Study lifts lid on polystyrene pollution in Yarra River
Polystyrene is the most common item of litter in the Yarra River and a Docklands litter trap collected more pieces of the macroplastic than any other in inner-Melbourne, new research from the Yarra Riverkeeper Association shows.
The Polystyrene Pollution in the Yarra River: Deep Dive study also shone new light on how the plastic, which is widely used in the packaging and construction industries, finds its way into the river.
It found that construction sites contributed the highest amount of polystyrene pollution, followed by whitewoods retailers and markets.
Of 16 litter traps set up along the river from Docklands to Hawthorn from which samples were taken, a trap at Charles Grimes Bridge in Docklands captures the most pieces of polystyrene.
Yarra Riverkeeper Association (YRKA) litter officer Anthony Despotellis, who managed what was the group’s second piece of research on polystyrene in the river, said the study proved where the common pollutant was coming from.
“What we found mostly proved our hypothesis,” he told Docklands News.
“We suspected that construction sites have a large role to play, we suspected that whitewoods retailers and shopping centres had a role to play. And what we found was that the numbers backed that up. We hadn’t yet been able to prove that it was happening regularly, but this time finally we were able to put numbers [and say] ‘yes, this is happening constantly and it’s happening in small to moderate amounts’. We’re getting regular pollution, from many places in small amounts, and that’s what is contributing to this problem.”
The data collection involved going to the source of the pollution, which included inspecting 80 construction sites.
It found that 98 per cent of sites were confirmed to have polystyrene pollution either on site, just outside the site, on the nature strip, or in a drain within a few houses of the site.
On the river itself, a team of volunteers from the YRKA — an independent community of citizen advocates who work to protect the river — were tasked with sorting samples from the litter traps, which was no mean feat according to Mr Despotellis.
“What that involved was taking a whole lot of samples, and going through those and counting every bead of polystyrene that we could find. That was a really big effort because you’re getting samples that have anywhere from 150 to well over 1000 pieces.”
He said he was not overly shocked at the high figure seen from the Docklands litter trap.
“It was interesting to have a look at that when I mapped it onto the river there,” he said.
“It gets a bit complicated in that area because there’s so many drains coming out [onto the river]. The closer you get to the CBD there’s a whole range of drains coming from all over Melbourne … in terms of that spot specifically, I wouldn’t say it was overly surprising. Having seen how much plastic just ends up in our streets and how much gets into the river, not much surprises me.”
He said the true extent of polystyrene pollution in the river was not immediately apparent to most, with the often small size of the litter and colour of the water hiding it from the naked eye.
“What I can say is that down in the city stretches, it doesn’t look like it’s polluted but then you look at the litter traps and it’s another story.”
Polystyrene is widely used as a low-cost, lightweight, moisture resistant and shock absorbent product that makes it great for packaging, however it has a considerable environmental impact.
It is easily transported by wind and water and can mimic fish eggs — a food source for a range of species. It can also leach toxic chemicals into the water.
In March 2021 the Australian Government released the National Plastics Plan, which included an action for government to work with industry to phase out certain problematic plastics.
This included polystyrene commonly used to package consumer goods.
Mr Despotellis remained hopeful the harmful pollutant which eventually be phased out, although acknowledged this would take some time.
“Ultimately the goal is focused on using sustainable alternatives. That’s on its way but we’ve still got a few years before the average business that you encounter that is using polystyrene alternatives,” he said.
“We’ve definitely got things that we could do today, tomorrow or next year, but generally what we need is better awareness. Once we can raise awareness and work with people who need it most, hopefully we can start to transition away from polystyrene. And we can — there’s no reason why we can’t.” •
Caption: A litter trap along the Yarra River
Picture: Karin Traeger, YRKA.