TRANSCRIPT
They're the tiny particles causing big problems.
Microplastics are out of sight but front of mind ((the focus)) for scientists trawling Sydney Harbour in a quest to determine the scale of pollution in one of world's most iconic waterways.
"We find plastics in almost every trawl that we do. That's the most shocking part. We have microplastics everywhere we go...the Whitsundays, the Pacific, everywhere."
That's Dr Khay Fong, a senior lecturer in the school of chemistry at Monash University.
She's leading the research.
The team is using what's called a manta trawl - a net, designed to collect tiny particles and debris. It's lowered into the harbour and after 20 minutes, it's hauled onto the deck of the boat.
Within seconds, Dr Fong detects what she believes are tiny plastic particles.
"That's probably polystyrene..."
The results are still being determined but based on preliminary findings, one thing's for certain:
"There are plastics in every single sample - and a lot of them. So it's a concentration that's akin to the Mediterranean, which is one of the most polluted places in the world mainly because it's one of the most populated."
Further north, on a different mission there's a similar discovery.
University of Queensland researchers have collected surface sediment samples from 50 sites across Brisbane's Moreton Bay.
Lead researcher, Dr Elvis Okoffo from the Queensland Alliance for Environmental Health Sciences, says the samples were taken back to the lab to be analysed, and once the data was extrapolated, they made a startling estimation.
"There are about 7,000 metric tonnes of microplastics in the bay. This was surprising, looking at the fact that the bay is very protected and we were not expecting to see this much plastics."
That's equivalent to 1.5 million plastic bags, or enough to fill three Olympic-sized swimming pools.
The main type of plastic detected, Dr Okoffo says, is polyethylene, which is typically found in single-use items like plastic bags, bottles and food wrapping.
"That actually tells us there is a direct link between the amount of plastics we consume in Australia and the amount that's being washed into the environment."
Microplastics, tiny fragments measuring less than five millimetres, end up in the environment as a result of the breakdown of larger plastic products. Evidence suggests humans are ingesting them through contaminated seafood.
And that's not the only way microplastic can enter the human body. As well as oceans, they've infiltrated soil, the air we breathe, some tap water and bottled beverages.
Scientists have found microplastics in our blood and in human placentas.
But the University of Queensland's Dr Cassandra Rauert says the direct health impacts aren't yet known.
"We definitely know we're exposed every day. We know that we are breathing in plastics every day, and we know that we're ingesting them through food and water, especially bottled water. But we really don't have conclusive evidence yet of what's actually the fate of these plastics after we're exposed to them in our bodies."
Dr Rauert, a Senior Research Fellow at the Queensland Alliance for Environmental Health Sciences, is currently leading a study into the risks of human exposure to microplastics.
She's one of a number of scientists around the world who are racing to determine the risks of microplastics.
The good news, she says, is there are steps we can take to minimise exposure.
"We're actually doing some research here that's showing that especially the single use plastic containers, like your takeaway containers, do shed a lot of particles as they're being washed, whether it's in cold water or hot water. So try and avoid those plastic using stainless steel if you can.”
She adds that clothing is one of the biggest sources of microplastics.
"What a lot of people don't know is that two of the biggest sources of microplastics are actually synthetic fibres that we're wearing and small fibres that come off the clothing that we then breathing in. So try to avoid synthetic clothing, if you can. Try and use a reusable water bottle instead of buying bottled water, try and avoid single-use plastics. All those small things can make a big difference."
