This Is Where We’re Most at Risk From Toxic Microplastics

Australians are eating and inhaling significant numbers of tiny plastics at home, our new research shows. These “microplastics”, which are derived from petrochemicals extracted from oil and gas products, are settling in dust around the house. Some of these particles are toxic to humans — they can carry carcinogenic or mutagenic chemicals, meaning they potentially cause cancer and/or damage our DNA.

We still don’t know the true impact of these microplastics on human health. But the good news is, having hard floors, using more natural fibres in clothing, furnishings and homewares, along with vacuuming at least weekly can reduce your exposure.

What are microplastics?

Microplastics are plastic particles less than five millimetres across. They come from a range of household and everyday items such as the clothes we wear, home furnishings, and food and beverage packaging. We know microplastics are pervasive outdoors, reaching remote and inaccessible locations such as the Arctic, the Mariana Trench (the world’s deepest ocean trench), and the Italian Alps. Our study demonstrates it’s an inescapable reality that we’re living in a sea of microplastics — they’re in our food and drinks, our oceans, and our homes.

What we did and what we found

While research has focused mainly on microplastics in the natural environment, a handful of studies have looked at how much we’re exposed to indoors. People spend up to 90% of their time indoors and therefore the greatest risk of exposure to microplastics is in the home. Our study is the first to examine how much microplastic we’re exposed to in Australian homes. We analysed dust deposited from indoor air in 32 homes across Sydney over a one-month period in 2019.

We asked members of the public to collect dust in specially prepared glass dishes, which we then analysed. We found 39% of the deposited dust particles were microplastics; 42% were natural fibres such as cotton, hair and wool; and 18% were transformed natural-based fibres such as viscose and cellophane. The remaining 1% were film and fragments consisting of various materials. Between 22 and 6,169 microfibres were deposited as dust per square metre, each day.

Homes with carpet as the main floor covering had nearly double the number of petrochemical-based fibres (including polyethylene, polyamide and polyacrylic) than homes without carpeted floors. Conversely, polyvinyl fibres (synthetic fibres made of vinyl chloride) were two times more prevalent in homes without carpet. This is because the coating applied to hard flooring degrades over time, producing polyvinyl fibres in house dust.

Microplastics can be ingested by various animals, ranging in size from tiny creatures like zooplankton to sharks and whales. The likelihood of microplastics being eaten is influenced by the amount in the environment and how closely they resemble food. Laboratory studies indicate that microplastics can potentially transfer through the food web when marine, terrestrial and freshwater species that have previously ingested microplastics are preyed on by other animals.

Microplastics eaten by larger marine animals will generally pass through their bodies. However, research does show that microplastics can be retained in the gut for extended periods where they may cause abrasion and damage to internal tissues. Nanoplastics can pass through the gut wall and travel to different parts of the body, such as the lungs and liver, where they can cause damage. Further research is required to understand the potential health implications from ingesting microplastics.

Microplastics can be toxic

Microplastics can carry a range of contaminants such as trace metals and some potentially harmful organic chemicals. These chemicals can leach from the plastic surface once in the body, increasing the potential for toxic effects. Microplastics can have carcinogenic properties, meaning they potentially cause cancer. They can also be mutagenic, meaning they can damage DNA.

However, even though some of the microplastics measured in our study are composed of potentially carcinogenic and/or mutagenic compounds, the actual risk to human health is unclear. Given the pervasiveness of microplastics not only in homes but in food and beverages, the crucial next step in this research area is to establish what, if any, are safe levels of exposure.

How much are we exposed to? And can this be minimised?

Roughly a quarter of all of the fibres we recorded were less than 250 micrometres in size, meaning they can be inhaled. This means we can be internally exposed to these microplastics and any contaminants attached to them.

Using human exposure models, we calculated that inhalation and ingestion rates were greatest in children under six years old. This is due to their lower relative body weight, smaller size, and higher breathing rate than adults. What’s more, young children typically have more contact with the floor, and tend to put their hands in their mouths more often than adults.

What is the World Economic Forum doing about plastic pollution?

More than 90% of plastic is never recycled, and a whopping 8 million metric tons of plastic waste are dumped into the oceans annually. At this rate, there will be more plastic than fish in the world’s oceans by 2050. The Global Plastic Action Partnership (GPAP) is a collaboration between businesses, international donors, national and local governments, community groups and world-class experts seeking meaningful actions to beat plastic pollution.

In Ghana, for example, GPAP is working with technology giant SAP to create a group of more than 2,000 waste pickers and measuring the quantities and types of plastic that they collect. This data is then analysed alongside the prices that are paid throughout the value chain by buyers in Ghana and internationally. It aims to show how businesses, communities and governments can redesign the global “take-make-dispose” economy as a circular one in which products and materials are redesigned, recovered and reused to reduce environmental impacts.

Children under six inhale around three times more microplastics than the average — 18,000 fibres, or 0.3 milligrams per kilogram of body weight per year. They would also ingest on average 6.1 milligrams of microplastics in dust per kg of body weight per year. For a five-year-old, this would be equivalent to eating a garden pea’s worth of microplastics over the course of a year. But for many of these plastics there is no established safe level of exposure. Our study indicated there are effective ways to minimise exposure.

First is the choice of flooring, with hard surfaces, including polished wood floors, likely to have fewer microplastics than carpeted floors. Also, how often you clean makes a difference. Vacuuming floors at least weekly was associated with less microplastics in dust than those that were less frequently cleaned. So get cleaning! Some pollutants and heavy metals can also adsorb or stick to plastic surfaces. As a result, plastics can act like sponges in the environment, passively collecting chemicals onto their surfaces.

While plastics can remove some persistent organic pollutants (POPs) from the surrounding water, there is concern about what happens when plastics containing these adsorbed pollutants are ingested by animals. The ability of some POPs to bind to plastics is particularly concerning due to their toxicity at low doses. These toxic and persistent chemicals are widely distributed in the marine environment and are readily concentrated onto plastic surfaces at up to 1 million times the concentration than in the surrounding water.

Studies have shown that these chemicals can transfer from ingested plastics to animal tissue where they can become concentrated within the animal and transfer through the food chain. Plastics are beneficial to human health through their use in medical applications and for protecting our food and beverages. Plastics have revolutionized healthcare through improving sterility by the use of disposable syringes, gloves, IV tubes and catheters and providing increased comfort with hypoallergenic medical devices, heart valves, and flexible prosthetics (artificial body parts).

Plastic bottles and containers provide a way of distributing water that is safe to drink in locations where there are major issues of water contamination. Plastic packaging limits food and beverage spoilage through microbial contamination. It is likely that we are ingesting some level of plastics in our diet. A rapidly growing body of research is showing that ongoing accumulation of toxins associated with plastics poses a risk to our food safety and public health. However, the levels of plastics and associated chemicals we are exposed to in our diet compared with other everyday activities has not been assessed.

Written by:

Mark Patrick Taylor, Professor of Environmental Science and Human Health, Macquarie University, Scott P. Wilson, Senior Lecturer, Macquarie University, Neda Sharifi Soltani, Academic Casual, Macquarie University

Source: This is where we’re most at risk from toxic microplastics | World Economic Forum