While individual bits of plastic may stay airborne for only hours, days, or weeks, there is so much plastic in the air that it is consistently inhaled by humans. Studies have estimated that the average human inhales up to 16.2 bits of plastic every hour, or the equivalent of a credit card's worth of plastic microfibers per week.

Plastic nanoparticles in mothers' bodies transferred to foetuses

The average person consumes between 78,000 and 211,000 microplastic particles every year through food, drink, and inhalation. While the health impact of these plastic particles is still unknown, scientists say there is an urgent need to assess the issue, especially for developing foetuses and babies, as plastics can carry harmful chemicals.

A rat study published in the journal Particle and Fibre Toxicology revealed that plastic nanoparticles can pass from a mother's body to her foetus's brain, heart, lungs, liver, and kidneys. The polystyrene nanoparticles were also found in the placenta, suggesting maternal lung-to-fetal tissue nanoparticle translocation in late-stage pregnancy. The rat foetuses exposed to the particles had lower weights towards the end of gestation, with a 7% reduction in weight compared to control animals.

Dunzhu Li from Trinity College Dublin, who was not part of the research, expressed concern about the findings: "This study is very important because it proves the potential to transfer [plastic particles] in mammal pregnancy – maybe it is happening from the very beginning of human life as well." Prof John Boland, also from Trinity College Dublin, cautioned against over-interpreting the results, noting that the nanoparticles used in the study were spherical, while real microplastics are irregular flake-like objects.

While the exact impact of plastic particles on foetal growth remains unknown, the researchers have a working theory. They suggest that something in the maternal vasculature changes, leading to a reduction in blood flow and, consequently, a reduction in nutrient and oxygen delivery to the foetus. More research is needed to determine whether the particles become lodged in the foetal compartment or if they are walled off by the body, thus avoiding additional toxicity.

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