We're consuming a lot of plastic and have no idea of the risks
Plastic is in seafood, salt, sugar, beer, drinking water and the air we breathe
A new study by Canadian scientists has calculated that we're probably consuming on the order of a hundred thousand plastic particles a year, and that may well be a low estimate of the amount of microplastic in our diet.
In the past few years, studies have shown that our environment is saturated with tiny microplastic particles. Fragments ranging in from five millimetres down to microns in size are contaminating arctic ice, the deep ocean, freshwater lakes and rivers and agricultural soils. Even air samples taken around the world show tiny particles of plastic pollution.
Our appetite for plastics
The research team from the University of Victoria and Fisheries and Oceans Canada reviewed the scientific literature about plastic contamination of food, drink and air to try and figure out how much plastic we're consuming. The studies on food and drink included information on seafood, salt, sugar, beer and water.
They found that people were consuming between 40,000 and 50,000 microplastic particles per year in food and drink. People who drank bottled water exclusively, which contains a large number of plastic particles, might be consuming double or triple that. "We estimated that bottled water could contain 22 times more micro plastic particles than tap water," said marine biologist Garth Covernton, who was part of the research team.
In addition, they calculated that we're probably breathing in another 30,000 to 70,000 particles from the air around us.
The sources of these particles are diverse. Seafood and sea-salt, for example, can be contaminated with particles from refuse that ends up in the oceans and plastic fishing gear. The plastic in food and beverages can come from plastic packaging.
"One big source actually is fibers," Covernton told Quirks & Quarks host Bob McDonald. "This could be things from textiles like our clothing such as polyester or nylon or acrylic as well as anything like a carpet."
The researchers also point out that their estimates for microplastic plastic consumption are likely low. Studies have not been done on plastic contamination of a large range of foods, including meat, poultry, vegetables and grains, so there was no way to include these in their estimates.
Health risks of consuming plastics
Another significant unknown, the researchers said, is what risk the consumption of plastics might pose to human health.
Much of the plastic we consume is probably excreted from the body through the digestive tract. Most of the plastic inhaled into the lungs is probably cleared by the same mechanisms that clear other kinds of particulates - the mucosal and ciliary systems that capture particles and transport them out of the lungs.
On the other hand, there is some evidence in animal studies that consumption of microplastics can lead to health risks, particularly from the smallest particles. "There are sometimes changes in gene regulation that can be associated with some sort of inflammation or stress response," said Covernton. He cautioned, however, that this evidence comes from studies with much higher consumption levels than the researchers found for humans.
One lesson from this study is how much more we need to understand about this issue considering how much we're exposed to microplastic.
"Microplastics really are everywhere," said Covernton, and we're surrounded by materials "shedding thousands of particles in any given moment that could end up in our food and in our drinking water."