Australasian Science: Australia's authority on science since 1938

Our Plastic Rubbish Is Littering Australia’s Coast

Australia’s coastal rubbish is mainly plastic from Australian sources, according to a CSIRO study that surveyed sites every 100 km along the Australian coastline.

“We found about three-quarters of the rubbish along the coast is plastic,” says Dr Denise Hardesty of CSIRO Wealth from Oceans. “Most is from Australian sources, not the high seas, with debris concentrated near cities.”

Hardesty says the density of plastic in Australian waters ranges from a few thousand pieces of plastic per square kilometre to more than 40,000 pieces.

Marine debris includes items such as glass or plastic bottles, cans, bags, balloons, rubber, metal, fibreglass, cigarettes and other manufactured materials that end up in the ocean and along the coast. It can smother coral reefs, kill wildlife, and may pose a threat to human health.

“Approximately one-third of marine turtles around the world have likely ingested debris, and this has increased since plastic production began in the 1950s,” Hardesty says. “We also estimate that between 5000 and 15,000 turtles have been killed in the Gulf of Carpentaria after becoming ensnared by derelict fishing nets, mostly originating from overseas.”

She says the Tasman Sea south of Australia is a global hotspot for seabird impacts. “We found that 43% of seabirds have plastic in their gut. Globally, nearly half of all seabird species are likely to ingest debris, eating everything from balloons to glow sticks, industrial plastic pellets, rubber, foam and string.

“By garnering the information needed to identify sources and hotspots of debris, we can better develop effective solutions to tackle marine debris,” Hardesty says.