Plastic Consumption: How Much Plastic Do We Ingest?

Plastic waste is engulfing the planet and its ecosystems, but we don't know the full extent of its impact on human health. It is estimated that the average person consumes between 0.06 and 0.10 grams of plastic from drinking water per year, and between 10.87 and 20.88 grams per year from food. This means that an average person could be taking in anywhere from 18.33 to 71.69 grams of plastic per year.

How much plastic do we ingest from drinking water?

Drinking water, especially bottled water, is the greatest source of microplastics in our diet. A research paper found that water in reusable and recycled plastic water bottles has more microplastic particles than water in single-use plastic bottles.

To calculate the amount of microplastics in drinking water, researchers filter the water, take a sample of what the filter caught, and look at it under a microscope. They count the number of particles, estimate their size, and look for signs of what kind of plastic they are. They then multiply the average number of particles by the average weight of a particle, and multiply again by how much water an average human adult consumes, to get an estimate of how much microplastic we consume through our drinking water.

Boiling and filtering water can help remove up to 90% of plastic particles in drinking water, but experts warn that it could also increase the leaching of toxic chemicals into the water.

How much plastic do we ingest from food?

People eat at least 50,000 plastic particles a year, according to a study by the National Library of Medicine. Another study found microplastics in 16 commonly consumed protein products purchased in the United States. It is estimated that Americans ingest more than 11,000 microplastic particles a year via their protein consumption alone.

There are many different vectors for us to ingest microplastics through our diet, including fish and shellfish, salt, honey, sugar, beer, and drinking water (both tap and bottled). Fish and shellfish are more likely to pass microplastics on to us if we eat them whole, including their guts, as opposed to just eating the meat. The salt we use, often captured from evaporated seawater, can also contain microplastics.

How much plastic do we inhale?

A study by Good Morning Britain (GMB) and the University of Portsmouth found that families are likely each inhaling between 2,000 and 7,000 microplastic particles a day. The highest amount of microplastics were found in an eight-year-old girl's bedroom, due to the carpets, non-cotton bed linen and soft toys.

The study used new technology to measure the very small, breathable microplastics from the indoor air for the first time. Samples were taken from three rooms: the kitchen, the mother's bedroom, and her children's bedrooms.

The University of Portsmouth is committed to tackling global plastics problems through Revolution Plastics. Professor Fay Couceiro, a reader in environmental pollution at the university, said: "Potentially we each inhale or swallow up to 1.8 million microplastics every year and once in the body, it’s hard to imagine they’re not doing irreversible damage."

Another study in the journal *Environmental Science and Technology* says it's possible that humans may be consuming anywhere from 39,000 to 52,000 microplastic particles a year. With added estimates of how much microplastic might be inhaled, that number is more than 70,000.

How much plastic do we ingest dermally?

It is estimated that humans ingest 0.1–5 g of microplastics weekly through various pathways, including food and drink, inhalation, and dermally. These minute particles (less than 5mm) can be absorbed through the skin, with microplastics found in consumer products such as face creams, face washes, and hand cleansers.

Microplastics can carry a wide range of chemicals, the most common being polyethylene, which has been associated with serious health outcomes including cancer, heart disease, and poor foetal development. Researchers are investigating whether these plastic particles can penetrate the deeper layers of the skin and the possible detrimental effects of extensive skin contact with plastic particles.

A 2021 paper suggests that adults ingest about 900 particles per day, with separate studies finding that we defecate about 200 particles per day. The remaining 700 particles are not currently accounted for, with some breathed in and out, and a few leaving the body in urine.

Estimations of the total mass of ingested microplastic particles correspond to 50 plastic bags per year, one credit card per week, or a median value of 4.1 μg/week for adults. These estimations highlight the significant amount of plastic that humans are unknowingly ingesting, with potential health consequences that are not yet fully understood.

How much plastic do we ingest from plasticware?

It is estimated that an average person ingests between 18.33 and 71.69 grams of plastic particles per year. This includes plastic ingested from drinking water, food and plasticware.

The Environmental Working Group (EWG) Investigations team reviewed recent studies on dietary plastic particle contamination and combined reported values on particle numbers and mass by performing downstream calculations. They included five studies that addressed their three target components of ingestion: water, food and plasticware. Based on the plastic particle mass values reported by Senathirajah et al., they estimate that the plastic mass ingested per person from drinking water alone is between 0.06 and 0.10 grams per year.

For plasticware, the EWG aggregated the direct mass values from Yadav et al. and the particle number ranges from Zhou et al. and Du et al. for cutting boards, plastic cups and takeout containers respectively. The result was a per-person plastic mass estimate of 7.40-50.71 grams per year.

Another recent study commissioned by the World Wildlife Fund and conducted by researchers at the University of Newcastle in Australia estimated that people consume about 5 grams of plastic a week, roughly the equivalent of a credit card.

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