Five Dubbo sites selected for first ever Key Littered Items Study for inland rivers

They're all items professor Steve Smith from Southern Cross University and Bron Powell from OzFish dug out from the bank of the Macquarie River as they set up for a first-of-its kind litter study.

"This is a really interesting site because we're getting a huge mix of old and new litter, and this is a demonstration that litter can be in the environment for a very long time," he told the Daily Liberal.

"We've got a rubber chook which is obviously recent. But a lot of the old beer bottles have their date stamped on the bottom, we've got one here from 1967 - that's when this was manufactured.

"We've got another piece of glass we found which is even older, bottle experts may be able to tell us, but it's a really old bottle which probably dates back to when Dubbo was established."

With the help of a team of eager citizen scientists, professor Smith and Ms Powell set up five sites along the Macquarie River in Dubbo this week for the first ever Key Littered Items Study for inland rivers.

"At the moment we're trying to establish a standardised method for assessing litter in rivers. We already have very good methods for beaches and estuaries on the coast - but there's no consistent standard method for looking at litter in rivers," professor Smith explained.

"The work that Bron's been doing here with OzFish has identified the need for that and so Dubbo's the spot where we're going to try to kick it off."

The Key Littered Items Study contributes data to the state government so that they can see if government litter reduction targets are being met.

The data is also used to identify which single-use plastics should be banned next and informs the NSW EPA's state litter prevention strategy.

Currently, the data has been collected from coastal areas only, meaning the impact and spread of litter in inland rivers has not been able to be measured in the same way. With the help of volunteer citizen scientists in Dubbo, this will soon change.

"It's probably not been done so far because, in Australia, a majority of the population live on the coast [...] but it's important to look at litter everywhere because we know there's a massive increase globally," Mr Smith said.

"One thing that's become very evident from international research is that the majority of litter entering the ocean comes from rivers. Even within the local setting litter can have an amazing impact - plastic bags, for example, can smother animals.

"Probably the thing that's motivating governments more than anything else is the potential economic cost. If you're trying to advertise your area for tourists and you've got litter everywhere it's not somewhere they'll come back to."

Ms Powell said she and the Dubbo River Repair Bus team were keen to get professor Smith to Dubbo because local recreational fisherman and the community "really care" about the river.

"The more we can understand what's going on - what types of litter there are and whether it's increasing or decreasing - then we get a better picture of how to tackle that problem and try to stop it at its source," she said.

"We do a lot of clean ups of rubbish but we also want to be working further up that litter journey in terms of trying to prevent the litter getting in the river to start with."

To prepare the sites for the research - which will be ongoing for many years - Ms Powell and Mr Smith measured 30 metre lengths on the banks of the Macquarie River and cleared out all the existing rubbish in the area to create a baseline.

Then, through OzFish, volunteer citizen scientists will return to the site every three months to collect and sort through any litter they can find.

Mr Smith hopes the Dubbo sites will be the first of many in inland NSW.

"We don't just pick everything up and put it in the trash, we want to know what it is, how many of each different item there are and - in particular - if there are items which have already been targeted for some kind of mitigation," he said.

"We're already finding lots of containers - despite the container deposit scheme - and lots of soft plastic bags.

"On the back of these initial results, Bron and her team will keep the monitoring going. The whole point is to track debris through time to see if government and community led initiatives are successful."

Ms Powell said there has already been a number of OzFish members and River Repair Bus volunteers who have jumped on board with the project.

"Our members love helping with clean ups and because this has an even more important meaning and significance - we're actually collecting that data - then people really enjoy it," she said.

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