Millions of pieces of polystyrene are polluting Melbourne's Yarra River, with environmental advocates warning the increasing amount of plastic waste will have long-term ecological consequences for the river and Port Phillip Bay.
A new report from environmental advocate the Yarra Riverkeeper Association has found expanded polystyrene (EPS) is the most common macroplastic in the river, with the majority of it coming from the construction industry.
Retail whitegoods, market produce industries and manufacturers were also sources of EPS waste ending up in the river.
Yarra Riverkeeper Association litter officer Anthony Despotellis said there was a problem with handling.
"Polystyrene is cut up and then the excess is left in a pile, sometimes it's put in a bin, often it's not.
"When it's left outside, it just breaks up, escapes and goes down the drain.
"Every year, we're just adding more and more plastic to our river and to Port Phillip Bay."
The researchers said polystyrene was more harmful than other types of plastic because it contained hazardous chemicals, with studies suggesting it can impact the weight and reproduction of invertebrate species.
From surveys of the Yarra River's 16 litter traps between December 2020 and October 2021, the researchers estimated more than 382 million pieces of EPS waste were flowing through the river annually.
Due to limitations in sorting litter traps and accessing waste in reedbeds, it said that number was almost certainly an underestimate.
The researchers also examined 80 construction sites within the Yarra River catchment area as part of the report, and found 98 per cent of them had polystyrene pollution either on site or in the drains nearby.
A useful construction material, but difficult to contain
Expanded polystyrene is used in residential housing construction and becoming increasingly popular as building activity accelerates across Australia post COVID-19 lockdowns.
"It's cheap, it's lightweight, and it's thermally efficient," said Beacher Townsend, CEO of Expanded Polystyrene Australia.
The industry body, which represents polystyrene manufacturers and recyclers, said about 70 per cent of the polystyrene made in Australia was used for construction, including as cheap cladding to insulate homes.
Polystyrene "waffle pods" are used to fill concrete slabs to reduce the volume of concrete, something Mr Townsend said can help to reduce greenhouse gas emissions from cement.
He acknowledged waste disposal was an issue, despite the fact that EPS used in construction is 100 per cent recyclable if it remains clean and in good condition.
"It can be used over again," he said.
He said an industry code of conduct requires manufacturers to supply bags to store EPS in, and collect any excess product for recycling, but said builders were "the weak link in the chain".
"We're very keen to work with government, with professional associations and with the builders themselves in order to ensure improved compliance," Mr Townsend said.
Calls for more regulatory action
Mr Despotellis said polystyrene was a difficult material to store because it was so light and brittle, but more regulations were needed to make sure industry was doing the right thing.
The Yarra Riverkeepers report found cladding offcuts were being stored in bags at only one of the 80 construction sites it examined.
"You do see the odd building sites that are taking care of their polystyrene, they're putting it in bags, and it gets taken back for recycling," Mr Despotellis said.
"But unfortunately, the vast majority are not."
Victoria's environmental watchdog said builders were obligated to secure all waste "to prevent it escaping to the environment".
"If there are incidents such as the escape of waffle slab styrene, which is common on residential construction sites, they should contact us so we can help them take appropriate action," Environmental Protection Authority CEO Lee Miezis said.
"We prefer prevention, but EPA has and will penalise builders who have not properly managed their onsite waste and will use its powers through the courts to enforce compliance where stronger action is needed."
Future changes should support consumers as well as industry
Mr Despotellis also said changes should be made to support individual efforts to keep polystyrene out of waterways.
Some consumer polystyrene products are recyclable but none are accepted through kerbside waste disposal.
However, several Melbourne councils including Yarra, Boroondara and Moonee Valley offer polystyrene recycling for council residents at waste depots.
"A lot of the polystyrene recyclers are quite far away, it's not always clear where you can go or can't go," Mr Despotellis said.
"For the average person, it's really about being mindful about where you leave it and trying to as best you can take it where it needs to go to be recycled."
