Concerns over microplastics in the food chain

Microplastics (dark fibres pictured) next to grains of sand to show their actual size. Source: UNSW

Tiny pieces of plastic found in cosmetics, cleaning products and toothpastes may be a ticking time bomb.   

The so-called micro plastics are increasingly making their way into water supplies, sparking concerns they may travel up the foodchain to humans.

It's hard to complete your grocery shopping these days without purchasing them.

Plastic beads are found in exfoliating body washes, facial scrubs, washing detergent and even some toilet cleaners.

University of New South Wales PhD candidate Vivian Sim has been studying the prevalence of microplastics in the Sydney Harbour and says even she struggles to find products free of the pollutants.

"When I started this research I spent three hours in the supermarket trying to find products to replace all the current products I had that had microplastics and it's pretty much near impossible."

Microplastics are fragments of plastic less than five millimetres long.

They're too small to be sifted out at sewage treatment plants and so they often end up in the ocean.

In the past, manufacturers have used things like sand or sugar as an exfoliants.

But plastic microbeads are now often cheaper, and give products a longer shelf-life.

Scientists aren't worried about the plastic itself so much as the chemical pollutants attached to them.

The microplastics can act like magnets attracting pollutants already within the ocean water, like insecticides and fire retardants.

The Sydney Institute of Marine Science takes in researchers from six New South Wales universities.

It recently tested 27 sites across Sydney Harbour and found up to 60 microplastics per 100 milligrams of sediment.

Researchers point out that's more plastic than was found near an old plastic plant in Sweden.

Vivian Sim, who's been involved in the study, says now the test is whether or not those pollutants could eventually make their way up the foodchain to humans.

"Once it gets into the marine eco-system, when an organism ingests the microplastics - because they're pretty much the same size as a sand grain and there are organisms that eat sand grains to get their nutrients. So once it gets taken up into their body system it's possible that the contaminants from the plastics actually get absorbed into the tissue. And then if another larger organism - say a fish - eats a worm that ate the plastics, do those contaminants that are in a worm get transferred to the tissue of the fish."

Simon Mustoe is the founder of another Australian study into microplastics.

The project combines tourism, cutting edge technology and an 80-year-old tall ship from Scandinavia.

The ship has been dragging a very fine net from Hobart to Brisbane over the past year, collecting everything from floating rubbish, to algae and fish.

The material will be analysed for its plastic content at the Australian Nuclear Science and Technology Organisation.

Simon Mustoe says while many microplastics come from the break-down of larger plastics, the smaller pollutants may be more dangerous.

"We suspect from some evidence out there already that plastic has a toxification effect - its surface area increases as it breaks down, it can bind heavy metals and other contaminants to itself and therefore possibly even have a bigger impact than it does when it's in large pieces."

Overseas studies have shown once microplastics are eaten by marine organisms, they can cause premature death and transfer up the foodchain, for example, from mussels to crabs.

The US state of Illinois has already banned plastic microbeads in consumer products, and similar legislation is being considered in other states.

Some multinationals have vowed to phase out microbeads over the next few years.

The New South Wales government says it will ask manufacturers to voluntarily phase them out.

In the meantime, Vivian Sim says it's difficult, but not impossible, to avoid purchasing microplastics.

"If you do some research online you can find products. Some people have actually created a full list of products that don't have microplastics. If you look on the ingredient list and it says copolymer, polymer, or sometimes it even just says plastic, generally avoid that. If it's a facial scrubber and you're not sure if it has a plastic component, avoid that. So if it looks like a bead generally don't buy it."

Source: World News Australia

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