The study, led by UNSW Science, has filtered – excuse the pun – and analysed 10 years of data collected from 150,000 individuals taking part in beach clean-ups organised by the Australian Marine Debris Initiative to create a national map of what sort of marine debris washes up where.
It found that cities were clearly identified by a threefold increase in the number of durrie butts washed up on beaches around some of Australia’s premier fishing and boating destinations such as Melbourne’s Port Phillip Bay, Sydney’s Sydney Harbour the Gold Coast Broadwater and Perth’s Swan River.
Outside the heavily populated urban areas, abandoned fishing gear such as floats and nets tend to be more prevalent.
Study co-author and Tangaroa Blue Foundation founder and chief executive officer Heidi Tait said the source of rubbish varied by location.
“The data shows that what we find in Cape York is completely different to what we find in Port Phillip Bay in Melbourne,” Tait said.
The data shows about 40 per cent of all marine debris across Australia was from littering, particularly near capital cities where a lot of plastic ends up on the beach after being washed into stormwater drains.
However, more remote areas with lots of washed-up debris, such as Cape York in Queensland, tended to have collected rubbish such as floats and plastic bottles that had been dumped at sea in another country and washed ashore here.
Unsurprisingly, most of the rubbish washed ashore is plastic, making up 84 per cent of the data collected over the 10-year period. However, 42 per cent of the plastic washed up on Australian beaches could not be traced back to a source because it had broken up into smaller, unidentifiable pieces as it progressively breaks down into damaging microplastics.
According to Tait, a global treaty on single-use plastics formalised through the United Nations could reduce the amount of rubbish washed up in Cape York reduce by up to 95 per cent.
Outboard engine maker Suzuki has started trialling a filter that is fitted to its engine-cooling system that is designed to scrub out microplastics found in the marine environment.